2000-2021 was the driest 22-year period since the year 800 in the Southwest

This aerial view of Lake Mead shows declining water levels. Credit: NOAA Drought Task Force

Since the year 2000, southwestern North America (SWNA) has been unusually dry due to low precipitation totals and heat - most recently embodied by the exceptional drought in 2021. From 2000 to 2021, mean water-year (October–September) SWNA precipitation was 8.3% below the 1950–1999 average and the temperature was 0.91°C above average. No other 22-year period since at least 1901 was as dry or as hot. How does this exceptionally dry period compare to historical droughts? 

In a new Nature Climate Change article, authors A. Park Williams, Benjamin I. Cook, and Jason E. Smerdon extended the SWNA summer soil moisture record back to 800 CE using a tree-ring reconstruction and compared the observed drought of 2000–2018 to the infamous megadroughts that occurred repeatedly from 800–1600.

Read more at the link below.