Carbon majors and the scientific case for climate liability by Christopher W. Callahan & Justin S. Mankin , April 23, 2025
Nature volume 640, pages 893–901 (2025)
Abstract
Will it ever be possible to sue anyone for damaging the climate? Twenty years after this question was first posed, we argue that the scientific case for climate liability is closed.
Here we detail the scientific and legal implications of an ‘end-to-end’ attribution that links fossil fuel producers to specific damages from warming. Using scope 1 and 3 emissions data from major fossil fuel companies, peer-reviewed attribution methods and advances in empirical climate economics, we illustrate the trillions in economic losses attributable to the extreme heat caused by emissions from individual companies. Emissions linked to Chevron, the highest-emitting investor-owned company in our data, for example, very likely caused between US $791 billion and $3.6 trillion in heat-related losses over the period 1991–2020, disproportionately harming the tropical regions least culpable for warming. More broadly, we outline a transparent, reproducible and flexible framework that formalizes how end-to-end attribution could inform litigation by assessing whose emissions are responsible and for which harms. Drawing quantitative linkages between individual emitters and particularized harms is now feasible, making science no longer an obstacle to the justiciability of climate liability claims.
Scientific path to recouping the costs of climate change, Framework for tying emissions from individual fossil-fuel companies to specific damages linked to climate change by Dartmouth College, April 23, 2025
Summary: A new study lays out a scientific framework for holding individual fossil fuel companies liable for the costs of climate change by tracing specific damages back to their emissions. The researchers use the tool to provide the first causal estimate of economic losses due to extreme heat driven by emissions.
They report that carbon dioxide and methane output from just 111 companies cost the world economy $28 trillion from 1991 to 2020, with the five top-emitting firms linked to $9 trillion of those losses.
FULL STORY
Drought-fueled wildfires in Southern California, a devastating hurricane in the southern Appalachian Mountains, and catastrophic floods in New England are among the most recent disasters to bring the increasingly astronomical costs of climate change into focus.
As a growing number of local and national governments struggle to recover from — and protect against — more frequent and destructive climate disasters, some have directly sought compensation from fossil fuel companies through civil cases and “polluters pay” laws. But many of these actions are being challenged or slowed in court, partly due to the difficulty in showing that specific climate impacts occurred because of any one company’s greenhouse gas emissions.
A new study published April 23 in the journal Nature, however, provides a tool for potentially recouping the costs of extreme weather amplified by climate change. The researchers lay out a scientific framework they report can be used to trace specific climate damages back to emissions from individual fossil fuel companies.
The framework combines climate modeling with publicly available emissions data to contrast the current climate and its impacts to what it would be like without the heat-trapping gases a company’s activities released into the atmosphere. This causal link is known as a “but for” standard — as in, a climate catastrophe likely would not have occurred but for an individual firm’s actions, the researchers report.
“We argue that the scientific case for climate liability is closed, even if the future of these cases remains an open question,” says Justin Mankin, the study’s senior author and associate professor of geography at Dartmouth. The study, he says, answers a question first posed in 2003 of whether science could ever link an individual firm’s emissions to climate change.
No wonder Nazis and con gov’ts the world over hate science.
“Just over 20 years later, we find the answer to be ‘yes,’” says Mankin, who directs the Climate Modeling and Impacts Group at Dartmouth. “Our framework can provide robust emissions-based attributions of climate damages at the corporate scale. This should help courts better evaluate liability claims for the losses and disruptions resulting from human-caused climate change.”
Mankin and the study’s first author, Christopher Callahan, a postdoctoral scholar at Stanford who began working on the project as a PhD candidate at Dartmouth, deploy the framework to provide the first causal estimates of regional economic losses due to extreme heat resulting from the emissions of individual fossil fuel companies.
Extreme heat linked to carbon dioxide and methane from just 111 companies cost the world economy $28 trillion from 1991 to 2020, with $9 trillion of those losses attributable to the five top-emitting firms, according to the study. The highest-emitting investor-owned firm they examined may be responsible for $791 billion to $3.6 trillion in heat-related losses over that period, the researchers report.
“Our findings demonstrate that it is in fact possible to compare the world as it is to a world absent individual emitters,” Callahan says.
“The affluence of the Western economy has been based on fossil fuels,” he says, “but just as a pharmaceutical company would not be absolved from the negative effects of a drug by the benefits of that drug, fossil fuel companies should not be excused for the damage they’ve caused by the prosperity their products have generated.”
The study, Callahan and Mankin say, benefits from 20 years of accumulating real-world climate impacts, the increased availability of climate and socioeconomic data, and methodological advances in “climate attribution science,” a form of modeling that allows scientists to track the effects of climate change almost in real time.
Climate attribution is the crux of Vermont’s 2024 Climate Superfund Act, which was partially informed by Mankin’s testimony and an early version of the Nature study. Passed in the wake of devastating statewide floods in 2023, the law empowers the state attorney general to compel major fossil fuel companies to help cover the cost of disasters that can be scientifically linked to their emissions. A recent lawsuit challenges the state’s authority to collect such damages, as well as Vermont’s ability to accurately use climate attribution science to determine them.
The attribution framework reported in Nature incorporates established, peer-reviewed scientific methods for identifying the effect of specific emission levels on extreme weather. Callahan and Mankin also build on advances in the physical and social sciences that have drawn clearer connects between greenhouse gases, local climate change, and economic losses.
Critically, the model goes a step further than existing research by removing total emissions — measured in billions of tons — from the equation to identify a company’s specific greenhouse gas footprint. Previous attribution models have hinged on concentrations of greenhouse gases in the atmosphere, which are measured in parts-per-million that are harder to attribute to specific sources, Callahan says.
“Our approach simulates emissions directly, allowing us to trace warming and its repercussions back to specific emitters,” Callahan says. His and Mankin’s focus on extreme heat builds on their previous work calculating global financial losses due to heat waves and the economic damages individual countries have caused to others by contributing to climate warming.
“Extreme heat is indelibly linked to climate change itself and the losses from it have been an instigator for legal claims. So, it’s an obvious place to illustrate the broad application of our approach,” Mankin says.
“We also live in a world that has warmed considerably over the past 20 years,” he says. “This analysis is not a predictive exercise where we ask what the future holds. Instead, it’s a documentary effort where we show what has already happened and provide the reason why.”
Story Source:
Materials provided by Dartmouth College. Original written by Morgan Kelly. Note: Content may be edited for style and length.
Journal Reference:
- Christopher W. Callahan, Justin S. Mankin. Carbon majors and the scientific case for climate liability. Nature, 2025; 640 (8060): 893 DOI: 10.1038/s41586-025-08751-3
The world’s biggest companies have caused $28 trillion in climate damage, a new study estimates by SETH BORENSTEIN, April 23, 2025
WASHINGTON (AP) — The world’s biggest corporations have caused $28 trillion in climate damage, a new study estimates as part of an effort to make it easier for people and governments to hold companies financially accountable, like the tobacco giants have been.
A Dartmouth College research team came up with the estimated pollution caused by 111 companies, with more than half of the total dollar figure coming from 10 fossil fuel providers: Saudi Aramco, Gazprom, Chevron, ExxonMobil, BP, Shell, National Iranian Oil Co., Pemex, Coal India and the British Coal Corporation.
For comparison, $28 trillion is a shade less than the sum of all goods and services produced in the United States last year.
At the top of the list, Saudi Aramco and Gazprom have each caused a bit more than $2 trillion in heat damage over the decades, the team calculated in a study published in Wednesday’s journal Nature. The researchers figured that every 1% of greenhouse gas put into the atmosphere since 1990 has caused $502 billion in damage from heat alone, which doesn’t include the costs incurred by other extreme weather such as hurricanes, droughts and floods.
People talk about making polluters pay, and sometimes even take them to court or pass laws meant to rein them in.
The study is an attempt to determine “the causal linkages that underlie many of these theories of accountability,” said its lead author, Christopher Callahan, who did the work at Dartmouth but is now an Earth systems scientist at Stanford University. The research firm Zero Carbon Analytics counts 68 lawsuits filed globally about climate change damage, with more than half of them in the United States.
“Everybody’s asking the same question: What can we actually claim about who has caused this?” said Dartmouth climate scientist Justin Mankin, co-author of the study. “And that really comes down to a thermodynamic question of can we trace climate hazards and/or their damages back to particular emitters?”
The answer is yes, Callahan and Mankin said.
The researchers started with known final emissions of the products — such as gasoline or electricity from coal-fired power plants — produced by the 111 biggest carbon-oriented companies going as far back as 137 years, because that’s as far back as any of the companies’ emissions data go and carbon dioxide stays in the air for much longer than that. They used 1,000 different computer simulations to translate those emissions into changes for Earth’s global average surface temperature by comparing it to a world without that company’s emissions.
Using this approach, they determined that pollution from Chevron, for example, has raised the Earth’s temperature by .045 degrees Fahrenheit (.025 degrees Celsius).
The researchers also calculated how much each company’s pollution contributed to the five hottest days of the year using 80 more computer simulations and then applying a formula that connects extreme heat intensity to changes in economic output.
This system is modeled on the established techniques scientists have been using for more than a decade to attribute extreme weather events, such as the 2021 Pacific Northwest heat wave, to climate change.
Mankin said that in the past, there was an argument of, “Who’s to say that it’s my molecule of CO2 that’s contributed to these damages versus any other one?” He said his study “really laid clear how the veil of plausible deniability doesn’t exist anymore scientifically. We can actually trace harms back to major emitters.”
Shell declined to comment. Aramco, Gazprom, Chevron, Exxon Mobil and BP did not respond to requests for comment.
“All methods they use are quite robust,” said Imperial College London climate scientist Friederike Otto, who heads World Weather Attribution, a collection of scientists who try rapid attribution studies to see if specific extreme weather events are worsened by climate change and, if so, by how much. She didn’t take part in the study.
“It would be good in my view if this approach would be taken up more by different groups. As with event attribution, the more groups do it, the better the science gets and the better we know what makes a difference and what does not,” Otto said. So far, no climate liability lawsuit against a major carbon emitter has been successful, but maybe showing “how overwhelmingly strong the scientific evidence” is can change that, she said.
In the past, damage caused by individual companies were lost in the noise of data, so it couldn’t be calculated, Callahan said.
“We have now reached a point in the climate crisis where the total damages are so immense that the contributions of a single company’s product can amount to tens of billions of dollars a year,” said Chris Field, a Stanford University climate scientist who didn’t take part in the research.
This is a good exercise and proof of concept, but there are so many other climate variables that the numbers that Callahan and Mankin came up with are probably a vast underestimate of the damage the companies have really caused, said Michael Mann, a University of Pennsylvania climate scientist who wasn’t involved in the study.
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Follow Seth Borenstein on X at @borenbears. The Associated Press’ climate and environmental coverage receives financial support from multiple private foundations. AP is solely responsible for all content. Find AP’s standards for working with philanthropies, a list of supporters and funded coverage areas at AP.org.
Refer also to:
2013: Methane Leaks from Fracking are Much Worse than We Thought
2012 07 26: Texas Judge Rules ‘The Sky Belongs To Everyone’
The lawsuit argued, “The atmosphere, including the air, is one of the most crucial assets of our public trust….Global climate change threatensto dry up most of these waters, turning them from gorgeous, life-giving springs into dangerous flash-flooding drainages when the rare, heavy rains do come. The outdoors will be inhospitable and the children will have few places to recreate in nature as the climate changes. They will be living in a world of drought, water shortages and restrictions, and desertification.”
The TCEQ argued the public trust doctrine applies only to water.
Judge Gisela Triana, of the Travis County District Court disagreed. Her letter decision, issued on July 12, 2012 stated, “[t]he doctrine includes all natural resources of the State.”
The court went further to argue that the public trust doctrine “is not simply a common law doctrine” but is incorporated into the Texas Constitution, which (1) protects “the conservation and development of all the resources of the State,” (2) declares conservation of those resources “public rights and duties,” and (3) directs the Legislature to pass appropriate laws to protect these resources. … But a few days after Judge Triana’s ruling, Judge Sarah Singleton of the New Mexico District Court denied the state’s motion to dismiss a similar case.
2011: Gwyn Morgan, was CEO of illegal aquifer frac’er Encana, gets Order of Canada. It doesn’t get much more disgusting and unjust than this in corporate polluter Canada.
Ya, sure, you sleazy little aquifer fucker, blame Trudeau.
Living frac’d by Gwyn Morgan-led Encana is horrendous hell.
2006:Photo below of my explosive well water after it was illegally frac’d and contaminated by Encana/Ovintiv. I try hard to reduce my pollution as much as possible. I do not travel for fun, I avoid doing things like visiting friends or to art galleries etc if it requires driving and related pollution. This breaks my heart, that all I do to reduce my footprint and pollution, is wiped out by Encana’s methane and ethane venting from my contaminated water well.
Still, 21 years after Encana intentionally broke the law, no authority has punished the criminal polluter, and no authority has ordered Encana to repair the multiple drinking water aquifers it illegally frac’d.
And, no one has yet ordered Gwyn Morgan to return his Order of Canada.
2006 Photo of my methane and ethane contaminated flammable well water by Colin Smith