Fuel-efficiency bill only a step to curb warming

A boost in fuel economy to 35 miles per gallon would trim about 250 million metric tons of carbon dioxide by 2020.

"Swiss cheese."

That's how one critic describes the new fuel-efficiency bill that just cleared the Senate Commerce, Science and Transportation Committee.

The measure sounds good: It calls for automakers to achieve a fleet average of 35 miles a gallon by 2020, about 10 miles per gallon higher than today. The problem: The measure includes varied "off ramp" mechanisms that give them a pass on meeting mileage requirements, if those standards are deemed by a future administration to be onerous, this critic says.

"If they actually locked in a 35-mile-per-gallon mandate, then Congress could get up and say, 'We've done something to cut oil addiction and help the climate-change problem,' " says David Friedman, research director of the vehicles program at the Union of Concerned Scientists (UCS). "But they haven't done that yet with this bill. Right now it's full of holes."

But even that would be only a first step, such critics add.

On emissions, for instance, a patched-up bill would help America trim about 250 million metric tons of carbon dioxide by 2020 compared with a business-as-usual scenario. Such a 10-year effort would keep emissions roughly the same as today's 1.6 billion tons coming annually from 230 million cars and trucks. That cut is the equivalent of taking 30 million of today's cars and trucks off the road, he says.

Slashing a quarter-billion tons of carbon sounds like a lot, but it's not as impressive when considering the US emits 6 billion tons of CO2 from all sources each year. So the proposed legislation should be viewed as just one piece of an overall greenhouse-gas-reduction puzzle, says Paul Bledsoe, a spokesman for the National Commission on Energy Policy, an energy think tank in Washington, D.C. "You need each piece of the puzzle: a moderate carbon price, significant fuel-economy increases, increased energy research and tax incentives for deploying low-carbon technology," he says. "If you don't do all these things, it will be very difficult to get a handle on total US emissions."

Alongside emissions reductions, energy security is another key goal of the national commission. Fuel economy is a key weapon in making the nation less reliant on imported oil – and oil overall. Not burning gasoline is as effective at improving energy security as making tens of billions of gallons of biofuels annually, experts say.

In a recently revamped energy plan to slash oil use, the national commission recommended a fuel-economy measure similar to the goals mapped out in the current Senate legislation.