Tracking Carbon Responsibility in the American West
Fossil fuel companies and cement producers hold responsibility for half of the water loss recorded in the American West between 2014 and 2024. A study published Tuesday in the journal Communications Earth and Environment links the emissions of 122 specific entities to the current regional water crisis. Researchers found that climate change reduced annual snowpack by more than one-third and lowered streamflows by 13 percent during that decade. The findings offer a clear metric for the toll exacted by these carbon majors on the nation’s most vital reservoirs.
The volume of water lost to these emissions totals trillions of gallons. This amount matches the full capacity of Lake Mead, which currently serves 40 million people across the region. Carly Phillips, a senior research scientist at the Union of Concerned Scientists and a co-author of the paper, notes that these changes directly impact millions of residents. The data shows the consequences are no longer abstract; they are present in every dry stream and depleted reservoir.
The Mechanism of Attribution Science
Researchers determined these figures by subtracting emissions from the 122 identified carbon majors from total global output for the decade. They modeled the remaining emissions against a hypothetical Earth without climate change to isolate the specific impact on western hydrology. This methodology relies on a database from the independent think tank InfluenceMap. It accounts for a total of 1.44 trillion tons of carbon dioxide emitted since the start of the Industrial Revolution.
Rising temperatures in the West change how water moves through the landscape. Precipitation now falls more often as rain rather than snow. This shift causes earlier melting and creates challenges for water management and forecasting. Lower snowpack levels reduce surface reflectivity, which traps more heat at the ground level. This process increases evaporation rates in soil and groundwater, leaving less water to feed rivers and irrigation canals. Irrigation demand spiked by 4 percent over the study period, with more than half of that need linked directly to emissions from carbon majors.
Legal Implications and Industry History
This study provides new data for ongoing litigation against oil and gas companies. Numerous states and cities have filed suits seeking damages for environmental harm caused by fossil fuel products. Plaintiffs can now use these findings to establish a more precise link between industry emissions and regional water scarcity. Graham Fogg, a professor emeritus at the University of California, Davis, called the work a groundbreaking effort that creates a foundation for future research.
History indicates that many of these producers understood the risks associated with their products decades ago. Phillips points out that significant emission growth occurred after the 1950s. Rather than warning the public, some firms initiated campaigns to challenge the underlying science. The present drought reflects these past choices. As the West faces record-low snowpack and constant wildfire threats, the question of accountability remains a central issue for courts and policymakers alike.