STEVE INSKEEP, host:
Now let's go from California's efforts to save money to this plan to save you gasoline and prevent future pollution.
President Obama laid out fuel efficiency standards that would put industry, states and environmentalists on the same page. The changes address global warming, though they represent a slice of what's needed. Here's NPR's Elizabeth Shogren.
ELIZABETH SHOGREN: White House officials say the proposal would cut greenhouse gas emissions by about 900 million metric tons. That's a big number. It refers to the total reduction of pollution from the five model years of cars and trucks covered by the initiative.
Ms. LISA JACKSON (Environmental Protection Agency): I'd like to call it a lasting and significant down payment on the work we have to do to address climate change emissions in our country.
SHOGREN: Lisa Jackson heads the Environmental Protection Agency. Jackson says even though the pollution reductions are big, they're dwarfed by the massive challenge of global warming.
Ms. JACKSON: This action alone - I don't want mislead anyone - is not going to change, you know, global temperatures. Obviously, it is one step on a long road.
SHOGREN: Stanford University climate scientist Ken Caldeira says we have to travel that long road because we face possible grave, irreversible damages from climate change, like rapid sea level rise.
Dr. KEN CALDEIRA (Climate Scientist, Stanford University): These cuts are important as an act of political leadership, but these cuts in themselves will not produce any significant climate effect.
SHOGREN: But David Friedman from the environmental group Union of Concerned Scientists says the president's initiative should not be underestimated.
Dr. DAVID FRIEDMAN (Union of Concerned Scientists): U.S. cars and trucks produce more global warming pollution than the entire economy of almost every single nation in the world. This plan would cut those emissions by about 14 percent in 2020. I think that everyone would impressed if India, for example, committed to cutting their emissions by that amount.
SHOGREN: Friedman used his own models to come up with these figures. He says that's a cut compared with what emissions would be without the proposed standards. He concedes that total greenhouse gas pollution from vehicles might not be less 10 years from now because of more motorists on the road driving more miles.
Experts say one limitation to this proposal is that it would drive up the cost of new cars by about $1,300 each, according to the White House. Robert Stavins, the director Harvard University's environmental economics program, says as a result, people would be more likely to hold on to their old cars.
Professor ROBERT STAVINS (Director, Environmental Economics Program, Harvard University): Those older cars tend to be of lower fuel efficiency and significantly more polluting. So there's a counterproductive effect of this.
SHOGREN: Stavins says there's another shortcoming of the fuel economy standards.
Prof. STAVINS: Once you've bought the car, it doesn't provide an incentive to drive it any less. In fact, by increasing fuel efficiency, it actually provides an incentive to use the car more because it lowers the operating costs.
SHOGREN: Still, Stavins says the tougher requirements for automakers are important, especially when combined with other initiatives that are in the works.
Prof. STAVINS: It's one step in the process. It's trivial if you compare it to what the effects would be of a nationwide apprehensive cap and trade system along the lines of what President Obama had proposed in his budget message.
SHOGREN: In fact, the House Energy and Commerce committee is currently drafting a sweeping bill that would cut greenhouse gas emissions 17 percent below 2005 levels by 2020 from all sectors of the economy. Stavins says that measure would force additional reductions of greenhouse gases from cars because it would make gasoline more expensive. That would give people incentives to buy fuel-efficient vehicles and deter them from driving so much.
President Obama supports the House bill, but it faces a lot of political hurdles, and there's no guarantee it would reach his desk.
Elizabeth Shogren, NPR News, Washington.
INSKEEP: You hear Elizabeth on MORNING EDITION from NPR News.