Anthropogenic Climate Change Negatively Impacts Vegetation and Forage Conditions in the Greater Four Corners Region

The Southwestern U.S. has been in a megadrought for the past two decades, stressing vegetation across region and leading to poor forage conditions on rangelands. How human-induced climate change affected air temperatures atmospheric evaporative demand greater Four Corners of Southwest, what have corresponding impacts vegetative productivity? We address this question via multi-step detection attribution analysis. first relate (quantified by Vapor Pressure Deficit, or VPD) precipitation Normalized Difference Vegetation Index (NDVI) six unique plant-precipitation zones. VPD is strongly negatively related NDVI, strength relation similar magnitude precipitation. then use large ensemble simulations estimate increases attributable change. find that modest led VPD, with influence about twice inter-annual standard deviation 2020. Finally, we reductions NDVI due increased present terms total annual Aboveground Net Primary Productivity. conclude warming roughly doubled recent deficits, especially mid-precipitation areas (receiving 250–500 mm annually), concentrated New Mexico. These results indicate from human-caused are having persistent damaging productivity, significant implications ranchers other land users region.