Scientist testifies on federal waiver to regulate auto exhaust

Mark Jacobson

Mark Jacobson

"We will restore science to its rightful place."

For many Americans, those eight words were among the most hopeful spoken by Barack Obama in his inaugural address.

On March 5, the Environmental Protection Agency took a step in that direction by holding a hearing to reconsider California's application for a waiver that would allow the state to regulate greenhouse gases from motor vehicles. Mark Z. Jacobson, a professor of civil and environmental engineering, testified on the main points that the agency cited in a Feb. 28, 2008, written analysis that explained why the waiver was denied.

Jacobson came away from the hearing cautiously optimistic, saying he felt the agency was inclined to grant the waiver, but that it had to justify the decision scientifically, because "there was an elaborate justification last year for denying it."

"I feel more confident that their decision will be based on known science this time around," he said.

The 2008 decision, signed by Stephen L. Johnson, the administrator of the agency, stated that compared to the nation as a whole, California lacked the "compelling and extraordinary conditions" that would merit a waiver to allow the state to set greenhouse gas regulations on emissions from new automobiles independently of the federal government.

The decision was the first by the agency to deny California the freedom to set its own environmental standards. Gov. Arnold Schwarzenegger issued a statement after the denial noting that the agency had previously granted more than 40 waivers to the state.

Jacobson said there were two ways in which California could qualify for the waiver. The state could demonstrate that greenhouse gases from vehicles, most notably carbon dioxide, had a greater environmental impact on California than other states, or show that the pollutant caused local impacts on air pollution. Jacobson has conducted research studies that have shown both to be true.

In a study published Feb. 12, 2008, in Geophysical Research Letters, Jacobson demonstrated that for each 1 degree Celsius increase in temperature caused by carbon dioxide, the resulting air pollution would lead to approximately 1,000 additional deaths and many more cases of respiratory illness and asthma in the United States.

The study also found that the effects of carbon dioxide's warming were most pronounced in areas where air pollution is already severe. "With six of the 10 most polluted cities in the nation being in California, that alone creates a special circumstance for the state," Jacobson said in an earlier interview about that study. He found that although California has only 12 percent of the nation's population, it suffers about 30 percent of the additional air pollution-related mortality resulting from higher carbon dioxide levels. Chemical and meteorological changes caused by the carbon dioxide itself increase mortality due to heightened levels of ozone, particles and carcinogens in the air.

In more recent research, Jacobson examined the effect of locally emitted carbon dioxide emissions on local air pollution in cities and determined that those emissions do have a negative impact on local air quality and human health.

Representatives of the automobile industry also testified at the hearing, as did Sen. Carl Levin, D-Mich., who supported the industry's call for a single national standard.

Supporters of the waiver argue that a national standard will take longer to develop and would likely be weaker than the proposed California standards, which call for a 30 percent reduction in tailpipe emissions of carbon dioxide from cars and light trucks by 2016. Emissions from heavier trucks would be cut by a lesser amount.

Jacobson said that when Levin testified, he argued to the effect that the agency couldn't approve the waiver application because "there is no difference in the carbon dioxide emissions between California and anywhere else."

In his testimony, Jacobson replied, "There is no basis in science for this quote. In fact, we have scientific results that show the opposite."

Fourteen other states are poised to enact regulations similar to California's if the waiver application is granted, Jacobson said, adding, "There is a chance, if this is granted, to completely change control of greenhouse gases, particularly from vehicles."

The agency has said it will accept written comments on the waiver application until April 6, 2009.