News & Analysis
July 16, 2025
A climate accountability lawsuit from Oregon’s most populous county is based on valid evidence and science, briefs filed by a wide range of experts in support of the county’s case against Big Oil state. As Multnomah County continues to advance its climate deception lawsuit, fossil fuel giants are fighting tooth and nail to evade accountability and have made several arguments for the court to dismiss the case.
Multnomah County first filed its case in 2023, in an effort to put ExxonMobil, Shell, Chevron, and other Big Oil companies on trial for their decades of lies that fueled climate disasters like the 2021 Pacific Northwest heat dome, which killed 69 county residents and racked up massive climate costs for the region.
In newly filed court briefs, academics and local officials point to the evidence of Big Oil’s decades of climate lies and scientific research on how fossil fuels increased the severity and frequency of climate events, like the 2021 Pacific Northwest heat dome. Multnomah County cites the vast evidence as reasons for the court to reject Big Oil’s arguments and give residents their day in court to hold fossil fuel companies accountable for the catastrophic climate harms they have knowingly caused.
Local officials: Multnomah County Director of Sustainability John Wasiutynski submitted a brief outlining just how unprecedented and severe the 2021 Pacific Northwest heat dome was for the region. While Portland, the largest city in Multnomah County, normally sees highs of 78 degrees in late June, the heat dome broke all-time heat records three days in a row, topping out at 116 degrees. In some areas of the city, according to Wasiutynski, unofficial temperatures were recorded at 124 degrees. The heat overwhelmed residents and caused more deaths in a single heat event than the number of people that died from extreme heat in the entire state of Oregon over the past 20 years.
“The County was unaware that extreme temperatures, such as those that occurred in June of 2021, were possible for Multnomah County,” Wasiutynski wrote. “[I]n fact, [the county] had to contend with misinformation fossil fuel producers have long used to deny or downplay the magnitude and timing of harmful climate change — misinformation that needlessly but effectively sewed substantial public doubt about the likelihood, severity, and imminence of human-made climate destruction in our community, like that rendered by the extreme heat of 2021.”
Fossil fuel industry deception experts: Benjamin Franta, a Senior Research Fellow in Climate Litigation at Oxford, submitted a brief detailing how Big Oil has spent decades lying to the public about the reality of climate change. Franta cites evidence as early as the 1950s showing how fossil fuel companies like Exxon and BP learned about the harms of their product, and chose to devise a campaign of disinformation about climate change in order to continue business as usual. In the 1990s, Franta notes, as the evidence of climate change became increasingly difficult to ignore, oil and gas companies changed their tactic, opting to peddle false solutions to the climate crisis that assuaged public concern while maintaining our collective reliance on fossil fuels. “The industry’s rhetorical postures both before and after this shift communicated to the public not to worry about fossil fuels or climate change by stating, first, not to worry because climate change was not proved to exist, and then, not to worry because climate change was being fixed,” Franta writes.
Climate scientists: Despite increasingly dire warnings about the need to transition off fossil fuels, oil and gas companies have been doubling down on emissions, according to a brief submitted by Richard Heede, a climate scientist and director of the Climate Accountability Institute. More than half of all-time emissions from fossil fuels and cement have occurred since 1995. Climate scientist Daniel Swain also submitted an expert report showing evidence that the 2021 heat dome, summer drought conditions from 2010 to 2023 in the county, and wildfire smoke in the region during September 2020 were all made more severe and likely by climate change fueled by the Big Oil defendants. Swain also concludes that it is "virtually certain” that future extreme heat, drought, and wildfire events will be made more severe and common because of these major polluters’ historical and ongoing actions.
Exxon, Chevron, and other fossil fuel defendants are attempting to dismiss Multnomah County’s climate accountability lawsuit in part by claiming the case infringes on the oil companies’ free speech — a claim that has become increasingly common as the oil majors fight off a growing wave of climate accountability cases. The county rightly rejects that claim, writing that Big Oil defendants are citing a law that aims to “prevent frivolous lawsuits that chill free speech, not to grant immunity to powerful corporations that intentionally deceived the public for financial gain,” ultimately intending to delay legal proceedings and evade accountability.
The evidence is clear that Multnomah County deserves its day in court with Big Oil.