The ocean plays a vital role in regulating the climate, storing roughly 50 times more carbon dioxide (CO2) than the atmosphere.
Marine life plays a significant part in this process, as organisms transfer carbon from the ocean surface to the deep sea upon death or as they migrate.
Our new research, published in Nature Communications, suggests the contribution of ocean biology to climate regulation is more complex than previously thought.
To explore how ocean biology shapes the past, present and future climate, we explore an extreme scenario where all marine life has been wiped out.
We find that – in a pre-industrial climate – CO2 levels would rise by 50% without marine life, leading to 1.6C of global warming.
In a separate study in Nature Climate Change, we estimate that ocean biology sequesters the equivalent of 10bn tonnes of CO2 each year.
This is more than one quarter of annual fossil-fuel emissions from human activity.
We also calculate that the contribution of marine life to carbon storage is worth hundreds of billions of dollars each year.
Biological carbon pump
The ocean takes up and stores vast amounts of CO2 every year through two mechanisms known as “carbon pumps”.
The first is the “solubility pump”. This is the process by which dissolved CO2 in seawater is transported from the ocean’s surface to its depth through the sinking and upwelling of water mass.
The second is the “biological carbon pump”. This is the process where carbon is converted into organic materials by plankton and other marine organisms at the ocean’s surface and then transported to the deep sea when they die or migrate.
Scientists have long known that the biological carbon pump played an essential role in maintaining low atmospheric CO2 levels before the industrial revolution.
However, the conventional view is that the solubility pump has been responsible for the ocean’s steady absorption of rising CO2 emissions caused by human activity.
Our findings challenge this view, by showing the biological carbon pump plays a crucial role in the modern ocean’s sequestration of atmospheric CO2.
We find that, without marine life, the ocean’s capacity to capture CO2 emissions would be significantly diminished.
Two scenarios
To get an estimate of the contribution of the marine carbon pump in a stable pre-industrial climate, we simulate the planet’s climate as it was before the industrial era using a complex Earth system model.
(This is the second generation of the Norwegian Earth system model, which contributed to the sixth Coupled Model Intercomparison Project.)
We then explore what would happen to the Earth’s climate system under two scenarios:
- A reference, “healthy ocean” scenario where ocean biology conditions were as realistic as possible.
- An “abiotic” scenario where all marine life is removed.
In a pre-industrial scenario with no marine life, we find that atmospheric CO2 levels would rise to 445 parts per million (ppm). This is an increase of more than 50% on the “healthy ocean” scenario, where CO2 levels are 282ppm.
(This suggests that the influence of marine life on global CO2 levels is greater than the sum of all human activity, which has – so far – raised atmospheric CO2 concentrations to around 425ppm).
The rise in CO2 levels caused by the absence of marine life would result in about 1.64C of global warming at the surface and a 1.15C increase in global sea surface temperature.
This warming would have considerable impacts on the wider world, including declines in sea ice area at the Arctic and Antarctic of close to 25% and an Atlantic Meridional Overturning Circulation that was around 9% weaker.
The value of exploring such an extreme scenario is to investigate the role biological processes in the ocean play in carbon storage, as well as the implications of damage to marine life.
The role of terrestrial ecosystems
Our estimation that pre-industrial atmospheric CO2 would rise by 163ppm without ocean biology is on the lower end of the 150-240ppm range approximated by some previous studies.
However, previous estimates of the contribution of the biological carbon pump in a pre-industrial climate neglect the interactions between oceanic and terrestrial biospheres.
Our research reveals that terrestrial ecosystems – such as tropical forests and grasslands – play a crucial role in compensating for the increase in CO2 concentrations when ocean life declines. (This is due to the CO2 fertilisation effect, when higher CO2 concentrations speed up photosynthesis).
We find that in the extreme pre-industrial scenario, approximately half the carbon lost from the ocean is absorbed by the land.
The figure below illustrates the Earth’s carbon reservoirs in a pre-industrial climate with (left) and without (right) marine life. It shows how, if marine life is wiped out, carbon content decreases in the ocean and marine sediment, whereas more carbon accumulates in the atmosphere and on land.
Ramifications for the future
Today, the ocean captures approximately 25% of human-caused CO2 emissions – which allows it to play a crucial role in slowing global warming.
In order to estimate the overall importance of marine life to carbon sequestration in the ocean, we also conduct experiments for various future emission pathways – both with, and without, marine life.
In all cases, we find that more CO2 emitted by human activities remains in the atmosphere when there is no marine life.
One might think that the ocean’s lower concentrations of carbon in the pre-industrial climate, relative to the atmosphere, might mean it would be able to absorb more additional carbon.
However, we find the absence of marine life fundamentally alters the vertical distribution of carbon in the ocean. Although the total amount of carbon stored is lower, there is more carbon at the surface due to an absence of organisms. This, in turn, hinders additional CO2 from entering the ocean.
Another surprising finding of the simulations was that the terrestrial biosphere’s capacity to absorb excess CO2 by increasing its vegetation mass diminishes over time, potentially due to limited nutrients.
The figure below shows the distribution of human-caused CO2 in the Earth’s carbon reservoirs under two 2100 scenarios. The chart on the left shows a scenario with ocean life, and the chart on the right shows one without ocean biology.
It illustrates how, without marine life, more CO2 stays in the atmosphere and less goes into the land and the ocean.
The study shows that in the absence of marine life, future warming would occur faster and more intensely.
This acceleration in warming would potentially trigger other processes that could further amplify warming, such as greater ocean stratification, longer sea-ice free Arctic summers and greater loss of permafrost.
Economic benefits
Damaging marine life is economically costly given the many and various benefits – or “ecosystem services” – provided by carbon sequestration.
We estimate that the sinking of organic matter sequesters approximately 2.8bn tonnes of carbon annually, locking it away from the atmosphere for at least 50 years.
This carbon sequestration capacity is equivalent to 10bn tonnes of atmospheric CO2 – or roughly 27% of emissions generated by fossil fuels in 2024.
We estimate – based on a carbon price of $90 per tonne of CO2 – that the carbon storage provided by the marine carbon pump is worth $545bn per year in international waters and $383bn per year within national waters. Its total value is projected to exceed $2.2tn by 2030.
Carbon storage is valuable because it helps avoid climate impacts.
This economic value is important for developing countries, particularly small island developing states whose national waters are collectively responsible for 11% of biological carbon pump sequestration activity, in terms of carbon stored.
The top eight countries where the biological carbon pump value is highest in proportion to gross domestic product (GDP) are small island states. These are the Cook Islands, Kiribati, the Marshall Islands, Micronesia, Nauru, Niue, Palau and Tuvalu. Of these nations, just one – the Cook Islands – is classified by the World Bank as high income.
These climate-impacted nations’ key role in preserving ocean health should be considered in discussions of international climate finance.
The figure below shows the economic value of carbon sequestration of the biological carbon pump for each of these eight small island states, calculated on the basis of a carbon price of $90 per tonne of CO2.
For example, it illustrates how Micronesia and Kiribati have an estimated biological carbon pump value of $4,620m and $8,525m each year, respectively.
A healthy ocean buys the world time in the battle against global warming, but the window to protect it is closing rapidly.
Marine ecosystems remain vulnerable to a raft of human activities, including industrial fishing, pollution, shipping and deep-sea mining. Stronger conservation policies, enhanced financial incentives for lower income countries and increased international cooperation are essential to protect the services provided by ecosystems.
These are important steps towards not only protecting 30% of the global ocean as agreed under the new Global Biodiversity Framework – but it will help to reach the Paris Agreement’s climate target.
There are a number of tools at governments disposal to protect the valuable services provided by marine ecosystems. This includes promoting sustainable fishing and ecotourism, establishing marine protected areas and undertaking robust environmental impact assessments.
Nations can also support protection of the biological heat pump within international waters by ratifying the High Seas Treaty, which recognises the importance of protecting biogeochemical cycles.
The post Guest post: How marine life provides climate benefits worth billions of dollars appeared first on Carbon Brief.
Guest post: How marine life provides climate benefits worth billions of dollars
The US is expected to resume its attempt to sink measures for a greener global shipping sector at closed-door talks between governments at the International Maritime Organization (IMO) in early September.
The US and oil-producing allies like Saudi Arabia want to weaken a proposed plan for cleaner fuels that aims to reduce planet-heating emissions from the industry, which relies heavily on dirty bunker fuels. Shipping currently represents 3% of global emissions.
Those that want a softer system are likely to back a Liberian proposal which expert analysis suggests would see emissions fall by only half at most by 2050, far short of the sector’s agreed climate goals.
After several years of debate, governments provisionally agreed in April 2025 on the “Net Zero Framework” (NZF), a series of emissions reduction targets for shipowners, backed up with financial rewards for meeting the targets and fees for missing them.
But in October 2025, after a high-profile intervention from US President Donald Trump and threats of sanctions and visa restrictions, the US convinced a majority of voting nations to postpone the adoption of the NZF for a year.
Ralph Regenvanu, climate minister for the Pacific nation of Vanuatu, called the delay “unacceptable” given the urgency of accelerating climate change.
After a round of low-profile talks in May, the first of three further sets of talks on how to clean up shipping will begin at the IMO’s riverside headquarters in London on Tuesday, culminating in a final public session in November.
Em Fenton, who follows the talks as senior director of climate diplomacy at Opportunity Green, an NGO focused on aviation and shipping, said governments should not be sidetracked by alternative proposals to the NZF, calling them “a distraction from a hard-fought multilateral compromise”.
“If countries want to deliver a just and fair maritime transition, there is really only one choice: back the NZF and stand together in solidarity against those who would tear it apart,” Fenton added.
Five proposals on the table
Governments will discuss five different proposals submitted in advance of next week’s meeting. The most ambitious of these is from the Pacific island nation of Tuvalu, which has proposed a levy on the entirety of a ship’s emissions rather than just those above a certain level, as the NZF envisions.
That had been the original demand of Pacific nations before the NZF was provisionally adopted in April 2025. At the time, Tuvalu’s transport minister Simon Kofe described the NZF as disappointing and not ambitious enough.
For this reason, six Pacific countries abstained in the vote on the NZF. While they supported the original plan for its adoption in October 2025, they have used the delay to push again for more ambition.
John Kautoke, advisor to a group of Pacific nations called 6PAC+, told Climate Home News that the NZF “cannot diminish its already inadequate ambition. If anything, the NZF must increase in ambition if we are going to renegotiate its parameters.”
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Analysis by the Institute of Marine Engineering, Science and Technology (IMarEST) suggests that, of the five proposals, only Tuvalu’s would meet the 2030 and 2040 emissions reduction targets for global shipping that were agreed by governments in 2023. Those were for cuts of 20% between 2008 and 2030, 70% by 2040 and then reaching net zero “by or around, i.e. close to 2050”.
Despite this, the UK, Australia, Canada and South Africa have formally proposed that governments adopt the NZF, which won support in a 63-13 vote among governments at the April 2025 talks. Trump’s US walked out halfway through.
According to IMarEst’s analysis, while the NZF proposal will not be enough to meet the industry’s targets, it will reduce emissions more cheaply than the Pacific proposal.
A proposal by Brazil – which fought hard for the NZF last October – suggests tweaking the framework to make meeting targets easier in the short term and harder in the long term.
While this compromise will make it more appealing to the owners of polluting ships and countries that support them, IMarEst estimates it would lead to higher cumulative emissions than either the NZF or Pacific proposals.
The NZF stipulates that fees for high-polluting shipowners should be be put into a Net Zero Fund and used to promote clean shipping fuels and a fairer transition. The Brazilian proposal would delay raising and spending these funds by two years, from 2029 to 2031.
Liberia’s proposal weakens emissions cuts
The US and Saudi Arabia are likely to swing behind a new proposal from Liberia, whose government makes millions of dollars a year selling the right for shipowners to register their vessels in the small West African nation via a US-based company.
This proposal would weaken the emissions reduction targets. IMarEst says it would cut the industry’s emissions at most by a half by 2050, falling far short of the target agreed in 2023 for international shipping to reach net zero “close to 2050”.
It would also replace the NZF’s fees for missing targets with a carbon trading system. As a result, there would be no Net Zero Fund and therefore less money available to incentivise green fuels and make the transition more equitable for poorer nations.
Pacific advisor Kautoke said that, as well as preventing shipping from reaching zero emissions by 2050, Liberia’s proposal would mean the Pacific “will not receive any support to deal with the disproportionately negative impacts created by the cost of the transition”.
“We get a double blow if we adopt the Liberian proposal,” he warned. “We get all the cost of a transition without any support, and we have an industry that continues to burn fossil fuels to an unforeseen point.”
Japanese proposal favours shipowners
Japan has submitted a late proposal to amend the NZF so that shipowners have more control over how the fees they would pay for emitting above a set threshold are spent.
University College London professor Tristan Smith has argued that this change means there will be no central mechanism to incentivise investments in clean fuels. He wrote on LinkedIn that under the system put forward by Japan, shipowners would be able to select which green projects their fees would go to. They could choose their own or those of a sister company or other shipowners, rather than funding broader just transition projects that would benefit marine workers or developing countries hit by rising shipping costs.
Despite its flaws, Smith added that Japan’s proposal “could still get taken seriously by some, given how appealing it may seem to shipowners who have consistently demanded control of revenues, and given how the US and other member states have pushed back against the IMO Net Zero Fund and [greenhouse gas] pricing.”
Tacit or explicit approval?
Next week, governments are expected to make statements saying which proposals – or which aspects of proposals – they prefer. Another set of talks will be held from November 23-27 before a potentially final round from November 30-December 4.
A new framework to tackle shipping emissions could be adopted at those talks if two-thirds of countries that are present and signed up to a regulation called Marpol Annex VI – endorsed by just over 100 states – vote in favour of it, as they did in April 2025.
The US and its allies are also trying to change the rules to make the next stage more difficult. Decisions that have been adopted at IMO meetings usually take effect automatically unless a certain number of countries object within a certain time period decided by governments, a system known as tacit approval.
But the US wants that to require explicit approval instead, so that any new emissions standard would not come into force unless enough governments – representing a certain percentage of the world’s shipping fleet – actively indicate support for it.
Critics say this change would give a small number of countries with large shipping registries the power to block implementation. Liberia has the world’s biggest shipping registry, run by an American company, followed by Panama and the Republic of the Marshall Islands.
Liberia and Panama have supported the US at the talks on the Net Zero Framework. The Marshall Islands has long been one of the most vocal supporters of climate action in shipping but, with its officials and shipping registry income vulnerable to US retaliation, did not sign on to the recent Pacific proposal vowing to strengthen the NZF if it is re-opened.
Brazilian negotiator Adriana de Medeiros Gabinio warned in April that the NZF’s opponents are trying to change the rules by which it comes into force as a “safety net to block” it.
The post Battle over cleaning up shipping set to resume at London talks appeared first on Climate Home News.
Battle over cleaning up shipping set to resume at London talks
SYDNEY, Wednesday 26 August 2026 — New 2026 Sustainability Reports released by supermarket giants Coles and Woolworths this week demonstrate the retailers are failing on their commitments to end deforestation in their supply chains.
Adele Chasson, Nature Policy Lead at Greenpeace Australia Pacific said:
“These so-called sustainability reports are revealing. Despite their public commitments in 2024 and 2025, neither Coles nor Woolworths have taken deforestation-linked beef off their shelves. Meanwhile, bulldozers continue to tear up forests and bushland, pushing wildlife closer to extinction and causing mass toxic runoff to flow into the Great Barrier Reef. Millions of native animals like koalas are losing their homes to beef pastures each year, while the big supermarkets put off action.
“Australians would be shocked to know that beef on the shelves of our biggest supermarkets could be pushing threatened species to the brink of extinction. Collectively Coles and Woolworths have made more than $2 billion in profits in the last year, profiting from the destruction of wildlife and precious Australian nature. Coles and Woolworths owe it to shoppers to deliver on their promises and end deforestation in their supply chains now.
“As big beef buyers, Coles and Woolworths have an essential role to play in keeping Australia’s unique forests standing. They can help stop the Great Barrier Reef from being poisoned by runoff and protect iconic forest wildlife by taking deforestation off their shelves. It’s time these big companies put their money where their mouths are and follow through on their promise of sourcing and supplying deforestation-free beef.”
New Zealand’s parliament has adopted a controversial new law blocking a whole avenue of climate litigation and shutting down its most advanced corporate lawsuit, which has been blamed by the government for shaking business confidence and investment.
The Climate Change Response (Tort Liability) Amendment Bill, expected to take effect in the coming days after it is formally signed by the Governor-General, prevents all current and future civil claims for climate loss or harm under tort law.
Justice minister Paul Goldsmith said last week that the aim was to give businesses “certainty around their climate change obligations”, noting it would not alter the government’s responsibilities under the Climate Change Response Act 2002 nor business obligations under the Emissions Trading Scheme.
“Our response to climate change is best managed by the Government at a national level and not through piece-meal litigation in the courts,” he added in a statement.
Such litigation, he said, “risks developing a new regime that contradicts the framework Parliament has already enacted” to tackle climate change.
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Experts say that despite dismissing the lawsuit, the ruling sets a precedent by confirming that climate science can establish legal liability for the damage caused by emissions
Goldsmith singled out a key domestic climate lawsuit brought by Northland iwi leader and activist Mike Smith against six big companies: dairy firms Fonterra and Dairy Holdings, energy firms Genesis Energy and Z Energy, New Zealand Steel and coal mining firm BT Mining. A seventh original defendant, Channel Infrastructure, was dropped after it permanently decommissioned its Marsden Point oil refinery.
Smith argued that these companies had caused him harm under public nuisance and negligence law, as well as a third breach of a duty to cease contributing to climate change that has yet to be tested domestically. He did not seek financial compensation, instead asking for the companies to immediately stop emitting or contributing to net greenhouse gas emissions.
In one of the most advanced corporate climate accountability lawsuits in the world, a trial had been scheduled for April 2027 after the Supreme Court unanimously allowed the case to continue.
Corporate lobbying in the shadows
Smith described the passing of the bill as “deeply concerning”, particularly as it coincided with the Supreme Court hearing another of his climate lawsuits. In that case, Smith v Attorney-General, he argues that the government’s response to climate change and its impacts on Māori communities in particular breaches rights to life and culture.
“That timing raises profound questions about the separation of powers and the rule of law,” said Smith. “Whatever one’s view of the merits of these cases, it is deeply troubling when parliament intervenes to remove a legal pathway while the courts are actively considering fundamental questions about climate responsibility, rights and the crown’s obligations.”
The bill – which says that no person (including the government) can be found liable in tort for emissions-related climate change effects – followed major lobbying efforts by the companies defending themselves in Smith’s lawsuit. They outlined a proposed legal amendment in a briefing note to the government in 2024.
The centre-right government has been fiercely criticised over its lack of transparency in relation to this lobbying activity. The national ombudsman recently found that the Prime Minister’s Office effectively withheld information requested by the Environmental Law Initiative about meetings, discussions and conversations regarding Smith’s case.
Green groups fail to stop bill
The bill sparked huge concern among environmental campaigners in New Zealand and elsewhere. Greenpeace Aotearoa called it a “shocking abuse of executive power” and the vast majority of submissions to a parliamentary inquiry said it should be rejected.
But in the end, it was adopted with little resistance, moving relatively smoothly through parliament, passing its third reading by 67 votes to 53. Sam Bookman, climate law lecturer at Melbourne Law School, told Climate Home News he was not surprised by this, given that the coalition government has a secure majority.
A complaint has been made to the UN special rapporteur on climate change and human rights by Smith, the National Iwi Chairs Forum Pou Tikanga and youth coalition Climate Clinic Aotearoa over what they see as the government’s heavy-handed approach. Smith is also challenging the new law in yet another lawsuit.
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Bookman thinks it “very unlikely” that such a challenge will succeed, noting that New Zealand’s constitution is firmly anchored in parliamentary sovereignty.
But the expert in climate law does not see the bill as the end of legal action in the country, noting that New Zealand has a “sophisticated climate litigation landscape with a growing number of specialist and experienced lawyers and NGOs”.
The country is also approaching its next general election in November, and some opposition parties have pledged to restore access to the courts if elected.
Amanda Larsson, global project lead on agriculture for Greenpeace International, said: “This law deserves to be tested, and I strongly encourage the international climate litigation community to unite and help defend New Zealanders’ fundamental right to hold polluters accountable before this becomes a global blueprint.”
Copycat legislation on the rise
New Zealand’s move is part of a small but growing legislative effort to shut down climate litigation around the world.
In the US, Republican politicians introduced legislation in the House and Senate in April that would shield fossil fuel firms from climate liability lawsuits. Similar laws have already been passed at state level in Tennessee, Utah, Iowa and Louisiana.
The German state of Bavaria has put forward a similar proposal to the Federal Council, aiming to block private climate claims as well as the recognition and enforcement of foreign judgments imposing such liability. There are also proposals to limit available remedies and actions in the Netherlands and Belgium.
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Bookman said he expects more efforts to counter climate damages litigation and advised plaintiffs to think about how to respond, including drawing on broader support in opposing them.
“Even though it’s very hard for plaintiffs to win these types of cases, companies are very eager to avoid the expense, embarrassment and political accountability that come even with unsuccessful lawsuits,” he said.
The post New Zealand moves to protect business with law curtailing climate litigation appeared first on Climate Home News.
New Zealand moves to protect business with law curtailing climate litigation
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