Research Article: Increasing prevalence of hot drought across western North America since the 16th century — Science Advances

Fig. 1. Subregional expression of reconstructed temperatures across WNA since 1553 CE. (Left) First four varimax-rotated eOF factor scores (ranging from −1.0 to +1.0) are mapped and labeled with the variance explained by each factor. (Right) Annual (thin black line) and 10-year low pass–filtered (thick red lines) reconstruction time series of JJA maximum temperatures for four major regions of WnA, spanning the period 1553 to 2020 ce. Anomalies are relative to the 1951 to 1980 ce mean. the four regional time series are calculated using the rotated varimax factor loadings over the period 1901 to 2000 ce. Credit: Science Advances

Click the link to access the article on the Science Advances website (Karen E. KingEdward R. CookKevin J. AnchukaitisBenjamin I. CookJason E. SmerdonRichard SeagerGrant L. Harley, and Benjamin Spei). Here’s the 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.

Leave a Reply