Ocean and land forcing of the record-breaking Dust Bowl heatwaves across central United States

• Published in: Nature Communications
• Main Authors: Cowan, Tim, Hegerl, Gabriele C., Schurer, Andrew, Tett, Simon F. B., Vautard, Robert, Yiou, Pascal, Jézéquel, Aglaé, Otto, Friederike E. L., Harrington, Luke J., Ng, Benjamin
• Format: Article in Journal/Newspaper
• Language: English
• Published: Springer Science and Business Media LLC 2020
• Subjects: General Physics and Astronomy; General Biochemistry, Genetics and Molecular Biology; General Chemistry; North Atlantic
• Online Access: http://dx.doi.org/10.1038/s41467-020-16676-w; http://www.nature.com/articles/s41467-020-16676-w.pdf; http://www.nature.com/articles/s41467-020-16676-w

Abstract The severe drought of the 1930s Dust Bowl decade coincided with record-breaking summer heatwaves that contributed to the socio-economic and ecological disaster over North America’s Great Plains. It remains unresolved to what extent these exceptional heatwaves, hotter than in historically forced coupled climate model simulations, were forced by sea surface temperatures (SSTs) and exacerbated through human-induced deterioration of land cover. Here we show, using an atmospheric-only model, that anomalously warm North Atlantic SSTs enhance heatwave activity through an association with drier spring conditions resulting from weaker moisture transport. Model devegetation simulations, that represent the wide-spread exposure of bare soil in the 1930s, suggest human activity fueled stronger and more frequent heatwaves through greater evaporative drying in the warmer months. This study highlights the potential for the amplification of naturally occurring extreme events like droughts by vegetation feedbacks to create more extreme heatwaves in a warmer world.