EVs are reducing CO2 emissions in the Bay Area. Is it enough?

A network of air monitors installed in Northern California has provided scientists with some of the first measurable evidence quantifying how much electric vehicles are reducing the carbon footprint of a large urban area.

Researchers at UC Berkeley have installed dozens of sensors throughout the Bay Area to monitor global warming carbon dioxide, the superabundant greenhouse gas produced when burning fossil fuels.

Between 2018 and 2022, the region’s carbon emissions fell 1.8% each year, which Berkeley researchers said was almost exclusively due to drivers switching to electric vehicles, according to a study published Thursday in the Environmental Science & Technology magazine.

During that period, Californians purchased about 719,500 zero-emission or plug-in hybrid vehicles, more than triple the amount compared to the previous five years, according to the California Department of Energy. The Bay Area also had a higher electric vehicle adoption rate than the state as a whole.

While the results confirm that the state’s transition to zero-emission vehicles significantly reduces carbon emissions, they also reveal that these reductions are still unable to meet the state’s ambitious climate goals.

Emissions must be reduced by about 3.7 percent per year, nearly twice the rate observed by monitors, according to Ronald Cohen, a chemistry professor at UC Berkeley. Although cars and trucks are the state’s largest source of carbon emissions, this highlights the need to deploy zero-emission technology inside homes and for the power grid.

“I think what we’re seeing right now is evidence of great success in the transportation sector,” Cohen said. “We will need equally significant success in domestic and commercial heating, as well as (industrial) sources. We are not yet seeing significant progress in this area, but the policy on this subject is not as advanced as that relating to electric vehicles.

Although cities cover only about 3% of the world’s land area, they produce about 70% of carbon emissions. Urban monitoring networks could give policy makers a more precise view of pollution sources.

Los Angeles and other major cities have installed Cohen’s monitors in hopes they can reveal more information about carbon emissions and air pollution.

As government agencies continue to evaluate efforts to decarbonize the economy using socioeconomic data and computer models, experts say monitoring networks like Berkeley’s could provide a reality check sorely needed for some communities and offer another tool to verify the effectiveness of climate policies.

“I think the best contribution this makes is to show how we can verify what’s happening,” said Danny Cullenward, a climate economist and senior fellow at the Kleinman Center for Energy Policy at the University of Pennsylvania. “It’s probably not the last word. But it’s an elegant way to check some of these things. We need more of these approaches, not fewer.

These systems could also reveal blind spots. California, for example, doesn’t account for greenhouse gases escaping from uncapped oil wells or carbon emissions from biofuels, such as power plants that burn wood waste.

“The atmosphere doesn’t care,” Cullenward said. “You can always measure it.”

The main obstacle to the installation of such networks is financing. But the equipment has gotten cheaper over the years: Each of Berkeley’s sensors costs less than $10,000.

But the intention, Cohen said, is not to replace current modes of climate accounting. He hopes these methods and his own will work together.

“We are not suggesting that one should be done in the absence of the other, but that they are stronger together.”