The version of the economic stimulus plan proposed by President Obama could cut U.S. carbon dioxide emissions by at least 61 million metric tons annually -- an impact equivalent to taking 13 million cars off the road.

That's the finding of a new analysis commissioned by the environmental advocacy group Greenpeace and conducted by the Virginia-based consulting firm ICF International. The researchers examined the potential greenhouse gas reductions for the legislation's 16 key energy, environment, technology and highway infrastructure provisions.

"The fact that the federal government could spend so much money and actually help slow global warming means we've really turned the page as a country," said Greenpeace Research Director Kert Davies. "This is a real sign that we're starting to move beyond the era of fossil fuels."

The report found that the $2.5 billion proposed for energy efficiency upgrades to homes could reduce carbon emissions by 7.3 million metric tons and save $1.25 billion in annual utility costs, while a proposed $6.9 billion investment to help state and local governments become more energy efficient could generate $3 billion in savings each year and cut carbon emissions by over 20 million tons annually. But if the transportation portion of the bill focuses on new highway construction instead of road repair or public transit, the carbon emission reductions would themselves be reduced by up to 5 million tons annually.

However, it appear increasingly unlikely that the version of the stimulus plan proposed by President Obama will make it through the Senate, where centrist lawmakers in both parties are working to strip as much as $200 billion from the almost $900 billion package, the New York Times reports. The Senate expects to vote on its version of the plan later today.

The House already passed its own version of the stimulus package. For an Associated Press comparison of the House plan and the original Senate proposal, click here.