Major fossil fuel companies are significantly contributing to the water crisis in the American West, according to a groundbreaking study published Tuesday.
The study, featured in Nature’s Communications Earth and Environment journal, found that from 2014 to 2024, climate change reduced over a third of the region’s annual snowpack and decreased streamflows by about 13%. About half of these losses are linked to emissions from 122 fossil fuel companies and cement producers, identified as “carbon majors.”
This pollution has depleted the West of trillions of gallons of water—equivalent to the full capacity of Lake Mead, the largest reservoir in the U.S.
“Millions rely on these water resources,” said Carly Phillips, a senior research scientist at the Union of Concerned Scientists and co-author of the study. “The impacts of these changes are evident for those on the ground.”
As fossil fuel burning continues, trapping heat in Earth’s atmosphere, the West is facing a prolonged drought, exacerbated by climate change. This leads to higher temperatures, which further deplete regional water supplies. The region is currently enduring a very dry summer following a low-snowpack winter and record high runoff after a March heatwave.
Wildfires, partly caused by moisture shortages, are now widespread, pushing some areas to their limits. Nevada recently sued the federal government over its Colorado River management plan, which provides water for 40 million people.
To assess emissions from major fossil fuel companies and cement producers, the study used data from a peer-reviewed paper and the Carbon Majors database. This project, by the think tank InfluenceMap, tracks global fossil fuel emissions.
The researchers quantified the effect of these emissions on regional snowpack and river flows by comparing actual data with a hypothetical scenario without climate change.
This method, known as attribution science, is increasingly used to connect extreme weather events and environmental shifts to greenhouse gas effects, primarily from fossil fuels. Rising temperatures cause more rainfall than snowfall, which melts earlier, complicating water forecasts. Less snow reduces reflectivity, increasing surface heat, evaporation, and reducing water runoff into rivers and reservoirs.
Between 2014 and 2024, the Pacific Northwest and California’s Central Valley recorded the largest declines in snow water equivalent—an estimate of water content in snowpack—and peak streamflow. The lower Colorado River basin, although losing less moisture absolutely, saw a 76% decrease in snow water equivalent and a 21% drop in streamflow.
As snow and water levels fell, irrigation demand rose over 4% during this period, with over half attributed to Carbon Majors’ emissions, 97% of which have occurred since the 1950s.
Phillips emphasized that in the 1950s, some fossil fuel producers recognized the risks of their products but chose to obscure the science instead of informing the public and policymakers.
Graham Fogg, a professor emeritus of hydrogeology at the University of California, Davis, praised the study’s approach to linking carbon major emissions to climate impacts, calling it “groundbreaking” and foreseeing many follow-up studies to refine these estimates.
Numerous U.S. states and cities have sued large oil and gas companies for environmental damages linked to emissions. According to Phillips, this study bolsters plaintiffs’ claims in these cases, aiming to hold fossil fuel companies accountable for climate change impacts.
“It didn’t have to be this way,” Phillips noted, pointing to fossil fuel companies’ choices that led to the current situation.
Original Story at insideclimatenews.org