Science lays out framework to assess climate liability of fossil fuel majors

Article from MONGABAY (original article linked here):

As billion-dollar climate disasters pile up, and world leaders fail to act against global warming, lawsuits on behalf of impacted states, cities and other government entities have increased in number with the intent of holding the fossil fuel industry accountable for its contribution to climate change-caused economic damages.

But directly linking specific companies and their emissions to the financial harm done by actual climate change-intensified extreme weather events has remained a stumbling block.

Now, a new study published in Nature offers a framework to potentially strengthen such legal arguments by enabling plaintiffs to calculate contributions made by individual companies to rising temperatures, tying their emissions directly to extreme-heat disasters.

"Advances in climate economics over the last 10 years have told us quite a bit about the way that local climate hazards translate into damage for people [and places]," said study co-author Christopher Callahan, a postdoctoral scholar in earth system science at Stanford University. "But putting these pieces together in a single causal chain is the novel contribution here," helping to create linkages that can strengthen pending and future cases.

Policymakers and litigators may know these climate data exist, Callahan told Mongabay, but they may not know how they can bring all this evidence together in a way that more clearly illustrates causation and thus legal liability by major greenhouse gas polluters.

"Causal linkages from emitters to impact have been termed the Holy Grail of climate litigation," the study states.

Michael Gerrard, director of the Sabin Center for Climate Change Law at Columbia University Law School, who was not involved in the study, reviewed the research for Mongabay. He tracks climate litigation internationally and knows well the potential and pitfalls for success in court.

"There are 34 pending lawsuits brought by states and cities against fossil fuel companies," Gerrard said. "All of them have, and still are, held up by legal issues such as whether they belong in federal or state courts… and how much power state courts have over out-of-state action by defendant companies."

Gerrard said the study will not clear up such legal issues and fossil fuel companies will continue pushing back against any and all evidence with their well-funded legal defenses. But, he added, "If any of the cases eventually make it past these legal issues and get to the merits, the study may be really helpful to plaintiffs."

Calculating specific Big Oil damages

The Nature study's premise leans heavily on attribution science, also called climate attribution. It's a fast-advancing field of research that tries to measures the extent to which greenhouse gas emissions from specific polluters have influenced or contributed to extreme weather events including heat waves, floods and droughts and the monetary damages accumulating in their wake.

In the study, Callahan and co-author Justin Mankin, a climate scientist at Dartmouth College, write that because climate attribution modeling makes it possible to go from emissions at the corporate level to the socioeconomic impact at the community level, a substantial hurdle in climate litigation can be addressed.

"Using peer-reviewed methods, we estimate the economic losses resulting from the extreme heat caused by emissions from [five] major fossil fuel companies … over the period 1991–2020," the authors write. "We present two actionable approaches for the end-to-end attribution framework: one considering the accumulated harms from a hazard, such as heatwaves over 1991–2020, and another considering the harms from a specific event, such as the 2003 European heatwave."

Between 1991 and 2000, the study found that extreme heat linked to greenhouse gas emissions from 111 companies cost the world economy $28 trillion; $9 trillion of that amount, or 32%, is traceable to just five major oil companies based on public reporting of their emissions from production and combustion.

These so-called "carbon majors" are BP, ExxonMobil, Chevron, Saudi Aramco and Gazprom.

The study used a peer-reviewed, three-step framework to link those companies to specific climate impacts: determining how much the carbon majors' collective emissions have contributed to global temperature rise, identifying where extreme heat is causing economic losses in specific regions around the world and calculating a "but for" scenario wherein the absence of those carbon majors' emissions would have made the climate impacts far less.

The determined difference between what is, and what would have been, is the carbon majors' contribution to damages, the authors estimate. Mankin told Mongabay, "If an emitter is responsible for 10% of emissions, that doesn't mean it is only responsible for 10% of damages. A court or judge would decide that."

In their study, the researchers illustrate their calculation results very specifically: They write that the established emissions from the carbon majors increased temperatures by precise amounts in four historic disastrous heat waves: India (1998), France (2003), Russia (2010) and the continental United States (2012). Chevron's emissions alone, the authors estimate, contributed as much as $61 billion in economic damages in the U.S. in 2012.

"Collectively, these results provide the first estimate of the global economic toll that individual fossil fuel companies have produced owing to extreme heat caused by their emissions," the study notes.

Limits of litigation

The world's largest oil companies have argued, often successfully, that legal liability for climate impacts is impossible to determine because so many factors contribute to global warming beyond burning fossil fuels — including deforestation, agricultural practices, wildfires, cement making, methane leaks and more.

But, Mankin said, "The scientific link between emissions and damages is only part of the equation. The big companies have long known from their own research the connection between carbon emissions and climate change.

"They hid that information from the public and their investors and engaged in a decades-long campaign of disinformation and delay to prevent climate action," he explained. "So, the combination of that fact with our approach, I think, is a critical combination," in strengthening existing and future litigation.

Callahan and Mankin acknowledged that their framework focuses only on economic damages from extreme heat events, like the sustained heat wave in the Pacific Northwest in 2021 that claimed 69 lives. Multnomah County, Oregon, where the city of Portland is located, has sued major oil companies for $50 billion in damages for contributing to that disaster.

But potential plaintiffs in western North Carolina, which sustained more than $50 billion in damages from Hurricane Helene flooding and high winds in October 2024 could not easily and readily apply the liability framework spelled out in the Nature study, should litigation be forthcoming.

Callahan said it's possible that in a few years, researchers will develop models for evaluating contributing causes of other extreme weather events like hurricanes, flooding, sea level rise and wildfires "that can be easily ported into our step-by-step framework."

Beyond the courtroom

Dan Galpern, an Oregon-based environmental lawyer, has pursued many climate-related lawsuits and spoken at United Nations climate summits regarding climate litigation. He reviewed the Nature study for Mongabay, saying, "I think the authors are onto something here," and he can envision the framework's broader use in court and beyond.

"The general logic of their three-step modeling approach seems unassailable to me," Galpern said. "Move from emissions to warming, warming to hazards and, finally, hazards to damages. And that framework clearly seems applicable to the attribution of specific damages arising from climate impacts other than heat."

He noted that while the carbon majors will likely argue that they are not responsible for emissions produced by end users of fossil fuels they manufacture, he agreed with the authors that the "end-to-end attribution approach could advance the ball in a number of types of climate cases seeking to pin liability of specific large climate polluters."

Galpern thinks precise tools and modeling for establishing climate liability could also prove useful beyond the courtroom, allowing policymakers to apply aspects of the climate attribution framework to establish emissions-related regulations of the fossil fuel industry.

Co-author Mankin agreed. Highlighting a central premise in the Nature study, he said, "From a purely climate perspective, there are detectable and meaningful differences between the world as it has been and the world as it would have been absent any of these emitters. And that's really, really crucial."

Trump's anti-environment roadblocks

How the increased ability of science to attribute climate harm and assess damages will play out in U.S. courtrooms remains to be seen. But any impact on national policy changes under the Trump administration will surely not favor climate plaintiffs nor the environment.

Also, the fossil fuel industry, with its staggering annual profits, has deep pockets for litigation, and it contributed $75 million to Trump's election campaign in order to influence U.S. environmental policy. In early May, the U.S. Justice Department filed suits against four states, claiming the legal actions planned by Vermont, New York, Hawaii and Michigan to hold fossil fuel companies liable for climate change damages will conflict with President Trump's "energy dominance" executive order.

But climate scientists and comprehensive assessment reports by the U.N. Intergovernmental Panel on Climate Change stress that billion-dollar climate disasters — with the death, destruction and misery they cause — will escalate until carbon emissions are drastically slashed.

 

Banner image: The sun sets over New York City. Lengthy record-setting heat waves can be costly, greatly increasing ozone and other air pollutants, resulting in deaths and hospitalizations, while also straining energy grids, transportation networks and water supplies. Image by Johannes Plenio (@jplenio) via Unsplash.

Article from MONGABAY (original article linked here):