A new climate change lawsuit filed last week in Washington State takes a novel approach by arguing that the fossil-fuel industry is responsible for rising homeowners’ insurance premiums. The plaintiffs, two Washington residents, claim their costs have increased because of a growing number of climate-related natural disasters. But the complaint offers a thin scientific foundation and does not convincingly show how the defendants directly caused premium increases, which reflect a complex mix of economic and actuarial factors.

Like other recent climate change cases, the lawsuit draws on a familiar litigation playbook, alleging that “Big Oil” knowingly misled the public for decades about the dangers of its products. This strategy is modeled on the “Big Tobacco” litigation of the 1990s (and the lead attorney, Steve Berman, was co-lead counsel in a state lawsuit against tobacco manufacturers). What is new here is the attempt to link the defendants, including major fossil-fuel companies and the American Petroleum Institute, to higher insurance premiums supposedly caused by an increase in extreme weather events and disasters such as hurricanes, convective storms, and wildfires. 

The problem is that the link between fossil-fuel emissions and rising premiums is riddled with scientific uncertainty and logical gaps. To make a convincing causal argument would require showing that: 

1. homeowners’ premiums are rising specifically because of disaster-related losses; 
2. those losses are increasing as a result of higher frequency or severity of natural disasters; 
3. that increase is driven by anthropogenic climate change; and 
4. a measurable share of that climate impact can be attributed to the defendants’ actions in a way that directly affected the plaintiffs. 

None of these steps is straightforward.

Insurance premiums in Washington have undoubtedly risen over the past several years, but there are multiple causes, including factors unrelated to climate change, such as inflation and rising construction and labor costs. The lawsuit does not attempt to distinguish climate-driven factors from non-climate ones. As evidence of the impact of climate change on insurance costs, it cites a January 2025 report from the U.S. Treasury’s Federal Insurance Office that finds that insurance costs are higher in ZIP codes with a greater risk of “climate-related perils”, as defined by FEMA’s National Risk Index. But neither the FIO report nor FEMA’s risk index attempts to attribute those hazard levels or premium increases to climate change. The report simply shows a correlation between premiums and hazard risk levels, not that the risk levels themselves have changed or that fossil-fuel companies caused any such change.

How, then, has climate change actually affected disaster risk and damages? The short answer is that it is difficult to determine. Economic losses from disasters depend heavily on how many people and how much property lie in harm’s way. Though damages from some events have increased, this does not necessarily reflect changes in the underlying hazard. For example, as Roger Pielke Jr. of the American Enterprise Institute has long noted, U.S. hurricane damages have increased largely because of denser coastal development, not because more hurricanes are making landfall. When historical damages are normalized to account for today’s level of exposure and vulnerability, there is no long-term upward trend in economic losses created by hurricanes.

Detecting changes in underlying disaster risk is difficult, and attributing those changes to anthropogenic climate change is even harder. In the mid-2000s, motivated by the prospect of climate litigation, scientists developed the field of “extreme event attribution” to assess whether warming had altered the likelihood or severity of different weather events. Over time, some scientists and activists have come to see event attribution as a tool to emphasize the urgency of climate change and spur calls for action.

The problem is that the discipline faces some fundamental challenges. A complex interplay of factors shapes weather, and any single event can result from a mix of natural and human influences, making it impossible to definitively say that climate change caused a particular storm, flood, or fire. At best, scientists can ask whether human-driven warming has made certain events more likely or more intense.

But climate and weather data are noisy, and there is a lot of natural variability. For many phenomena, the window of reliable observations is too short to distinguish a long-term trend from random fluctuations. This does not mean such trends don’t exist or that they are not caused by human activity, but rather that they cannot be detected given the data we have. Strong statements attributing observed weather outcomes to greenhouse gas emissions often go beyond what the evidence can support.

Notably, the Intergovernmental Panel on Climate Change’s conclusions are significantly more restrained than the media narrative suggests. According to the IPCC’s most recent assessment, only a small set of extreme events shows clear, globally consistent trends that can be confidently attributed to climate change. The strongest evidence is for increases in extreme heat, which are observed across most regions of the world. Beyond that, the IPCC finds mixed results, often with limited evidence or a lack of agreement across regions, for attributing changes in heavy rainfall, droughts, and storm-related factors to human influence.

Wildfire risk, central to the Washington lawsuit, illustrates the difficulties of disentangling natural and human factors when attributing disasters to climate change. Some evidence suggests that the frequency and magnitude of wildfires in the Pacific Northwest have increased over the past several decades, but there is no statistical link to climate variables. Other research shows that climate change has contributed to an increase in hotter and drier conditions (known as “fire weather”) that create more favorable conditions for wildfires. But the translation of those conditions into actual wildfire damages depends on ignition sources, land-use patterns, fire suppression strategies, and forest management. And, like hurricanes, as development expands in the “Wildland-Urban Interface,” more people and property are being exposed to fire risk, resulting in greater damage from fires independent of climate change.

All of this makes it extraordinarily difficult to parse the defendants’ specific contribution to the plaintiffs’ higher insurance costs. Demonstrating a persuasive causal link between the fossil-fuel industry and higher insurance premiums would require isolating the defendants’ share of emissions, providing a definitive link between those emissions and a detectable increase in the risk of natural disasters, connecting that increased risk to higher insured losses, and proving that those losses, rather than broader economic forces, drove the premium increases. This cannot be done with the available evidence.

More fundamentally, the lawsuit is an example of attempts to use the courts as a substitute for democratic policymaking on climate change. But this type of litigation is just a way to shift blame and avoid the hard work of crafting climate policy that balances climate risks with economic prosperity and looks for ways to mitigate the risks of hurricanes, wildfires, and other climate-related hazards.

The views and opinions expressed are those of the author’s and do not necessarily reflect the official policy or position of C3.