In 2023, the Winooski River in Vermont spilled a bank and kissed the Green Truss Bridge that spans it. River water was poured into the marble floor of the state house. Up to 9 inches of rain fell within 48 hours, causing hundreds of millions of dollars in damage.
A year later, Vermont enacted the Climate Change Superfund Act. It holds an oil and gas company that is financially responsible for the state's climate damage. A similar law was passed in New York in 2024 and is pending in California, Maryland and Massachusetts.
Understanding the law is attribution science, an attribute science that uses global temperature data to model vast numbers of scenarios to determine whether extreme weather events like floods and heat waves are related to emissions from burning oil, gas and coal.
A new paper published Wednesday in the Nature Journal expands this type of work, linking emissions from certain emitters to the economic burden of extreme events.
“The oil industry is amazed by the state's climate superfund laws and growing popularity, as they are the first policy in the world to pay a significant share of the big losses that caused massive damage to their products.”
The response to the law was quick. In February, West Virginia and other Republican-led states appealed to block New York's laws, saying only the federal government can regulate emissions. This month, President Trump signed an executive order calling state law “burden and ideological motivation,” calling Attorney General Pam Bondy to block their enforcement.
Environmental lawyers have been looking at how harm can be attributed to greenhouse gas emissions for decades, according to Martin Rockman, a climate law fellow at Columbia University's Sabine Center.
“Attribute science is extremely important because it elicits links between specific activities from businesses that benefit from fossil fuels and specific harm to states and communities,” Megaman said. “If you're doing harm, you should be responsible for cleaning it, it's just as easy.”
The new research will improve on an approach known as the “end-to-end” attribute. This links a particular emitter (e.g., a company) to a certain climate-related impact (e.g., an extreme heat, e.g.) to a certain damage (slowness in the global economy).
The study found that Chevron's emissions caused heat-related losses of up to $3.6 trillion in total world product. Christopher Callahan, a postdoctoral geoscientist at Stanford University and the author of the study, said such high costs still underestimate the global impact of fossil fuel burning in poor tropical regions with the least responsibility for emissions.
Chevron did not respond to requests for comment.
“That incredible person represents the damage from one of the climate impacts,” says Delta Melner, associate director of the Science Hub for Climate Litigation for the Coalition of Concern Scientists. “The total harm caused by major emitters is undoubtedly much greater if the full range of climate risks are considered.”
Overall, the paper found that the world would reach $28 trillion due to the extreme heat caused by emissions from 111 major carbon producers between 1991 and 2020.
More than 100 climate-related lawsuits have been filed every year since 2017, according to a new study. However, these cases investigate attribute studies that rely on failing to link emissions to estimated economic damages.
This new framework can provide similar capabilities to other major damage and loss cases, such as working for tobacco companies responsible for lung cancer cases and pharmaceutical companies for drug addiction.
Justin Mankin, professor of geography focused on climate science at Dartmouth University and professor of geography, author of Nature Paper, said:
World Weather Attribution, a group that has exhausted Imperial College London, has published regular attribution reports over the past decade.
“The sad thing is, we are still the only person who really does this, and we are not an institution. It's basically a project I do as a university professor in collaboration with a team of people,” said Friedrike Otto, a physicist who helps to assign global weather.
Dr. Callahan and Dr. Mankin used open source tools in their models to create code and data sources that they used to publish the global costs of climate change on their website.
“We believe in openly and transparent science, especially since the work was paid by US taxpayers,” Dr. Mankin said, noting that much of the support for the research was funded by NOAA, the country's largest climate science agency targeting cuts in funding under the Trump administration.
Extreme weather events have disrupted communities and continue to finance tensions. The 2023 flood cost Vermont hundreds of millions of dollars, according to Vermont Sen. Anne Watson, who sponsored a bill quantifying state damage between 1995 and 2024.
Julie Moore, secretary at the Vermont Natural Resources Agency, helped states organize their requests for more information so that they can better understand the different approaches to attribution science and better understand how to assign damage caused by greenhouse gas emissions.
“The accusation against us is to adopt rules on how to apply attribution science and ultimately send out a cost recovery letter,” Moore said. State law says oil and gas companies will receive a letter in early 2027.
“The hope is that it's going to help Vermont come in a substantial amount and help pay for the damage and adapt to a hotter, humid climate that is the result of this carbon in the atmosphere,” Watson said. “We need to go to a source of information on who is responsible for this.”
