WASHINGTON — President Barack Obama is expected Monday to give California and other states the green light to impose their own, stricter fuel emissions standards.

Obama was scheduled to make a significant announcement on climate change midday at the White House, press aides said Sunday. Aides declined to confirm details.

An e-mail from the White House public liaison office to interested parties, including environmental activists, invited their representatives to attend an “important” ceremony to mark “the first environment and energy actions taken by the president helping our country move toward energy independence.”

Sierra Club spokesman David Willett said that in addition to instructing the Environmental Protection Agency to sign the waiver allowing the states to go forward, activists expected the president to make announcements of improving national fuel economy standards and creating green jobs.

“We’re very excited,” Willett said. “Bush said he would regulate carbon, but when it got into office he never did. Now we have a president who is following through with his campaign promise.”

“This is a presidential trifecta less than one week in office,” said David G. Hawkins, director of climate programs for the Natural Resources Defense Council who received the e-mail.

“This will cut global warming pollution, reduce oil dependence and help build a stronger auto industry,” he said.

Automakers, who pushed to keep the Environmental Protection Agency under President Bush from signing off on California’s higher standards, “have got their eyes on the rearview mirror, but if they’d look ahead they’d see this is exactly the medicine they need,” Hawkins said. “This is Dr. Obama saying, ‘Here’s the exercise regime you need.'”

Activists and officials from at least 14 states seeking waivers from the federal Clean Air Act have been urging Obama since he took office last week to move quickly on such a change. California Gov. Arnold Schwarzenegger wrote to Obama last week asking him to move forward. A spokesman for the governor declined to comment Sunday on the anticipated step by the Obama administration, saying the governor would wait until formal action was taken to react.

The anticipated step by the president would reverse President Bush’s policies and pave the way to force carmakers to sell more fuel efficient vehicles. California’s law, enacted in 2002, would require new cars to reduce emissions by roughly 30 percent and translate to a comparable increase in fuel economy, Hawkins said.

The standards had been due to start with the 2009 model year but were delayed by automaker lawsuits and the Bush administration’s denial of the California waivers. The other states have sought to adopt California’s standards.

Obama also was expected to direct the Department of Transportation to complete rulemaking for higher national fuel efficiency standards.

The president’s campaign platform included promises to tackle global warming and greenhouse gases, through stricter auto emissions standards, more renewable energy and initiating a cap-and-trade program affecting high-emissions producers such as power plants.

He also has said the federal government’s buildings and fleets should be more energy efficient, and on Saturday, in his first weekly address as president, said some of the money in the $825 billion-plus economic stimulus package under consideration by Congress would go toward making federal buildings and individual homes more energy efficient.

McClatchy Newspapers correspondent Renee Schoof contributed to this report.

(c) 2009, McClatchy-Tribune Information Services.