The Supreme Court is preparing to hear Suncor Energy v. Boulder County, a climate liability case that could reshape how energy companies are held financially accountable for global warming. But a major shift in climate science is raising questions about the very assumptions the lawsuit depends on.
At issue is whether Boulder, Colorado, can use state tort law to sue energy producers for damages linked to climate change, bypassing federal regulations under the Clean Air Act and Clean Water Act. Supporters frame these lawsuits as accountability mechanisms; critics see them as an end-run around democratic lawmaking.
Regardless of one's view, the case rests on projections of future climate harms that now appear outdated. For years, the most widely used climate scenario in such litigation was RCP8.5, which assumed a dramatic rise in global coal use and greenhouse gas emissions. That scenario underpinned thousands of studies and was frequently cited in climate damage assessments.
But in late May, the international team of scientists responsible for crafting the next IPCC assessment framework dropped RCP8.5-like pathways from their scenarios. Their reasoning: the scenario is no longer realistic, given the rapid growth of renewables, market shifts, and technological advances that make a coal-heavy future highly unlikely. The IPCC is the United Nations body charged with evaluating climate science.
This does not challenge the fundamental science of climate change or the reality that emissions have consequences. But it does call into question the accuracy of damage estimates that rely on RCP8.5. As in other fields—medicine, engineering, economics—courts expect evidence to reflect current knowledge. Climate litigation should be no different.
Boulder's case is part of a wave of similar lawsuits filed by municipalities across the country, seeking billions in retroactive damages from energy companies operating under a federal regulatory framework. These cases aim to impose massive financial liability based on projections that may no longer hold.
The stakes extend beyond this single case. As the Supreme Court weighs privacy in the digital age, it also faces the question of how to handle evolving science in liability claims. Meanwhile, energy demand is surging due to AI infrastructure, advanced manufacturing, and data centers, even as the U.S. competes with China and rebuilds its industrial base.
These challenges demand robust policy debates through the democratic process, where elected officials can weigh competing priorities and voters can hold them accountable. They should not be resolved in courtrooms based on scientific assumptions that are increasingly being revised.
Science evolves, models improve, and assumptions are refined. That is a strength, not a weakness. The legal system should be willing to do the same before entertaining sweeping climate liability claims that could reshape America’s energy future.
Bud Albright served as an assistant U.S. attorney and under secretary of Energy.
