On a cold October Saturday in 2020, Elisa got a panicked call from her brother in France. He hadn’t heard from their mother in several days.

In the hazy hours of caring for a newborn, Elisa hadn’t known a major storm was pummeling Europe. Abnormally warm air had risen above Greenland, swirling into a cyclone that swept toward the Alps. When Storm Alex finally made landfall, it dropped 19 inches of rain over the course of the next day, the equivalent of six months’ average precipitation. Flash floods began to pour down the mountain sides, the worst deluge since France began keeping records 120 years ago.

All communications to the Vésubie Valley, where their mother lived in southeastern part of the country, were cut off. (To protect her family’s privacy, Elisa asked to be identified only by her first name.)

Elisa tried calling the emergency hotline in nearby Nice, the closest city, but the road to her mother’s village had been destroyed, and hundreds of people were evacuated. In the chaos, no one could tell them if she had managed to get out.

So Elisa got online. Into the dark hours of the night, she watched video after video of floodwaters sweeping houses away. “I was trying to find any footage, like anything on the Internet,” she says, “trying to see her home.”

Each time she clicked a new video and witnessed another house crumbling, or someone with a flashlight wading through the murky floodwaters, her breath caught. “I was like, ‘Oh my God, where [is] my mom? What happened to her?” she says. As the clips blurred together, a dawning horror began to pierce Elisa’s shock.

Meanwhile, her brother and uncle hiked on foot over a mountain into St. Martin Vésubie. Elisa waited anxiously by her phone until William found enough reception to call his sister. “There was no trace,” he told her. The house had been torn completely off its foundation. Eventually, her brother tracked down an emergency responder, who said by the time officials tried to evacuate that part of the valley, it was already too late. Land routes were impossible, and rescue helicopters couldn’t withstand the gale-force winds.

It would take another ten days for her mother’s body to be found. Even then, her remains were only discovered because a neighbor noticed wolves behind his house. “I guess they were smelling the body decomposing,” Elisa says. Her mother was only 67 years old.

Watching the familiar made strange in all those videos, Elisa immediately wondered about the climate’s role. Storm Alex hit unusually early in the season; the national weather service Météo-France later found that these kinds of extreme events have intensified by 22 percent since 1961.

This spring, she and her brother became two of eight plaintiffs in a criminal lawsuittargeting TotalEnergies, a French oil company that’s one of the world’s six largest carbon emitters. It’s the first-ever attempt to claim polluters are guilty of homicide.

The involuntary manslaughter case claims that TotalEnergies’ board of directors and its main shareholders, like global asset company BlackRock, have deliberately endangered the lives of others. Each offense in the lawsuit is punishable with at least a year in prison, as well as a fine. (TotalEnergies did not respond to requests for comment.)

Climate disasters, including this summer’s extreme heat, are claiming ever more lives. At the same time, advances in science have made it possible to pinpoint the responsibility for the emissions that caused these catastrophes, meaning the world can begin trying to hold the culprits accountable.

While dozens of civil cases have already been filed against fossil fuel companies, some believe that to capture the true scale of climate crimes — and their growing death toll — companies should also be tried for homicide. Advocates in the United States and abroad hope these cases can help spur urgent changes.

“When I saw the images of that storm, I was like, my mom died [from] climate change,” Elisa says. Now, she’s trying to bring those responsible to justice.

Identifying the suspects

Oil has always been a bloody business. In the heady days following World War I, when the internal combustion engine transformed armies and navies, governments began to scramble for control over the fuel of the future. In 1924, France’s prime minister createda private company, Compagnie française des pétroles, to secure petroleum access. A few years later, it sent several geologists into the dry wadis of Mesopotamia, what is today’s Iraq.

The employees camped in tents near the low hills of Kirkuk, where a steam engine drove a drill bit through the night. Then, ninety-three years before Storm Alex hit France, as dawn rose over the desert, crude oil burst out of the ground. A huge geyser shimmered into billowing clouds. “A black cloud hung like an upturned umbrella,” an eyewitness recalled. Before the well could be capped, close to a million barrels of oil spilled onto the sands. The company’s first Middle East strike was also its first environmental disaster.

After a few decades of discoveries and acquisitions, the Compagnie française des pétroles rebranded as Total, a name specifically chosen because it “hinted at the Group’s intention to expand.” Today, the company is still planning more new fossil fuel development than almost any other.

TotalEnergies’ central role in the climate crisis weighs heavily on Hadrien Goux, an anti-fossil fuel campaigner at the French nonprofit Bloom Association, one of several organizations behind the climate homicide case Elisa and seven other victims filed this spring.

Sitting in his office in Paris, Goux’s dressed casually in a cheerful graphic shirt with clashing colors, but his face’s angular lines grow serious as he argues that it’s time to move beyond civil lawsuits against major oil companies, since they’ve failed to spur systematic changes.

“The main objective of our litigation is really to hold [TotalEnergies] responsible for past decisions, and past and current and future impacts of climate change,” he says.

To support the case, Bloom and its collaborators have turned to attribution researchers, scientists trying to determine how climate change is intensifying extreme weather. It’s now possible to say with confidence just how much warmer temperatures have contributed to a particular heat wave or hurricane, says Fredi Otto, a senior lecturer at the Grantham Institute for Climate Science at Imperial College London.

Otto is one of the world’s leading climate attribution researchers. In 2015, she formed a group of international scientists called World Weather Attribution, who quantify how climate change influences the intensity and likelihood of disasters in almost real time, circumventing the lengthy academic process that normally takes years.

They’ve now conducted dozens of rapid attribution studies. When the Pacific Northwest hit a record-shattering 116 degrees in 2021, for example, World Weather Attribution found less than two weeks later that the heat dome was “virtually impossible” without climate change.

Otto explains that advances in computing power have increased climate models’ accuracy and precision, as well as made it much easier to combine them, increasing confidence in their results.

“A few years ago, many people were still thinking this is uncertain,” she says, “and I think that has changed.”

Otto says that robust research now clearly supports the argument that the emissions of a company like TotalEnergies have made climate change worse, and that warming temperatures have led to more people in certain regions dying. “There’s just nothing scientifically you can say against that,” she says.

Read: Climate change played a role in killing tens of thousands of people in 2023

She recently spoke to defense attorneys in states from Oregon to Texas who are considering pursuing climate homicide lawsuits, an experience that she says highlighted the difference in how scientists and lawyers think about uncertainty. Researchers like her see calculating uncertainty as a sign of a study’s strengths, whereas lawyers see it as liability.

To avoid this conflict, Otto encouraged the prosecutors to think about qualitative statements that can be made with very high levels of certainty, like the fact that major oil companies’ emissions knowingly and definitively made heatwaves worse, rather than focusing on specific numbers, such as the exact degree of change compared to historical temperatures.

But attribution science hasn’t yet had its day in court, says Delta Merner, the lead scientist for climate litigation at the Union of Concerned Scientists, who develops scientific evidence to support legal cases. Courtrooms often lag behind science: It took many years to bring DNA evidence into criminal cases, for example.

“The scientific community needs to be thinking about the needs of the litigation community,” Merner says, “asking relevant questions in time to be meaningful for court cases.”

Nevertheless, a growing body of evidence has been gathering to support these types of legal arguments. In 2017, Merner’s colleagues used attribution analysis to find that 90 companies contributed to over half of all global temperature rise. More than half of these emissions were produced after 1986, they write, “the period in which the climate risks of fossil fuel combustion were well established.”

Merner herself published a paper last year finding the emissions from a similar list of fossil fuel companies were responsible for more than a third of the total area burned by forest fires in North America. “Just to give you an idea, that’s roughly equivalent to the size of the state of Maine,” she says — forest that otherwise might not have burned.

Now, groups like Bloom are hoping to use this kind of research to demonstrate how oil and gas companies like TotalEnergies are directly responsible for deaths of people like Elisa’s mother.

“This causal link could end up being a proof for the judges of the link between activities of fossil fuel companies, and impacts of climate change,” Goux says.

Collecting the evidence

Watching it rain during Rhode Island’s winters when it used to snow depressed Aaron Regunberg, but it wasn’t until he decided to have a kid that he felt the creeping changes around him with a new urgency. What would winters be like for his son, when he reached adulthood?

These kinds of questions prompted Regunberg, as senior climate policy counsel at the non-profit think tank Public Citizen, to try to lay the groundwork for potential U.S. climate homicide cases.

The first challenge, he says, is establishing the causal chain between a fossil fuel company’s conduct and climate-related deaths. To do so, you have to show beyond a reasonable doubt that a company’s emissions contributed to climate change, which caused a climate-related disaster, which led to someone’s death.

“We should be thinking of those harms not just as tragedies, but as crimes,” he says.

In the United States, the law considers some killings worse than others, separated in degree from negligence to extreme indifference to human life. The least serious homicide charge Public Citizen believes that fossil fuel companies can be tried for is negligent homicide, meaning that the company caused deaths through their careless behavior. The most would be second-degree murder, which implies acting with indifference to human life.

In addition to how recklessly someone acts, their intent also matters, a legal concept sometimes called mens rea. You don’t necessarily have to intend to kill someone to be charged. If “you basically knew if you do this thing, people are probably going to die, and you did it anyway,” Regunberg says, that’s a crime.

It’s surprisingly easy to show that oil companies knew that their behavior was harmful — decades earlier than they admitted to the public. All the way back in 1965, the American Petroleum Institute found that fossil fuels were causing rising amounts of carbon dioxide.

“The substance of the report is that there is still time to save the world’s peoples from the catastrophic consequences of pollution, but time is running out,” the institute’s President, Frank Ikard, wrote then. “Carbon dioxide is being added to the Earth’s atmosphere by the burning of coal, oil, and natural gas at such a rate that by the year 2000, the heat balance will be so modified as possibly to cause marked changes in climate beyond local or even national efforts.”

The consequences were well understood within the industry. Last year, researchers at Harvard University and the Potsdam Institute for Climate Impact Research found that forty years ago, ExxonMobil also knew the repercussions of their business with shocking precision. In the 1980s, company scientists projected fossil fuel burning would cause around 0.2 degrees Celsius of global warming per decade.

“We find that most of their projections accurately forecast warming consistent with subsequent observations,” the researchers concluded in their 2023 report.

But there was a huge gap between what ExxonMobil knew and what it told the public. Oil companies denied and delayed releasing this kind of information, spending millionson research and campaigns to refute climate science.

ExxonMobil continues to use third-party groups to mask its involvement. Former ExxonMobil lobbyist Keith McCoy admitted in 2021 to Unearthed, a journalism project funded by the environmental nonprofit Greenpeace, “Did we join some of these ‘shadow groups’ to work against some of the early efforts on climate? Yes… Did we aggressively fight against some of the science? Yes.” (ExxonMobil did not respond to requests for comment.)

These strategies make it difficult to calculate the true extent of fossil fuel companies’ ongoing spending on climate denial. Well-known conservative foundations consistently fund these tactics, including through groups like DonorsTrust and Donors Capital Fund, which as donor-advised funds are not required to disclose their funding sources.

Billionaire Charles Koch, who made his fortune in oil, has funneled at least $8 million — and likely much more untraceably — through Donors Trust. In 2022, Donors Trust in turn gave more than a million to the climate-denying Heartland Institute; roughly $600,000 to the American Enterprise Institute, which has claimed “climate change is not an existential threat”; and $130,000 to the Committee for a Constructive Tomorrow, which in 2009 called global warming “man-made hysteria.”

This dark money has buoyed the efforts of fossil fuel companies. ExxonMobil, for example, has continued to publish advertising in the New York Times with misleading statements about unproven biofuels, while companies like Shell and BP spend millionson climate branding, despite only investing negligible amounts in renewable energy.

Regunberg argues that companies’ potentially criminal recklessness hinges not just on their total greenhouse gas contributions, but on their ongoing duplicity.

“They deceive the public about the dangers,” he says, “specifically in order to produce, market, and sell fossil fuels.”

This misinformation campaign has undeniably made climate change worse. The Intergovernmental Panel on Climate Change’s sixth assessment report directly blames“vested economic and political interests for organising and financing misinformation and ‘contrarian’ climate change communication” for delaying climate action.

Underscoring how industry influence shapes American climate policy, Project 2025, a lengthy manifesto that outlines goals for a future Republican administration, aims to “stop the war on oil and natural gas,” cut clean energy programs, and abolish the national climate assessment, a federal report that monitors the impacts of climate change.

Meanwhile, former President Donald Trump has overtly promised to aid the oil and gas industry, going so far as to ask executives from companies like ExxonMobil, Chevron, and ConocoPhillips for $1 billion in campaign donations.

But distinguishing between fossil fuel companies and the people working for them isn’t always straight-forward. Public Citizen acknowledges this could be a legal challenge, but explains that in most jurisdictions, companies can be held criminally liable for the behavior of their employees, or activities done at the behest of the company. The CEO and top management, Regunburg argues, controlled decisions about the quantity of oil production, marketing and advertising of decisions, and how they communicated the link between climate change and fossil fuels.

“And they were absolutely aware of the decades of internal research,” Regunberg says, “precisely predicting the exact climate harms that we’re seeing now.”

In July, Public Citizen published a prosecutorial memo outlining a potential legal strategy for trying such a case in the U.S., using a lethal heat wave in Phoenix last year as an example. As temperatures stayed above 110 degrees for a record-breaking 31 days, an average of 13 people died from the heat every day.

The task will require rethinking the definition of violent crime, says Cindy Cho, who after a decade as a federal prosecutor now teaches at Indiana University’s Maurer School of Law. At a recent Public Citizen meeting, she explained that when she first read the proposal, she was pretty skeptical. But the longer she thought about it, the more enthusiastic she became.

In Arizona, for example, research shows the extended heat wave likely wouldn’t have occurred without climate change. The heat was the direct cause of death for hundreds of victims.

“It is violence,” Cho says, “And prosecutors are concerned with looking for solutions to violence.”

She points to legal precedents in cases against Big Tobacco, which just like fossil fuel companies, once marshaled a formidable arsenal of lawyers, deep-pocketed budgets, and widespread advertising. For years, the tobacco industry argued people chose to use their products and that there was no definitive proof of their harms, efforts that were accompanied by aggressive lobbying.

But in the 1990s, mounting scientific evidence undermined the companies’ claims. Leaked documents and whistleblowers emerged, proving that the companies knew their products were dangerous. A turning point came when state attorneys general began filing civil lawsuits against cigarette manufacturers for deaths and illnesses caused by smoking.

Regunberg believes that the threat of matters escalating to criminal charges led the corporations to come to the table — leading to a major $206 billion settlement agreement that substantially shaped public opinion about the dangers of tobacco products.

Cho believes a similar process may now play out for oil companies. “Drawing a line from one person’s decisions to five people down the line, that’s the prosecutor’s work,” she says.

Of course, oil companies disagree they should be held responsible for the emissions they’ve made possible. “We expect the oil majors to use as much defense as they can,” says Goux at Bloom. Since their lawsuit was filed in France this spring, Goux says TotalEnergies has argued that it was being singled out, that other companies behaved worse, and that its pollution was the responsibility of consumers using its products.

Legally, prosecutors don’t have to prove that fossil fuel companies were the only or exclusive cause of climate-induced deaths — just that they contributed in a significant way. In previous civil lawsuits, even small amounts of emissions, like 2.5 percent of global totals, have been considered a meaningful contribution to climate harms.

Blaming consumers is also a tenuous defense. Companies like TotalEnergies may try to claim that the people burning the fuels they produce in their cars or houses breaks the chain of causation, but it will be hard to argue that companies didn’t foresee their products being used just as they were intended.

Regunberg says his goal for climate homicide cases isn’t necessarily to put people in jail, but to apply pressure on fossil fuel companies to change their business model. The best outcome, he says, would be a bellwether case that led to a significant settlement or court order, like Purdue Pharma’s recent $4.5 billion settlement over its role in the deadly opioid epidemic.

Even if climate homicide cases aren’t initially successful, Merner says these lawsuits could reveal critical information about the industry’s behavior.

In late July, for example, Ohio-based Marathon Petroleum released documents as part of a lawsuit brought by the city of Honolulu against several fossil fuel companies for allegedly violating public- and private-nuisance laws. The files showed the company knew almost fifty years ago that global temperature rise linked to their product could eventually cause “widespread starvation and other social and economic calamities.”

In the Big Tobacco cases, this discovery process played an important role in shifting public opinion, as the industry had to disclose internal scientific studies and corporate communication that showed just how clearly the companies knew their products were causing harm.

“That was really when the industry said, ‘Oh no, we don’t want all of this out there,’” Merner says. “Those pieces can be really transformative for how the public sees these industries, because they can understand what’s really happening.”

Awaiting justice

In late June of 2021, the National Weather Service announced a warning for residents of Oregon. A looming high-pressure system had effectively trapped a mass of hot air over the Northwest, like a lid on a simmering pot. The forecast predicted “life-threatening” conditions.

Jollene “Jolly” Brown was one of many Portland-area residents who weren’t ready for it. The sixty-seven-year-old lived alone in an apartment, and her air conditioner was broken. As the mercury climbed, Brown’s son Shane stopped by one evening to see if he could fix it. She shrugged her situation off, saying, “I’ll get through it.” By the next morning, the city’s crisping hills shimmered, the air blistering as soon as you opened the door. The sidewalks grew hot enough to give third-degree burns.

When Brown didn’t answer his calls, Shane drove over and found his mother had passed away in her recliner. Inside, it was 99.5 degrees. Brown was one of sixty-nine people to eventually die in Multnomah County, where Portland is located. The record-breaking heat dome was the county’s largest-ever single mortality event.

“Even in an environmentally conscious community like Multnomah County, people never imagined it would be 124 degrees in downtown Portland,” said Jeffrey Simon, a trial lawyer and outside counsel to Multnomah County. “And so they weren’t ready for it.”

Like Brown, many lacked air-conditioning; it didn’t used to be necessary.

Simon is now helping Multnomah County sue fossil fuel companies for $52 billion in damages and future costs for climate adaptation — one of the most ambitious civil lawsuits to date.

While no criminal climate cases have yet been filed in the U.S., Multnomah County’s effort is  part of a groundswell of civil lawsuits against Big Oil. The attorneys general of California, Connecticut, Delaware, Massachusetts, Minnesota, New Jersey, Rhode Island, Vermont, and the District of Columbia, as well as dozens of municipal governments have recently filed cases against major oil and gas companies.

Part of the impetus, says Multnomah County chair Jessica Vega Pederson, is that managing the climate emergency is extremely expensive. In a written statement, she said, “They have profited massively from their lies and left the rest of us to suffer the consequences and pay for the damages.”

The 2021 heat dome is a harbinger of what’s to come. Since 2015, says Chris Voss, the director of emergency management for Multnomah County, the county has seen a dramatic uptick in people seeking heat-related medical assistance. Last year, for the first time, the County allocated $2.3 million just to deal with severe weather as part of its regular budget cycle. Now, “we have these events every summer,” Voss says.

While extreme heat is the deadliest natural disaster, the Federal Emergency Management Agency doesn’t offer assistance for events like heat domes. That’s because the Stafford Act, the federal law that gives the agency the authority to respond to emergencies, doesn’t include heat in its list of major disasters. Last year, Rep. Ruben Gallego (D-Arizona) introduced legislation to add heat to FEMA’s classification, but the bill failed to progress. This June, 14 attorney generals petitioned the agency to expand its list to include extreme heat and wildfire smoke.

In the meantime, local governments like Multnomah County have been left to grapple with the rising costs of climate change alone. That’s especially true in small jurisdictions, Voss says, which can be severely impacted without the damage reaching the necessary financial thresholds to qualify for state assistance. These are the kinds of costs Multnomah’s lawsuit aims to recoup from fossil fuel companies.

But climate lawsuits are not just about recouping losses; they’re about changing people’s minds. Elisa, mourning for her mother in Montreal, hopes these legal tactics can help shatter the illusion that these disasters will only affect someone else.

“If we talk about our own experiences, and how climate change affects us personally, and the people we love,” she says, people are “going to realize that this can happen to anyone — to everyone.”

Before the flood, Elisa’s mother had recently retired and was loving spending time in her garden. Two days before it hit, when Elisa called to show off her new son, she admired the strawberries and raspberries her mother had just picked. That’s what Elisa was remembering when her older son recently asked how his grandmother died.

“I told him the truth, but without too much explanation,” she says. “I just said that it was a storm, and she was in the house, and the house was [taken] away by the water.”

Last month, another devastating flood swept over the Alps, killing at least seven in the same region where Elisa’s mother died. A few weeks after that, an extreme heatwave swept over Oregon, killing 17 others.

Environmental scholar Joanna Macy says the only alternative to despair is something she calls active hope, or the idea that hope is something we do, not something we have. Elisa has come to the same conclusion.

To her, that means taking steps to hold the people who made this crisis accountable. In 2022, ExxonMobil made a record nearly $56 billion in profit. That’s more than $100,000 every minute. And last year, ExxonMobil, Chevron, and Shell collectively made another $85.6 billion — producing more oil and gas in the U.S. than ever before.

Elisa still struggles to talk about what happened to her mom. “I feel like I’m putting myself naked in the middle of the road, basically.”

But she worries about the environment her children are growing up in. At the end of July, the Earth hit the highest temperatures in recorded history — twice. It’s heartbreaking to know the world she was born into has vanished. In Elisa’s lifetime, Montreal’s climate is expected to match that of southwestern Kentucky’s.

“It’s just going to happen again and again and again,” she says. And she wants to be able to tell her kids that she did what she could to try to turn things around, that as hard as it is to talk about her mother’s death, “I tried something.”