By Valerie Volcovici

WASHINGTON (Reuters) - The United States will not be able to meet its goal of slashing greenhouse gases 17 percent by 2020 from a 2005 baseline without taking additional steps to target emissions, a new report found.

The economic downturn and an increase in supplies of cheap natural gas, which has displaced coal in some power plants, have slashed carbon emissions but are only temporary trends, according to the World Resources Institute, a think tank that focuses on global environmental issues

WRI recently shared its findings with administration officials.

After President Barack Obama pledged in his inaugural address last month to respond to the "threat of climate change," analysts have said the Environmental Protection Agency and other federal agencies will be charged with the task of carrying out that goal, in the absence of Congressional action.

"The administration has multiple ways to move forward with smart policies to reduce U.S. emissions. The best opportunity is to enact new standards for existing power plants, which represent one-third of all U.S. emissions," said Nicholas Bianco, a senior associate at WRI and the report's lead author.

Power plant standards are one of four key measures the Obama administration can take to curb greenhouse gases without legislation, said the report, which was entitled "Can we get there from here?"

Other measures include reducing hydroflourocarbons (HFCs), used mainly in cooling and refrigeration systems; curbing methane leaks from natural gas production; and boosting energy efficiency.

Non-energy greenhouse gases, such as methane and HFCs, are projected to rise 18 percent above 2005 levels by 2020 and 36 percent above that level by 2035 if no policies are implemented, the WRI said.

CLIMATE PLEDGE

The United States pledged to reduce its greenhouse gas emissions 17 percent below a 2005 baseline by 2020 at U.N. climate negotiations in Copenhagen in 2009, at a time when the White House assumed Congress might pass climate change legislation.

Partisan fights in Congress killed a measure in 2010, forcing Obama's administration to tap its existing authorities to regulate the heat-trapping gases.

The EPA is expected to take its first steps to regulate greenhouse gas emissions from existing power plants later this year, after it finalizes emissions performance standards for the construction of new power plants this April. Continued...