image: The Nothofagus pumilio forest in the valley of Río Frías, in northern Patagonia, Argentina. This tree species was instrumental in contributing 85 tree-ring chronologies to the development of the Drought Atlas. view more
Credit: Image credit: Ricardo Villalba
According to a study that recreated 600 years of South American hydroclimate records, prolonged droughts and rainfall events on the continent have become more frequent over the last 60 years. South America has experienced extreme climate events since the 1960s, including extended hydroclimatic extremes. However, comprehensive records on the continent's earlier climate are limited. Mariano Morales and colleagues combined existing observational data and 286 tree-ring records to recreate the variations in dry and wet events from 1400 to 2000 CE. The authors' South American Drought Atlas focuses on the austral summer climate south of latitude 12ºS. The authors found that recent prolonged droughts and rainfall events have increased in frequency. To validate the findings, the authors compared the reconstructions of wet and dry conditions with independent historical archives in three different areas of the continent. The analysis suggests that oscillations between El Niño and La Niña events, coupled with wind patterns at middle southern latitudes, are major drivers of spatially extended droughts and rainfall events on the continent. Combined with increasing greenhouse gas emissions, such drivers may cause more extreme climate events in the 21st century, according to the authors.
Article #20-02411: "Six hundred years of South American tree rings reveal an increase in severe hydroclimatic events since mid-20th century," by Mariano S. Morales et al.
MEDIA CONTACT: Mariano S. Morales, Instituto Argentino de Nivología, Glaciología y Cs. Ambientales, CONICET, Mendoza, ARGENTINA; e-mail: mmorales@mendoza-conicet.gob.ar
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Journal
Proceedings of the National Academy of Sciences