A National Oceanic and Atmospheric Administration (NOAA)-led drought taskforce has just completed a report on the record-breaking drought in the southwestern U.S. The study, NOAA Drought Task Force Report on the 2020–2021 Southwestern U.S. Drought, analyzed precipitation and temperature levels across six southwestern states—Arizona, California, Colorado, Nevada, New Mexico, and Utah—for 20-months from January 2020 through August 2021. The aggregate precipitation over the 20-month period was the lowest on record, dating back to 1895, leaving virtually the whole western half of the contiguous U.S. in some stage of drought by the end of August, according to the report. Average temperatures, over the same 20-months, were also near-record high because of human-caused global warming.

High temperatures significantly increase the evaporation of ground-based bodies of water, known as vapor pressure deficit, further exacerbating drought conditions. The report concludes that the current drought would not be nearly as intense without the extremely high temperatures induced by human-caused global warming and without measures to mitigate further warming extreme droughts will likely be more frequent in the future. Regarding the current drought the report states that “it will take several seasons (and potentially years) of above-average precipitation to replenish the reservoirs, rivers, streams, and soil moisture… [thus] the ongoing Southwestern U.S. drought will very likely last well into 2022, and potentially beyond.” Access the full report at NOAA or read a relevant article here.