The ecosystems on the American Southwest’s federal lands are hemorrhaging carbon dioxide into the atmosphere faster than any other region in the U.S., according to a recent study from the U.S. Geological Survey. While federal land ecosystems in most states are sequestering carbon dioxide on average, California’s lost six times more than any other state during the 17-year period from 2005 to 2021 that the study analyzed. “In California, it’s primarily a story of fire,” said Benjamin Sleeter, a research geographer with the USGS who led the ecosystem analysis in the new study. While scientists typically expect the movement of carbon in and out of ecosystems to cancel out in the long run, human intervention and climate change have destabilized the delicate balance. It’s made the daunting task of modeling carbon flowing between ecosystems and the atmosphere, which has challenged scientists for decades, even harder.