Dec 5, 2017

Future loss of Arctic sea-ice cover could drive a substantial decrease in California’s rainfall

Ivana Cvijanovic, Benjamin D. Santer, Céline Bonfils, Donald D. Lucas, John C. H. Chiang, Susan Zimmerman
Nature Communications
  • States that, as during previous dry periods, the 2012 to 2016 California drought featured precipitation-inducing winter storms that were steered away from California by a persistent atmospheric ridging system in the North Pacific
  • Identifies a new link between Arctic sea-ice loss and the North Pacific geopotential ridge development
  • Finds that, in a two-step teleconnection, sea-ice changes lead to reorganization of tropical convection that in turn triggers an anticyclonic response over the North Pacific, resulting in significant drying over California
  • These findings suggest that the ability of climate models to accurately estimate future precipitation changes over California is also linked to the fidelity with which future sea-ice changes are simulated
  • Concludes that sea-ice loss of the magnitude expected in the next decades could substantially impact California’s precipitation, thus highlighting another mechanism by which human-caused climate change could exacerbate future California droughts