California's advocates for tougher fuel economy standards and zero-emission vehicle mandates received fodder for standing firm with their rules, as a nonprofit's annual report found road emissions have undercut the state's efforts to reduce pollution.
Emissions from on-road transportation rose by the equivalent of 4.4 million metric tons of carbon dioxide in 2015 from a year earlier, the San Francisco-based non-profit Next 10 said Monday. Motorists traveled more and some may have abandoned public transportation as gasoline prices fell, according to the group's report, which found the the state's total greenhouse gas emissions dropped at less than half the rate of the prior year.
The report reinforces Gov. Jerry Brown and California Air Resources Board Chair Mary Nichols's opposition to softening the standards that the state agreed to in a three-way deal with automakers and then-President Barack Obama in 2011. The carmakers' trade groups have urged California to reconsider the rules after Donald Trump reinstated a review of them earlier this year.
Trump in March said national greenhouse-gas rules that run through 2025 would have "destroyed" the auto industry and reopened them to scrutiny. The EPA and National Highway Traffic Safety Administration have signaled since last month a willingness to alter standards starting with the 2021 model year.
"Transportation sector emissions vastly outweigh other carbon-producing areas of California's economy," Adam Fowler, an economist at Beacon Economics, the research and consulting firm that compiled Next 10's California Green Innovation Index, said in an emailed statement. "The recent spike should alert policy-makers that despite our best efforts, more must be done."
Low fuel prices and a lack of affordable housing prompted more driving and contributed to a 3.1 percent increase in tailpipe exhaust from cars, buses and trucks in 2015, according to the report. Total greenhouse gas emissions fell 0.34 percent, the group said.
Despite zero-emission vehicle mandates that have been in place for nearly two decades, transportation still accounted for 38.5 percent of the state's emissions in 2015, far more than any other sector. Last year, Governor Brown signed legislation requiring the state to cut CO2 emissions 40 percent below 1990 levels by 2030.
Despite its challenges with transportation, California remained a leader in fostering economic growth while limiting emissions, the report found. In 2014, $10,000 worth of economic activity in California generated 55 percent fewer CO2 emissions than the rest of the country.