Global warming and changes in risk of concurrent climate extremes: Insights from the 2014 California drought

TLDR

Global warming raises the likelihood of simultaneous droughts and heat waves, exemplified by the 2014 California drought, which combined low precipitation, extreme temperatures, widespread wildfires, and critical winter water shortages. We argue that a multivariate viewpoint is necessary for assessing risk of extreme events, especially in a warming climate. The study proposes a methodology for assessing the joint risk of droughts and extreme temperatures. Univariate precipitation‑based risk assessments underestimate the 2014 California drought risk by ignoring temperature effects.

Abstract

Abstract Global warming and the associated rise in extreme temperatures substantially increase the chance of concurrent droughts and heat waves. The 2014 California drought is an archetype of an event characterized by not only low precipitation but also extreme high temperatures. From the raging wildfires, to record low storage levels and snowpack conditions, the impacts of this event can be felt throughout California. Wintertime water shortages worry decision‐makers the most because it is the season to build up water supplies for the rest of the year. Here we show that the traditional univariate risk assessment methods based on precipitation condition may substantially underestimate the risk of extreme events such as the 2014 California drought because of ignoring the effects of temperature. We argue that a multivariate viewpoint is necessary for assessing risk of extreme events, especially in a warming climate. This study discusses a methodology for assessing the risk of concurrent extremes such as droughts and extreme temperatures.