Electric, hybrid cars cutting Bay Area's carbon footprint, UC Berkeley researchers say

Reversing global increases in carbon dioxide emissions, Cohen, Asimow and Turner said in their paper, “represents one of the greatest challenges facing humankind.”

When Cohen began building the network of sensors in 2012, he did not foresee using them to assess emissions reductions from electrified cars in a region that leads the way in adoption of EVs. “We lucked out on that,” said Cohen, whose project started out as a way to pinpoint emission sources by neighborhood to probe public-policy effects on climate. “We started here in the Bay Area because it was home and it was easy to do things and have them break and go fix them.”

To reach their conclusions about electrified vehicles, Cohen and the other researchers factored in traffic patterns, the share of electric and hybrid vehicles on the road, the effects of COVID shutdowns and the shift to remote work, emissions data from other sources such as residential gas heating, and the increasing fuel efficiency of gas-powered vehicles.

Eugene Cordero, a climate science professor at San Jose State University, said that the UC Berkeley researchers’ methods left some uncertainty, although he found their results credible. “When you just go out and measure a gas in the air, the sources could be from lots of different places,” Cordero said.

Because most of the sensors are in the East Bay, it’s possible that the San Jose area would show larger reductions in carbon dioxide emissions, as data indicate that the South Bay has higher EV adoption rates than elsewhere in the Bay Area, Cordero said.

The research is valuable and highlights the fact that more study is needed to find and implement solutions to climate change, Cordero said. “We need to have better data on where we are being successful and where we need to improve.”

While the Bay Area has leapt to the front in EV adoption, the market for those vehicles, including in this region, has run into headwinds. Auto-industry analysts say worries over charging hassles and range have led to a slowdown in EV sales nationwide, and in the Bay Area, such concerns are rising while many of the early adopters already have the vehicles. Hybrids are now widely seen as a more reliable step into electrified vehicles, said Ivan Drury, an analyst at Edmunds, which tracks the auto industry.

For California to meet its goals, however, “you don’t get there with hybrid-electric,” Cohen said. “At some point we have to be all electric.”