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

The Bay Area’s leading role in electric-vehicle adoption is producing a measurable drop in the region’s carbon footprint and contribution to the battle against climate change, new research from UC Berkeley suggests.

Last March, the Bay Area became the first U.S. metropolitan area where half of all new vehicle registrations were for EVs and hybrids, according to S&P Global Mobility.

In a paper published Thursday in the journal Environmental Science & Technology, UC Berkeley professor Ronald Cohen and researchers Naomi Asimow and Alexander Turner report that a network of nearly 60 carbon dioxide sensors around the Bay Area, mostly atop middle- and high-school buildings, provide the first evidence that electrified vehicles are lowering carbon emissions here.

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From 2018 and 2022, the sensors in the Berkeley Environmental Air Quality and CO2 Network recorded a small but consistent drop in CO2 emissions of about 1.8% a year, which the researchers say translates to an annual 2.6% drop in vehicle emission rates attributable to electric and hybrid cars.

“I would really like people to see this as an add-on to our success at reducing greenhouse gas emissions,” Cohen said. “We show from atmospheric measurements that adoption of electric vehicles is working, that it’s having the intended effect on CO2 emissions.”

To meet California’s goal to slash carbon emissions 85% from 1990 levels by 2045, that success would have to be doubled, Asimow pointed out.

Still, Cohen sees the emissions reduction as an encouraging sign that electrifying transportation can drive significant progress against climate change. “We really need to accelerate, but we’re on a track that’s not crazy difficult to get to where we want to get to,” Cohen said.

Electric transportation is seen as a key element in mitigating the effects of human-caused global warming by cutting the output of greenhouse gases from vehicle tailpipes. The White House has set a national goal for zero-emission vehicles representing half of all new vehicle sales by 2030. California in 2022 approved a regulation requiring all new cars sold to be zero-emission by 2035.

According to the Intergovernmental Panel on Climate Change, today’s carbon dioxide emissions are the main cause of global warming into the future. The group of scientists said last year that climate change is expected to continue causing widespread damage to water availability, crop production and fishery yields while boosting infectious disease, population displacement, wildfire conditions and sea levels. Choices made now and in the near future will determine the fate of future generations, the group said in its report.

The cost of protecting Bay Area homes, businesses and infrastructure from sea level rise alone was estimated at $110 billion by 2050 in a study last year by the Metropolitan Transportation Commission, the Association of Bay Area Governments and the Bay Conservation and Development Commission.

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.”