Continued anthropogenic climate change will increasingly enhance the odds of long, widespread and severe megadroughts
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-yr 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 800ce using a tree-ring reconstruction and compared the observed drought of 2000–2018 to the infamous megadroughts that occurred repeatedly from 800–1600.
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