Scientists Tally Oil Majors’ Climate Damage With Eye to Legal Liability

Over the last decade, scientists have rapidly developed the field of climate attribution research, teasing out the role played by global warming in individual natural disasters. Meanwhile, their ways of tracking a single emitter’s influence on temperature or sea-level rise have grown more sophisticated, as research into climate economics has advanced.

The result is that it’s now possible to quantify the climate damages caused by each of the world’s biggest oil and gas companies, according to in the journal Nature. Those calculations could be brought as evidence in court.

“This has long been articulated by the legal community as a barrier to legal pursuits for liability claims” for harmful climate impacts, said co-author Justin Mankin, a climate scientist and associate professor of geography at Dartmouth College. “Scientifically, it’s not really an issue anymore.”

In the paper, Mankin and co-author Christopher Callahan, a postdoctoral researcher in Earth system science at Stanford University, say they have devised a transparent, low-cost analytical tool for interrogating a key question in liability, or tort, law. Many such cases pivot on whether a plaintiff would have suffered “but for” actions of the defendant. The new paper offers what’s described as a way to demonstrate harm that wouldn’t have occurred “but for” a company’s or companies’ greenhouse gas pollution.

Climate lawsuits have multiplied around the world in recent years. In the US, , have sought redress for climate impacts, with different groups testing different legal theories. The cases vary wildly in approach and many drag on for years, end up dismissed or both. Only a small fraction have succeeded globally, and none of those resulted in liability damages.

Mankin and co-author Christopher Callahan start with the database, a project of the UK nonprofit InfluenceMap, which tallies the annual emissions from fossil fuel and cement companies. With computer modeling, theysimulate two worlds, the one we live in and one without the greenhouse gas emissions of whatever company or country is under study. For each region, they use thousands of simulations to estimate how the pollution affects the global temperature and how that influences heat waves locally and the resulting economic drag. By comparing the two scenarios, they can put a value on the impact of the particular emissions. Each step is resolved with an open, peer-reviewed process.

Among their conclusions:

The world would have become as much as $28 trillion richer between 1991 and 2020 without the greenhouse gas pollution put out historically by 111 of the companies listed in the database.
The two biggest state-owned fossil-fuel companies, Aramco and Gazprom PJSC, are each responsible for about $2 trillion in lost global economic growth from extreme heat. That’s incrementally more than the estimate for two public companies, Chevron Corp. and Exxon Mobil Corp.; BP Plc is linked in the study to $1.45 trillion in losses.
The top five emitters, according to the paper, are responsible for increasing the intensity of a 2010 extreme heat wave in Russia by 0.27C, or 0.5F.

The paper focuses on the effects major carbon emitters may have on economic losses from heat waves. Extreme heat is the hazard most easily attributable to greenhouse gas pollution.

But that’s only one example of how the method can be used, the authors said. Basically, it can estimate the impacts of any source of emissions 鈥� an oil company, a country, a private plane 鈥� on any instance of harm.

Two scientific developments enable “end-to-end climate attribution,” they write, one on either end of the causality chain. Scientists have learned to connect individual emitters to local climate change and, at the other end, to tie local climate change to real-world impacts.

Climate attribution research started up in the years after asked, “Will it ever be possible to sue anyone for damaging the climate?” The measuring the effect of greenhouse gas emissions on a heat wave came out the next year. Several groups of researchers in the last decade developed approaches to quantify the climate impact on extreme events quickly, culminating in the work’s inclusion in the most recent UN climate science assessment.

Chevron cast both the study and attribution science as dubious. Theodore Boutrous of Gibson, Dunn and Crutcher LLP, counsel for Chevron, called the paper “baseless,” saying it “ignores the scientific impossibility of attributing particular climate and weather events to any specific country, company or energy user.” He associated the work with “a misleading advocacy campaign on behalf of wasteful and unconstitutional state lawsuits and energy penalty laws.”

Gazprom detailed several criticisms of the study. The company expressed concern that the Carbon Majors emissions data counts gas that wasn’t actually burned for energy, but bought for use as a feedstock in fertilizer, plastics or industrial solvents, as combustion emissions, inflating the likely total. Gazprom said its gas sales to foreign markets have cut carbon dioxide emissions because the fuel has been replacing coal.

“If Gazprom didn’t supply gas, energy importers would burn coal,” the company said.

Aramco declined to comment. Exxon and BP did not return requests for comment.

Friederike Otto, co-founder of the research group World Weather Attribution, said the paper is important and based on transparent and well-tested methods. But she said the science of attribution was already strong based on years of extensive work. Courts may not begin to rule in favor of climate litigants until society internalizes, as scientists have, the nature of the problem, she said.

“The problem with the current lack of success of litigation against carbon majors is not the lack of scientific evidence,” she said.

Environmental attorney Matthew Pawa, who has been involved in against energy and chemical companies, said the new paper gives an important analytical tool to plaintiffs, particularly in courts that are more inclined to consider direct (“but for”) causation. But public nuisance law doesn’t necessarily rely on that, he said; individual companies have been held liable even when, as with climate change, there are many polluters and many people harmed.

“It’s inevitable that at some point the fossil fuel companies will be held liable,” he said. “I’m where I was 20 years ago: You can’t do this much harm and not have committed a tort.”

Although no one has won a liability suit against a large emitter, some cases are now lasting longer and reaching fact-finding stages, said Martin Lockman, a climate law fellow at Columbia University’s Sabin Center for Climate Change Law. (Two Sabin Center researchers are thanked in the paper’s acknowledgements.)

“We’re well past the exploratory stage, and starting to get to the stage where courts are really getting to grips with the facts and this chain of causation,” he said.

The new research comes as some US states move to hold large emitters responsible for their contributions to climate change. New York and Vermont both recently passed “climate Superfund” laws, which would require energy companies to pay toward the repair and resilience of infrastructure threatened by global warming. Other states are discussing similar laws. Mankin to the Vermont legislature in February 2024, which included a draft of the Nature paper.

Both and face legal challenges to their new measures. More than in February to block New York’s law. President Donald Trump this month signed an order directing the Justice Department to look at state and local climate laws for “overreach.”

“There is a long way to go before a plaintiff actually recovers damages from a fossil fuel producer,” said Callahan, the paper’s co-author, noting that strength of scientific evidence is only one factor in a case’s success. “That said, we believe our study closes a significant scientific gap in the theories underlying those cases.”

Top photograph: The Sinclair Wyoming Refining Co. oil refinery in Sinclair, Wyoming, U.S., on Thursday, Feb. 24. 2022. Photo credit: Bing Guan/Bloomberg

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