"Colorado Supreme Court advances historic Boulder climate accountability case", 12 May 2025.

...The Colorado Supreme Court ruled today that Boulder County and the City of Boulder can move forward with their climate case against Exxon Mobil and Colorado Suncor entities. This case seeks to hold these companies responsible for knowingly contributing to climate change while concealing the dangers of their products. 

Boulder County and the City of Boulder face significant rising costs to address the impacts of climate change—costs that would otherwise fall entirely on local taxpayers. This lawsuit aims to ensure that the corporations that caused the harm pay their fair share, rather than shifting the burden to Colorado communities. 

The decision comes as the realities of climate alteration continue to mount for Colorado. Colorado is one of the fastest-warming U.S. states and continues to experience problems associated with rising temperatures. Over the next three decades, Colorado communities are expected to face costs reaching hundreds of millions of dollars or more to adapt to and mitigate the impacts of climate change. 

The Colorado Supreme Court recognized that while the case “presents substantial issues of global import,” its opinion was narrowly focused on whether federal law blocked the application of Colorado law, concluding that “defendants’ arguments do not convince us that federal law preempts Boulder’s state law claims in this case.”

This is only the second state supreme court decision to address whether this type of climate case can move forward, following a decision from the Hawaii Supreme Court in 2023...

Boulder County, San Miguel County, and the City of Boulder originally sued Suncor and Exxon in April 2018 for the costs that they face due to climate harms, and for decades of misinformation. After the state district court rejected the companies’ attempt to have the lawsuit dismissed, Exxon directly petitioned the Colorado Supreme Court to overturn the result. Exxon argued that federal law bars Colorado from applying its own state law to these in-state injuries, meaning that Exxon’s actions would be beyond the reach of any law....