The state of California, Alameda County and the city of Oakland have declared states of emergency in response to recent and upcoming storms. Michael Wehner, a senior scientist in the applied math and computational sciences division at Lawrence Berkeley National Laboratory, says the intensity of these storms can be attributed to climate change.

Governor Gavin Newsom declared the state of emergency Jan. 4. According to a state press release, the proclamation supports relief efforts during the storms, including authorizing mobilization of the California National Guard, supporting highway repairs through CalTrans and supporting local relief.

In Oakland, city administrator Ed Reiskin issued the Proclamation of Local Emergency on the same day. According to the city’s acting director of communications, Nicole Neditch, Reiskin issued the proclamation after determining that the city would need to provide some indoor shelter and that the proclamation would fast track the process.

“The order allows the City to address public safety, transportation, public works, and other needs, procure equipment and materials and/or activate emergency workers on an expedited basis,” Neditch said in an email.

Wehner said the recent storm on Wednesday and Thursday, which was a combination of an atmospheric river and extratropical cyclone, had 5% more precipitation because of increases in temperature due to climate change.

In a recent paper commissioned by the San Francisco Public Utilities Commission and co-authored by Wehner, he simulated five recent storms that have hit the Bay Area, both as they actually happened and under hypothetical warmer conditions. The researchers found that increases in temperature increased extreme precipitation at an above average rate in storms — much like the one that just occurred.

Wehner then used the same model to determine how this storm played out, as well as how it would have played out without the approximately one degree Fahrenheit increase in ocean temperature off the coast of San Francisco, finding that the increase resulted in 5% more precipitation.

“5% may not sound like a lot, but when you’re talking about extreme events a little bit can go a long way and push things to a breaking point, like a river overtopping or breaking levees, or flooding over the banks of streams and rivers, or mudslides for that matter,” Wehner said. “So while 5% doesn’t sound like a lot, it indeed is.”

In terms of other aspects of storms, like wind and lightning, Wehner said it has been harder to determine the changes.

Wehner added that the “human fingerprint” on wind is more subtle and has not yet been determined.

According to the modeling, storms and precipitation will continue to worsen as climate change worsens. Wehner says the solution will have to be large-scale.

“The biggest thing to do is vote,” he said. “One can take personal actions and that’s not a bad thing, it’s a good thing. But the reality is this is a very macro problem. So if we’re going to reduce our emissions, we have to have real national and international policies in place. What really makes a difference is to change our entire energy economy. And that’s not something individuals can do; that has to be done on a macro level.”