AGU: Geophysical Research Letters

 

Editors' Highlight

Over the twentieth century, droughts became shorter and less frequent over much of the United States

Droughts cause adverse effects on water management and aquatic ecosystems, with estimated annual losses between $6 and $8 billion. Some climate models have predicted changes in the severity and duration of drought, though temperature and precipitation over the continental United States have likely increased in the latter half of the twentieth century. To examine trends in drought characteristics, Andreadis and Lettenmaier (2006) constructed a time series of soil moisture and runoff over the continental United States for the period between 1925 and 2003. Their results show a wetting trend and an increase in runoff over most of the United States, consistent with observed precipitation increases and streamflow records from streams minimally affected by dams and other anthropogenic activities. Over most of the United States, droughts became shorter and less frequent and covered a smaller portion of the country. The main exception is the Southwest and parts of the interior of the West, where increased temperature led to longer and more severe droughts during the time period studied.

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