Can a County Sue Oil Companies Over Climate Change?

Can a Colorado county sue oil companies for damage caused by climate change? The Supreme Court heard that question on October 5. Here is what is at stake, and why the answer could reach far beyond Boulder.

The case began in 2018, when Boulder County and the City of Boulder sued ExxonMobil and Suncor. They say the companies knew about the dangers of their products and should pay for local harm, both past and future. They are asking for money, not a ban on oil sales.

Colorado’s Supreme Court let the case move forward in May 2025. The oil companies then asked the United States Supreme Court to step in. They argue that the federal Clean Air Act, and the Constitution’s structure of state power, should keep this kind of claim out of state courts.

Justice Samuel Alito stepped aside before the argument, and the court gave no reason. That leaves eight justices. Reporters say the justices seemed torn, both on the legal questions and on how far these lawsuits could spread.

Here is the strongest case on the other side. The companies say that if every state court could judge global emissions, the result would be chaos, with many conflicting rules for one national energy market. Boulder says these are ordinary state claims for harm done at home.

Why does this reach past one county? A ruling could decide whether local governments can seek damages from fossil fuel companies, or whether only Congress can set those rules. The justices are expected to decide by early summer.

So, can a county sue oil companies for climate damage? The justices have not answered yet. Watch for the ruling, because it may decide who gets to write the rules.