Increasing prevalence of hot drought across western North America since the 16th century

Karen E King; Edward R Cook; Kevin J Anchukaitis; Benjamin I Cook; Jason E Smerdon; Richard Seager; Grant L Harley; Benjamin Spei

doi:10.1126/sciadv.adj4289

Increasing prevalence of hot drought across western North America since the 16th century

Sci Adv. 2024 Jan 26;10(4):eadj4289. doi: 10.1126/sciadv.adj4289. Epub 2024 Jan 24.

Authors

Karen E King¹, Edward R Cook², Kevin J Anchukaitis^{2

3

4}, Benjamin I Cook^{5

6}, Jason E Smerdon^{6

7}, Richard Seager⁶, Grant L Harley⁸, Benjamin Spei⁹

Affiliations

¹ Department of Geography and Sustainability, University of Tennessee, Knoxville, 1000 Phillip Fulmer Way, Knoxville, TN 37996, USA.
² Tree Ring Laboratory, Lamont-Doherty Earth Observatory of Columbia University, 61 Route 9W, Palisades, NY 10964, USA.
³ School of Geography, Development, and Environment, University of Arizona, 1064 Lowell Street, Tucson, AZ 85721, USA.
⁴ Laboratory of Tree-Ring Research, University of Arizona, 1215 E Lowell Street, Tucson, AZ 85721, USA.
⁵ NASA Goddard Institute for Space Studies, 2880 Broadway, New York, NY 10025, USA.
⁶ Ocean and Climate Physics Division, Lamont-Doherty Earth Observatory of Columbia University, 61 Route 9W, Palisades, NY 10964, USA.
⁷ Columbia Climate School, Columbia University, New York, NY 10027, USA.
⁸ Department of Earth and Spatial Sciences, University of Idaho, 875 Perimeter Drive MS3021, Moscow, ID 83843, USA.
⁹ Department of Forest, Rangeland, and Fire Sciences, University of Idaho, 975 West 6th Street, Moscow, ID 83843, USA.

Abstract

Across western North America (WNA), 20th-21st century anthropogenic warming has increased the prevalence and severity of concurrent drought and heat events, also termed hot droughts. However, the lack of independent spatial reconstructions of both soil moisture and temperature limits the potential to identify these events in the past and to place them in a long-term context. We develop the Western North American Temperature Atlas (WNATA), a data-independent 0.5° gridded reconstruction of summer maximum temperatures back to the 16th century. Our evaluation of the WNATA with existing hydroclimate reconstructions reveals an increasing association between maximum temperature and drought severity in recent decades, relative to the past five centuries. The synthesis of these paleo-reconstructions indicates that the amplification of the modern WNA megadrought by increased temperatures and the frequency and spatial extent of compound hot and dry conditions in the 21st century are likely unprecedented since at least the 16th century.