WASHINGTON - President Obama today declared a goal of reversing America's dependence on foreign oil and announced a series of steps to reshape the nation's climate policy and auto market.

In a news briefing at the start of his second week in office, Obama announced he is directing federal agencies to reexamine two policies that could force automakers to produce more fuel-efficient cars yielding fewer greenhouse gas emissions.

Smoke billows from a car's tailpipe in San Francisco, California. Barack Obama intends to reduce US carbon emissions from 1990 levels by 80 percent in 2050. International environmental groups have praised evidence of swift change by US President Barack Obama in his inaugural week, saying it could transform Washington from a green "pariah" into a world leader. (AFP/Getty Images/File/David Paul Morris) The moves are aimed at reversing decisions by Bush administration, which he said had stood in the way of bold action by California and other states to reduce greenhouse gas emissions.

"The days of Washington dragging its heels are over," Obama said.

He said he could not promise a "quick fix" for the nation's dependence on foreign oil, but he pledged to "commit ourselves to the steady, focused, pragmatic pursuit" of energy independence.

Obama said the administration would ensure that the fuel-efficient cars of the future are built in the United States and would start by implementing new fuel efficiency standards for the 2011 model year.

"Our goal is not to further burden an already struggling auto industry," he said, but to help American automakers prepare for the future and "thrive by building the cars of tomorrow."

Separately, the State Department is expected to name Todd Stern, formerly a senior official in the Clinton administration, as the new U.S. envoy on climate change, news agencies reported. Stern, a partner in a Washington law firm and a senior fellow at the Center for American Progress think tank, coordinated the Clinton administration's Initiative on Global Climate Change from 1997 to 1999 and served as the top White House negotiator on the Kyoto talks on global warming from 1999 to 2001.

In executive orders he signed today, Obama instructed the Environmental Protection Agency to reconsider whether to grant California a waiver to regulate automobile tailpipe emissions linked to global warming, and he ordered the Transportation Department to issue guidelines to ensure that the nation's auto fleet reaches an average fuel efficiency of 35 miles per gallon by 2020, if not earlier.

On Dec. 19, 2007, then-EPA Administrator Stephen L. Johnson blocked the efforts of California and more than a dozen other states to limit automobiles' carbon dioxide emissions, arguing that President George W. Bush had addressed the issue by signing a law that same day raising the corporate average fuel-efficiency standard to 35 miles per gallon by 2020. But California's tailpipe emissions rules would have effectively required even greater fuel-efficiency increases, by seeking to cut vehicles' greenhouse gas emissions by 30 percent between 2009 and 2016, something American automakers have resisted.

The Bush administration never issued near-term guidelines for tighter fuel-efficiency standards. The Transportation Department circulated a proposal last fall that would have required auto companies to build new cars averaging as much as 31.8 miles per gallon by 2015, compared with the current level of 27.5 miles per gallon, but it announced less than two weeks before Bush left office that it would not issue formal guidelines.

Daniel J. Weiss, who directs climate strategy at the Center for American Progress, a liberal think tank, praised the new administration for pressing ahead with ambitious fuel economy goals.

"President Obama's actions will reduce our oil dependence by speeding the production of the gas-sipping cars of the future," Weiss said before today's announcements. "He understands that oil and gasoline prices will rise with our recovering economy, and more fuel-efficient cars will help families cope with higher prices. And other countries will want to buy our more-efficient vehicles."

Obama, who has consistently urged U.S. automakers to produce more fuel-efficient cars, is likely to accelerate the timeline for raising the nation's corporate average fuel economy for cars and trucks. The Transportation Department guidelines must be issued by April in order to affect the 2011 auto fleet.

Granting a waiver for California to regulate tailpipe emissions would affect nearly half the U.S. auto market. Thirteen other states -- including Maryland -- and the District have already adopted California's proposal, while at least four others have pledged to do so. When the EPA rejected the waiver, Obama issued a statement saying the decision "is yet another example of how this Administration has put corporate interests ahead of the public interest. If the courts do not overturn this decision, I will after I am elected president."

"Not only is the new president a man of his word, but he's making a dramatic break with the Bush administration's climate policy," said Frank O'Donnell, who heads the advocacy group Clean Air Watch. "It's a powerful signal that science -- and the law -- will guide his administration's decisions. This should prompt cheers from California to Maine."