Climate change could mean a wetter California

Californians have been bracing themselves for a drier future accompanying a warming climate. But research by scientists at the University of California, Riverside, suggests that the state may actually get wetter in the event of severe climate change.

The study, published July 6 in Nature Communications, reports that more years in the state could look like El Niño ones, when California typically has wetter winters. The authors found that average annual precipitation in California could increase by about 12 percent if nothing is done to curb carbon emissions. Average precipitation in the winter could increase by as much as 30 percent. A wetter climate, however, might not offset the overwhelmingly negative effects of a warming climate.

That wetter scenario would take place in a future where atmospheric carbon dioxide reaches almost 1,000 parts per million, more than doubling what it is now and corresponding to the planet heating by between 5 and 9 degrees Fahrenheit. So far, the planet has warmed about 2 degrees Fahrenheit since the late 1800s. The climate change treaty signed by 195 countries in Paris aims to keep warming to 3.6 degrees Fahrenheit this century.

The area north of Santa Rosa could receive 14 percent more precipitation, the study found. Central California, stretching to just south of San Luis Obispo, could see increases of about 15 percent, while precipitation in Southern California would decrease by about 3 percent.

Most previous studies predicted that California would be drier with climate change, said Robert Allen, one of the authors of the paper and an assistant professor of climatology at UC Riverside.

California stretches between two different climate zones, making it especially difficult to predict changes to future precipitation. The Pacific Northwest to the north is expected to get wetter with a warming planet, while drier weather is expected in Southern California and Mexico.