The American West is experiencing the worst mega-drought in over a thousand years.
A mega-drought is categorized as a prolonged drought that persists for two decades or longer. A new study, published in the journal Nature Climate Change, found the past 22 years have been the driest in at least 1,200 years, and scientists estimate nearly 50% of the drought's severity can be attributed to climate change. The region is actively home to tens of millions of people with massive agricultural centers and some of the fastest-growing major cities in the U.S. — and now, all in an area where there is less water available than there was in the past. "We have a society that's relying on there being the amount of water there was in the 1900s," said the study's lead author, Park Williams, a bioclimatologist at the University of California, Los Angeles. "But now with the number of water molecules available to us declining, it really is time for us to get real about how much water there is for us to use."
Water reservoirs seemed to give signs of hope at the beginning of the year, following the tail-end of winter in California where the Sierra Nevada had record-breaking snowfall, and big snowstorms blanketed the northern Rockies. But a hot, dry start and forecast for the mid half of the year has since dropped snowpack levels to below average in many places. Multiple reservoirs and lakes that are home to most of the Western states water supply have been lower than regular capacity, and communities, ranchers and farmers have depleted groundwater stores to meet demands.
Williams said roughly one-fifth of the current megadrought can be attributed to human-caused climate change, which mainly includes greenhouse gas emissions that are warming the world, speeding evaporation and disrupting weather patterns. These emissions have caused alternating water patterns in the West, and the trend is plummeting down, Williams says, "and we cannot let ourselves get tricked by a few wet years into giving up on the progress we've been making."