On 12 February, US president Donald Trump revoked the “endangerment finding”, the bedrock of federal climate policy.
The 2009 finding concluded that six key greenhouse gases, including carbon dioxide (CO2), were a threat to human health – triggering a legal requirement to regulate them.
It has been key to the rollout of policies such as federal emission standards for vehicles, power plants, factories and other sources.
Speaking at the White House, US Environmental Protection Agency (EPA) administrator Lee Zeldin claimed that the “elimination” of the endangerment finding would save “trillions”.
The revocation is expected to face multiple legal challenges, but, if it succeeds, it is expected to have a “sweeping” impact on federal emissions regulations for many years.
Nevertheless, US emissions are expected to continue falling, albeit at a slower pace.
Carbon Brief takes a look at what the endangerment finding was, how it has shaped US climate policy in the past and what its repeal could mean for action in the future.
- What is the ‘endangerment finding’?
- How has it shaped federal climate policy?
- How is the finding being repealed and will it face legal challenge?
- What does this mean for federal efforts to address climate change?
- What has the reaction been?
- What will the repeal mean for US emissions?
What is the ‘endangerment finding’?
The challenges of passing climate legislation in the US have meant that the federal government has often turned instead to regulations – principally, under the 1970 Clean Air Act.
The act requires the EPA to regulate pollutants, if they are found to pose a danger to public health and the environment.
In a 2007 legal case known as Massachusetts vs EPA, the Supreme Court ruled that greenhouse gases qualify as pollutants under the Clean Air Act. It also directed the EPA to determine whether these gases posed a threat to human health.
The 2009 “endangerment finding” was the result of this process and found that greenhouse gas emissions do indeed pose such a threat. Subsequently, it has underpinned federal emissions regulations for more than 15 years.
In developing the endangerment finding, the EPA pulled together evidence from its own experts, the US National Academies of Sciences, Engineering and Medicine and the wider scientific community.
On 7 December 2009, it concluded that US greenhouse gas emissions “in the atmosphere threaten the public health and welfare of current and future generations”.
In particular, the finding highlighted six “well-mixed” greenhouse gases: carbon dioxide (CO2); methane (CH4); nitrous oxide (N2O); hydrofluorocarbons (HFCs); perfluorocarbons (PFCs); and sulfur hexafluoride (SF6).
A second part of the finding stated that new vehicles contribute to the greenhouse gas pollution that endangers public health and welfare, opening the door to these emissions being regulated.
At the time, the EPA noted that, while the finding itself does not impose any requirements on industry or other entities, “this action was a prerequisite for implementing greenhouse gas emissions standards for vehicles and other sectors”.
On 15 December 2009, the finding was published in the federal register – the official record of US federal legislation – and the final rule came into effect on 14 January 2010.
At the time, then-EPA administrator Lisa Jackson said in a statement:
“This finding confirms that greenhouse gas pollution is a serious problem now and for future generations. Fortunately, it follows President [Barack] Obama’s call for a low-carbon economy and strong leadership in Congress on clean energy and climate legislation.
“This pollution problem has a solution – one that will create millions of green jobs and end our country’s dependence on foreign oil.”
How has it shaped federal climate policy?
The endangerment finding originated from a part of the Clean Air Act regulating emissions from new vehicles and so it was first applied in that sector.
However, it came to underpin greenhouse gas emission regulation across a range of sectors.
In May 2010, shortly after the Obama EPA finalised the finding, it was used to set the country’s first-ever limits on greenhouse gas emissions from light-duty engines in motor vehicles.
The following year, the EPA also released emissions standards for heavy-duty vehicles and engines.
However, findings made under one part of the Clean Air Act can also be applied to other articles of the law. David Widawsky, director of the US programme at the World Resources Institute (WRI), tells Carbon Brief:
“You can take that finding – and that scientific basis and evidence – and apply it in other instances where air pollutants are subject or required to be regulated under the Clean Air Act or other statutes.
“Revoking the endangerment finding then creates a thread that can be pulled out of not just vehicles, but a whole lot of other [sources].”
Since being entered into the federal register, the endangerment finding has also been applied to stationary sources of emissions, such as fossil-fuelled power plants and factories, as well as an expanded range of non-stationary emissions sources, including aviation.
(In fact, the EPA is compelled to regulate emissions of a pollutant – such as CO2 as identified in the endangerment finding – from stationary sources, once it has been regulated anywhere else under the Clean Air Act.)
In 2015, the EPA finalised its guidance on regulating emissions from fossil-fuelled power plants. These performance standards applied to newly constructed plants, as well as those that underwent major modifications.
This ruling noted that “because the EPA is not listing a new source category in this rule, the EPA is not required to make a new endangerment finding…in order to establish standards of performance for the CO2”.
The following year, the agency established rules on methane emissions from oil and gas sources, including wells and processing plants. Again, this was based on the 2009 finding.
The 2016 aircraft endangerment finding also explicitly references the vehicle-emissions endangerment finding. That rule says that the “body of scientific evidence amassed in the record for the 2009 endangerment finding also compellingly supports an endangerment finding” for aircraft.
The endangerment finding has also played a critical role in shaping the trajectory of climate litigation in the US.
In a 2011 case, American Electric Power Co. vs Connecticut, the Supreme Court unanimously found that, because greenhouse gas emissions were already regulated by the EPA under the Clean Air Act, companies could not be sued under federal common law over their greenhouse gas emissions.
Widawsky tells Carbon Brief that repealing the endangerment finding therefore “opens the door” to climate litigation of other kinds:
“When plaintiffs would introduce litigation in federal courts, the answer or the courts would find that EPA is ‘handling it’ and there’s not necessarily a basis for federal litigation. By removing the endangerment finding…it actually opens the door to the question – not necessarily successful litigation – and the courts will make that determination.”
How is the finding being repealed and will it face legal challenge?
The official revocation of the endangerment finding is yet to be posted to the federal register. It will be effective 60 days after the text is published in the journal.
It is set to face no shortage of legal challenges. The state of California has “vowed” to sue, as have a number of environmental groups, including Sierra Club, Earthjustice and the National Resources Defense Council.
Dena Adler, an adjunct professor of law at New York University School of Law, tells Carbon Brief there are “significant legal and analytical vulnerabilities” in the EPA’s ruling. She explains:
“This repeal will only stick if it can survive legal challenge in the courts. But it could take months, if not years, to get a final judicial decision.”
At the heart of the federal agency’s argument is that it claims to lack the authority to regulate greenhouse gas emissions in response to “global climate change concerns” under the Clean Air Act.
In the ruling, the EPA says the section of the Act focused on vehicle emissions is “best read” as authorising the agency to regulate air pollution that harms the public through “local or regional exposure” – for instance, smog or acid rain – but not pollution from “well-mixed” greenhouse gases that, it claims, “impact public health and welfare only indirectly”.
This distinction directly contradicts the landmark 2007 Supreme Court decision in Massachusetts vs EPA. (See: What is the ‘endangerment finding’?)
The EPA’s case also rests on an argument that the agency violated the “major questions doctrine” when it started regulating greenhouse gas emissions from vehicles.
This legal principle holds that federal agencies need explicit authorisation from Congress to press ahead with actions in certain “extraordinary” cases.
In a policy brief in January, legal experts from New York University School of Law’s Institute of Policy Integrity argued that the “major questions doctrine” argument “fails for several reasons”.
Regulating greenhouse gas emissions under the Clean Air Act is “neither unheralded nor transformative” – both of which are needed for the legal principle to apply, the lawyers said.
Furthermore, the policy brief noted that – even if the doctrine were triggered – the Clean Air Act does, in fact, supply the EPA with the “clear authority” required.
Mark Drajem, director of public affairs at NRDC, says the endangerment finding has been “firmly established in the courts”. He tells Carbon Brief:
“In 2007, the Supreme Court directed EPA to look at the science and determine if greenhouse gases pose a risk to human health and welfare. EPA did that in 2009 and federal courts rejected a challenge to that in 2012.
“Since then, the Supreme Court has considered EPA’s greenhouse gas regulations three separate times and never questioned whether it has the authority to regulate greenhouse gases. It has only ruled on how it can regulate that pollution.”
However, experts have noted that the Trump administration is banking on legal challenges making their way to the Supreme Court – and the now conservative-leaning bench then upholding the repeal of the endangerment finding.
Elsewhere, the EPA’s new ruling argues that regulating emissions from vehicles has “no material impact on global climate change concerns…much less the adverse public health or welfare impacts attributed to such global climate trends”.
“Climate impact modelling”, it continues, shows that “even the complete elimination of all greenhouse gas emissions” of vehicles in the US would have impacts that fall “within the standard margin of error” for global temperature and sea level rise.
In this context, it argues, regulations on emissions are “futile”.
(The US is more historically responsible for climate change than any other country. In its 2022 sixth assessment report, the Intergovernmental Panel on Climate Change said that further delaying action to cut emissions would “miss a brief and rapidly closing window of opportunity to secure a liveable and sustainable future for all”.)
However, the final rule stops short of attempting to justify the plans by disputing the scientific basis for climate change.
Notably, the EPA has abandoned plans to rely on the findings of a controversial climate science report commissioned by the Department of Energy (DoE) last year.
This is a marked departure from the draft ruling, published in August, which argued there were “significant questions and ambiguities presented by both the observable realities of the past nearly two decades and the recent findings of the scientific community, including those summarised in the draft CWG [‘climate working group’] report”.
The CWG report – written by five researchers known for rejecting the scientific consensus on human influence on global warming – faced significant criticism for inaccurate conclusions and a flawed review process. (Carbon Brief’s factcheck found more than 100 misleading or false statements in the report.)
A judge ruled in January that the DoE had broken the law when energy secretary Chris Wright “hand-picked five researchers who reject the scientific consensus on climate change to work in secret on a sweeping government report on global warming”, according to the New York Times.
In a press release in July, the EPA said “updated studies and information” set out in the CWG report would serve to “challenge the assumptions” of the 2009 finding.
But, in the footnotes to its final ruling, the EPA notes it is not relying on the report for “any aspect of this final action” in light of “concerns raised by some commenters”.
Legal experts have argued that the pivot away from arguments undermining climate science is designed with future legal battles over the attempted repeal in mind.
What does this mean for federal efforts to address climate change?
As mentioned above, a number of groups have already filed legal actions against the Trump administration’s move to repeal the endangerment finding – leaving the future uncertain.
However, if the repeal does survive legal challenges, it would have far-reaching implications for federal efforts to address greenhouse gas emissions, experts say.
In a blog post, the WRI’s Widawsky said that the repeal would have a “sweeping” impact on federal emissions regulations for cars, coal-fired power stations and gas power plants, adding:
“In practical terms, without the endangerment finding, regulating greenhouse gas emissions is no longer a legal requirement. The science hasn’t changed, but the obligation to act on it has been removed.”
Speaking to Carbon Brief, Widawsky adds that, despite this large immediate impact, there are “a lot of mechanisms” future US administrations might be able to pursue if they wanted to reinstate the federal government’s obligation to address greenhouse gas emissions:
“Probably the most direct way – rather than talk about ‘pollutants’, in general, and the EPA, say, making a science-specific finding for that pollutant – [is] for Congress simply to declare a particular pollutant to be a hazard for human health and welfare. [This] has been done in other instances.”
If federal efforts to address greenhouse gas emissions decline, there will likely still be attempts to regulate at the state level.
Previous analysis from the University of Oxford noted that, despite a walkback on federal climate policy in Trump’s second presidential term, 19 US states – covering nearly half of the country’s population – remain committed to net-zero targets.
Widawksy tells Carbon Brief that it is possible that states may be able to leverage legislation, including the Clean Air Act, to enact regulations to address emissions at the state level.
However, in some cases, states may be prevented from doing so by “preemption”, a US legal doctrine where higher-level federal laws override lower-level state laws, he adds:
“There are a whole lot of other sections of the Clean Air Act that may either inhibit that kind of ability for states to act through preemption or allow for that to happen.”
What has the reaction been?
The Trump administration’s decision has received widespread global condemnation, although it has been celebrated by some right-wing newspapers, politicians and commentators.
In the US, former US president Barack Obama said on Twitter that the move will leave Americans “less safe, less healthy and less able to fight climate change – all so the fossil-fuel industry can make even more money”.
Similarly, California governor Gavin Newsom called the decision “reckless”, arguing that it will lead to “more deadly wildfires, more extreme heat deaths, more climate-driven floods and droughts and greater threats to communities nationwide”.
Former US secretary of state and climate envoy John Kerry called the decision “un-American”, according to a story on the frontpage of the Guardian. He continued:
“[It] takes Orwellian governance to new heights and invites enormous damage to people and property around the world.”
An editorial in the Guardian dubbed the repeal as “just one part of Trump’s assault on environmental controls and promotion of fossil fuels”, but added that it “may be his most consequential”.
Similarly, an editorial in the Hindu said that Trump is “trying to turn back the clock on environmental issues”.
In China, state-run news agency Xinhua published a cartoon depicting Uncle Sam attempting to turn an ageing car, marked “US climate policy”, away from the road marked “green development”, back towards a city engulfed in flames and pollution that swells towards dark clouds labelled “greenhouse gas catastrophe”.
Conversely, Trump described the finding as “the legal foundation for the green new scam”, which he claimed “the Obama and Biden administration used to destroy countless jobs”.
Similarly, Al Jazeera reported that EPA administrator Zeldin said the endangerment finding “led to trillions of dollars in regulations that strangled entire sectors of the US economy, including the American auto industry”. The outlet quoted him saying:
“The Obama and Biden administrations used it to steamroll into existence a left-wing wish list of costly climate policies, electric vehicle mandates and other requirements that assaulted consumer choice and affordability.”
An editorial in the Washington Post also praises the move, saying “it’s about time” that the endangerment finding was revoked. It argued – without evidence – that the benefits of regulating emissions are “modest” and that “free-market-driven innovation has done more to combat climate change than regulatory power grabs like the ‘endangerment finding’ ever did”.
The Heritage Foundation – the climate-sceptic US lobby group that published the influential “Project 2025” document before Trump took office – has also celebrated the decision.
Time reported that the group previously criticised the endangerment finding, saying that it was used to “justify sweeping restrictions on CO2 and other greenhouse gas emissions across the economy, imposing huge costs”. The magazine added that Project 2025 laid out plans to “establish a system, with an appropriate deadline, to update the 2009 endangerment finding”.
Climate scientists have also weighed in on the administration’s repeal efforts. Prof Andrew Dessler, a climate scientist at Texas A&M University in College Station, argued that there is “no legitimate scientific rationale” for the EPA decision.
Similarly, Dr Katharine Hayhoe, chief scientist at the Nature Conservancy, said in a statement that, since the establishment of the 2009 endangerment finding, the evidence showing greenhouse gases pose a threat to human health and the environment “has only grown stronger”.
Dr Gretchen Goldman, president and CEO of the Union of Concerned Scientists and a former White House official, gave a statement, arguing that “ramming through this unlawful, destructive action at the behest of polluters is an obvious example of what happens when a corrupt administration and fossil fuel interests are allowed to run amok”.
In the San Francisco Chronicle, Prof Michael Mann, a climate scientist at the University of Pennsylvania, and Bob Ward, policy and communications director at the Grantham Research Institute, wrote that Trump is “slowing climate progress”, but that “it won’t put a stop to global climate action”. They added:
“The rest of the world is moving on and thanks to Trump’s ridiculous insistence that climate change is a ‘hoax’, the US now stands to lose out in the great economic revolution of the modern era – the clean-energy transition.”
What will the repeal mean for US emissions?
Federal regulations and standards underpinned by the endangerment finding have been at the heart of US government plans to reduce the nation’s emissions.
For example, NRDC analysis of EPA data suggests that Biden-era vehicle standards, combined with other policies to boost electric cars, were set to avoid nearly 8bn tonnes of CO2 equivalent (GtCO2e) over the next three decades.
By removing the legal requirement to regulate greenhouse gases at a federal level from such high-emitting sectors, the EPA could instead be driving higher emissions.
Nevertheless, some climate experts argue that the repeal is more of a “symbolic” action and that EPA regulations have not historically been the main drivers of US emissions cuts.
Rhodium Group analysis last year estimated the impact of the EPA removing 31 regulatory policies, including the endangerment finding and “actions that rely on that finding”. Most of these had already been proposed for repeal independently by the Trump administration.
Ben King, the organisation’s climate and energy director, tells Carbon Brief this “has the same effect on the system as repealing the endangerment finding”.
The Rhodium Group concluded that, in this scenario, emissions would continue falling to 26-35% below 2005 levels by 2035, as the chart below shows. If the regulations remained in place, it estimated that emissions would fall faster, by around 32-44%.
(Notably, neither of these scenarios would be in line with the Biden administration’s international climate pledge, which was a 61-66% reduction by 2035).
There are various factors that could contribute to continued – albeit slower – decline in US emissions, in the absence of federal regulations. These include falling costs for clean technologies, higher fossil-fuel prices and state-level legislation.
Despite Trump’s rhetoric, coal plants have become uneconomic to operate in the US compared with cheaper renewables and gas. As a result, Trump has overseen a larger reduction in coal-fired capacity than any other US president.
Meanwhile, in spite of the openly hostile policy environment, relatively low-cost US wind and solar projects are competitive with gas power and are still likely to be built in large numbers.
The vast majority of new US power capacity in recent years has been solar, wind and storage. Around 92% of power projects seeking electricity interconnection in the US are solar, wind and storage, with the remainder nearly all gas.
The broader transition to low-carbon transport is well underway in the US, with electric vehicle sales breaking records during nearly every month in 2025.
This can partly be attributed to federal tax credits, which the Trump administration is now cutting. However, cheaper models, growing consumer preference and state policies are likely to continue strengthening support.
Even if emissions continue on a downward trajectory, repealing the endangerment finding could make it harder to drive more ambitious climate action in the future. Some climate experts also point to the uncertainty of future emissions reductions.
“[It] depends on a number of technology, policy, economic and behavioural factors. Other folks are less sanguine about greenhouse gas declines,” WRI’s Widawsky tells Carbon Brief.
The post Q&A: What does Trump’s repeal of US ‘endangerment finding’ mean for climate action? appeared first on Carbon Brief.
Q&A: What does Trump’s repeal of US ‘endangerment finding’ mean for climate action?
Climate Change
We need no-go mining zones for the energy transition to be just: Here’s how it could work
Perrine Fournier is a trade, mining, and forest campaigner at Fern.
The threat that mining critical raw materials poses to some of the planet’s most important ecosystems is beyond dispute. To prevent it, some places on Earth must be declared off-limits for mining under any circumstances. Work has already began to identify them.
A global power struggle to secure strategic resources powering the energy transition, AI and weapons systems is driving growing demand for minerals such as copper, cobalt, lithium, nickel and manganese, which are used to make electric vehicles (EVs), batteries, wind turbines and other clean energy technologies needed to transition away from fossil fuels.
This mining boom is compounding the threats that extraction poses to precious ecosystems – including tropical forests which are vital to address climate change – and the communities who depend on them.
Preventing this environmental destruction and ensuring that mining is carried out within planetary boundaries is urgent. One solution that is gaining traction has long been advocated by Indigenous groups: creating mining no-go zones.
Fern and a group of NGOs in consultations with Indigenous Peoples’ organisations have began to sketch out a methodology to map out where mining poses unacceptable social, environmental and human rights-related risks and should be prohibited.
Off-limits: Fragile ecosystems that store carbon
The methodology is based on six criteria to determine where mining should be off-limits.
This includes areas protected under international conventions; areas with high conservation value from intact forests to key biodiversity hotspots; forests, peatlands and wetlands that are critical for carbon storage; significant ecosystems such as small islands, mangroves and grasslands; critical water bodies and Indigenous Peoples’ territories.
Around half of the of the metals and minerals needed for the energy transition are located on or near Indigenous Peoples’ territories.
A case in point is Brazil, one of the most mineral-rich countries on earth. Recent research shows that the expansion of mining threatens the conservation of about 363,000 km2 of protected land in the Brazilian Amazon, which consist mainly of forests, and is home to 195,000 traditional and Indigenous people.
Deforestation is a major driver of climate change as it releases carbon stored in the trees into the atmosphere, weakening the forests’ role as a carbon sink. Most of the Brazilian Amazon should therefore be off-limits to mining, both to protect Indigenous Peoples’ rights and because of its crucial role for the climate and biodiversity.
In the Democratic Republic of Congo, mining has had a devastating impact on the precious Miombo forest, one of the world’s largest dry forest ecosystems, and local peoples’ food security. This too is an area where mining should not be allowed to take place.
Protected areas must be default no-go zones
In Europe, efforts to secure access to minerals is also threatening fragile ecosystems. Recent reporting revealed that the European Commission disregarded expert advice when selecting “strategic” mining sites eligible for streamlined permitting procedures, with several environmentally and socially controversial projects added to the list after they initially failed to meet expert assessments.
One project which met the expert assessment but is nevertheless attracting controversy is the Sakatti nickel mining project in Finnish Lapland.
-
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Part of its nickel deposit lies under a rich peat bog ecosystem, a major carbon store which developed when glacial rivers and a lake melted at the end of the late Ice Age. The site is protected under Finnish law and is as part of the Natura 2000 network intended to protect Europe’s most valuable species and habitats. These legal safeguards are on the verge of being overridden. Such protected areas should always remain off-limits to mining.
Kicking starting a discussion
To prevent mining from undermining human rights and global climate and biodiversity goals, we urgently need to adopt a global and precautionary approach. This should start with a shared definition of which areas on land and sea should be considered off-limits for extraction.
The methodology we propose is intended to kick-start a broader and transparent discussion, based on scientific, legal and social criteria, in which rights-holders and Indigenous Peoples’ organisations have a seat at the table. No mining should go ahead if it doesn’t have the Free Prior and Informed Consent (FPIC) of Indigenous Peoples’ or local communities.
Many of the restricted areas are bound to lie in forested tropical countries in the Global South, which understandably want to capitalise on their resources to spur industrial development and create jobs. But history has taught us that relying on a single resource for development runs the risk of being trapped in a resource curse. The more diversified an economy is, the more secure it is.
Reducing mineral demand
Our modelling shows that for minerals such as nickel, cobalt, lithium, there are sufficient resources that could be mined outside of these restrictive areas to wean the global economy away from climate-wrecking fossil fuels and shift to clean energy systems.
However, that requires hard policy choices, such as reducing mineral demand by promoting more efficient vehicles and alternative battery technologies that are less reliant on critical minerals, as well as better public transport, active travel and car sharing opportunities.
In addition, recycling has a major role to play. A major study recently showed that Europe could meet half of its critical mineral needs through recycling by 2050.
Some mining to access the materials the world needs to address climate change is both inevitable and necessary. But agreeing on a framework to restrict mining in the world’s most sensitive areas will protect them from its ravages, and break the destructive patterns of the past.
The post We need no-go mining zones for the energy transition to be just: Here’s how it could work appeared first on Climate Home News.
We need no-go mining zones for the energy transition to be just: Here’s how it could work
The Pine Island glacier in West Antarctica is one of the fastest-changing glaciers in the world.
Alongside its neighbour, the Thwaites glacier, it is responsible for almost half the sea level rise caused by melting ice sheets in Antarctica.
Scientists know the West Antarctic ice sheet – which includes Thwaites and Pine Island – is retreating because of warm water eroding the ice sheet from below.
But the extent to which this process has been driven by human-caused greenhouse gas emissions, as opposed to natural variations to the Earth’s climate, remains unknown.
Our study, published in the Cryosphere, looks at how human-caused warming has contributed to the retreat of the Pine Island glacier since pre-industrial times.
The research, the first attribution study of glacier retreat on Antarctica, finds that climate change has been responsible for around 4km – roughly a fifth – of the glacier’s retreat.
The West Antarctic ice sheet
Glaciers are frozen rivers of ice and snow that move slowly over land. They are found at high elevations on mountains and on ice sheets.
There are two ice sheets on Earth – covering Antarctica and Greenland. Both were formed over millennia, as layers of snow compressed into dense ice.
Ice sheets grow and shrink depending on temperature and snowfall conditions. In the past, when global temperatures were much colder than present day, vast ice sheets also covered large areas of North America, Scandinavia and Patagonia.
Today, human-driven climate change is accelerating the retreat of ice sheets. This is contributing to sea level rise and altering the Earth’s climate system by pumping vast quantities of fresh melt water into the ocean.
Our research looks at the Pine Island glacier, which is found on the western part of the Antarctic ice sheet.
It is one of the fastest-melting glaciers in the world. Research has shown it has been responsible for a fifth of net ice loss from the West Antarctic ice sheet, which, in turn, has been responsible for almost all ice loss in Antarctica over the past 40 years.
At the coldest point of the last ice age – the “last glacial maximum” period around 20,000 years ago – the West Antarctic ice sheet was much bigger than it is today. Since then, it has retreated by approximately 500km – roughly the distance from Paris to London.
Most of this retreat took place between 10,000 and 20,000 years ago. For the past 10,000 years or so, the ice sheet has been about as big as it is today.
Sediment records beneath the Pine Island glacier reveal that, for hundreds of years until the 1940s, the glacier rested on a seabed ridge that is about 30km ahead of where it sits today.
The sediment records also tell us that the Pine Island glacier started to retreat in the 1940s. This coincided with a strong El Niño event, a recurring climate pattern in the tropical Pacific that drives up global temperatures, that brought a large pulse of warm water to the ice sheet.
This is illustrated in the figures below, which shows how the grounding line – the boundary between grounded and floating ice – of the Pine Island glacier shifted between pre-industrial times (red line) and 2015 (bright blue line).
The map on the left shows an aerial view of grounding line retreat from pre-industrial times (red) to 2015 (blue). The graphic on the right illustrates how the grounding line has shifted across a cross-section of the glacier.
Both illustrate how the glacier has contracted.
Climate reconstructions suggest that human-caused climate change only started to increase the amount of warm water reaching the West Antarctic ice sheet in the 1960s.
This indicates that climate change started to affect the melt rate in the region 20 years after the retreat had already been initiated.
In our research, we wanted to find out how important climate change was to the overall retreat since the 1940s.
Attributing ice sheet retreat
Currently, scientists do not know precisely how much of the retreat of the world’s ice sheets – and the associated sea level rise – is due to human-caused global warming.
Through the field of attribution science, the links between climate change and extreme weather and climate events, including heatwaves, wildfires and droughts, are routinely quantified by scientists.
In attribution studies, scientists typically use climate models to simulate the severity or frequency of an event in two worlds. The first is our existing, climate-changed world and the second is a “counterfactual” world that has not been affected by human-caused warming.
By comparing the model runs, scientists can assess how much climate change influenced an event.
To create these two modelled worlds in an Antarctic context, scientists need to run historical models for at least 200 years into the past. This is because ice sheets respond very slowly to changes in the climate, with very small changes year-on-year.
This presents a challenge, given the limited information available about ice sheet change before satellite records began in the 1970s.
To build a picture of the ice sheets prior to this, scientists have to rely on a few, sparse, palaeoclimate records – including sediment records and seafloor imprints – which tell us where ice was present in the past.
Reconstructing Pine Island’s past
To reconstruct the retreat of the Pine Island glacier – and, therefore, determine the role of climate change – we used a combination of physical climate models and machine learning.
First, we ran many simulations of our model under a range of different settings. This included variations in how important processes are represented, such as how the ice moves and interacts with the ocean.
Then, we compared the results of these simulations to modern satellite observations and older sediment records, allowing us to narrow down the settings that were most realistic. This gave us a set of plausible simulations that agreed with the available observational data.
However, to reconstruct the retreat in full, we needed to find all settings of our model that would agree with the observational data.
Because simulations take a lot of time to run, this was not possible.
Therefore, to fill the gaps and find all plausible simulations, we used machine learning to identify relationships between model settings and simulated glacier retreat.
This exercise allowed us to build a good picture of how the glacier actually retreated over the past 250 years. We call this our “reconstructed” scenario.
We then compared the glacier retreat in this reconstructed world with changes that took place in a counterfactual scenario where there had been no human-caused climate change.
In doing so, we were able to quantify the role that warming played in the shrinking of the Pine Island glacier since the 1940s.
Overall, we estimate that warming has been responsible for around 4km – roughly a fifth – of the glacier’s retreat since 1940.
This is shown in the figure below, which shows how grounding line retreat in the reconstructed scenario (blue) is more extreme than projected by the counterfactual scenario (green).
Interpreting the numbers
Our work quantifies, for the first time, the role of climate change in the retreat of a glacier in the world’s ice sheets – directly linking greenhouse gas emissions with glacier decline.
We also find that the Pine Island glacier may have retreated even without climate change, just not as far. This is similar to how extreme weather events, such as drought or extreme rainfall, could still happen without climate change, just with less frequency or intensity.
One of the key challenges in our research arises from not knowing exactly how large the ice sheet was prior to satellite records.
Although the sediment records tell us where the ice was grounded – that is, what its footprint was – they do not tell us exactly how much ice there was.
This means we do not know exactly how to set up our model at the start of the simulations, which leads to uncertainty in our predictions.
Further work is underway to determine exactly how to best set up the simulations for future research.
The post Guest post: Climate change has caused one-fifth of Pine Island glacier retreat appeared first on Carbon Brief.
Guest post: Climate change has caused one-fifth of Pine Island glacier retreat
Ellen Davies is head of programmes at the African Climate Foundation and is based in Kenya. Wole Hammond is programme officer for adaptation and resilience at the foundation, based in Nigeria.
For generations, African communities have lived on the frontlines of climate disruption, managing erratic rainfall, prolonged droughts and the slow erosion of their livelihoods, which depend on predictable seasons.
When the rains failed across Southern Africa in 2024, it was but the latest chapter of a crisis already long underway. During that season, maize crop failures of 40-80% devastated farming communities in Zambia, Zimbabwe and Malawi, where roughly 70% of people depend on rain-fed agriculture. Governments already stretched by debt were forced to raid development budgets, trading long-term growth for emergency relief.
Then came the floods. In early 2026, parts of Mozambique, Zimbabwe and South Africa received over a year’s worth of rain in days. More than 2 million people were affected. In East Africa, drought has displaced nearly 62,000 people in Somalia this year alone, with nearly one in four Somalis now facing acute food insecurity.
This is what climate change looks like on the ground – not parts per million or diplomatic jargon, but whether a school stays open after floods cut off the road, whether a clinic can function in extreme heat, whether a country can still invest in its future when every year brings another disaster bill.
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Africa as a continent contributes the least to global emissions yet bears a disproportionate share of the consequences. Nine of the ten countries most vulnerable to climate change are African. As livelihoods collapse and rural economies fail, migration pressures will intensify, driven by climate change intersecting with poverty, conflict and constrained opportunity.
Chronic under-funding
Europe is only now beginning to experience, in more limited form, what African communities have navigated for decades with far less fiscal space, thinner insurance coverage and fewer resources for recovery. With El Niño conditions confirmed and a “super” version of the naturally occurring weather pattern possible later this year, the pressure is set to intensify further.
In Africa, climate action is fundamentally a development challenge where adaptation and mitigation must go hand in hand. Building a solar grid and flood-proofing the road that serves it are not separate agendas. Yet for too long, the global climate conversation has prioritised mitigation while leaving adaptation – the work of protecting lives, livelihoods and economies in a changing climate – chronically under-funded.
The result is three compounding gaps. A visibility gap: much of Africa’s adaptation work remains under-documented and under-recognised in global climate narratives. A financing gap: capital does not flow at the scale or speed required to the people and institutions best placed to use it. And a decision-making gap: too many solutions are still designed elsewhere and imported into African contexts, rather than backing African-led platforms to scale what is already working.
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Solutions ready for finance
The solutions exist. Rwanda’s green investment fund has mobilised climate finance at national scale through its own systems. Egypt’s Nexus of Water, Food and Energy programme has shown how integrated planning can stretch limited resources across interdependent systems.
Zambia’s Presidential Irrigation Initiative is building climate-resilient food production from the ground up. In Pata, Senegal, a solar irrigation project has unlocked agricultural production and created jobs, demonstrating how integrated investments in water, energy and livelihoods can deliver resilience and development gains simultaneously.
In South Africa, the African Climate Foundation’s work with the South African Local Government Association (SALGA) is supporting district municipalities to assess their climate risks and develop fit-for-purpose Climate Action Plans, building adaptation capacity where it is needed most – at the local level.
These are not pilot projects waiting to be validated. They are working systems waiting for investment.
Closing the gaps requires a decisive shift in posture from global finance, philanthropy and development institutions. It means backing country-led platforms that can prepare, aggregate and finance adaptation projects. It means investing in place-based initiatives grounded in local knowledge.
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It means fostering intra- and inter-continental collaboration, so that lessons from Kigali inform decisions in Nairobi and innovations in Lagos reach communities in Dakar. And it means treating adaptation as core economic infrastructure, not charitable relief.
Invest now for future gains
The economic case is clear. Every dollar invested in climate adaptation returns an estimated four dollars in benefits on average – and up to five in the poorest economies. Under-investment in African adaptation is as economically irrational as it is morally unjust.
The world depends on Africa’s food systems, its young workforce – the majority of the continent’s population is under 25 – and its minerals. Several African countries supply a substantial share of the copper, cobalt and other critical materials underpinning the global clean energy transition.
Drought in Zambia has already shown how climate stress can disrupt hydropower, electricity supply and mining output. A transition that depends on African minerals cannot afford to ignore African climate resilience.
The world can continue to under-fund adaptation and pay repeatedly for emergencies, instability and lost development. Or it can invest now in the people, institutions and systems already doing the work on the ground in Africa, not in solutions imported from elsewhere.
Africa has the agency, the knowledge and the platforms. What it needs is the finance to match. A super El Niño will not wait for consensus to form. Neither, frankly, should we.
The post Climate adaptation in Africa needs investment, not imported solutions appeared first on Climate Home News.
Climate adaptation in Africa needs investment, not imported solutions
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