Somewhere off the Ningaloo coast of Western Australia, in a submarine canyon that drops to more than four and a half kilometres, a giant squid shed a few cells into the surrounding seawater. It may have brushed against a rock, expelled waste, or simply moved through the water column. The cells drifted. Months later, a team of scientists on the research vessel Falkor filtered a sample of that water, extracted the DNA it contained, and matched it to Architeuthis dux, the largest invertebrate on the planet. Nobody saw the animal. Nobody needed to. Its genetic signature was enough.

That story leads this week’s Deep Brief, alongside a new gasfield approval ten kilometres from the Twelve Apostles on Australia’s Great Ocean Road, and a reflection on what David Attenborough, who turned 100 yesterday, showed the world about the ocean and what governments have done with the knowledge since. Three deep dives. Three quick hits. One hard truth from the sea.

Deep Dives

A giant squid’s DNA has been found in Western Australian waters for the first time in over 25 years. It was one of 226 species detected by filtering seawater.

Scientists from Curtin University, the University of Western Australia, and the Western Australian Museum collected more than 1,000 water samples from the deep Cape Range and Cloates submarine canyons off the Ningaloo coast, roughly 1,200 kilometres north of Perth, at depths reaching 4,510 metres. They were looking for environmental DNA, the genetic material that every living animal sheds invisibly into the water around it through skin cells, waste, mucus, and reproductive material.

From those samples, the team identified 226 species across 11 major animal groups. Among them: the giant squid (Architeuthis dux), detected in six separate samples from both canyons, the first record of the species in Western Australian waters in more than a quarter of a century and the northernmost confirmed detection of giant squid in the entire eastern Indian Ocean.

Giant squid can grow longer than a school bus, typically between 10 and 13 metres, and weigh up to 275 kilograms. Their eyes, at up to 30 centimetres in diameter, are the largest of any animal on Earth. Despite their size and near-global distribution, they are almost never seen alive. Fewer than a dozen have been filmed in their natural habitat in the deep ocean.

The survey also detected Cuvier’s beaked whales, the deepest-diving mammals known to science, pygmy sperm whales, sleeper sharks, the faceless cusk eel, and the slender snaggletooth. Dozens of species had never been recorded in Western Australian waters before. Some of the DNA sequences did not match anything in existing genetic databases, meaning they may belong to species that have not yet been formally described.

The study, published this week in the journal Environmental DNA, was conducted aboard the Schmidt Ocean Institute’s research vessel Falkor. Lead author Georgia Nester, who carried out the research as part of her PhD at Curtin University and is now at the University of Western Australia, described the results as transformative. “With eDNA, a single water sample can tell us about hundreds of species at once,” she said. “That means we can dramatically expand our understanding of deep-water environments in a way that simply hasn’t been possible before.”

The implications stretch beyond Western Australia. Environmental DNA surveys are fast, non-invasive, and scalable. They do not require scientists to see, capture, or disturb any animal. A single filtered water sample from a deep-sea canyon can reveal the presence of species that traditional surveys using nets, cameras, or submersibles might never detect. For regions of the ocean that are too deep, too remote, or too expensive to survey by conventional means, which is most of the deep ocean, eDNA may be the only realistic way to establish what lives there.

“Deep-sea ecosystems are vast, remote and expensive to study, yet they face growing pressure from climate change, fishing and resource extraction,” said Zoe Richards, a co-author and associate professor at Curtin University. “You can’t protect what you don’t know exists.”

Australia has approved a new gasfield ten kilometres from the Twelve Apostles. The government that greenlit it has a 95 per cent renewable energy target.

The Victorian and Australian federal governments, both Labor, announced on Thursday that they had granted a production licence for Amplitude Energy’s Annie gasfield in the Otway Basin, off the coast of Victoria. The site sits roughly nine kilometres offshore from Peterborough and Port Campbell, on the Great Ocean Road, about twelve kilometres west of the Twelve Apostles, one of Australia’s most visited natural landmarks and a designated marine national park.

Federal Resources Minister Madeleine King said the project would supply gas exclusively to the domestic market, easing the risk of potential shortfalls on Australia’s east coast. Amplitude Energy estimates the field will supply about four per cent of east coast gas demand for five years. Gas from the Annie field, in water depths of roughly 55 metres, will be processed at the existing Athena plant. Production is expected by 2028.

The approval is the second major gas project Labor has authorised this term, following the 2022 Victorian election in which then-Premier Daniel Andrews campaigned heavily on reviving the State Electricity Commission and accelerating the transition to renewables. Victoria has a legislated target of 95 per cent renewable energy by 2035.

For environmentalists, the approval undercuts the government’s own climate ambitions. Approving new fossil fuel extraction while pursuing aggressive renewable energy targets sends contradictory signals. The argument from government is that the transition requires bridging fuel to maintain energy security during the shift from coal and gas to renewables, and that domestic gas supply reduces reliance on more carbon-intensive imports.

The counter-argument, made by conservation and climate groups, is that new gas infrastructure locks in emissions for the life of the asset and that alternative sources of energy security, including battery storage, demand management, and accelerated renewable build-out, are available and increasingly cost-competitive. The presence of the gasfield near a marine national park adds an environmental dimension beyond carbon: the risk of operational discharges, spills, and acoustic disturbance to a stretch of coastline that is nationally significant for both tourism and marine biodiversity.

This story will be familiar to readers of this newsletter. In Australia, as in the UK, the gap between what governments promise on climate and what they approve in practice continues to widen. Whether the Annie gasfield turns out to be a necessary bridge or an unnecessary lock-in depends on how fast the renewable transition actually moves, and on whether the government that approved it is held to its own targets.

David Attenborough turned 100 yesterday. The ocean he showed the world is in worse shape than when he started filming it.

David Attenborough was born on 8 May 1926. Yesterday, on his 100th birthday, he remains the most recognisable voice in nature broadcasting and one of the most trusted figures in public life anywhere in the world. His career spans the transition from black-and-white studio television to 4K underwater cinematography. His programmes, from The Blue Planet in 2001 to Ocean in 2025, have brought the deep sea, coral reefs, open ocean ecosystems, and the creatures that inhabit them into hundreds of millions of living rooms.

What Attenborough did, more than any other broadcaster, was show people the ocean as a living system rather than a backdrop. The Blue Planet and its sequel Blue Planet II revealed the complexity of marine ecosystems in ways that shifted public attitudes. Blue Planet II in particular is widely credited with sparking a global movement against single-use plastics, leading several countries to introduce bans or restrictions. His 2025 feature-length documentary Ocean, now streaming on Disney+, went further, including footage of bottom trawlers ploughing up the seabed off the UK coast.

The New Statesman, in a piece published to mark his birthday, argues that governments must honour his legacy with action rather than warm words and commemorative stamps. The piece, written by Greenpeace’s Will McCallum, calls on the UK to use the Global Ocean Treaty to protect areas of the Atlantic, to ensure its marine protected areas are genuinely managed, and to implement a full ban on bottom trawling.

The timing is pointed. Last week’s Deep Brief covered the UK Marine Strategy report, which found that 13 of 15 indicators of ocean health are failing, uncertain, or declining, despite 377 marine protected areas covering 38 per cent of UK seas. Attenborough’s legacy includes both what he showed us and the uncomfortable question of whether knowing about the ocean’s wonders and its decline has produced commensurate action. The evidence, on his 100th birthday, suggests it has not.

Attenborough himself has shifted from traditional broadcaster to something closer to a campaigner in recent years, using his authority to advocate for systemic change. His witness statement film A Life on Our Planet (2020) laid out both the problem and his proposed solutions. Whether those solutions are adopted is no longer a question for Attenborough. It is a question for the people who grew up watching his programmes and now hold the positions of power that could deliver them.

Quick Hits

The deepest hydrothermal vents on Earth sit nearly five kilometres below the Caribbean Sea, and they are teeming with life. The Beebe Vent Field, discovered in 2010 by the crew of the RRS James Cook in the Cayman Trough, lies at 4,968 metres depth. Water erupting from its black smoker chimneys reaches 401°C but does not boil because the pressure at that depth is roughly 500 times atmospheric pressure. Despite the extreme heat and total darkness, the vents support thriving communities of shrimp, snails, and microbial life that derive their energy from chemical reactions rather than sunlight, a process called chemosynthesis. Discover Wildlife published a detailed profile of the Beebe field this week, and it is worth reading for anyone interested in the conditions under which life can persist.

Researchers in China sank a cow carcass to 1,629 metres in the South China Sea to mimic a whale fall, and eight Pacific sleeper sharks showed up. The study, published in Ocean-Land-Atmosphere Research in June 2025 and resurfacing in coverage this week, documented the first recorded appearance of Pacific sleeper sharks in the South China Sea, significantly expanding the known range of a species typically associated with the cold deep waters of the Bering Sea, the Gulf of Alaska, and Baja California. The researchers at Sun Yat-sen University observed larger sharks tearing aggressively at the carcass while smaller individuals circled and waited, suggesting a feeding hierarchy. Every shark observed was female, raising the possibility that the South China Sea may serve as a nursery ground for the species.

Scientists in Halifax are testing whether adding alkaline minerals to seawater can help the ocean absorb more carbon dioxide. Planetary Technologies is running one of the world’s first coastal ocean alkalinity enhancement projects in Halifax Harbour, Canada, introducing alkaline minerals through the cooling water discharge pipe of a natural gas power plant. Researchers from Duke University deployed instruments in August 2025 to measure how the surrounding ecosystem is responding. Ocean alkalinity enhancement works by reducing seawater acidity, which increases its capacity to absorb and store atmospheric CO2 for centuries. The approach is gaining attention as a potential complement to emissions reductions, though questions about ecological impact, monitoring, and scale remain unresolved.

Hard Truth From The Sea

David Attenborough turned 100 yesterday. He spent a career showing people what lives in the ocean, and in doing so made it harder for anyone to claim they did not know. That knowledge has not translated into proportionate action. The UK still allows bottom trawling in its marine protected areas. Australia approves new gasfields within sight of its most famous coastline. And in a canyon off Western Australia, a giant squid leaves its DNA in the water for scientists to find, in a region so unexplored that more than 200 species had never been recorded there before. Attenborough’s gift was wonder. The question his centenary poses is whether wonder, on its own, was ever enough.

Paid subscribers fund the reporting that tracks what is changing in the ocean and why. If you want accountability journalism on the systems we depend on and the institutions responsible for protecting them.

Subscribe now

See you next week.

-Luke

A study published last week in Communications Earth & Environment makes a measurement that hasn’t been made before. Over the past two decades, a layer of warm water deep beneath the Southern Ocean has been shifting south, towards the Antarctic continent, at an average rate of about 1.26 kilometres per year. Compounded over twenty years, that comes to roughly 25 kilometres of poleward redistribution, a meaningful fraction of the distance between the typical core of this warm layer and the Antarctic continental shelf.

The water is called Circumpolar Deep Water. It sits between roughly 200 and 2,000 metres down, wrapping around the continent, and it carries the heat that melts Antarctic ice shelves from below.

Those shelves matter because they hold back the much larger ice sheet behind them. The ice that sits on the Antarctic continent, if it eventually entered the ocean, would raise global sea level by about 58 metres.

The new study, led by Joshua Lanham at the University of Cambridge with colleagues at Scripps Institution of Oceanography and UCLA, uses two independent datasets to show that the warm layer is expanding nearer the continent and contracting further north. Both methods reach the same conclusion. Earlier observational work had already detected poleward shifts in specific regions of East Antarctica. What is new here is a circumpolar picture, built from a methodology that bridges two very different kinds of ocean data.

Why warm water at depth matters

Circumpolar Deep Water is warm because of where it came from. It originated in the North Atlantic and Pacific, sank with more heat than the abyssal water around it, and travelled south on timescales of decades to centuries, retaining much of that heat as it went. By the time it reaches the Southern Ocean it is no longer warm in any everyday sense, typically a degree or two above freezing, but compared with the near-freezing surface waters around Antarctica and the ice it might encounter, the temperature difference is substantial. When it reaches the underside of an ice shelf, that small difference is enough to drive significant melting.

The reason warm water can sit beneath cold water in this part of the ocean is salinity. Cold water near Antarctica is freshened by sea ice melt and precipitation, while the deeper layer carries higher salt content from its origins thousands of kilometres away. Salt makes water heavier. The deeper layer is denser despite being warmer, and stratification holds it in place.

Ice shelves are floating extensions of the ice sheet that sits on the Antarctic continent. They do not themselves contribute to sea level when they melt, because they are already in the water. What they do is buttress the glaciers and ice behind them. When ice shelves thin or collapse, the inland ice flows faster into the sea. Basal melt, driven by ocean heat reaching the underside of these shelves, is the dominant control on ice shelf mass loss. Surface melt matters far less than what is going on underneath.

What the study did

The first dataset is a network of repeat ship surveys called GO-SHIP, in which research vessels sail the same lines across the world’s oceans every decade or so, lowering instruments that measure temperature, salinity, oxygen, and a handful of other chemical tracers from surface to seabed. These measurements are precise but the lines are widely spaced and visited infrequently. Comparing surveys from 2005-2010 against surveys from 2015 onwards, the team found that warm Circumpolar Deep Water had increased in concentration nearer the Antarctic continent and decreased further north.

The second dataset is the Argo float programme: nearly four thousand robotic floats drifting through the world’s oceans, surfacing every ten days to transmit profiles of temperature and salinity in the upper 2,000 metres. The Argo data offers monthly resolution and global coverage, which the ship surveys cannot. The floats only measure two variables, however, which is not enough to identify water masses using the standard chemical-fingerprint method that ship surveys allow.

The team’s solution was to train a machine learning model on the rich GO-SHIP data, where water masses can be identified directly from the chemistry, and then apply that model to the sparser Argo measurements to fill in the spatial and temporal gaps. When tested against ship measurements it had not been trained on, the model performed well in nearly every region of the Southern Ocean. Applied to twenty years of Argo data, it produced the same poleward shift the ship surveys had shown, with finer detail. The pattern is the dominant feature of the twenty-year record once seasonal variation is removed, which is what makes the paper persuasive.

What the paper does and does not show

The study demonstrates that warm deep water has shifted closer to the Antarctic continent. It does not directly measure how much additional heat is reaching the ice shelves themselves. The Argo float data used in the analysis stops at 65°S, the latitude band immediately north of the Antarctic shelf, and it cannot sample the near-shelf waters where ice melt actually happens.

What the study does show is that within the band of ocean immediately north of the continent, ocean heat content in the warm-water layer has been accumulating at a rate equivalent to a continuous 2.81 terawatts of energy. That is a substantial amount of heat building up close to where the ice meets the sea. Whether and how much of it is currently crossing onto the shelves depends on local processes the study cannot resolve at continental scale. Winds, eddies, bathymetry, and the behaviour of dense shelf water that can act as a barrier all shape what happens at the final stretch.

The mechanism behind the migration is also unsettled. The paper presents two broad candidates. The first is that dense, cold water that normally sinks near the Antarctic coast (Antarctic Bottom Water) has been weakening, a trend already observed in independent studies, and as it contracts the warm layer migrates south to fill the space. The second is that wind-driven changes in the Southern Ocean, including strengthening westerly winds and a poleward shift in the wind belt itself, have moved the position of the Antarctic Circumpolar Current and the upwelling pathways of warm water along with it. The two mechanisms are not mutually exclusive, and the paper does not pick between them.

Why this is significant

Until now, scientists have relied largely on climate models to project what would happen as the Southern Ocean warmed. The models suggested that warm deep water would shift poleward and that ice shelf melt would accelerate as a result. Observational evidence for the shift has been piecemeal and regional.

This study is the first to show, from observations rather than projections, that the predicted shift is already underway across the entire Southern Ocean. As Lanham put it in the Cambridge press release, this is no longer a possible future scenario, it is something that is happening now.

The timescales over which the world is making decisions about climate, ice loss, and sea level rise rely on assumptions about what is happening to Antarctic ice. If the heat delivery system is shifting in the way this study describes, the question is not whether basal melting accelerates but how quickly. The paper does not answer that question, but it does establish that the question has stopped being hypothetical.

Ocean Rising depends on paid subscribers. Explainers like this one stay free. The investigations, which take longer and go deeper than a single newsletter can carry, are for paid readers. If you want the work that follows the questions this piece raises, that's where it lives.

Subscribe now

The UK protects 38 per cent of its seas by law. It has 377 marine protected areas. It committed, years ago, to achieving what the government calls “good environmental status” across 15 measures of ocean health. This week, the Department for Environment, Food and Rural Affairs published its latest assessment. Of those 15 measures, two are meeting the standard. The other 13 are failing, uncertain, or getting worse. The target date for achieving the standard was 2020.

That story opens this week’s Deep Brief, alongside a new study suggesting the Atlantic’s great overturning circulation could weaken by half this century, far more than previous models predicted, and two research expeditions that sent a robot and a net system into the deep Atlantic to track how the largest daily animal migration on Earth moves carbon out of the atmosphere.

Deep Dives

The UK protects a third of its seas. Its own government report says the ocean is still in decline.

The UK Marine Strategy report, published by Defra in April 2026, assesses the health of UK seas against 15 indicators covering everything from fish populations and seabed habitats to marine litter, underwater noise, and contamination of seafood. The benchmark is good environmental status, a standard the UK committed to reaching by 2020 under the UK Marine Strategy Regulations, which originally derived from the EU Marine Strategy Framework Directive.

Only two of the 15 indicators clearly meet that standard. Fish communities are deteriorating. Seabed habitats continue to decline. Marine bird populations are falling. Contamination levels in some species remain above safe thresholds. The assessment notes that while climate-related pressures, including rising sea surface temperatures, more frequent marine heatwaves, ocean acidification, and oxygen depletion, are evident across many indicators, most have not yet identified climate change as the primary driver of their current status. The primary drivers, for now, remain overfishing, habitat damage from bottom-contact fishing gear, pollution, and nutrient runoff.

The gap between the UK’s marine protection on paper and its ocean health in practice is the central tension. The country now has 377 marine protected areas covering 38 per cent of its waters, a figure that comfortably exceeds the 30 per cent target that governments agreed to at the UN Biodiversity Conference in 2022. The problem, as conservation groups have argued for years, is that designation without meaningful management achieves very little.

“Continued massive overfishing, refusal to ban bottom trawling even in supposedly protected areas and non-existent monitoring or enforcement means it’s hardly surprising that the seas are in such a bad state,” said Jonny Hughes, Fisheries Policy Lead at the Blue Marine Foundation.

Oceana UK echoed the criticism. Izzy Ross, Oceana’s fisheries campaigner, said MPAs had to be more than “lines on a map” and pointed out that the government’s own deadline for achieving good environmental status had passed five years ago.

The report itself acknowledges that “more remains to be done” and notes “encouraging signs of recovery” in some areas, though it does not specify which indicators are improving or by how much. Defra has not announced any new enforcement measures or management changes in response to the findings.

For readers of this newsletter, the UK report card is a case study in a pattern visible across many maritime nations: governments count protected areas as a measure of progress while the ecosystems inside those areas continue to decline. Protection that does not change what happens in the water is not protection. It is cartography.

A new study says the AMOC could weaken by half this century, far more than previous models predicted.

Three weeks ago, Deep Brief #36 covered research showing that the Atlantic Meridional Overturning Circulation (the word meridional just means running north to south) had weakened by roughly 10 per cent between 2004 and 2023, based on mooring array data from four locations across the Atlantic. That study, led by Qianjiang Xing at the University of Miami and published in Science Advances, provided the strongest direct observational evidence so far that the system is slowing.

This week, a separate team has published a study in the same journal that asks a different question: how much worse could it get?

The answer, according to a team led by Valentin Portmann at the Inria Centre de recherche Bordeaux Sud-Ouest in France, is significantly worse than most climate models have predicted. Their study projects that the AMOC could weaken by 51 per cent by 2100 under medium to high emissions scenarios. That figure is around 60 per cent higher than the average projection produced by standard climate models.

The reason for the discrepancy is methodological. Portmann’s team identified two systematic errors running through many of the most widely used climate models: they simulate the South Atlantic as not salty enough and the North Atlantic as too cold. Both biases cause the models to underestimate a key process in which dense, salty water sinks at the northern end of the system and drives the entire circulation. After correcting for both biases using a statistical technique called ridge-regularised linear regression, the projected weakening rose substantially and the uncertainty around the estimate dropped.

The study tested four emissions scenarios. Three of them, ranging from medium to very high, converged on a similar outcome of roughly 50 per cent weakening, suggesting that beyond a certain threshold of emissions, much of the damage may already be locked in by the heat the ocean has already absorbed. The most optimistic scenario, representing aggressive and sustained emissions reductions, produced a weakening of only around 20 per cent.

A 51 per cent weakening would not be a collapse, and the study’s authors are careful to distinguish the two. The Intergovernmental Panel on Climate Change has said it has medium confidence that a full AMOC collapse will not occur before 2100. What each additional weakening does, however, is push the system closer to a tipping point, the threshold beyond which the circulation reorganises into a fundamentally weaker state that could take thousands of years to reverse. Where that threshold sits is unknown.

The consequences of the kind of weakening Portmann’s study projects would include colder, harsher winters across Northern Europe, a southward shift of tropical rain belts threatening monsoon systems that hundreds of millions of people in West Africa and South Asia depend on for food, and accelerated sea level rise along the US East Coast. A 2025 study published in Geophysical Research Letters found that in a full collapse scenario, cold extremes could reach minus 20°C in London and minus 48°C in Oslo, even with greenhouse-driven global warming pushing temperatures up everywhere else.

“We have put a lot of heat into the ocean that is going to cool down over centuries,” Portmann told BBC Science Focus. “But on the other hand, you can say that before the tipping point, we can avoid a severe weakening with a strong reduction of CO2.”

Two research expeditions sent a robot and a deep-sea net system into the Atlantic to track how animals move carbon out of the atmosphere.

Every night, across the entire ocean, trillions of small animals rise from the deep toward the surface to feed. Before dawn, they descend again, carrying the carbon they consumed at the surface back down to depths of 200 to 1,000 metres, where it can be stored for decades to centuries. This daily cycle, called diel vertical migration (the word diel means happening over a 24-hour period), is the largest synchronised movement of biomass on the planet and a significant but poorly measured component of the ocean’s ability to absorb carbon dioxide from the atmosphere.

Two back-to-back expeditions aboard the Schmidt Ocean Institute’s research vessel Falkor (too), working in the Southwest Atlantic off the coast of Brazil and Uruguay, have been investigating the mechanics of this process and the broader question of how carbon moves through the ocean’s interior.

The first expedition, called “Animals as Living Bioreactors” and led by Anitra Ingalls of the University of Washington, focused on the animals themselves. The team used the remotely operated vehicle SuBastian and a system of deep-sea nets called MOCNESS (an acronym for Multiple Opening and Closing Net and Environmental Sensing System, essentially a stack of nets that can be opened and closed at specific depths to sample different layers of the water column) to collect animals at various stages of their nightly migration. Among the questions the researchers are pursuing is whether the gut microbiomes of migrating animals are transforming the food they eat at the surface into essential nutrients, including vitamin B12, for organisms living in deeper waters. Many of the animals collected are new to the South Atlantic record, and some are likely new species.

The second expedition, called SUBSEA (Subtropical Underwater Biogeochemistry and Subsurface Export Alliance), was led by Matthew Church of the University of Montana and focused not on animals but on phytoplankton, the microscopic algae that form the base of the ocean food web. Church’s team worked more than 200 miles offshore in the Southeastern Atlantic Gyre, one of the vast, nutrient-poor regions that make up more than half the ocean’s surface. These gyres are often described as ocean deserts because their surface waters contain so few nutrients, but Church’s team was looking beneath the surface. Phytoplankton living at depth in gyres, below the sunlit surface layer, may be playing a larger role in carbon cycling than scientists previously recognised.

Together, the two expeditions address a gap in climate science that has persisted for decades: how much carbon the ocean’s biological pump actually moves, and how much of that movement is driven by living animals rather than by the passive sinking of dead organic material. Estimates of the contribution of diel vertical migration to total carbon export have ranged from 10 per cent to as high as 80 per cent, depending on the region and the study. The uncertainty is enormous, and resolving it matters because the ocean’s capacity to absorb atmospheric carbon dioxide is central to every climate projection.

Quick Hits

A humpback whale named Timmy is being transported by barge from the Baltic Sea toward the North Sea after weeks of failed rescue attempts. The whale has been stranded in shallow waters near the German city of Lübeck since 3 March, far from its natural habitat in the Atlantic. Multiple attempts to guide it toward deeper water failed. In early April, German authorities gave up, saying they believed the animal could not be saved. Private entrepreneurs then stepped in, funding a rescue operation that lifted Timmy into a flooded cargo barge. The barge, towed by two tugboats, began its journey on 29 April, heading around the northern tip of Denmark via the Skagerrak strait toward the North Sea. The journey will take roughly three days. Scientists are divided on whether the whale is strong enough to survive the trip or will find its way to the open Atlantic if released. Fans are tracking Timmy’s journey in real time. “You could see that the whale fought and wanted to live,” Karin Walter-Mommert, one of the entrepreneurs financing the rescue, told the German newspaper Bild.

The world’s first purpose-built offshore platform for ocean thermal energy conversion has been installed in the Canary Islands. UK-based Global OTEC completed the deployment of its floating platform prototype this week, marking a milestone for a technology that has been discussed for decades but never scaled offshore. Ocean thermal energy conversion, or OTEC, generates electricity by harnessing the temperature difference between warm surface seawater and cold water drawn from the deep ocean. The technology offers continuous, baseload power without the intermittency problems of wind and solar, and it targets a specific market: tropical island nations where most electricity is still generated from imported diesel and heavy fuel oil. Global OTEC estimates that more than 25 gigawatts of existing fossil fuel capacity across tropical islands could eventually be replaced by OTEC systems. Whether the technology can move from prototype to commercial deployment remains the open question.

Hard Truth From The Sea

The UK protects 38 per cent of its seas and 13 of 15 health indicators are failing. The AMOC is weakening faster than the models predicted, and corrections to those models suggest the models were wrong in a direction that made things look better than they are. The ocean’s biological pump moves carbon from the atmosphere to the deep, and scientists are only now sending robots to measure how much. Each of these stories describes a version of the same problem: the distance between what we claim to know about the ocean and what we have actually bothered to measure. The ocean does not wait for our instruments to catch up.

Paid subscribers fund the reporting that tracks what is changing in the ocean and why. If you want accountability journalism on the systems we depend on and the institutions responsible for protecting them, please consider upgrading your subscription.

Subscribe now

See you next week.

- Luke

A 4,000-word Special Feature on deep-sea mining is out this week in Oceanographic Magazine, commissioned by the Charles Douglas-Home Memorial Trust. It is one of the deepest pieces of reporting I have done. It examines the science, the governance, the economics, and the company at the centre of the most advanced attempt to mine the deep ocean, a Canadian-listed firm called The Metals Company.

Read the full article in Oceanographic

If you’ve subscribed to this Substack and wondered where I went, this was where. The piece took months. Document review, interviews, legal reads, fact-checks. The kind of reporting that does not produce a steady stream of posts, because the work is invisible.

The week before the article published, I sat on a panel at The Conduit Club in London alongside Louisa Casson, who leads Greenpeace’s global anti-deep-sea-mining campaign, and Oliver Steeds OBE, founder of Nekton and director of the UN’s Ocean Census. The event was called The Scramble for the Seabed. The room was full. It was chaired by Jeevan Vasagar, climate editor of The Observer.

The Metals Company was invited.

They sent a video message in their place.

In it, an unnamed company spokesperson argued that what deep-sea mining would do to the seabed should not be called habitat destruction. The correct word, they said, was modification. The video also disputed the idea that sediment plumes would significantly affect untouched areas of the seabed. Both claims are contested by the peer-reviewed science I examine in the Oceanographic piece.

The panel watched the video. Then we took our seats. There was no one in the room to defend the position the video had just put forward.

That, in itself, is part of the story. The most advanced commercial attempt to mine the deep ocean is being made by a company that, when offered a serious public forum to argue its case, declined to send a person.

Recycling came up early. I had raised it briefly; Louisa Casson made the case in detail. The metals we need for the energy transition are largely already above ground, in old phones, batteries, cars. The systems to recover them at scale do not yet fully exist. We are reaching for the deep sea before we have built the alternatives to it.

Later, an audience member working in green energy asked the question I had been dreading. He was not attacking the panel. He was genuinely uncertain.

What’s the balance? We can debate whether deep-sea mining is good or bad. But we are heading in a direction where it almost feels inevitable. So, do we allow it and govern it carefully? Or do we say no, and slow the transition away from fossil fuels?

I took it first.

What I said, more or less, was this. We are at a real moment of transition, and the world does need metals to power it. But people have zeroed in on deep-sea mining as the only alternative to terrestrial mining, and that framing is largely driven by the financial interests of the companies that want to mine. We need to know for sure the damage this will produce before we can press go or say no. Science has to win out.

That was the answer. It was not the cleanest, but it was honest.

The strongest line of the night was Casson’s.

“The idea of mining the deep sea is like burning a library when you haven’t even finished reading the first book.”

Ninety per cent of the species being found in the Clarion-Clipperton Zone, the patch of Pacific seabed at the centre of the mining race, are new to science. We do not yet know what we would be losing.

Oliver Steeds put the financial case in similar terms. The economics of deep-sea mining, he argued, do not add up before you even consider the environmental costs. Major mining companies have pulled out. Lockheed Martin has divested. A previous attempt in Papua New Guinea collapsed and left the government as a creditor with no recovery mechanism. The Norwegian government opened the Arctic seabed to exploration in January 2024, then halted its licensing programme until at least 2029.

The article goes deeper than I can here. The 1980 US law The Metals Company is filing under, which the International Seabed Authority says has no authority over the international seabed. The unfinished rulebook fifteen years in the making. The 44-year-old machine tracks still visible on the abyssal plain from a 1979 test. The food web disruption that could carry mining sediment into the depth band where mercury enters the human food chain. The science being funded, in significant part, by the companies that want to do the mining.

And the question the panel could not resolve, because the world has not resolved it yet.

Read the full article in Oceanographic

Commissions like this one, from the Charles Douglas-Home Memorial Trust, are rare, and they make ambitious reporting possible. But the work between commissions is what your subscriptions support: the calls that go nowhere, the documents that do not pan out, the months when nothing is publishable. The CDHMT funding bought the time to write the article. Your subscriptions buy the time to find the next one.

Thank you for sticking around.

Reporter’s note: Research support was provided by Blue Marine Foundation, which has publicly supported a precautionary pause on deep-sea mining. The article was researched and written independently. Blue Marine had no editorial control over its findings or conclusions. The Conduit panel referenced above was held on Tuesday 21 April 2026 in collaboration with Pranvera Shema Smith, founder of On Front Line, and chaired by Jeevan Vasagar, climate editor of The Observer. Luke McMillan is Head of Hunting & Captivity at Whale and Dolphin Conservation. The views in this post are his own and do not represent WDC’s institutional position.

In a warehouse somewhere in Iceland, fin whale meat from the 2023 hunt is still sitting unsold. Japan, the only export market, has stopped buying it. The whaling company that killed those animals lost roughly $20 million over eight years of operations. The government has publicly committed to banning commercial whaling this autumn. And yet, earlier this month, that same company announced it intends to hunt fin whales again this summer. Whether it does depends on a single decision by a single minister who has already said the practice is not in the public interest.

That story leads this week’s Deep Brief, alongside a photojournalist’s account of Indonesia’s shark meat trade, where the world’s second-largest animal by global trade value now sells for 29 cents a skewer, and a legal challenge that could force France to confront the tens of thousands of seabirds dying in its fishing nets each year. Three deep dives. Three quick hits. One hard truth from the sea.

Deep Dives

Iceland’s government says it will end whaling. Hvalur hf. is betting it won’t.

Iceland’s whaling company Hvalur hf. has announced its intention to hunt fin whales in 2026, despite two consecutive seasons without a hunt, a government commitment to introduce legislation banning commercial whaling later this year, and an Icelandic warehouse full of unsold meat from the last hunt in 2023.

The decision now rests entirely with Hanna Katrín Friðriksson, Iceland’s Minister of Industries. Friðriksson has publicly stated that commercial whaling is not in the public interest and has confirmed that legislation to end the practice will be tabled this autumn. For conservation groups, that makes any decision to authorise a 2026 hunt difficult to justify.

“Not a single whale should die this summer for a practice the government itself has said it will end this autumn,” said Valgerður Árnadóttir, Chair of Hvalavinir, an Icelandic whale conservation organisation.

Fin whales are the second-largest animals on Earth and are listed as Vulnerable on the IUCN Red List. Iceland is the only country in Europe that still hunts them. Only three nations continue commercial whaling in defiance of the International Whaling Commission’s moratorium: Iceland, Norway, and Japan.

The Marine and Freshwater Research Institute has issued advice capping any fin whale catch at 150 animals, a reduction of roughly 20 per cent on previous quotas. Hvalur hf. holds a five-year licence issued in late 2024, with a combined annual quota permitting up to 400 whales.

The economics of Icelandic whaling have been deteriorating for years. Between 2012 and 2020, Hvalur hf. recorded combined losses of approximately three billion Icelandic krónur, around $20 million, from its whaling operations. Japan, historically the sole export market for Icelandic fin whale meat, has stopped importing it, weighed down by its own stockpiles and falling domestic demand. By contrast, whale watching generates an estimated $26 million annually for Iceland’s economy.

The welfare case is equally difficult to defend. In 2023, one in five fin whales shot required a second harpoon and suffered for up to 35 minutes before death, in what I have argued publicly constitutes a breach of Iceland’s own animal welfare legislation. WDC is calling on the Minister to revoke Hvalur’s licence immediately and to begin the formal process of withdrawing Iceland’s reservation to the International Whaling Commission moratorium.

Three previous ministers have opposed whaling and none succeeded in stopping it. The pattern is familiar: governments declare their opposition, promise legislation, and then allow another season to pass while the bills wait in a queue. Each time, more whales die for a product that nobody is buying.

Disclosure: I am Head of Hunting and Captivity at Whale and Dolphin Conservation. I am quoted in the Oceanographic article by Rob Hutchins that prompted this story. The analysis and framing here are my own.

In Indonesia, shark meat has quietly become bigger business than shark fins. A photojournalist went to see what that looks like.

Indonesia consistently ranks as the top shark-catching nation in the world. At the fish market in Tanjung Luar, a village on the island of Lombok, photojournalist Garry Lolutung documented what the trade looks like up close for Mongabay.

Fishing boats from nearby islands arrive each morning carrying fresh catches. Sharks are placed on the auction floor and sold for 600,000 to one million rupiah each, roughly $35 to $58. The sharks are supplied by longline vessels that deliberately target them, which is generally legal in Indonesia, and by gillnet fishers who take them as bycatch.

Twenty kilometres inland, in Rumbuk village, the meat is processed into smoked jerky, shredded fish, crackers, meatballs, fish cakes, and satay. A kilogram of shark meat in Rumbuk costs between $1.46 and $2.33. A skewer of shark satay costs 5,000 rupiah, which is 29 US cents. It is an affordable source of protein that has become a local staple.

The global picture has shifted. For decades, the shark fin trade dominated. Shark fin soup remains a luxury item in parts of East Asia, and fins are still by far the most valuable part of the animal per kilogram. What has changed is that shark meat has overtaken fins in both trade volume and total value. A 2021 WWF report placed the value of all shark and ray meat traded globally between 2012 and 2019 at $2.6 billion.

Indonesia is a major exporter of shark products, including meat, liver oil, and skin, and its bilateral trade with China represents the world’s fifth-largest flow for blue shark meat, according to a 2022 Oceana report. Researchers have identified significant discrepancies between Indonesia’s reported shark landings and its declared exports, and between its export figures and what its trading partners report importing. This points to a combination of illegal trade, inconsistent data collection, and high levels of domestic consumption.

Protections for sharks in Indonesia exist for some species. Whale sharks, sawfish, and manta rays are protected by law. Fishers in Tanjung Luar told Mongabay they would not hunt whale sharks, citing a long-standing belief that the animals bring good luck. For most other shark species, including threatened ones, hunting is legal.

Shark meat made national headlines in Indonesia in September 2025, when 16 students at a school in Ketapang district on the island of Borneo were poisoned by shark meat served through the national free school meals programme. Other countries, particularly Brazil, have faced scrutiny for including shark meat in school and institutional meals, because the flesh tends to contain high concentrations of heavy metals that can harm human health, especially in children.

Globally, shark and ray populations have declined steadily due to overfishing, combined with the animals’ slow growth and reproduction rates. The market in Tanjung Luar, where baby sharks lie on the auction floor beside adults and fins dry on racks in the sun, is one window into a trade that is accelerating even as the animals that sustain it disappear.

Three environmental groups have taken France to its highest court over the killing of tens of thousands of seabirds.

ClientEarth, Sea Shepherd France, and Défense des Milieux Aquatiques filed a complaint before the Conseil d’État on 21 April 2026, demanding that French authorities enforce existing EU laws on fishing sustainability and biodiversity protection. The groups allege that France has failed to collect adequate data on seabird deaths in fishing gear and has not implemented measures to reduce them, in breach of the Birds and Habitats Directives, the Technical Measures Regulation, and other European legislation.

Scientific extrapolations from available monitoring suggest that France may have the highest seabird bycatch figures in Europe, with an estimated 34,600 birds killed annually. The most affected species include the Balearic shearwater, a medium-sized seabird that breeds in the western Mediterranean and is classified as critically endangered on the IUCN Red List, the northern gannet, now classified as near threatened, and the common guillemot, classified as endangered. Longlines, gillnets, and pelagic trawls targeting commercial species including hake, sea bass, and tuna are the main killers.

Most of the birds drown without ever washing ashore, which is why the crisis has remained largely invisible to the public and to policymakers. Because most deaths happen underwater and the bodies sink, the scale of the problem only becomes clear through observer programmes on fishing vessels and statistical extrapolation, both of which the NGOs argue France has failed to maintain adequately.

The legal action complements an infringement procedure already opened by the European Commission against France for similar failings. The Commission has challenged France on this issue before, and France has not responded with the monitoring or mitigation measures required by European law.

One French fisherman, identified by the pseudonym Ludovic in the case briefing, described a worsening dynamic. Declining fish stocks have led some operators to leave nets in the water for longer, increasing the chance that birds and other non-target species become entangled. “The best way to avoid bycatch is to fish at night and haul the nets back before sunrise,” Ludovic told the briefing. He warned that current trends could create a cycle that depletes fish populations, protected species, and the future of fishing itself.

France oversees the world’s second-largest exclusive economic zone. The gap between that global reach and its failure to monitor what is dying in its own nets is the core of the legal challenge.

Quick Hits

Chile’s new president has suspended two vast marine parks that his predecessor created on his last day in office. Former President Gabriel Boric signed a decree on 10 March creating Juan Fernández II and Nazca-Desventuradas II, which together would have protected roughly 337,000 square kilometres of Pacific Ocean, around 10 per cent of Chile’s exclusive economic zone. President José Antonio Kast suspended the decree on his first day in office as part of a broader review of environmental measures. The region has one of the highest rates of endemic species in the world, higher than the Galápagos or Hawai’i, with 87 per cent of fish in the Juan Fernández archipelago found nowhere else. Conservation groups fear the protections could be weakened under pressure from fishing interests, particularly the semi-industrial swordfish fleet. If the parks survive, Chile would join Palau as the only countries to protect more than half their exclusive economic zones.

Singapore’s Resorts World Sentosa will stop sourcing wild dolphins and is suspending its captive breeding programme. The resort obtained 27 Indo-Pacific bottlenose dolphins from the Solomon Islands in 2008 and 2009. At least four died during transit or from infections. The facility still holds more than 20 dolphins, the youngest a seven-year-old male named Kenzo. An expert panel is being assembled to determine the animals’ future. Staff who spoke to Mongabay said they doubted the dolphins could survive in the wild after so long in captivity. An international movement against cetacean captivity for entertainment is growing, with Mexico, Canada, and France among the countries that have recently banned the practice.

More than 17 million Americans along the Atlantic and Gulf coasts are living in areas at the highest risk of flooding, according to a new study in Science Advances. Researchers at the University of Alabama used 16 factors related to hazard, exposure, and vulnerability, combined with three machine learning models and historical damage data from FEMA, to identify eight cities at greatest risk: New York, Norfolk, Charleston, Jacksonville, Miami, Mobile, New Orleans, and Houston. New York has the largest population at risk, with roughly 4.75 million people in the two highest risk categories. New Orleans has the highest proportional exposure, with 99 per cent of the city’s population at elevated flood risk. The lead author, Wanyun Shao, described the figures as “shocking” and “alarming.”

Hard Truth From The Sea

A minister in Reykjavik is deciding whether to authorise a hunt for an animal the government has already said it will stop killing. A warehouse of unsold whale meat sits in storage while the decision is made. In Indonesia, baby sharks lie on auction floors beside adults, feeding a trade that has grown even as the populations that sustain it have shrunk. In France, tens of thousands of seabirds drown in fishing nets each year, and nobody has to watch because the bodies sink. The ocean absorbs a great deal of what humans would rather not see. The question, as always, is whether the things we choose not to look at will still be there when we finally do.

Paid subscribers fund the reporting that tracks what is changing in the ocean and why. If you want accountability journalism on the systems we depend on and the institutions responsible for protecting them.

Subscribe now

See you next week.

- Luke

Six hundred metres below the surface of the Pacific, off the coast of Long Beach, California, a hollow concrete sphere the size of a small house will soon sit on the seabed. When electricity is cheap, a pump will force seawater out of it, leaving a vacuum inside. When electricity is needed, a valve will open, and the ocean’s own pressure will drive water back in through a turbine, generating power. The sphere is a battery, and the ocean is the charger. If it works, there are plans for fields of them.

This is the Good News Edition. Once a month, this newsletter reports on what is working: the engineering, the science, the governance, and the people who are building, measuring, and protecting, often in places nobody else is looking.

Deep Dives

The ocean floor as a battery. A German-American experiment off California could change how the world stores renewable energy.

The problem with solar and wind power has never been generation, it has been storage. The sun does not shine at night and the wind does not blow on command, so every country trying to run its grid on renewables eventually hits the same wall: what do you do with the surplus electricity when you have too much, and where do you find more when you run out?

One answer, tested successfully on a small scale in 2017 and now heading for its first full-size ocean trial, is to store that energy underwater in concrete spheres.

The StEnSea project, short for Stored Energy in the Sea, was developed by the Fraunhofer Institute for Energy Economics and Energy Systems Technology in Germany. The concept borrows from pumped hydroelectric storage, the most established form of grid-scale energy storage on Earth, which works by pumping water uphill into a reservoir when power is cheap and letting it flow back down through turbines when power is needed. Pumped hydro is efficient, reliable, and well understood. It also requires mountains, dams, and large tracts of land, which limits where it can be built and often generates public opposition.

StEnSea replaces the mountain with the ocean. A hollow concrete sphere on the seabed acts as the lower reservoir. The surrounding ocean acts as the upper one. When surplus electricity is available, it powers a pump that forces seawater out of the sphere, creating a pressure differential with the ocean outside. When the grid needs power, the valve opens, water rushes back in under the enormous pressure at depth, spins a turbine, and feeds electricity back to shore.

In 2017, the Fraunhofer team tested a three-metre prototype in Lake Constance in Germany. It worked. The system handled repeated charge-discharge cycles through the winter and proved the engineering was sound. The next step is a nine-metre sphere, weighing 400 tonnes, to be built using 3D concrete printing by Sperra, a US startup based in Long Beach, and deployed at a depth of 500 to 600 metres off the California coast by the end of 2026. The US Department of Energy has invested $4 million in the project. The German government is contributing roughly €3.4 million.

The prototype will store 0.4 megawatt-hours of electricity, enough to power a typical home for about two weeks. That sounds modest, but the technology is designed to scale. A park of six full-sized spheres, each around 30 metres in diameter, could deliver 120 megawatt-hours of storage and 30 megawatts of power output, cycling hundreds of times a year. The Fraunhofer team estimates a global storage potential of 817,000 gigawatt-hours across suitable coastal seabeds worldwide, based on depth, seafloor slope, and proximity to ports and grid infrastructure.

The efficiency of the system sits at around 75 to 80 per cent, slightly below pumped hydro on land. The lifespan of the concrete spheres is estimated at 50 to 60 years, with turbines and generators needing replacement roughly every 20 years. The estimated cost is 4.6 euro cents per kilowatt-hour stored, competitive with many existing grid-scale storage technologies.

There are unknowns. The California deployment is the first time the system will operate in saltwater at depth, which introduces corrosion, biofouling, and maintenance challenges that did not exist in Lake Constance. Environmental assessments from the lake trial suggested low impact under the conditions tested, but ocean ecosystems at 600 metres depth are different, and the effects of deploying large numbers of spheres on deep-sea habitats have not been studied. These are questions that need answering before any large-scale rollout.

The logic of the design is what makes it compelling. The deeper the water, the greater the pressure, and the more energy each sphere can store. The spheres can be manufactured on shore and towed to site. They require no land, generate no emissions in operation, use no rare materials, and sit out of sight on the seabed. If the California trial succeeds, the technology could pair directly with offshore wind farms, storing their surplus output within reach of the turbines that produce it.

One bay, 28 years, every week. The quiet science that makes Antarctic research possible.

It is 8.30 in the morning at Rothera Research Station on the Antarctic Peninsula, and the marine team is gathered for its daily briefing. Outside, Ryder Bay stretches into a pewter sky. Someone checks the weather. Someone checks sea ice conditions. Within fifteen minutes, a decision is made: it is a sampling day.

The Rothera Time Series, known as RaTS, has been running since 1997. Every five to seven days, weather and ice permitting, a small rigid inflatable boat pushes out from the station ramp into the bay, carrying Niskin bottles for water sampling and a CTD instrument that measures conductivity (a proxy for salinity), temperature, and depth as it descends through the water column. The team profiles to roughly 500 metres and collects water samples at 15 metres depth. They have been doing this, in one form or another, for nearly three decades.

What they are building is one of the most significant long-term ocean measurement records in Antarctica, and one of the very few that includes winter data from either pole. Almost all Antarctic ocean science happens in the austral summer, when ships can reach the continent and conditions permit fieldwork. RaTS runs year-round because Rothera is staffed through the winter, and because the marine team can reach Ryder Bay by boat or, when sea ice covers the surface, by sled. That winter coverage makes the dataset exceptionally valuable. The processes that control how the Southern Ocean absorbs heat and carbon dioxide, the formation of sea ice, the behaviour of phytoplankton, the timing of seasonal cycles, all of these look different in winter than in summer, and almost nobody else is measuring them.

The data has already shown that the ocean around the Antarctic Peninsula is sensitive to large-scale global climate patterns, including El Niño. Summer ocean surface temperatures in the region have increased by more than 1°C. Atmospheric temperatures on the peninsula rose by almost 0.4°C per decade in the second half of the twentieth century, making it one of the most rapidly warming regions in the Southern Hemisphere.

Rothera itself has undergone a transformation. The £670 million Antarctic Infrastructure Modernisation Programme, the largest UK government investment in polar science infrastructure since the 1980s, has delivered a new research vessel (RRS Sir David Attenborough), upgraded wharves, a new runway, and the Discovery Building, a £100 million facility that in April 2026 became the first building in Antarctica to achieve an Outstanding BREEAM sustainability rating, a standard met by fewer than one in a hundred accredited buildings globally. The building is on track to reduce the station’s carbon emissions by 25 per cent through combined heat and power generators, waste heat recovery, solar panels, and automated heating systems.

None of this makes headlines, and it is not meant to. Long-term monitoring is, by definition, unglamorous. It requires people willing to work long hours in a constantly changing environment, to exercise judgement about when conditions are safe enough to go out on the water, and to hand something precious on to the next person without hesitation. “It’s never your data set,” said Allie Mayall, a former marine team lead at Rothera, in the BAS blog post that prompted this story. “You’re just the person looking after it for that time being.”

That care is the infrastructure that everything else depends on. The climate models that predict ice sheet behaviour, the assessments that inform international policy, the studies that track how ecosystems respond to warming, all of them need continuous data from places like Ryder Bay. RaTS is a commitment as much as a monitoring programme, sustained across nearly three decades by the people who go south to keep it running.

On a Mediterranean beach, 3D-printed modules inspired by mangroves are trying to hold the coastline together.

The Gulf of Lion, along the southern coast of France, is losing sand. Storms strip it from beaches faster than natural processes can replace it. In the 2010s, local authorities spent millions of euros on beach replenishment, dredging sand from offshore and pumping it back onto the shore. The sand was supposed to last a decade, but storms stripped most of it away in less than five years.

Lineup Ocean, a French startup, is testing a different approach. Their SURFREEF project, deployed at the beach of Zénith in Palavas-les-Flots near Montpellier, uses submerged structures called UpBlock modules to break the energy of incoming waves before they reach the shore. The modules are 3D-printed from a bio-based material described as low-carbon shell mortar and are designed to mimic the way mangrove root systems dissipate wave energy naturally. Where traditional coastal engineering fights the ocean with seawalls and rock armour, the SURFREEF approach works with the water, reducing the force of waves gradually so that sand has a chance to accumulate rather than being stripped away.

The project is still in its early stages. A baseline mapping of the beach was completed using drone-mounted bathymetric LiDAR (a laser scanning system that measures the shape of both the water surface and the seabed beneath it), and the first demonstrator segment of UpBlock modules is being installed. The next data collection will happen after the first storm, when researchers will measure whether sandbanks have shifted in the way the models predict.

Lineup Ocean won the Eco-Enterprise Innovation Trophy at France’s national eco-enterprise forum in 2026 and received a trophée de reconnaissance from the municipality of Palavas-les-Flots. The SURFREEF project has been granted a five-year temporary occupation authorisation for the maritime public domain by the Hérault prefecture, and a larger project called BIOMIM’4SHORE, backed by €375,000 in French government funding through the i-Lab innovation competition, aims to deploy a full range of nature-based coastal resilience solutions across the town by 2027.

The engineering is modest in scale but interesting in principle. Rather than armouring the coast against the sea, it is attempting to rebuild the conditions under which the coast can protect itself. Whether the modules hold up under real storm conditions, and whether the ecological benefits (increased biodiversity, habitat creation on the submerged structures) materialise as hoped, remains to be demonstrated. The early results will matter for Mediterranean coastal communities that are running out of sand and running out of options.

Quick Hits

Forty-six countries, including major oil and gas producers, will gather in Santa Marta, Colombia later this month for the first international conference dedicated to transitioning away from fossil fuels. Co-hosted by the governments of Colombia and the Netherlands, the conference runs from 24 to 29 April and will bring together government representatives from countries including Canada, Australia, Brazil, Norway, Angola, and several Pacific island nations. The conference operates outside the UN consensus framework that has repeatedly failed to include fossil fuel language in COP final texts, using majority rule instead. One area of focus relevant to ocean governance: new analysis by Earth Insight shows that 19 per cent of the world’s Marine Protected Areas are already overlapped by active oil and gas blocks. The concept of Fossil-Free Zones, geographically defined areas where fossil fuel extraction is permanently off limits, will be central to discussions.

The EU and Iceland held their first annual high-level dialogue on ocean cooperation in Reykjavik on 17 April. Commissioner for fisheries and oceans Costas Kadis met with Iceland’s Minister of Industries Hanna Katrín Friðriksson to review progress under a Memorandum of Understanding signed in July 2025. Topics covered included Arctic governance, management of shared fish stocks in the North-East Atlantic, the blue economy, and mutual commitment to ratifying the High Seas Treaty. During the visit, Kadis travelled to Grindavík, the coastal town severely affected by volcanic eruptions since 2023, to meet with local fishing communities. Iceland is expected to hold a referendum before 2027 on reopening EU accession talks.

The UNFCCC Standing Committee on Finance has chosen “Financing Climate Action in Water Systems and the Ocean” as the topic of its 2026 Forum. The SCF Forum selects a different theme each year, and this is the first time the ocean has been chosen as the focus, a decision supported by submissions from UN-Water, UNICEF, and private sector actors including Fugro. The forum will feed into the 2026 UN Water Conference scheduled for 2 to 4 December in the United Arab Emirates. Combined with the Santa Marta fossil fuel conference and the ongoing BBNJ treaty implementation process, 2026 is turning into a year in which the institutional plumbing for ocean governance is being assembled faster than at any point in the past decade.

Hard Truth From The Sea

The good news in this edition is evidence that effort produces results, which is a different thing from optimism. A concrete sphere works as a battery because the physics was tested, refined, and funded over fifteen years. A monitoring programme in Antarctica exists because people kept going out on the water every week for twenty-eight years. A beach in the south of France might hold its sand because engineers studied how mangroves break waves and then 3D-printed the principle into concrete. Each of these stories started with someone deciding to do the work, and then keeping at it long after anyone was paying attention.

Paid subscribers fund the reporting that tracks what is working in the ocean and why. If you want accountability journalism on the systems that protect the ocean and the people building them.

See you next week.

- Luke

South Africa’s coastal fishing communities have forced the courts to intervene against offshore seismic and drilling permits five times since 2021. The blasting may have happened regardless. This is an Ocean Rising investigation, part one.

In March 2022, a fourth-generation fisher named Christian John Adams went to the Western Cape High Court in Cape Town and heard a judge confirm what he had argued for months: an Australian seismic company had begun firing airguns across the seabed off his fishing grounds without consulting his community, without obtaining the required environmental authorisation, and without so much as translating its notices into isiXhosa, one of the three official languages of the Western Cape.

The company’s executive vice-president, Alan Hopping, said South Africa was “un-investable for us.”

Four months later, they were back.

This is a story about how South Africa’s offshore oil and gas permitting system is designed, and what that design means for the fishing communities that depend on the same waters.

What a seismic survey actually is

A seismic survey for oil and gas works by firing compressed air from guns towed behind a ship. The blast, at Searcher’s source level roughly 255 decibels measured underwater and one of the loudest sounds produced by human activity, travels down through the water, hits the seabed, bounces back, and is captured by sensors trailing behind the vessel on cables stretching 8.1 kilometres. The returning signals are used to map what lies beneath the seabed: the geological formations that might contain oil or gas. (Underwater decibels are measured relative to one micropascal at one metre, a different scale to in-air decibels, but at this source level the signal is detectable thousands of kilometres away; airgun noise from surveys has been recorded at ranges exceeding 3,000 kilometres.)

The blasts repeat every ten seconds, around the clock, for months at a time.

For marine life, the noise is unavoidable. Fish with swim bladders (the air-filled organ that controls buoyancy) can suffer physical injury close to the source. Further away, evidence from multiple studies points to behavioural disruption: fish move, stop feeding, alter their migration routes. The science is genuinely contested. A large-scale Australian study published in PNAS in 2021, partly funded by the oil and gas companies Santos and Woodside, found no evidence of short-term or long-term effects on demersal fish populations on the North West Shelf of Western Australia. An Australian research team published a preprint in 2025 with starkly different findings: catch rates for eastern school whiting fell by 99 per cent following a 3D seismic survey, with effects persisting for at least ten months, and tiger flathead fell by 75 per cent. The authors attributed the declines to fish displacement rather than mortality, and the methodology has not yet been through peer review. What both studies agree on is that results vary significantly by species, and that the cumulative effect of repeated surveys in the same waters has barely been studied anywhere.

Snoek, the fast, predatory fish that is as close to a cultural staple as the West Coast has, has never been studied in this context. No species-specific research exists on what seismic surveys do to snoek populations. What West Coast fishers know is what they observe: that snoek are harder to find, that seasons are shorter, that the effort required to catch the same haul keeps increasing.

Whether that is because of seismic surveys, climate change, overfishing, or some combination, no institution has been tasked with finding out.

This is where the Ocean Rising investigation begins. What follows, the legal record, the permitting pattern, and the structural question no one in government wants to answer, is for paid subscribers.

Read more

Stretched across the Atlantic at twenty-six and a half degrees north, running from the Bahamas toward the Canary Islands, a network of anchored instruments has spent the past two decades measuring how much water is moving through the ocean’s largest heat engine. They record temperature, salinity, velocity and pressure to build a continuous picture of the current that keeps Europe warm. This week, scientists using that data published the strongest direct observational evidence yet that the engine is slowing down across four separate locations in the Atlantic basin.

That story sits alongside a study of four sperm whales that washed ashore in the southeastern United States with fishing gear in their stomachs and undersized squid in their guts, and research into how the planet’s most powerful ocean current, a flow carrying more than a hundred times the water of every river on Earth combined, first came into being. Three deep dives. Three quick hits. One hard truth from the sea.

Deep Dives

The Atlantic’s great heat engine is slowing. Scientists now have the strongest evidence yet.

The Atlantic Meridional Overturning Circulation, known as the AMOC (the word meridional just means running north to south), is a system of ocean currents that moves warm, salty water from the tropics north toward the Arctic, releases its heat into the atmosphere, and sends the cooled, denser water back south along the seafloor. It is the reason Western Europe has milder winters than parts of Canada at the same latitude, and it is part of the global conveyor belt that redistributes heat around the planet. Climate scientists have warned for years that it is slowing down, and that a complete collapse would reshape weather, rainfall, and sea levels across much of the Northern Hemisphere.

A new study led by Qianjiang Xing at the University of Miami, published this week in Science Advances, now provides what the German oceanographer Stefan Rahmstorf, who was not involved in the work, called the strongest direct observational evidence so far that the AMOC is weakening.

The researchers drew on data from RAPID-MOCHA, a network of anchored instruments that has monitored the Atlantic since 2004. The array stretches across the ocean at roughly 26.5 degrees north. It measures temperature, salinity, and water velocity, which together allow scientists to estimate pressure on either side of the basin. Pressure differences matter because water flows from high pressure to low pressure, the same way air moves from a pumped-up tyre when you open the valve, so changes in pressure across the ocean are a direct fingerprint of how much water is moving. The team examined pressure data from three additional mooring arrays installed since 2004 along the western side of the Atlantic, the side closest to North America, off the West Indies, the US East Coast, and Nova Scotia. Across all four locations, the signal was consistent: the circulation is weakening, and the weakening is real, not an artefact of one mooring or one latitude.

The measured decline, based on RAPID-MOCHA data alone, amounts to roughly 10 per cent between 2004 and 2023. The margin of error on that figure is almost as large as the figure itself, which is why the pressure analysis matters. When Xing’s team looked at pressure data from the other three arrays, the weakening became clearer and the uncertainty dropped. The signal that started along the western side of the basin was propagating across the wider Atlantic.

There is a complication to flag. In 2024, a separate team led by Denis Volkov at NOAA published findings showing that the Florida Current, which forms the beginning of the Gulf Stream and is itself a key component of the AMOC, has remained remarkably stable over forty years of observations. Volkov’s team noted that their finding did not refute a broader AMOC slowdown. The AMOC is not one current but a system with multiple branches that can behave differently at different depths and latitudes, which means Xing’s study does not contradict Volkov’s so much as suggest that the weakening is showing up in parts of the system that Volkov’s instruments do not monitor.

The underlying mechanism that scientists worry about is simple in outline. As the Greenland ice sheet melts, fresh water pours into the North Atlantic, and fresh water is less dense than salty water. Less dense water does not sink as readily, which means the cooled water at the northern end of the conveyor belt struggles to descend and complete the loop. If the loop slows enough, it can reach what physicists call a tipping point, beyond which the entire system reorganises into a weaker state. Climate models have predicted this for decades, and the instruments in the water are now starting to see it.

The consequences of a significant AMOC slowdown, according to climate modelling, would include colder winters across Northern Europe, disruption to the monsoon rains that sustain agriculture across parts of Africa and Asia, and a pronounced rise in sea levels along the US East Coast. None of these would happen overnight, and a collapse, if it came, would unfold over decades. What Xing’s study adds is observational evidence that the process which might lead to one has already begun.

In January 2026, Iceland formally classified a potential AMOC collapse as a national security risk. Other countries have not yet followed.

Four sperm whales washed ashore with empty stomachs and pockets full of fishing gear.

Between 2020 and 2022, four sperm whales stranded separately on the beaches of Florida and Alabama. Each was alive when found, and each died shortly afterwards. Because they were alive at the time of stranding, researchers were able to conduct full post-mortem examinations, which is rare. Most stranded whales have decomposed by the time anyone reaches them, destroying the tissue evidence that might explain what killed them.

The four whales were examined by a team led by Jennifer Bloodgood, now at Cornell University, along with collaborators at the Dauphin Island Sea Lab and the Harbor Branch Oceanographic Institute. Their findings, published 9 April in the journal Diseases of Aquatic Organisms, describe a consistent pattern across all four animals: emaciation, malnutrition, and in two of the whales, large quantities of ingested fishing gear. One had a length of longline gear, the kind used for commercial deep-sea fishing, with a minimum of 480 branch lines, wrapped around its lower jaw, with a wad of trawl net in its throat and more gear in its stomach. Another had sections of gill net, trawl net and longline gear in its stomach.

The stomach contents also revealed something subtler. The whales had been eating their normal prey, mostly squid, in quantities that should have been enough to sustain them. Two contained well over 1,000 squid beaks, which is how researchers identify what a whale has been eating after the soft body parts have been digested. The beaks allow scientists to estimate the size of the squid the whale was consuming. The beaks in these whales were, on average, smaller than expected. The whales were eating squid, but they were eating smaller, less nutritious squid than sperm whales normally eat.

This matters because a sperm whale that has to eat smaller squid to stay fed has to dive more often and work harder for the same amount of energy. Sperm whales hunt by echolocation, the use of internal sonar to find prey in total darkness. Human activities that produce underwater noise, including seismic surveys for oil and gas exploration in the Gulf of Mexico and the movement of commercial shipping, can disrupt that sonar. The study cannot prove that any specific whale’s death was caused by any specific noise source. What it can do is identify a pattern: emaciated whales, derelict fishing gear in their bodies, a documented trend toward smaller prey, and an environment in which the tools they use to find food are increasingly contaminated by human sound.

“Many of the issues come back to potential human influences,” Bloodgood said in a statement released by Cornell. “We’re the ones causing many of these issues and many of them should be entirely preventable.”

Sperm whales are listed as endangered under the US Endangered Species Act. They were hunted close to extinction in the 19th and 20th centuries, primarily for the waxy oil in their heads, which was used in candles and lubricants. Commercial whaling for sperm whales ended in 1987, and the species has been recovering slowly ever since. The four whales in this study died of something else entirely.

The planet’s most powerful ocean current carries more water than every river combined. Scientists have now worked out how it was born.

The Antarctic Circumpolar Current runs clockwise around Antarctica, uninterrupted by any landmass, carrying more than a hundred times the water that flows in every river on Earth combined. It isolates the southern continent thermally, which is the reason Antarctica has been able to build and hold its enormous ice sheet. It draws down carbon dioxide from the atmosphere. It is, along with the AMOC, one of the two largest circulation systems in the global ocean, and it shapes climate everywhere.

For decades, scientists assumed the current formed when tectonic plates pulled South America and Australia away from Antarctica around 34 million years ago, opening the Drake Passage and the Tasman Gateway and allowing water to flow freely around the pole. That was the moment, the standard explanation held, that the current came into being and the planet began its long slide from a warm world with little permanent ice into the colder state we live in now, with permanent ice caps at both poles. It is a transition climate scientists call the move from a greenhouse to an icehouse climate.

A new study published in the Proceedings of the National Academy of Sciences by a team led by Hanna Knahl at the Alfred Wegener Institute in Germany suggests the standard explanation is incomplete. The opening of the sea gateways was necessary, but on its own, it was not enough to ignite the current.

Knahl and her colleagues ran detailed climate simulations using the geography of the Earth as it was roughly 33.5 million years ago, when Australia and South America were much closer to Antarctica than they are today. They coupled those simulations to a model of the early Antarctic ice sheet developed in a 2024 study. The results showed that even after the sea gateways had widened, the circumpolar current remained weak and incomplete, with strong flow developing in the Atlantic and Indian sectors while the Pacific sector stayed largely stagnant. The planet’s dominant ocean current had not yet come into being.

What eventually ignited it, according to the study, was wind. As Australia continued to drift north, the Tasman Gateway, the sea passage between Antarctica and Australia, eventually lined up with the band of westerly winds that still roar across the Southern Ocean today. Once those winds could blow directly through the gateway without obstruction, they drove the current into its modern, continuous loop, completing the ring around Antarctica. The continent’s thermal isolation deepened, carbon dioxide drawdown accelerated, and the planet cooled into the icehouse state that still defines the present climate system.

The atmospheric CO2 concentration at the time the current was forming was around 600 parts per million. That level has not been reached in the 34 million years since. Current concentrations are around 425 parts per million and rising. Under some projected emissions pathways, the 600 ppm figure could be exceeded before the end of this century.

Knahl urges caution about drawing direct parallels. “The climate of the past can of course not be projected one to one onto the future,” she said in a statement released with the study. The circumpolar current in its infancy, her team found, behaved differently from the mature current that exists today. What the study does make clear is that ocean circulation systems that feel permanent, that have shaped life on the planet for millions of years, depend on configurations of geography, wind, and temperature that are not guaranteed.

Quick Hits

A sleeper shark has been filmed in Antarctic waters for the first time. In January 2025, a camera deployed by the Minderoo-UWA Deep-Sea Research Centre captured footage of a southern sleeper shark cruising at around 500 metres depth off the South Shetland Islands, north of the Antarctic Peninsula. The water temperature was close to freezing. The footage, released in February and circulating again this week, was the first time any shark has been documented this far south. “There’s a general rule of thumb that you don’t get sharks in Antarctica,” said Alan Jamieson, the founding director of the research centre. “And it’s not even a little one either. It’s a hunk of a shark.” The specimen was estimated at between three and four metres in length. Scientists caution against immediately attributing the sighting to climate change. Antarctic waters are among the least studied on Earth, and research cameras operate only during the Southern Hemisphere summer, meaning that for roughly three quarters of the year, nobody is looking at all. The sharks may have been there all along.

An underwater mountain 4,200 metres tall has been mapped north of Palau. In September 2025, NOAA Ship Okeanos Explorer, working as part of the agency’s Beyond the Blue: Illuminating the Pacific campaign, used multibeam sonar to map a seamount roughly 250 miles north of Palau. The feature rises from the deep ocean floor at around 4,400 metres depth to a summit just 243 metres below the ocean surface, making it about half the height of Mount Everest. The seamount had been hinted at in nautical charts published in 2023, but the NOAA survey provided the first high-resolution picture of its shape. Scientists estimate there are more than 100,000 large seamounts on Earth. Less than one tenth of one per cent have been explored. Each one that gets mapped becomes a potential target for biological surveys, because seamounts tend to host dense concentrations of corals, sponges, and fish attracted to the hard substrate and accelerated currents their shapes create.

New Zealand is surrounded by some of the most energetic water on the planet. Tapping it is harder than it looks. Writing for The Conversation and RNZ, physical oceanographer Craig Stevens, who holds a joint position at Earth Sciences New Zealand (formerly NIWA) and the University of Auckland, lays out the country’s marine energy potential and the reasons so little of it has been harnessed. The west coast is swept by waves generated across the Southern Ocean. Cook Strait, between the North and South Islands, is one of the most energetic stretches of tidal water anywhere. Tidal energy globally now accounts for nearly two thirds of the non-wind ocean energy market, and the UK and France are planning 400 megawatts of new tidal stream infrastructure over the next decade. New Zealand, despite the resource, has yet to complete a single tidal energy project. The reasons, Stevens argues, are familiar: high upfront costs, limited economies of scale, cautious investors, and a history of schemes that over-promised what the technology of the day could deliver. A proposed tidal scheme in Kaipara Harbour, north of Auckland, was once billed as capable of powering 250,000 homes. It was never built.

Hard Truth From The Sea

Every ocean system in this week’s brief took millions of years to come into being. The currents that isolate Antarctica and warm Europe assembled themselves slowly, through the drift of continents and the alignment of winds, into states that have shaped life on the planet ever since. Sperm whales evolved into the deep-diving hunters they are today over a similar span of time, refining the sonar they use to find food in total darkness. Humans have managed, in roughly two centuries of industrial activity, to put measurable strain on all three. The relevant question is no longer whether we are changing the ocean. It is whether anyone with the power to act will move before the systems we depend on quietly stop working the way they always have.

Paid subscribers fund the reporting that tracks what is changing in the ocean and why. If you want accountability journalism on the systems we depend on and the institutions responsible for protecting them.

See you next week.

- Luke

Last week in New York, as negotiators gathered for the final preparatory meeting before the first Conference of the Parties to the High Seas Treaty, China arrived with a pitch. According to the Financial Times, which cited three people present at private meetings, China offered more than $70 million in funding for ocean protection, promised to be flexible on visas, and offered immunity to diplomats and assurances of access for campaigners attending future meetings in Xiamen. China’s foreign minister delivered a video message. Its UN ambassador told the room: “In a world of growing uncertainty, China will remain a steadfast pillar of multilateralism.”

The bid is for Xiamen to host the secretariat of the BBNJ (Biodiversity Beyond National Jurisdiction Agreement). This treaty entered into force in January 2026 after nearly two decades of negotiation. The secretariat is the institutional engine of the whole effort. It services the first marine protected areas on the high seas, houses the scientific body, and runs the clearing-house, a central database where countries submit information, through which they share data on marine genetic resources.

Marine genetic resources are biological materials found in ocean species, including deep-sea organisms such as microbes, sponges, and invertebrates, that can be used to develop pharmaceuticals, cosmetics, and industrial compounds. They are potentially worth billions, and until this treaty, entirely unregulated. The high seas are the ocean beyond any country’s exclusive economic zone, the area of ocean where it has sovereign rights over resources, roughly the outer 200 nautical miles from any coastline, covering about two-thirds of the world’s ocean surface. Until January this year, there was no legal framework to create protected areas there, no requirement for environmental impact assessments, and no rules on who profits from genetic resources found in the deep. The BBNJ Agreement changes that.

Whoever hosts the secretariat will shape how the treaty functions in practice. The vote between Xiamen, Chile’s Valparaiso, and Belgium’s Brussels will be taken by the 85 countries that have ratified the treaty as of April 2026, no later than January 2027.

China’s financial offer, if confirmed, is serious. Its institutional capacity is real. The argument about American retreat is not wrong. China co-chaired the COP15 meeting of the Convention on Biological Diversity, where the Kunming-Montreal framework, the global biodiversity agreement reached in Canada in 2022, which set the 30 by 30 target, was agreed. It has ratified the BBNJ agreement. It joined the Port State Measures Agreement, the principal international instrument targeting illegal fishing, in 2023, seven years after the agreement entered into force.

The fishing question

Between 2022 and 2024, vessels flagged to China conducted 44 per cent of the world’s visible fishing activity, according to an Oceana analysis of Global Fishing Watch satellite data. Chinese vessels accounted for 30 per cent of all fishing activity on the high seas specifically. The figures count apparent fishing effort based on vessel tracking signals and exclude vessels that switch off their tracking signals. The figures represent a lower bound on China’s true high seas presence. Independent analysts who have examined satellite tracking data have reached similar conclusions about the scale of China’s high seas presence. Oceana is an advocacy organisation, and these numbers deserve independent scrutiny.

China’s fleet has a larger documented stake in how those high seas zones are drawn than any other single flag state. It is now asking to draw them.

The Antarctic precedent

For six consecutive years, the CCAMLR (Commission for the Conservation of Antarctic Marine Living Resources), the international body responsible for protecting the Southern Ocean, failed to agree on new marine protected areas. Just two nations declined to support the proposals: China and Russia. Three protected areas, covering the East Antarctic, the Weddell Sea, and the Antarctic Peninsula, have been on the table for years, supported by the other commission members and described by independent scientists as grounded in the best available evidence.

The commission operates by consensus. There is no formal veto: any member declining to agree is enough to prevent adoption. Six consecutive years of declining, against the wishes of the other commission members, is the record.

Read more

Somewhere in the mid-Atlantic, a kilometre below the seafloor, hot rock is slowly splitting water molecules and releasing hydrogen. Microbial communities are feeding on it in the dark. Carbonate veins are trapping carbon dioxide in solid mineral form. None of this requires sunlight. None of it requires the surface world at all. Scientists pulled up 1,268 metres of that rock this and published what they found. It is the deepest continuous sample of Earth’s upper mantle ever recovered from the ocean floor.

That story sits alongside research showing that 21% of the global ocean has grown darker in the past two decades, and a governance fight at the United Nations that could determine whether the High Seas Treaty’s promise of marine protected areas survives first contact with the fishing industry. Three deep dives. Three quick hits. One hard truth from the sea

Deep Dives

One fifth of the ocean is getting darker.

Between 2003 and 2022, 21% of the global ocean became darker. Light penetrated less deeply into the water. The zone where sunlight reaches, called the photic zone, where roughly 90% of all marine life lives, shrank. In more than 9% of the ocean, an area larger than Africa, the photic zone contracted by more than 50 metres. In 2.6%, it contracted by more than 100 metres.

These findings come from a study published last year in Global Change Biology by researchers at the University of Plymouth and Plymouth Marine Laboratory, and resurfaced this week through a feature in New Scientist. The team used two decades of NASA satellite data and numerical modelling to track annual changes in photic zone depth across the entire planet.

The causes differ by location. In coastal areas, increased rainfall linked to climate change washes more sediment and nutrients from agricultural land into the sea. Those nutrients feed plankton blooms, which reduce the amount of light passing through the water. In the open ocean, the drivers are less clear. Scientists point to changes in plankton communities driven by rising sea surface temperatures, shifts in ocean circulation, and the increasing frequency of marine heatwaves that alter the conditions phytoplankton need to grow.

The most pronounced darkening appeared in three areas: the top of the Gulf Stream, the Arctic, and the Antarctic. All three are regions already experiencing the most severe effects of climate change.

The implications cascade through the food web. Phytoplankton, the microscopic plants that form the base of almost all marine food chains, need light to photosynthesise. Zooplankton, the tiny animals that eat phytoplankton, use light cues to time their daily vertical migration, the largest movement of biomass on the planet. Fish, seabirds, and marine mammals depend on that migration for food. Coral reefs depend on light for survival. If the lit zone compresses, animals that need light are pushed closer to the surface, where they must compete for food and space in a shrinking habitat.

“If the photic zone is reducing by around 50 metres in large swathes of the ocean, animals that need light will be forced closer to the surface,” said Professor Tim Smyth, head of science for marine biogeochemistry and observations at Plymouth Marine Laboratory. “That could bring about fundamental changes in the entire marine ecosystem.”

The picture is not entirely one-directional. Around 10% of the ocean, more than 37 million square kilometres, became lighter over the same period. The researchers are still investigating why. The overall trend, though, is toward a darker ocean, and the speed and scale of the change are what concern scientists most.

Scientists drilled a kilometre into the ocean floor.

Working from the research vessel JOIDES Resolution, an international team recovered a continuous 1,268-metre-long core of mantle rock from beneath the seafloor at the Atlantis Massif, a geological formation near the Mid-Atlantic Ridge. Published this week in Science, it is the deepest section of Earth’s upper mantle ever sampled directly from the ocean floor.

The mantle is the layer of hot rock between the Earth’s crust and its core. It holds roughly two thirds of the planet’s mass. Until now, scientists had to piece together what it looks like from fragments: ancient mantle rock pushed up onto land, bits carried to the surface by volcanic eruptions, or small samples dredged from fracture zones. Earlier attempts to drill into oceanic mantle barely passed 200 metres and recovered less than half the rock they cut. This core changes that. It provides a nearly complete column from the mantle melting zone up into the base of the oceanic crust.

Most of the rock is a type called peridotite, the dominant rock of the upper mantle, which had been transformed by a chemical reaction called serpentinisation. When seawater percolates down through cracks and meets the hot mantle rock, it reacts with the rock’s original minerals, converting them into new mineral forms. That reaction splits water molecules and releases molecular hydrogen.

That hydrogen is not just a chemical curiosity. Less than a kilometre from the drill site sits the Lost City hydrothermal field, where warm fluids rich in hydrogen, methane, and small organic molecules vent from tall white mineral chimneys and support dense microbial communities in total darkness. Lost City has long been considered a modern analogue for the kind of environment where life may have originated on early Earth, and possibly on ocean worlds like Jupiter’s moon Europa or Saturn’s moon Enceladus. The new core shows that the full depth of mantle beneath this field is heavily serpentinised and cut by multiple generations of mineral veins, supporting the idea that the energy source for these ecosystems is persistent and deep.

The core also revealed abundant carbonate veins threading through the rock, especially where the transformed mantle rock meets intrusions of a denser rock called gabbro. Those veins record carbon dioxide that has been locked away in solid mineral form rather than remaining in seawater or the atmosphere. Similar reactions in mantle rock are being studied as natural models for long-term carbon storage. At the same time, geologists are investigating hydrogen from serpentinisation as a potential source of clean energy. Natural hydrogen accumulations have been documented in several geological settings, and serpentinised mantle rock is one of the main generators.

There is a final twist. The record-breaking hole was drilled in 2023 during International Ocean Discovery Program Expedition 399, near the end of the JOIDES Resolution’s long career. The ship spent nearly four decades as the world’s primary scientific ocean drilling vessel, helping build much of what we know about plate tectonics, past climate, and deep biospheres. In 2024, the US National Science Foundation confirmed that funding for the ageing drillship would not be renewed. The vessel has now ended operations, with no direct replacement yet in the water. This core is both a scientific milestone and a farewell.

The fishing industry is trying to rewrite the High Seas Treaty before it has been used once.

Last week’s Deep Brief covered the High Seas Treaty’s third Preparatory Commission in New York. This week, as that meeting neared its close, a fight emerged over text that could determine whether the treaty can deliver on its central promise: creating marine protected areas on the high seas.

Regional Fisheries Management Organisations, the 17 bodies that already oversee fishing in international waters, proposed amendments to the draft text being prepared for the treaty’s first Conference of the Parties, the summit where member countries will set the rules for how the treaty works in practice. According to Greenpeace, which is tracking the negotiations, the proposed changes would give RFMOs additional powers to block or delay marine protected area proposals and would significantly restrict the treaty’s ability to deliver ocean protection measures.

The proposed text, documented in a UN negotiating document designated CRP6, goes beyond the existing Article 5 of the treaty, which already states that the agreement cannot undermine existing fisheries rules. The amendments would, in Greenpeace’s analysis, shore up RFMO supremacy and give fishing industry interests the ability to stall and derail conservation proposals.

“The organisations that have presided over decades of destruction on the high seas have made a completely unacceptable power-grab which would dramatically weaken the Treaty’s ability to protect the ocean,” said Megan Randles, Greenpeace’s head of delegation to the UN talks.

This matters because the treaty’s value depends almost entirely on whether it can establish marine protected areas that include meaningful restrictions on fishing. If RFMOs can block those proposals, or impose conditions that drain them of substance, the treaty becomes a legal framework without practical force.

The context here is important. RFMOs would argue they are protecting established management systems that have improved significantly in recent decades. Some have. Tuna RFMOs, for example, now manage 87% of assessed tuna stocks sustainably, according to the FAO’s most recent global assessment. The broader picture is less reassuring. A 2010 analysis cited by Dialogue Earth found that 67% of 48 assessed high seas fish stocks were depleted or overfished. High seas catches have risen by more than 400% since the 1950s. The treaty was designed, in part, to fill the governance gaps RFMOs left open. Giving them blocking power over the treaty’s most significant tool risks letting the institutions that oversaw decades of decline dictate the pace of reform.

PrepCom3 was scheduled to conclude on 2 April. The outcome of this text fight will shape everything that follows at the treaty’s first formal summit, now expected by January 2027.

Quick Hits

Zooplankton are pumping microplastics into the deep ocean. Copepods, tiny crustaceans that dominate zooplankton communities across the global ocean, ingest microplastics from the surrounding water, package them into faecal pellets, and sink them through the water column. A study published in the Journal of Hazardous Materials by researchers at Plymouth Marine Laboratory measured the process for the first time in real time and estimated that copepods in the western English Channel transport roughly 271 microplastic particles per cubic metre of seawater per day. With more than 125 trillion microplastic particles estimated to have accumulated in the ocean, even small per-animal contributions add up fast. “Copepods don’t just encounter microplastics,” said Professor Penelope Lindeque. “They are like mini biological pumps, processing and repackaging the microplastics into their faeces, which sink through the water column and accumulate in underlying sediment.”

Forty-year-old canned salmon is telling scientists the ocean may be recovering. Researchers at the University of Washington opened 178 cans of salmon spanning four decades from the Gulf of Alaska and Bristol Bay, counted the parasitic worms embedded in the flesh, and found that levels of anisakids, a common marine roundworm, rose in pink and chum salmon over the study period. That sounds like bad news. It is not. Anisakids need multiple hosts to complete their life cycle, including marine mammals. Rising parasite numbers suggest the food web is intact and that marine mammal populations, protected since the Marine Mammal Protection Act of 1972, have recovered enough to sustain the parasites’ reproduction. The study, published in Ecology and Evolution in 2024, resurfaced this week. “Everyone assumes that worms in your salmon is a sign that things have gone awry,” said Chelsea Wood, a University of Washington fishery scientist. “I see their presence as a signal that the fish on your plate came from a healthy ecosystem.”

The EU has launched its European Ocean Board. Twenty-eight members from trade associations, academia, research institutes, NGOs, and youth organisations met for the first time on 31 March to begin implementing the European Ocean Pact, the EU’s strategy for ocean protection, blue economy, and coastal community support adopted in June 2025. The board is chaired by Costas Kadis, Commissioner for fisheries and oceans. It will advise the European Commission on ocean health, economic competitiveness, maritime security, and international ocean governance. The creation of the board signals that the EU intends its ocean strategy to have teeth beyond the document. Whether it delivers depends on what the board actually recommends and whether the Commission acts on it.

Hard Truth From The Sea

The ocean is getting darker. One fifth of its lit zone has contracted in twenty years. The rock beneath the seafloor is producing hydrogen and trapping carbon in processes that have run for hundreds of thousands of years without human involvement. The fishing industry is attempting to rewrite a treaty designed to constrain it before that treaty has been used once. Each of these stories describes the same tension: the ocean has systems that work. The question is whether the institutions humans have built to manage it will let them.

Paid subscribers fund the reporting that tracks what is changing in the ocean and why. If you want accountability journalism on the systems we depend on and the institutions responsible for protecting them, please do consider upggrading your subscription.

Subscribe now

See you next week.

- Luke

This chapter didn’t make it into Finlay and the Whale, my forthcoming book about the ocean’s collapse and the systems keeping it that way. The first draft is nearly done. Then comes the search for a publisher. Some of the ideas I cut feel worth sharing on their own terms, and this one has been sitting in a folder long enough.

Imagine it is 1995. Your neighbour pulls into the driveway in a brand-new BMW. The street glances over… admiration, envy, maybe a flicker of pride that one of their own is doing well. The walls are thin, and an hour later you can hear the argument through the plaster. The car was never the whole story.

Fast forward. The walls are thicker, but the windows have been torn off. You see the driveway moment on repeat. The new car, the luxury holiday, the kitchen refit. The arguments and the sleepless nights are cut out. The curation is the point. The image is spotless because the mess has been edited away.

We compare our insides with other people’s outsides. Their gloss becomes our deficit. Every scroll is a prompt telling you that you are behind, you need more.

Your brain is not weak. It is being farmed.

***

In 2014, a film called The Gambler slipped under the radar. Critics were mixed, but buried inside its plot about a debt-ridden literature professor was, in my humble opinion, one of the sharpest monologues on freedom ever put to screen. A loan shark explains life’s real equation:

“You get a house with a 25-year roof, an indestructible economy shitbox car and you put the rest into the system at 3 to 5 percent... That’s your fortress of fucking solitude. That puts you, for the rest of your life, at a level of ‘Fuck You.’ Someone wants you to do something? Fuck You. Boss pisses you off? Fuck You.”

Crude, but also clarifying. The fortress has nothing to do with luxury. It is the ability to live without begging forgiveness from banks, bosses, or anyone else.

When I bought my 16-year-old Volvo, some people mocked it. No sat nav. No CarPlay. A CD player instead of Bluetooth. Dented doors, mismatched wheels, 130,000 miles already on the clock. My friends Dave and Alex, old-car people, gave me kudos. They saw what others missed: no payments, low insurance, cheap to run, a boot big enough for baby stuff, seats that fold flat if you need to sleep in the back on a camping trip.

It is creeping towards 200,000 miles now and still going. Every ignition is relief, not anxiety.

That is the fortress. That is what it feels like.

***

The logic of comparison is ancient and obvious. Humans are status animals. In every tribe and city, knowing where you ranked mattered for survival. Status brought resources, mates, security. That wiring has not gone anywhere.

What has changed is the scale. For most of human history, you measured yourself against a few dozen people you actually knew. Now you measure yourself against thousands of curated feeds, each one engineered to widen the gap.

Then the system offers to close it. Miss a payment? Spread it over four months. Want the new look? Pay later, no questions. They call it flexibility. It is absolution with interest.

The engineers of social platforms know this. They do not just sell ad space. They sell identity loops. Envy, desire, click, defer the cost. Buy now, pay later is a business model built on the distance between who you are and who the feed tells you to be.

The cost lands somewhere real. Outstanding credit card debt in the UK hit £76 billion in 2025. One in four British adults used a buy now, pay later service at least once last year, up from one in seven the year before. The financial regulator looked at what they were buying. The most common answer: lifestyle and beauty purchases. Globally, buy now, pay later spending has gone from $2 billion a decade ago to $342 billion today. Plastic surgeons worldwide performed more than 33 million procedures in 2022 alone, a 41 per cent increase over four years.

The system built a machine to monetise the gap. Then it built another one to finance closing it.

***

Escaping the loop is slow work. Praise the thing that lasted rather than the thing that is new. Post the ordinary dinner instead of the filtered highlight. Before you buy something, ask whether it makes your daily life better or just looks good for a moment. That pause, practised enough, becomes a muscle.

The loop survives because it is invisible, has momentum, and has been normalised. Name it, and it starts to wobble.

***

Ego rarely stays contained. What begins as envy becomes something harder when the scales tilt too far. The neighbour who flashes the BMW is one thing. The executive collecting bonuses after a bailout is another. We do not just measure ourselves against others. We measure whether others are playing fair. When the gap feels rigged, something ancient stirs.

That is where the next loop begins.

The book isn't out yet. It might not find a publisher on the first try. That's how this works. If you want occasional chapters when they're ready, before anyone else sees them, go annual. If you just want the journalism, a paid subscription gets you everything we publish. Either way: I'd like to know what you think about this chapter. Leave a comment below.

In a conference room at United Nations headquarters in New York this week, diplomats from more than 85 countries sat down to decide how the world’s first treaty for protecting the high seas will actually work. Outside, the rules-based international order the treaty depends on is under sustained attack. Inside, delegates debated committee structures, funding mechanisms, and decision-making procedures. The treaty is now law. The institutions to enforce it do not yet exist.

That meeting sits alongside a study revealing how the ocean seafloor processes carbon on a planetary scale, and research turning sea turtle shells into decades-long records of environmental stress. Three deep dives. Three quick hits. One hard truth from the sea.

Deep Dives

The high seas treaty is now law. Making it work is another matter entirely.

The High Seas Treaty, formally the Agreement on the Conservation and Sustainable Use of Marine Biological Diversity of Areas Beyond National Jurisdiction, entered into force on 17 January 2026. It took nearly 20 years to negotiate. It covers two thirds of the ocean, the vast expanse beyond any country’s exclusive economic zone, the 200-nautical-mile strip of sea that coastal nations control, where no single government has jurisdiction. For the first time, it provides a legal route for creating marine protected areas in international waters, requires environmental impact assessments for activities that could harm marine life, and establishes rules for sharing the benefits of marine genetic resources, the biological material from ocean organisms that can be used in pharmaceuticals, cosmetics, and other industries.

More than 85 countries have ratified it. The United States signed in September 2023 but has not ratified. President Biden transmitted the treaty to the Senate in December 2024, where it has not progressed. The current administration has not signalled intent to pursue ratification.

This week, the third and final Preparatory Commission is meeting in New York from 23 March to 2 April to hammer out the institutional architecture before the treaty’s first Conference of the Parties. That summit, where member countries will make binding decisions on how the treaty operates, must take place by January 2027. The agenda is procedural: rules of procedure, the structure of a scientific and technical body, the design of a central platform for sharing scientific data and technical support, and the governance of the treaty’s financial instruments.

Three funds sit at the centre of the financial architecture. One relies on voluntary donations to support developing country representatives attending meetings. A second is managed by the Global Environment Facility, an existing multilateral fund. A third “special fund” will draw mandatory contributions from developed countries, set at 50 per cent of their share of the treaty’s budget, alongside potential revenue from marine genetic resources and additional public and private donations. These financial obligations are now legally binding for ratifying states. The money is committed. It cannot flow until the fund’s governance, banking arrangements, and access procedures are established.

The practical challenges start with fishing. A clause in the treaty states it cannot undermine existing laws and organisations or override existing fisheries rules. Seventeen regional fisheries management organisations already oversee fishing across the high seas. Only in unregulated gaps will the treaty have clear authority to shape fishing rules. According to Dialogue Earth, citing FAO data, only about 5 per cent of global high seas fish catch comes from areas with no existing oversight. For everything else, the treaty must negotiate with existing bodies.

Then there is the question of how the treaty interacts with the International Seabed Authority, which governs deep-sea mining. Both bodies are developing environmental impact assessment frameworks. Countries that are parties to both instruments will need to ensure consistency between the two regimes. Any gaps between them could weaken protections rather than strengthen them.

Three countries are competing to host the treaty’s permanent secretariat: Belgium, Chile, and China. China’s bid for the city of Xiamen is particularly notable. Li Shuo, who directs the Asia Society Policy Institute’s China Climate Hub, described it as a significant escalation in China’s engagement with global governance, drawing parallels with Beijing hosting the UN biodiversity summit during the first Trump administration. Lynda Goldsworthy, a researcher on high seas and Antarctic governance at the University of Tasmania, told Dialogue Earth the bid was intriguing but raised concerns, given China’s reluctance to support marine protected areas in the Antarctic high seas.

Experts estimate it could take three years or more before the first marine protected area is established under the treaty. Conservation groups have already identified candidate sites, including the waters covering the Salas y Gomez and Nazca ridges off Chile and Peru, home to scores of endangered species. The distance between identifying a site and establishing legal protection is where treaties either deliver or quietly become irrelevant.

The ocean floor is processing carbon on a scale we could not measure until now.

A study published this week by researchers at the University of Manchester provides the first global-scale predictions of how dissolved organic carbon moves between seawater and marine sediments. Until now, this process was too computationally demanding to model at a planetary scale. The team, led by Dr Peyman Babakhani, solved the problem by training artificial intelligence to reproduce the behaviour of an existing computer model, one that simulates the physical and chemical processes of carbon cycling in ocean sediments. Once trained, the AI could be applied globally.

Dissolved organic carbon is the mix of natural chemicals floating in seawater. When it reaches the seafloor, some of it is absorbed by minerals in the sediment, some is returned to the water column, the full depth of water between the surface and the seafloor, and some is buried. These processes influence how much carbon the ocean stores over long timescales and how much cycles back into the water.

The study, published in *The Innovation*, found that 11 per cent of the particulate organic carbon, the tiny particles of organic matter that sink from the surface, arriving at the seafloor is returned to seawater as dissolved organic carbon. Twenty-four per cent is absorbed onto minerals. Most strikingly, the model predicts that about half of all the solid organic carbon locked in the upper metre of marine sediments got there not as sinking particles from the surface but as dissolved carbon that was absorbed onto minerals on the seafloor. That changes the picture of carbon storage in the deep ocean. It suggests that the interaction between dissolved carbon and mineral surfaces is a larger part of the ocean’s long-term carbon budget than previously recognised.

The methodological finding was almost as interesting as the science. The researchers tested several types of AI, from complex deep learning systems to simple algorithms. The simplest ones were the most accurate. Every time they made the AI more complex, the predictions got worse. That rarely happens in AI development. The old principle that simpler solutions tend to be better usually goes untested.

The framework can now be integrated into the large-scale computer models scientists use to simulate how the ocean and atmosphere work, allowing them to test how marine carbon reservoirs might respond to environmental change in the coming decades.

Sea turtle shells are recording decades of ocean stress. Scientists just learned how to read them.

Sea turtles grow continuously throughout their lives. As they do, their shells grow with them, laying down new tissue in layers. The oldest layers sit on the outside, the newest on the inside. Each layer incorporates chemicals from the surrounding water as it forms, creating a record of environmental conditions at the time.

Scientists have known this for years. The problem was that they could not tell how much time each layer represented. A seven-layer sample might cover seven months or seven years.

A study published this week in *Marine Biology*, led by Bethan Linscott at the University of Miami, solved that problem by borrowing a technique from archaeology. Linscott and her colleagues took shell samples from 24 stranded sea turtles, loggerheads and green turtles collected along the Florida coast between 2019 and 2022. They sliced the samples into sections one twentieth of a millimetre thick and dated each layer using radiocarbon, a naturally occurring form of carbon that decays at a known rate. They calibrated the measurements against the mid-20th century “bomb pulse”, a spike in radiocarbon from nuclear weapons testing that serves as a reference point in the marine environment. Using a statistical method normally applied to date sediment samples in archaeology, they calculated that each layer represents an average time span of seven to nine months.

With a reliable timeline, the researchers could compare the growth records of different turtles. They found periods when all the animals grew more slowly. Those slowdowns lined up with major environmental disturbances in Florida waters: harmful algal blooms known as red tides, and disruptive accumulations of Sargassum seaweed.

The implications go beyond turtles. If shell layers can be reliably dated, every stranded turtle becomes a potential record of environmental conditions stretching back years or decades. Scientists can match changes in foraging patterns and diet with specific environmental events, building a record of how marine ecosystems respond to climate change, pollution, and habitat degradation over time.

“The shells are effectively recording environmental stress in the ocean,” Linscott said.

Quick Hits

Every land animal on Earth descends from the ocean. A study in Nature mapped the genetics of how they got out. Researchers at the University of Bristol and the University of Barcelona compared 154 genomes across 21 animal groups to reconstruct the genetic changes behind 11 separate transitions from water to land over the past 487 million years. The transitions happened in three major waves. Arthropods went first. Land snails came last. The most revealing finding was convergence: separate evolutionary lineages, the family trees of entirely different animal groups, that had been separated for more than 500 million years independently evolved similar genetic solutions to the same problems, particularly managing water and salt balance, the fundamental challenge of life outside the ocean. Semi-terrestrial species, the small invertebrates that still depend on moist soil, shared the most adaptations. Fully terrestrial lineages like insects and vertebrates took more divergent paths, each evolving its own innovations. The study was published in Nature in November 2025 and resurfaced this week through The Conversation.

Ocean species are vanishing before scientists can identify them. An international team led by the University of Göttingen and the Leibniz Institute for Biodiversity Change Analysis has launched EuroWorm, a project to build the first comprehensive open-access genomic database of European marine annelids, the segmented worms found across nearly all ocean environments. These animals mix sediments, recycle nutrients, indicate pollution levels, and support marine food webs. The project will collect specimens from European locations where many species were originally described, identify them by physical form, photograph them at high resolution, and analyse them using advanced genomic tools. The database will be freely accessible worldwide, with the explicit goal of accelerating species discovery before extinction outpaces science. “We hope to accelerate the discovery of new species and biodiversity research worldwide, and thus counteract the ‘silent extinction’ of marine species,” said project leader Dr Jenna Moore.

An Arctic blast turned the Gulf of Mexico bright blue. In late January and early February, two winter storms drove Arctic air across Florida, dropping temperatures below freezing in parts of the state and chilling the shallow waters off the west coast. As the ocean cooled, denser cold water flowed offshore, stirring up calcium carbonate mud, the accumulated remains of marine organisms, from the West Florida Shelf. NASA satellites captured the transformation: deep azure waters turned a vivid pale blue across a wide area. Landsat 9 imagery revealed “hammerhead” eddies along the shelf slope, curling patterns formed as narrow streams of cold, sediment-laden water met the slower-flowing Gulf. The same fluid dynamics appear in dust storms on Mars. The event is not only visually striking. Carbonate sediment suspensions affect the ocean’s carbon cycle. These resuspension events usually happen during hurricanes. Scientists know far less about how winter cold fronts produce similar effects, and the difference matters for understanding local carbon sequestration, the process by which carbon gets locked into deep ocean storage.

Hard Truth From The Sea

This week, delegates in New York debated the procedural architecture of a treaty designed to protect two thirds of the ocean. They discussed committee structures and funding mechanisms while the multilateral system the treaty depends on faces its most serious challenge in decades. The treaty exists because more than 85 countries agreed it was necessary. Whether it delivers depends on whether that consensus survives contact with the institutions, competing interests, and geopolitical realities that have historically made high seas governance a promise rather than a practice.

Paid subscribers fund the reporting that tracks what is changing in the ocean and why. If you want accountability journalism on the systems we depend on and the institutions responsible for protecting them.

See you next week.

- Luke

It’s Sunday afternoon and I’m trying to make sense of my feed.

Climate change, again. Comments sections turning into trenches. People lobbing data at each other like it’s ammunition. Nobody listening. Everyone certain.

I’ve seen this film before, but something struck me differently this time.

It wasn’t the arguments. It was the certainty on both sides and what that certainty is actually costing us.

Here’s where I land on the science: climate change is real, it’s human-driven, and the evidence for that is substantial. I’m not hedging on that. But I want to talk to the other side for a moment, not to convert anyone, because that ship has clearly sailed, but to ask a simpler question.

Where’s your insurance policy?

Not a metaphor. An actual logical question. Because here’s the thing about insurance: you don’t buy it because you’re certain your house will burn down. You buy it because you can’t afford to be wrong.

Run the numbers on climate change the same way.

If the sceptics are right, if this is all overblown, if the models are wrong, if the scientists are mistaken, and we transition away from fossil fuels anyway... what happens? Energy gets more expensive for a while. Some industries restructure. Some politicians lose votes. It’s painful and disruptive and expensive.

But if the sceptics are wrong, and we do nothing, the cost isn’t inconvenience. It’s civilisational.

That asymmetry matters. It’s the whole game.

I’m not asking climate sceptics to accept the science. I’m asking them to apply the same logic they’d use buying car insurance or hedging a business risk. You don’t need certainty to justify precaution. You just need to take the downside seriously.

Here’s what makes this stranger still. The countries most economically dependent on fossil fuels, the ones with the most to lose from a global energy transition, are already hedging. Saudi Arabia has spent the last decade building out tourism, finance, and technology investment through Vision 2030. The UAE is positioning itself as a hub for everything that isn’t oil. These are not the actions of governments confident that the current model lasts forever. They are reading the same future the climate scientists are reading, and quietly buying the insurance policy, while their exports fund the politicians loudest about drilling more of it.

The noise is coming from one place. The hedging is happening somewhere else entirely.

What’s strange, what I keep coming back to as I watch these arguments play out, is that the certainty is loudest on the side with the most to lose if they’re wrong.

I don’t know why that is. Maybe it’s tribal. Maybe it’s economic. Maybe admitting doubt feels like surrender in a culture where everything has become a team sport.

The fact is, however, the house doesn’t care which team you’re on.

Every year for at least four decades, the ocean off Panama’s Pacific coast inhaled. Cold, nutrient-rich water rose from the deep, feeding the food web and cooling coral reefs. In 2025, for the first time on record, the breath did not come. The water stayed warm. The nutrients never arrived. A rhythm that coastal communities had depended on for generations simply stopped.

That finding, documented in a study published last year in the Proceedings of the National Academy of Sciences and resurfacing this week as scientists track whether the 2026 season recovers, is one of four stories shaping this week’s Deep Brief.

Alongside it: a 3-million-year ocean temperature record extracted from Antarctic ice, a chemical pollution study revealing how thoroughly humans have altered the ocean’s chemistry, and the oldest whale song ever recorded, a humpback singing into an ocean that was ten times quieter than it is today.

Three deep dives. Three quick hits. One hard truth from the sea.

Deep Dives

The ocean off Panama stopped breathing

Every dry season, strong seasonal winds called trade winds sweep from the north across Central America and into the Gulf of Panama. Those winds push warm surface water aside, allowing cold, nutrient-loaded water from the deep to rise and take its place. Scientists call this process upwelling. It is the foundation of the region’s marine food web. The nutrients feed phytoplankton, the tiny drifting plants at the base of the food chain, and that productivity cascades upward through fish, seabirds, and the coastal communities that depend on them. The same cold water gives nearby coral reefs a seasonal break from heat stress.

In 2025, this did not happen.

A study published last year in the Proceedings of the National Academy of Sciences, led by Aaron O’Dea at the Smithsonian Tropical Research Institute, documented that for the first time in at least 40 years of records, the seasonal upwelling in the Gulf of Panama failed completely. The story resurfaced this week as scientists tracking the 2026 season report that upwelling has returned, raising the question of whether 2025 was a one-off shock or a warning of what comes next. The expected temperature drop, which had arrived by 20 January in every previous year, did not begin until 4 March. When it did arrive, it lasted 12 days instead of the usual two months, and the water never reached the colder temperatures recorded in previous years.

The cause was not a lack of cold water at depth. It was there, waiting. The problem was atmospheric: the trade winds that normally drive the upwelling formed far less frequently than usual. When they did blow, they were roughly as strong as in past years, but the calm periods between them lengthened, and the total wind over the season was not enough to start the process.

The biological consequences were immediate. Phytoplankton production declined sharply. Satellite observations confirmed extremely low chlorophyll concentrations, a direct measure of plant life in the water, across the Gulf during a period when biological productivity normally peaks. Fish species that depend on the seasonal nutrient surge, including sardines, mackerel, and squid, lost their food source. Coastal fishing communities lost their catch.

“The tropical Panamanian sea has lost its vital breath,” O’Dea said.

Researchers aboard the S/Y Eugen Seibold, a sailing research vessel operated jointly by the Smithsonian and the Max Planck Institute for Chemistry, confirmed from direct measurements that the water column remained layered with warm water on top, with none of the vertical mixing that defines upwelling. “If our oceanographic mission had not taken place, no one would have known the upwelling had stopped,” said researcher Hanno Slagter.

That observation matters beyond Panama. Tropical upwelling systems are poorly monitored compared to their counterparts off California and Peru, which have long-standing observation networks. Similar failures in other poorly instrumented tropical regions could go entirely undetected. The O’Dea Lab’s public monitoring page shows the 2026 season has so far returned to strong cooling, with trade winds arriving and surface temperatures dropping to 16°C in parts of the Gulf by early February. That return suggests 2025 may have been an anomaly rather than a permanent shift. Whether this was a one-off shock or the beginning of an intermittent pattern is the question scientists are now tracking week by week.

Three million years of ocean temperature, read from bubbles in Antarctic ice

A study published this week in Nature presents the first direct record of average ocean temperature spanning the past 3 million years, extracted from ancient ice recovered in the Allan Hills blue ice area of Antarctica.

Here is how they did it. When snow falls and compresses into ice, it traps tiny bubbles of air. Noble gases like xenon and krypton do not react chemically with anything, so they faithfully record the conditions when they were trapped. The ratio of these gases in the bubbles reflects the temperature of the ocean at the time, because the ocean and atmosphere exchange them at rates that depend on water temperature. By comparing the amounts of xenon and krypton in ice cores of known age, scientists can reconstruct what the ocean’s average temperature was millions of years ago.

The record shows two significant findings. First, the ocean cooled sharply around 2.7 million years ago, during a period when ice sheets first formed over the Northern Hemisphere. Second, and more puzzling, a companion study published alongside it in the same issue of Nature found that atmospheric carbon dioxide levels remained largely stable during this cooling, hovering below 300 parts per million for most of the past 3 million years. That means the long-term cooling of the planet was driven by something other than a straightforward decline in greenhouse gases, likely changes in how the ocean circulates and distributes heat between the surface and the deep.

Current atmospheric CO₂ exceeds 425 parts per million, a level not seen in at least 3 million years. The ocean’s temperature is now climbing, not falling. The ice core record shows what stable ocean conditions looked like across geological time. We have left those conditions behind, and the rate of change is hundreds to thousands of times faster than anything in the record.

The ocean’s chemistry has a human fingerprint everywhere scientists look

A study published this week in Nature Geoscience examined more than 2,300 seawater samples collected between 2017 and 2022, making it one of the most comprehensive chemical analyses of the marine environment to date. Led by researchers at the University of California, Riverside, with contributions from the Scripps Institution of Oceanography, the work catalogued industrial compounds that are rarely included in routine monitoring.

Plastic additives. Synthetic fragrances. Pharmaceuticals. Pesticides. The researchers found human-made chemicals across the ocean, from coastal waters to more than 20 kilometres offshore. In coastal zones, these compounds made up a substantial fraction of the dissolved organic matter, the mix of natural chemicals floating in seawater. Even far from shore, human-derived chemicals accounted for roughly 1 per cent of detected organic matter. At a global scale, that is a very large amount of material.

Some of the compounds sit at the boundary between traditional chemical molecules and nanoplastics, the smallest fragments of plastic pollution, blurring the line between chemical contamination and plastic contamination. The researchers suggest these chemicals may play an unrecognised role in the ocean’s carbon cycle and ecosystem functioning.

“The human footprint is in everything,” said Lihini Aluwihare, a chemical oceanographer at Scripps and co-author of the study. “What determines whether you find it is whether you look for it in your data.”

The implications are straightforward. The ocean’s chemistry is no longer purely natural. The question is no longer whether human-made chemicals are present in the marine environment. It is what they are doing there, how they interact with marine life, and whether the monitoring systems designed to protect ocean health are looking for the right things.

Quick Hits

The oldest whale song ever recorded. Researchers at the Woods Hole Oceanographic Institution discovered a recording of a humpback whale singing off the coast of Bermuda in March 1949, preserved on a plastic disc from a 1940s dictation machine called a Gray Audograph. It is the oldest known recording of whale song, predating the discovery of whale song as a scientific phenomenon by nearly 20 years. The recording is significant not only for what the whale is doing, but for what the ocean sounds like around it. The ocean of the late 1940s was far quieter than today’s. Some parts of the ocean are now ten times louder than they were in the 1960s, largely due to shipping. The recording provides a baseline for understanding how increasing noise may be changing the way whales communicate. “Scientists are going to listen to these recordings and make discoveries that I can’t even begin to imagine yet,” said Ashley Jester, who found the disc while digitising old recordings.

Second ScotWind lease cancelled. Ocean Winds, an offshore wind developer backed by two European energy companies, is terminating the lease option, the agreement that gave it the right to build on the site, for the 500-megawatt (MW) Arven South floating wind project off the Shetland Islands. The developer cited no viable grid connection, the high fees charged for connecting to the electricity grid in northern Scotland, and requests from local and national fishing industry representatives to consolidate away from the site. Ocean Winds is pressing ahead with the larger 1,800 MW Arven North complex nearby, planning to develop it incrementally as floating wind technology matures. Arven South is the second ScotWind lease to be handed back after Shell returned the 2 GW CampionWind site last year. Two of 20 ScotWind projects have now been cancelled. The pattern raises questions about whether the ScotWind round, once billed as a transformational moment for Scottish offshore wind, can deliver at the scale originally promised when projects that were supposed to build it are being handed back.

Ocean heat content set another record in 2025. Global upper ocean heat content increased again last year, continuing a trend that has accelerated since the mid-2000s. The ocean absorbed an additional 23 zettajoules of heat compared to 2024. For scale, the entire United States uses roughly one tenth of a zettajoule of energy in a year. The ocean absorbed more than 200 times that amount, according to analysis published in Advances in Atmospheric Sciences. About a third of the global ocean ranked among its three warmest years on record, with particularly intense warming in the tropical and South Atlantic, Mediterranean, North Indian, and Southern Oceans. The ocean stores more than 90 per cent of the excess heat from human-caused greenhouse gas emissions. This record sits alongside the 3-million-year ice core reconstruction covered above: CO₂ has not been this high in at least 3 million years, and the ocean is absorbing the consequences.

Hard Truth From The Sea

For 40 years, the ocean off Panama breathed on schedule. In 2025, it didn’t. For 3 million years, atmospheric CO₂ stayed below 300 parts per million. It is now above 425. For as long as we have measured the ocean’s chemistry, we assumed the organic matter dissolved in seawater was natural. It is not.

Each of these findings describes the same thing from a different angle: the ocean is no longer operating within the conditions it maintained before we changed them. The rhythms are breaking. The chemistry is altered. The heat is accumulating. The records, whether they span 40 years or 3 million, all point in the same direction.

Paid subscribers fund the reporting that tracks what is changing in the ocean and why. If you want accountability journalism on the systems we depend on and the institutions responsible for protecting them, please consider upgrading your subscription today.

Subscribe now

See you next week.

- Luke

There is a toy that most people encounter in childhood. A gyroscope: a spinning disc mounted inside a frame, which resists any attempt to push it over. Press it sideways and it doesn’t fall. It pivots at a right angle to the force, tracing a slow, stubborn circle. The harder you push, the stranger the behaviour.

Takahito Iida, a naval engineer at the University of Osaka, has spent serious time thinking about what happens when you put one of those on the ocean.

His answer, published in the Journal of Fluid Mechanics in February, is that you can extract electricity from waves by mounting a spinning flywheel inside a floating platform and tuning it to respond to the pitch and roll of passing water. As waves push the platform, the flywheel’s axis shifts. That shift is called gyroscopic precession: the same force that keeps a spinning top from falling over. It drives a generator. The electricity follows.

Gyroscopic wave energy converters have been proposed before. What Iida’s analysis adds is mathematical precision: a framework that identifies the exact conditions under which one of these devices reaches its theoretical maximum efficiency. That maximum is 50%. Half the energy in any given wave, converted to electricity.

The 50% figure needs unpacking, because it’s easy to misread. This is not a ceiling Iida discovered. It is a long-established constraint in wave energy physics, analogous to the Betz limit in wind turbines. The Betz limit establishes that no turbine can extract more than around 59% of the energy in moving air, regardless of its design. Every technology has a theoretical ceiling it can approach but never pass. What Iida demonstrated is that a properly tuned gyroscopic converter can reach its equivalent wave energy ceiling not just at one specific wave frequency, as previous work assumed, but across a wide range of conditions. The ocean rarely delivers the consistent, predictable wave patterns that most converter designs rely on. A device that performs well only in one set of conditions is commercially useless. Iida’s modelling suggests this one doesn’t have to be.

A wave tank prototype is now being built to test whether the physics holds in water.

Why wave energy keeps losing to solar

In 2024, global renewable energy capacity grew by a record 585 gigawatts, according to the International Renewable Energy Agency. A gigawatt is roughly the output of a large power station. Solar accounted for more than three-quarters of that growth. Wind took most of the rest.

Wave energy contributed, in practical terms, nothing. IRENA’s annual capacity statistics track ocean energy as a category but do not report wave energy as a separate figure, because the global total is too small to distinguish from rounding. The International Energy Agency, in its most recent renewables outlook, noted that the role of ocean energy “is expected to decline due to a lack of policy support.”

Not because the resource isn’t there. The US Department of Energy estimates that wave energy available along American coastlines alone equals roughly 34% of the country’s total power generation. Globally, the theoretical resource is vast, consistent, and, unlike solar, continues through the night.

The problem has never been the resource. It has been converting it at a cost that makes commercial sense.

Wave energy’s commercial history is a series of promising devices that collapsed on contact with the real ocean. Scotland’s Pelamis project, once the leading edge of the technology, went into administration in 2014. Carnegie Clean Energy in Australia underwent repeated restructurings after its wave energy programme failed to reach commercial viability. The pattern is consistent: machinery placed in one of the world’s most corrosive and mechanically demanding environments, expensive to install and maintain, producing power in ways that electricity grid operators struggle to plan around. The resource is enormous. The economics have not worked.

The gap between research money and real money

The US government has committed more than any other institution to closing that gap. In September 2024, the Department of Energy’s Water Power Technologies Office announced a funding opportunity of up to $112.5 million over five years for open-water testing of wave energy converters, covering small-scale distributed devices, community power systems, and large utility-scale projects.

That is significant money by the standards of this sector. It is also research and development funding, not project finance. The distinction matters. Research grants pay for prototypes and testing. Project finance pays for construction at scale, and it comes from investors who need a predictable return. Wave energy has attracted the first kind of money. It has not yet attracted the second in any meaningful volume.

Offshore wind, by contrast, now has mature supply chains, standard contracts, and a track record long enough for large institutional investors such as pension funds to price the risk confidently. Wave energy is several stages of commercial development behind that. Private capital tends to wait until it doesn’t have to be first.

The IEA’s forecast is blunt: without a significant shift in policy support, ocean energy’s share of global capacity is likely to shrink, not grow, over the coming decade.

Where ships change the calculation

Iida is not framing his device as a rival to offshore wind. His stated target application is auxiliary power for ships: specifically, a 300-kilowatt output based on the energy demands of a typical commercial vessel. Auxiliary power means the electricity a ship uses to run its lights, navigation systems, refrigeration, and crew facilities, separate from the engines that move it through the water. The device is designed to operate without being fixed to the seabed, floating freely, which makes it suited to ships rather than fixed coastal installations.

That framing matters because it puts the gyroscopic converter into a different commercial conversation, and a more pressured one.

In April 2025, the International Maritime Organization’s Marine Environment Protection Committee approved the IMO Net-Zero Framework, described by the IMO itself as “the first in the world to combine mandatory emissions limits and GHG pricing across an entire industry sector.” GHG stands for greenhouse gas. The framework sets targets for how much greenhouse gas large ocean-going ships over 5,000 gross tonnage are allowed to emit per unit of energy used. These ships account for around 85% of the sector’s total emissions. Ships exceeding the thresholds face financial penalties. The net-zero target for the sector is by or around 2050.

Formal adoption was expected in October 2025 but was adjourned by a year after the US opposed the measures and several major shipping nations changed their votes. The framework is now expected to be adopted in October 2026 at the earliest, with compliance beginning in 2028 if that timeline holds. The direction of travel is not seriously in doubt. The underlying 2023 greenhouse gas strategy remains in force regardless of the framework’s adoption status, and the IMO has confirmed that work on implementation continues in the interim. The question is not whether shipowners will face binding obligations to cut emissions, but when those obligations take full legal effect.

Every technology that reduces fuel consumption has a potential role in meeting that requirement. A device that generates 300 kilowatts from wave motion, without burning fuel and without connecting to any shore-based grid, sits directly in that commercial space.

Wave energy’s problem has never been the resource. It has been finding a customer with a deadline. Maritime decarbonisation, with binding regulatory obligations and financial penalties for non-compliance, is one of the more credible candidates. It does not solve wave energy’s cost and durability problems. It does make those problems worth solving for a defined market.

What still has to hold

Iida is careful about what his paper does and doesn’t claim. The modelling was conducted under linear wave theory, an approach that works well for small, regular waves but simplifies the behaviour of real seas, where waves arrive from multiple directions at irregular intervals and varying heights. His own analysis shows efficiency degrading in larger, irregular wave conditions: not failing, but not reaching the theoretical ceiling either.

The cost of keeping the flywheel spinning, what engineers call parasitic load, is not yet accounted for in the efficiency calculations. That matters enormously. A device that theoretically captures half of available wave energy but consumes a significant portion of that output just keeping its flywheel spinning is not commercially interesting. This is a known open question, not a resolved one.

The maintenance economics also have to work. This is where previous wave energy technologies have most consistently broken down: not in laboratory conditions, but eighteen months into deployment, when the ocean has found every seal and bearing, and the cost of keeping equipment running has overtaken the revenue from the power it produces.

A wave tank prototype will begin to answer some of these questions. It will not answer all of them. There is a long distance between a controlled wave tank and the North Atlantic in winter.

What the paper does provide, and what wave energy has lacked in too many previous iterations, is a rigorous mathematical basis for understanding where the efficiency ceiling sits and how to approach it across variable conditions. Engineers building the next generation of devices now have a clearer target. Whether the physics survives contact with actual water, and whether the economics survive contact with actual shipowners, remains to be established.

The ocean’s surface holds more untapped kinetic energy than any land-based renewable resource. The difficulty has never been finding it. It has been building something that can last long enough to use it.

Ocean Rising covers ocean governance, marine science, and the institutions shaping both, including who funds what, and why. The investigations are behind the paywall.

Subscribe now

Coral reefs grew fastest at 25°C. The ocean is now warmer than that, and the atmosphere contains more carbon dioxide than at any point in the past 11,700 years. This week, a study spanning the entire history of human civilisation showed that the conditions under which reefs thrived no longer exist. That finding landed alongside escalating forecasts of a potentially very strong El Nino forming later this year, a $23.5 billion illegal fishing crisis laid bare at the World Ocean Summit, and a mass whale stranding in Indonesia that local scientists are calling a signal of deeper ecological trouble.

Three deep dives. Three quick hits. One hard truth from the sea.

Deep Dives

Coral reefs peaked at 25°C. We have already passed it

A study published this week in PLOS ONE examined coral cores, cylindrical samples drilled from reef structures that record thousands of years of growth, from 291 sites across the Pacific, Indian, and Atlantic Oceans. The cores date back 11,700 years to the beginning of the Holocene, the geological period that covers the entirety of human civilisation. The researchers used two different analytical methods to examine how environmental conditions influenced reef growth over that span.

The central finding: coral reef growth rates peaked at a sea-surface temperature of approximately 25°C, during a warm period between roughly 7,000 and 5,500 years ago. At that time, atmospheric carbon dioxide (CO₂), the greenhouse gas primarily responsible for warming the planet, was around 325 parts per million (ppm). To put that in context, current atmospheric CO₂ exceeds 425 ppm, roughly 30 per cent higher.

Sea-surface temperatures in many reef regions now regularly exceed 25°C. The study found that CO₂ levels above 335 ppm, combined with modern temperatures and the increasing frequency of marine heatwaves, are less than optimal for reef growth. The researchers describe this as an inhibition of reef capacity to keep pace with rising seas.

This is not a computer simulation about what might happen. It is a reconstruction of what actually happened over 11,700 years, using the physical record preserved in reef structures. The answer is clear: the conditions that built the world’s coral reefs no longer exist. We passed the optimal temperature. We passed the optimal CO₂ concentration. Reefs are now growing in conditions that the geological record shows are suboptimal, and those conditions are getting worse.

Why does CO₂ matter for reefs? Higher CO₂ in the atmosphere means more CO₂ dissolving into seawater, making it more acidic. More acidic water makes it harder for corals to build their calcium carbonate skeletons, the same material that forms the reef structure itself. At the same time, warmer water causes bleaching, where corals expel the tiny algae that live inside them and provide most of their energy. Bleached corals can recover if conditions improve quickly, but repeated bleaching kills them.

The study also found that when sea levels were rising during the Holocene, reefs grew faster, likely because rising water provided new space for coral to colonise. That relationship only holds when temperature and CO₂ remain within the range that supports reef building. When they do not, as now, sea-level rise becomes a threat reefs cannot outpace.

El Nino is loading. The forecasts just got worse

Multiple forecasting groups revised their predictions upward this week. What was a roughly 50/50 chance of El Nino developing by mid-year now looks increasingly likely, with some models projecting a very strong event for late 2026 and into 2027.

El Nino is a natural climate pattern in which the tropical Pacific Ocean warms significantly. It happens every two to seven years. The warming releases stored ocean heat into the atmosphere, temporarily driving up global temperatures. The last El Nino, in 2023-2024, helped make those two years the hottest ever recorded.

Climate scientist Zeke Hausfather at Berkeley Earth projects that a strong El Nino would have its largest effect on 2027 temperatures, potentially making it the warmest year on record. His central estimate for 2027 is approximately 1.57°C above the average temperatures of the 1800s, before fossil fuel burning began warming the planet. James Hansen’s team at Columbia University projects a peak of 1.7°C, though Hansen measures this as the highest 12-month average within the year rather than the calendar-year average Hausfather uses. The difference in method matters, but the direction is the same: both projections would surpass the 2024 record.

Several warning signs are already in place. Strong westerly winds in the western tropical Pacific are pushing warm water eastward, and large volumes of warm water are stored beneath the surface. The cool La Nina pattern, the opposite of El Nino in which the same region of the Pacific cools, ended quickly. Climate scientist Daniel Swain at the University of California described the emerging signal as potentially ‘very significant.’

For the ocean, El Nino means accelerated coral bleaching in waters that, as this week’s coral study shows, are already above the temperature at which reefs grow best. It means disrupted fisheries as species shift with changing currents. It means the cold, nutrient-rich water that normally rises to the surface off South America, supporting one of the world’s most productive fisheries, gets suppressed. For the Pacific island nations whose leaders spoke at this week’s World Ocean Summit, it means drought, food insecurity, and intensified pressure on the marine resources they depend on.

Forecasting accuracy for El Nino typically improves after the spring, when a well-documented drop in predictive skill, known among scientists as the ‘spring barrier,’ passes. By June, the picture will be clearer. What is already clear is that the system is primed.

Illegal fishing costs $23.5 billion a year. The World Ocean Summit asked what anyone plans to do about it

At the World Ocean Summit in Montreal this week, ocean leaders delivered a blunt assessment: international agreements to protect the ocean are piling up, but enforcement is not keeping pace.

The headline figure came from Niall O’Dea, Senior Assistant Deputy Minister at Canada’s Department of Fisheries and Oceans: roughly a third of the seafood on people’s plates comes from illegal, unreported, or unregulated (IUU) fishing. That is fishing that breaks the rules, goes unrecorded, or operates in areas where no rules exist. It drains an estimated $23.5 billion from the legal economy every year.

Papua New Guinea’s Minister for Fisheries, Jelta Wong, captured the enforcement gap in a single comparison: it is easier to locate and strike a target in Tehran than it is to monitor fishing in our own ocean.

The summit took place at a time when landmark international agreements are beginning to take effect. The High Seas Treaty, formally known as the Biodiversity Beyond National Jurisdiction (BBNJ) agreement, entered into force in January 2026. The World Trade Organization’s (WTO) agreement on fisheries subsidies, which aims to stop governments funding fishing that depletes stocks, took effect in its first phase in 2025, with negotiations on remaining provisions still underway. Governments have committed to protecting 30 per cent of the ocean by 2030. Speakers at the summit stressed that none of these commitments will work without investment in monitoring, enforcement, and financial mechanisms to support them.

The gap between ambition and enforcement is not new. What is new is the number of agreements that all depend on the same missing infrastructure: the ability to see what is happening in the ocean and act on it. Satellite monitoring, vessel tracking, and checks at ports exist but remain underfunded and unevenly applied. The EU’s OceanEye initiative, launched this month with €50 million in initial funding, is one attempt to close the observation gap. Whether monitoring capacity can scale fast enough to match what governments have promised is the question that hung over the entire summit.

Quick Hits

Ocean temperature patterns prevent global drought synchronisation. A study published this week in Communications Earth & Environment found that droughts rarely strike the entire planet at the same time. Synchronised drought, when multiple regions dry out simultaneously, affects only 1.8 to 6.5 per cent of global land at once, far less than earlier estimates suggested. The reason: shifting ocean temperature patterns, particularly the El Nino-La Nina cycle, create a patchwork of regional drought rather than one worldwide dry spell. For food security, this is important. It means crop failures in one region can be offset by harvests elsewhere, as long as trade and storage systems work properly. The researchers identified “drought hubs,” regions that repeatedly experience drought on different cycles, in Australia, South America, southern Africa, and parts of North America. Monitoring ocean temperatures could provide early warning of which hubs are next.

Mass pilot whale stranding in Indonesia. Fifty-five short-finned pilot whales stranded on 9 March near Kupang in East Nusa Tenggara province. Villagers and authorities worked past midnight to rescue 34, but 21 died. Post-mortem examinations were carried out immediately. Local scientists point to the region’s shallow waters and narrow bays, which can disrupt the echolocation, a form of biological sonar, that pilot whales use to navigate. Pilot whales are highly social; when one individual enters shallow water, the rest follow. Environmental organisations are calling for a broader investigation into whether the stranding reflects ecological disruption linked to climate change, shifting prey distribution, or ocean noise from shipping and industry. Indonesia’s Ocean Health Index score remains at 65 out of 100, indicating significant room for improvement in how the country manages and protects its marine environment.

Ocean data is being wasted. At the World Ocean Summit, Canada’s Chief Science Advisor Mona Nemer warned that too much ocean research data is collected for a single project and then filed away, never reused or combined with other datasets. The real value of ocean data, she argued, comes from connecting it: linking data on acidification, biodiversity, shipping, and pollution to build a fuller picture of what is happening and inform decisions. Governments need to fund not just data collection but the tools and expertise to make that data usable by others. This connects directly to the EU’s OceanEye initiative and the broader problem: ocean governance cannot function without ocean observation, and observation is only as good as the systems for sharing what it finds.

Hard Truth From The Sea

Coral reefs grew best at 25°C and 325 ppm of CO₂. We are now above 425 ppm and warming fast. A potentially very strong El Nino is forming in the Pacific, which will push temperatures higher still. The institutions responsible for managing these pressures met this week in Montreal and admitted they cannot monitor their own ocean.

Eleven thousand years of geological data show the conditions that built coral reefs. We have left those conditions behind. The question is no longer whether reefs are under threat. It is whether the speed of change will outpace the speed of response. This week’s evidence suggests it already has.

Paid subscribers fund the reporting that tracks the gap between what the ocean needs and what institutions deliver. If you want accountability journalism on the ocean, and the systems failing to protect it.

Subscribe now

See you next week.

- Luke

On 17 June last year, two oil tankers collided in the Persian Gulf. The vessel ADALYNN caught fire. An 8-kilometre oil slick spread across the water. Nobody ordered that spill. Nobody aimed at the sea. Investigators believe GPS spoofing, a form of electronic interference common in active conflict zones, may have contributed to the collision. Whether or not it did, the incident illustrated something the sea cannot explain away: when a body of water becomes a military corridor, accidents become more likely, and clean-up becomes less possible.

The ocean wasn’t a target… it was just in the way.

The sea generally isn’t damaged deliberately in a war. It happpens through consequence, through contamination, through the systems built for other purposes that treat the marine environment as an acceptable side effect. The Persian Gulf is burning again. The Strait of Hormuz, the narrow passage between Iran and Oman through which one fifth of the world’s oil consumption moves every day, has been largely closed to commercial traffic since 28 February 2026. Over 150 tankers sit at anchor. The water that connects the Gulf to the rest of the ocean has become a military corridor.

Nobody will be held accountable for what that does to what lives there.

Already Broken

The Persian Gulf is not a pristine ecosystem. Decades of oil industry activity have already stressed its coral systems, its dugong populations, and its fisheries. Dugongs are large marine mammals, relatives of the manatee, that graze on seagrass beds throughout the Gulf. Seawater temperatures in the Gulf are among the highest recorded for any sea on earth. The region’s marine protected areas, zones designated by governments where industrial activity is supposed to be restricted, exist in the shadow of the world’s largest fossil fuel infrastructure.

War arrives into this already-degraded environment and makes everything worse, and it does so with complete legal impunity. No one pays. No one is required to.

The legal principle that those who cause environmental damage should pay to clean it up has a name. In wartime, it has no application.

Consider what is happening right now. Iranian retaliatory strikes have targeted port infrastructure across the Gulf, in Abu Dhabi, Dubai, Jebel Ali, and Manama. The Conflict and Environment Observatory, an independent organisation that monitors environmental harm in active conflict zones, documents sunken vessels and damaged port infrastructure presenting significant pollution risks from fuels and oils. Emergency response capacity, already strained, is operating in conditions where the conflict actively prevents clean-up.

The ADALYNN spill last June was not from a direct strike. It came from GPS spoofing, the electronic interference that causes ships to lose their positional awareness and, in this case, each other. As long as electromagnetic warfare continues, as long as vessels navigate blind in contested waters, collisions will happen. Spills will happen. The sea absorbs the consequences.

The Last Time

This is one of the oldest patterns in modern warfare, and it has never produced accountability.

In 1991, Iraqi forces opened the valves at the Sea Island terminal off Kuwait and dumped between four and eight million barrels of crude oil into the Persian Gulf. The resulting slick was, at the time, the largest deliberate oil spill in history. It coated hundreds of kilometres of Saudi coastline. It killed seabirds, sea turtles, and fish in numbers that were never fully counted because no one was counting. The war ended. Reconstruction focused on infrastructure. The marine environment was not a line item.

No international legal mechanism existed to compel remediation. None exists today.

Iraq was eventually ordered to pay reparations through the UN Compensation Commission, a body created specifically to process Gulf War claims. Over three decades, it awarded $5.26 billion for environmental and public health damage, a genuine, if partial, precedent. Saudi Arabia alone had sought $4.7 billion for its fouled coastline. The final payment arrived in January 2022. The framework required a defeated aggressor, Security Council unanimity, and a mandatory ceasefire resolution. It was built for one war. It cannot be rebuilt for the next one.

For the marine environment of the Gulf in the conflict of 2026, there is no equivalent process underway. There is no institution monitoring marine damage as a primary concern. There is no legal obligation on any party to remediate what the sea absorbs.

A Different Sea, The Same Story

Ukraine offers the same lesson from a different body of water.

Since February 2022, the Black Sea has functioned as a battlefield. Within weeks of Russian warships entering the sea, dolphins and porpoises began washing up dead on Black Sea beaches in numbers researchers had never recorded. The largest counts came during May and June 2022, when fighting around Snake Island was most intense. Scientists attributed the deaths to acoustic trauma from naval activity. Research published through the European Commission’s Joint Research Centre, the EU’s in-house science body, documents further damage: contamination from sunken vessels, the disruption of spawning grounds, and oil slicks covering tens of thousands of square kilometres of Ukraine’s marine protected areas, recorded by satellite imagery. Snake Island itself, a designated marine reserve, was fought over from February to July 2022. Its waters absorbed the wreckage.

The war continues, and the damage compounds. The legal mechanisms for environmental remediation in armed conflict remain almost entirely theoretical.

The Rome Statute, the international treaty that established the International Criminal Court, includes environmental destruction as a potential war crime, but only when it causes ‘widespread, long-term and severe damage to the natural environment’, a threshold so high that, as of late 2025, no charges had ever been brought under it at all. The customary rules of international humanitarian law, the body of rules governing how wars are fought, on environmental protection are widely regarded by legal scholars as inadequate and unenforced. The countries most responsible for the most damage are also the countries with the most power to block reform of those frameworks.

The Same System

This war is being fought across the strait that carries one fifth of the world’s oil. Whatever its causes, its consequences run through these waters. The tankers at anchor, the contaminated ports, the GPS-spoofed shipping lanes: the marine environment is not collateral to this conflict. It is the terrain. When the ADALYNN spill happened, the news covered the shipping disruption. The market impact. The insurance premiums. The ecological harm received a paragraph in a specialist monitoring report, noted and filed.

That is the order of priority. That is what we have decided the sea is worth.

The Principle That Stops at the Waterline

The ‘polluter pays’ principle holds that those who cause environmental damage bear the cost of remediation. In peacetime, it is imperfectly applied. In wartime, it does not apply at all.

No mechanism exists to attribute marine environmental damage to a party in a war, calculate its cost, and compel payment. The International Maritime Organisation, the UN body that regulates global shipping, has no mandate in active conflict zones. The UN Environment Programme can monitor and report, as it does, with rigour and frustration. Reporting is not remediation.

The Persian Gulf’s dugongs do not know there is a war. The coral systems stressed by forty years of industry and a warming ocean do not know that the legal framework governing the water they live in contains no provision for what is happening above them. The fish spawning in waters designated as protected areas before the first missile was fired do not know that designation means nothing when the shooting starts.

They will absorb what they absorb. The law will not follow.

What No One Is Negotiating

After the next ceasefire, whenever it comes, there will be reconstruction efforts. Infrastructure will be assessed, economic losses will be calculated, and diplomatic frameworks will be negotiated.

The marine environment of the Persian Gulf will not be on that agenda, just as it wasn’t on the agenda after 1991. It was not on the agenda after the Iran-Iraq Tanker War of the 1980s either, which damaged or destroyed hundreds of vessels in this same body of water. The Black Sea’s damaged protected areas will not drive the terms of any eventual peace settlement in Ukraine.

What would accountability look like? It would look like a dedicated international mechanism for marine war damage restoration, with compulsory funding and defined standards for who pays. It would look like the Rome Statute’s environmental provisions being applied rather than cited.

None of that exists, and none of it is being seriously negotiated.

The tankers sit at anchor in the Gulf. The sea absorbs what it absorbs. Somewhere below the surface, in water already carrying more than it should, something is dying that no one is counting.

The sea has no seat at the table. Ocean Rising exists to put it there. Paid subscriptions make that possible.

Subscribe now

Pick a coastal city. Any coastal city. The sea level there is probably higher than the models say. On average, around 30 centimetres higher. In parts of the Indo-Pacific, more than a metre higher. A study published this week in Nature found that 90 per cent of coastal hazard assessments over the past 15 years used modelled estimates of sea level rather than actual measurements. The starting point was wrong. Every projection built on it was optimistic.

That finding sits alongside two other stories this week. The international body responsible for regulating deep-sea mining just spent two weeks trying to finish the rulebook. It failed. The company that wants to mine is not waiting for the rules. And in the Gulf of Maine, researchers tested whether adding chemicals to the ocean could help it absorb more carbon dioxide. The science is preliminary. Companies are already selling credits for the same technique.

Three deep dives. Three quick hits. One hard truth from the sea.

Deep Dives

The mining code that never arrives

The International Seabed Authority (ISA) was created to regulate mining of the deep seabed in international waters. It has been trying to finalise the rules, known as the Mining Code, for years. This week, the ISA’s Legal and Technical Commission, the preparatory body that reviews technical and legal questions before they reach the decision-making Council, wrapped up two weeks of work in Kingston, Jamaica. The code is still not ready for adoption. The Council, which is the body that would actually approve the rules, convenes on Monday for a session running 9 to 19 March. It inherits the same unresolved questions. The full 31st Session stretches all the way to July, when the Assembly meets. That timeline tells you something about the pace of progress.

The backdrop makes this failure more consequential than previous ones. In April 2025, President Trump signed an executive order directing the National Oceanic and Atmospheric Administration (NOAA) to accelerate permits for deep-sea mining under the US Deep Seabed Hard Mineral Resources Act (DSHMRA), a largely dormant 1980 law. In January 2026, NOAA issued a final rule modernising the application process. The Metals Company (TMC) filed for a commercial recovery permit covering 65,000 square kilometres of the Clarion-Clipperton Zone, a vast area of Pacific seabed rich in potato-sized rocks called polymetallic nodules that contain nickel, cobalt, copper, and manganese.

The US is not a party to the United Nations Convention on the Law of the Sea (UNCLOS), the treaty that established the ISA, and does not recognise the ISA’s authority over its nationals. The ISA has opened an investigation into whether TMC and its international subsidiaries are complying with the Convention. Delegates discussed revoking TMC’s existing exploratory permits but stopped short. ISA Secretary-General Leticia Carvalho put it plainly: what prevents unregulated exploitation is rules, and the ISA has yet to agree on them.

The governance framework is fracturing. China and the EU have criticised the US approach. Around 30 ISA member states support a moratorium or precautionary pause on mining. TMC’s exploration contracts through its Nauru and Tonga subsidiaries expire in July 2026 and January 2027 respectively. The company is simultaneously pursuing permits from a country that rejects the ISA’s jurisdiction while holding contracts issued by it. Legal scholars at the European Journal of International Law have described this as a system-breaking contradiction.

Mining the deep seabed carries documented environmental risks: sediment plumes that can travel hundreds of kilometres, destruction of habitats that take millions of years to form, and biodiversity loss in ecosystems we barely understand. TMC’s own test showed a 30 per cent decline in biodiversity and abundance in the affected area. Recovery timescales for abyssal ecosystems are measured in decades to centuries, if recovery occurs at all.

The deep-sea mining question is no longer primarily scientific. It is a governance question. Whether the seabed is a common heritage resource managed by the international community or a frontier open to whoever moves first is being decided right now, by default, because the ISA cannot finish the job it was created to do.

Sea levels are higher than we thought. The maths changes everything

A study published this week in Nature analysed 385 peer-reviewed coastal hazard assessments published over the past 15 years and found a systemic problem: 90 per cent relied on modelled estimates of sea level rather than direct measurements from satellites and tide gauges.

When the researchers compared those model-based assumptions against satellite observations at 90-metre resolution, they found that global coastal sea level is on average around 30 centimetres higher than assumed. In some regions, predominantly in the Indo-Pacific and the Global South, the difference exceeds one metre. The models estimate sea level using the Earth’s gravitational field, but that does not account for tides, winds, ocean currents, temperature, and salinity, all of which affect the actual height of the water along coastlines.

The consequences compound. With a hypothetical one metre of sea-level rise, the study estimates 31 to 37 per cent more land would fall below sea level than current assessments project, affecting 48 to 68 per cent more people, raising exposure estimates to between 77 and 132 million.

This is not a new projection of future sea-level rise. It is a correction to the starting point from which all projections are calculated. If you are measuring how much water is coming, it matters where the water already is. Coastal adaptation plans, climate finance allocations, and infrastructure investment decisions built on the lower starting point are systematically underestimating risk.

Philip Minderhoud, an author of the study at Wageningen University, described the reliance on modelled sea level rather than measured data as a methodological blind spot. The paper calls for re-evaluation of existing coastal impact assessments worldwide.

The first open-ocean alkalinity experiment is incomplete yet already being commercialised

Scientists at Woods Hole Oceanographic Institution (WHOI) presented preliminary results this week from LOC-NESS, the first controlled open-ocean trial of ocean alkalinity enhancement. The principle is straightforward: more alkaline seawater can absorb more carbon dioxide from the atmosphere, locking it away in dissolved form. The trial, conducted last summer in the Gulf of Maine, involved adding sodium hydroxide to surface waters to test whether this works at sea rather than just in a laboratory.

The results, presented at the Ocean Sciences Meeting 2026 in Glasgow: between 2 and 10 tonnes of CO₂ were drawn into the ocean during the four-day monitoring period. Modelling suggests the treated patch of water could absorb up to 50 tonnes over a year. The research team found no measurable impact on the marine organisms they studied, including bacteria, phytoplankton (the tiny algae that form the base of the ocean food web), and lobster larvae.

Those findings carry important caveats. The trial did not examine long-term impacts. It did not assess effects on organisms near the seafloor. And project lead Adam Subhas acknowledged to New Scientist that the team has yet to estimate the emissions involved in manufacturing and transporting the sodium hydroxide, meaning it remains unclear whether the trial achieved net carbon removal, that is, whether it removed more CO₂ than it created.

The LOC-NESS researchers are academic scientists, not a company. They stress this distinction. The private sector is not waiting. Microsoft and Google have signed agreements with Ebb Carbon for carbon offsets through alkalinity enhancement at desalination plants in Saudi Arabia. A Canada-based company announced the world’s first carbon credits for ocean alkalinity enhancement last year, selling over 600 tonnes of claimed removal to Shopify and British Airways.

The gap between cautious, small-scale science and commercial deployment is already wide and growing. As oceanographer Jannes Koelling at the University of Washington noted, history is full of examples where new technologies were deployed at scale before their environmental consequences were understood.

Quick Hits

EU launches OceanEye with €50 million

At the European Ocean Days in Brussels this week, Commission President Ursula von der Leyen formally launched OceanEye, a new ocean observation initiative first announced at the 2025 UN Ocean Conference in Nice. The EU will contribute €50 million from its Horizon Europe research programme for 2026-2027 and is calling for an international monitoring alliance. The initiative builds on the Copernicus Marine Service and the European Digital Twin of the Ocean. Von der Leyen described ocean monitoring as “vital planetary infrastructure” that needs stable, structured funding rather than voluntary cooperation. The goal is a fully operational European ocean observation system by 2030. Whether OceanEye delivers meaningful monitoring or joins the long list of EU announcements that sound better than they perform depends on whether member states and international partners commit real resources at the pledging event scheduled for September.

AI project to map vulnerable deep-sea ecosystems across the Atlantic

The Deep Vision project, led by Plymouth Marine Laboratory and the University of Plymouth, will use artificial intelligence to analyse thousands of hours of seafloor video footage and produce the first comprehensive maps of vulnerable marine ecosystems across the Atlantic. The project, funded by the Bezos Earth Fund, targets deep-sea corals, sponges, and other filter-feeding organisms that provide habitat for countless species, store carbon, and support food webs in the deep ocean. Policymakers currently lack maps showing where these ecosystems exist in international waters, making it nearly impossible to designate meaningful marine protected areas under the new High Seas Treaty, formally known as the Biodiversity Beyond National Jurisdiction (BBNJ) agreement. If Deep Vision delivers, it becomes the scientific foundation for the first generation of protected areas in the high seas. The treaty’s first Conference of the Parties is expected later this year.

Fish biomass study from last week’s Deep Brief is gaining traction

The Chaikin et al. study documenting a 7.2 per cent decline in fish biomass, the total weight of living fish in a given area, for every 0.1°C of seabed warming, covered in Deep Brief #30, has become one of the most-accessed recent papers at Nature Ecology & Evolution. The finding that marine heatwaves can temporarily inflate fish numbers in colder waters, masking long-term decline, has particular relevance for fisheries managers setting catch limits. Worth reading alongside this week’s sea-level correction: another case where the starting assumptions behind policy are worse than we thought.

Hard Truth From The Sea

The ISA’s preparatory commission just finished two weeks of work and the Mining Code still is not ready. The Council starts Monday. The US is not waiting. Scientists have shown that sea levels are higher than we assumed. So adaptation plans are built on underestimates. Researchers cannot yet confirm whether ocean alkalinity enhancement achieves net carbon removal. So companies are already selling credits for it.

In each case, the pattern is the same… action is outpacing understanding.

The institutions designed to govern these decisions are slower than the actors who want to exploit them, and the science that should inform these choices is still catching up to the scale of the questions being asked.

The ocean does not wait for consensus. Neither, it turns out, do the people who want to profit from it.

The distance between what we know and what we are doing grows wider every week. Paid subscribers fund the journalism that measures it. If you want accountability reporting on the ocean, and the institutions failing to protect it.

Subscribe now

See you next week.

- Luke

In the shallow waters off western Greenland, a species of slow-growing crusty seaweed has been quietly recording the chemical signature of everything that flows past it.

For more than a century, a coralline alga called Clathromorphum compactum (a hard, rock-like organism that builds up in layers on the seafloor) has been laying down annual growth bands, like tree rings, each one preserving a chemical fingerprint of the seawater it grew in.

A team of scientists from Kiel University in Germany, the University of Toronto Mississauga, and the University of Geneva has now read that record. What they found is alarming.

Their 115-year reconstruction of meltwater runoff into Disko Bay was posted online in February 2026 as a preprint, a research paper shared publicly before it has been through formal peer review (the process where other scientists scrutinise the methods and conclusions before a journal will publish it). It is currently under review for the journal Climate of the Past. The findings reveal that the Greenland Ice Sheet’s largest glacier crossed a critical threshold nearly two decades ago. Since 2007, runoff from the western ice sheet has permanently exceeded the entire range of natural variability observed throughout the 20th century.

The word ‘permanently’ matters here. This is not a spike, or a record year followed by recovery. The system shifted into a new state in the early 2000s and, as of 2018 when the algal record ends, has not returned.

How seaweed becomes a climate archive

The method is ingenious. Barium, a naturally occurring chemical element, is carried into the ocean by glacial meltwater, transported in fine sediment particles that wash off the ice sheet as it melts. When that barium-rich water reaches the shallow ocean, the algae absorb it into their hard chalky skeletons. More meltwater means more barium. The ratio of barium to calcium in each growth band becomes a stand-in measurement (what scientists call a proxy) for how much glacial runoff reached the bay that year.

The researchers collected nine specimens from sites in southern Disko Bay, southwest of Jakobshavn Glacier (also known as Sermeq Kujalleq). Jakobshavn is the fastest-flowing glacier on the Greenland Ice Sheet that terminates directly in the sea. It drains roughly 6.5% of the ice sheet’s total area. Between 2000 and 2012, it was one of just four glaciers responsible for approximately half of the entire ice sheet’s mass loss.

To read the chemical record locked inside the algae, the team used a technique that fires a laser at the specimen’s surface and analyses the vaporised material to determine its chemical composition. They measured the barium-to-calcium ratio along each specimen’s growth layers at a resolution finer than one year. The longest single specimen record extends back to 1903. By combining all nine specimens into a single composite record (with at least five specimens overlapping from 1932 onwards), they built a continuous timeline that captures both the stable baseline of 20th-century variability and the dramatic departure that followed.

The signal that temperature data missed

The study’s most striking finding is a disconnect between what the algal record shows and what temperature records show.

The researchers applied a statistical test called ‘time of emergence’ analysis. The idea is simple: define a range of normal variability based on the historical record, then determine when the signal moves outside that range and stays there. In this case, ‘outside normal’ means the signal exceeded the upper boundary of the historical range (the 1932-2000 reference period) and never came back down. For the algal barium-to-calcium record, that emergence point arrived in 2007. For modelled ice sheet mass balance (the difference between snowfall adding mass and melting removing it) across the western ice sheet, it arrived in 2010.

For temperature? It hasn’t arrived yet. None of the long-term temperature datasets for the Disko Bay region, including sea surface temperature, surface air temperature, and local weather station records, have exceeded their historical range of variability by the same measure.

This means the ice sheet’s response to warming has outpaced what surface temperature records alone would predict. The runoff is accelerating faster than the thermometer suggests it should.

The researchers identify a moment in the algal record, in summer 2001, after which the upward trend steepens sharply. Before that date, there was no statistically significant trend in the chemical signal. After it, the rate of increase was tenfold. The algal record peaked in 2012, the same year the Greenland Ice Sheet experienced its most extensive surface melting in the satellite era. Every year from 2007 onwards ranks above the emergence threshold. Twelve of the highest runoff years in the entire 115-year record occurred in the most recent two decades.

What’s driving the acceleration?

The authors point to the role of warm Atlantic water intruding into Disko Bay at depth. Since the mid-1990s, warmer water from the Atlantic has been flowing into the bay beneath the surface, particularly at 200 to 250 metres down. This warming had a direct effect on Jakobshavn Glacier, eating away at the floating shelf of ice where the glacier meets the ocean (what glaciologists call the ice tongue). That shelf disintegrated in the late 1990s and early 2000s, and the glacier sped up dramatically, peaking in 2012.

This deep-water warming is harder to detect in standard sea surface temperature records, which measure conditions at the top of the ocean. Higher-resolution satellite data from the US National Oceanic and Atmospheric Administration (NOAA), available from 1982, does show exceptionally rapid warming in the inner Disko Bay region: more than 1°C per decade since 1982. The coarser, longer-running temperature datasets that allow historical comparison simply cannot pick up this localised warming.

That matters for policy. If the monitoring tools we rely on for long-term comparison are missing the signal, we may be underestimating the speed of change.

The tipping point question

The paper’s language on tipping points is careful, and deliberately so. The authors write that their findings provide ‘independent evidence for a non-linear accelerated response’ of Greenland’s largest glacier, and that this ‘underscores modelling results that a tipping point in glacial mass balance might soon be reached.’

Note the phrasing: underscores modelling results. Might soon be reached. This is not a declaration that the tipping point has been crossed. It is evidence that the system is behaving in ways consistent with approaching one.

The distinction matters because ‘tipping point’ has a specific meaning in climate science: a threshold beyond which changes become self-reinforcing and effectively irreversible on human timescales. Think of a ball balanced on the rim of a bowl. A tipping point is when it rolls over the edge and can’t be pushed back. A separate study published in The Cryosphere in January 2025 estimated that such a threshold for the full Greenland Ice Sheet would be reached when approximately 230 gigatons of ice are lost in a single year. (A gigaton is a billion tonnes, roughly the weight of 3,500 Empire State Buildings.) The ice sheet is not losing that much yet, though annual losses have been accelerating.

What the Hetzinger study adds is a longer baseline against which to measure that acceleration. When you can see 115 years of relatively stable runoff, followed by a sharp, sustained departure starting around 2001, the word ‘nonlinear’ stops being abstract. The change is not gradual and proportional. It is accelerating. The algae are showing us the shape of the curve, and it is bending upward.

Why this matters beyond Greenland

The Greenland Ice Sheet is not just a regional concern. Between 1992 and 2020, melting of the polar ice sheets caused 21 millimetres of global sea level rise, and Greenland accounted for nearly two-thirds of that (approximately 13.5 millimetres), according to a comprehensive assessment published in Earth System Science Data in 2023.

The freshwater pouring into the North Atlantic also has potential consequences for ocean circulation. The Atlantic Meridional Overturning Circulation, or AMOC, is a vast system of ocean currents that carries warm water northward from the tropics and cold water back south at depth. It functions like a conveyor belt for heat, and is a major reason why northern Europe has a relatively mild climate. Research published in Nature in 2018 found evidence that this circulation may have weakened by roughly 15% since the mid-20th century. More recent modelling, published in Nature Geoscience in 2024, suggests that if Greenland meltwater is factored into projections, further weakening may occur sooner than previously expected. The mechanism: fresh meltwater is lighter than salty seawater, so large volumes of it can sit on the surface and prevent the sinking that drives the conveyor belt.

The Hetzinger study adds a caveat here. While the nonlinear runoff increase from western Greenland is now documented, it remains an open question whether the same pattern exists for glaciers draining the eastern ice sheet. The AMOC impact depends partly on where the freshwater enters the North Atlantic, and recent observational work suggests that currents off western Greenland may play a lesser role in driving AMOC changes than those off eastern Greenland.

What to watch

This study is a preprint. It was submitted in December 2025, posted for discussion on 5 February 2026, and is currently under peer review. The methodology builds on the research team’s previous validated work using the same chemical approach to reconstruct glacier runoff in Svalbard (a Norwegian archipelago in the high Arctic), published in Climate Dynamics in 2021. The technique is well-established across multiple studies using different shell-building organisms in different environments.

There are important caveats. The statistical correlation between the algal record and Jakobshavn Glacier mass loss estimates is very strong (0.91 on a scale where 1.0 would be a perfect match), but that figure is based on only 18 years of annual data (1995-2012). The longer correlation with modelled ice sheet mass balance (0.54, covering 1903-2012 with smoothed data) is statistically significant but more moderate. The paper does not claim to measure runoff directly. It reconstructs a chemical signal that tracks barium delivery to the surface ocean, which correlates with meltwater input.

The raw data will be deposited at PANGAEA, a publicly accessible scientific data library, after the paper is accepted. That transparency matters. It means other researchers can check the findings, replicate the analysis, and build on the record.

In the meantime, the message is clear enough. The ocean has been keeping receipts, recorded in the growth bands of organisms most people have never heard of. Those receipts show that the Greenland Ice Sheet’s behaviour changed fundamentally around the turn of the millennium and has not changed back.

The question is no longer whether the ice sheet is losing mass at an accelerating rate. Satellites have confirmed that. The question is whether that acceleration is tracking toward a point of no return, and whether the models we use to project the future are accounting for it.

These algae suggest the answer to the second question may be no.

Hetzinger, S., Halfar, J., Watanabe, T.K., and Tsay, A. (2026). Nonlinear increase of Greenland Ice Sheet runoff into Disko Bay. EGUsphere [preprint]. DOI: 10.5194/egusphere-2025-6074

Ocean Rising covers ocean governance, marine conservation, and the science that informs both. Subscribe to receive investigations, analysis, and reporting that holds institutions accountable for what happens to the ocean.

Somewhere in the South China Sea, a finless porpoise is carrying liquid crystal monomers from a discarded television screen in its brain tissue. It is not alone. This week, researchers documented for the first time that chemicals from household electronics are crossing the blood-brain barrier in marine mammals. That study landed alongside new research quantifying how fast the ocean is losing fish to long-term warming, and a UNESCO report revealing that the climate models guiding global emissions policy are built on a carbon sink we cannot accurately measure.

Three deep dives. Two quick hits. One hard truth from the sea.

Deep Dives

The ocean is heating. The fish are disappearing. The maths is worse than we knew.

A study published this week in Nature Ecology & Evolution analysed over 700,000 estimates of biomass change across more than 33,000 fish populations in the northern hemisphere between 1993 and 2021. The researchers, led by Shahar Chaikin at the Museo Nacional de Ciencias Naturales in Spain, isolated the effect of long-term, sustained seabed warming from short-term disruptions like marine heatwaves.

The headline number: a 7.2 per cent decline in fish biomass, the total weight of living fish in a given area, for every 0.1°C of seabed warming per decade. In the worst cases, long-term warming was associated with annual biomass declines of up to 19.8 per cent.

Here is the part that should alarm anyone involved in fisheries management. Marine heatwaves can temporarily increase biomass in colder waters by up to 176 per cent as species shift toward more comfortable temperatures, the range in which they can grow and reproduce effectively. That looks like good news on a quota spreadsheet. It is not. Those surges are temporary. If fisheries managers raise catch limits based on heatwave-driven abundance, they risk collapsing populations once conditions normalise or long-term warming catches up.

At the warm edges of species ranges, the picture is worse. Heatwaves there drove biomass crashes of up to 43.4 per cent.

The study also points to a governance headache that no single country can solve. As species track their thermal comfort zones, they cross national boundaries. A population declining in one country may be increasing in another. Static management models, the kind most fisheries regulators still use, cannot account for this. The researchers call for international coordination and joint resource-management agreements. Given the state of multilateral fisheries negotiations, that call will land somewhere between aspiration and fantasy.

The underlying mechanism is straightforward. Long-term warming is not a spike that ecosystems can absorb and recover from. It is a sustained pressure that compounds year after year. The noise of extreme events has been masking a signal that this study now quantifies with uncomfortable precision.

We do not understand the ocean’s largest climate function well enough to plan around it.

The ocean absorbs roughly 25 per cent of global CO₂ emissions. That single fact underpins virtually every national climate plan, every emissions target, and every adaptation strategy currently on the table. A new report from UNESCO’s Intergovernmental Oceanographic Commission, released this week at the Ocean Sciences Meeting 2026, says we do not understand this process well enough to rely on it.

The Integrated Ocean Carbon Research report, compiled by 72 authors across 23 countries, finds that scientific models estimating the ocean’s carbon uptake diverge by 10 to 20 per cent globally, and by more in certain regions. The gaps stem from limited long-term observational data and incomplete understanding of how warming, changing circulation, shifts in plankton populations, and human activities are altering the carbon cycle.

If the ocean absorbs less carbon in the future than models assume, more CO₂ stays in the atmosphere and warming accelerates. Current emissions targets, built on the assumption that the ocean will keep doing its job, could be systematically optimistic.

The report lays out a roadmap: better models, stronger monitoring in data-limited regions, and cross-disciplinary research connecting ocean carbon science to policy decisions.

We are making trillion-dollar climate decisions based on a carbon sink that scientists say they cannot accurately quantify within a 10 to 20 per cent margin. That is not a rounding error. That is a structural uncertainty at the foundation of global climate strategy.

Your old TV is in a dolphin’s brain.

Research published this week in Environmental Science & Technology provides the first evidence that liquid crystal monomers, the chemicals that make laptop, television, and smartphone screens work, are accumulating in the tissues of dolphins and porpoises, including their brains.

Researchers at City University of Hong Kong analysed tissue samples from Indo-Pacific humpback dolphins and finless porpoises collected between 2007 and 2021 in the South China Sea. They screened blubber, muscle, liver, kidney, and brain tissue for 62 individual liquid crystal monomers. They found them across multiple tissue types, with the highest concentrations in blubber. The finding that matters: these chemicals crossed the blood-brain barrier, the body’s defence system that stops most harmful substances reaching the brain, in both species.

The pathway is dietary. Earlier studies had already identified these chemicals in the fish and invertebrates that dolphins and porpoises eat. The pollutants enter coastal environments through household dust, wastewater, and e-waste, move through the food web, and accumulate in top predators.

In laboratory tests, several of the most common compounds altered gene activity in cultured dolphin cells, affecting DNA repair and cell division. The researchers describe this as evidence of potential neurotoxic risk, though they note further investigation is needed.

There is a sliver of a trend in the right direction. As manufacturers have shifted from LCD to LED displays, concentrations in porpoise blubber appear to have begun declining. That does not undo the accumulated contamination or address the 62 million tonnes of e-waste produced globally in 2022, roughly 80 per cent more than in 2010.

The study’s scope is limited to two species in one region. Whether similar contamination is present in dolphin and whale populations elsewhere remains unknown. For an industry where end-of-life disposal remains poorly regulated, and for governments that have not yet classified these compounds for environmental risk, this is the kind of evidence that should accelerate both.

Quick Hits

EU renews Pacific ocean partnership, at less than half the original budget.

The European Union signed the second phase of its Pacific-EU Marine Partnership (PEUMP) programme in Suva, Fiji this week, committing €20 million through 2030 to support ocean governance, fisheries management, and illegal, unreported, and unregulated (IUU) fishing enforcement across Pacific Island countries and Timor-Leste. Phase 1, launched in 2018, had a budget of €45 million with co-financing from Sweden. Phase 2 is less than half that, and Sweden does not appear in the announcement. The programme covers 15 Pacific countries and Timor-Leste. No public evaluation of Phase 1 outcomes was available at the time of writing. For context: the Western and Central Pacific tuna fishery was valued at US$6.1 billion in 2023. The EU’s contribution covers education, training, and technical assistance, not enforcement capacity or fleet monitoring at the scale the region needs.

Ocean Sciences Meeting 2026 is underway.

The biennial Ocean Sciences Meeting opened this week, bringing together marine researchers from around the world. Beyond the UNESCO carbon sink report covered above, the meeting covers topics including ocean deoxygenation, deep-sea ecosystem mapping, and polar ocean dynamics. Worth watching for papers that may shape the next round of implementation discussions for the Biodiversity Beyond National Jurisdiction (BBNJ) treaty, the new international agreement governing the high seas. The first Conference of the Parties is expected later this year, making 2026 a pivotal year for translating treaty text into functioning institutions.

Hard Truth From The Sea

Every one of this week’s stories shares the same structural problem: we are making decisions about the ocean based on what we assume rather than what we know. We assume fish stocks will hold. We assume the carbon sink will continue absorbing. We assume our waste stays where we put it. We assume small cheques solve large problems.

The ocean is not operating on our assumptions. It is operating on physics, chemistry, and biology. This week, all three sent the same message: the gap between what we think is happening and what is actually happening is growing wider, not narrower.

See you next week.

- Luke