(CNN) -- California Gov. Arnold Schwarzenegger plans to sue the federal government over its decision not to allow a California plan to reduce greenhouse gas emissions, he announced Thursday.

California Gov. Arnold Schwarzenegger says the state will sue the federal government.

Environmental Protection Agency chief Stephen Johnson announced the decision Wednesday, refusing the state's request for a waiver that would have allowed it to cut emissions faster than a new federal plan the president signed into law Wednesday.

"It's another example of the administration's failure to treat global warming with the seriousness that it actually demands," the governor said at a news conference Thursday.

Bush on Thursday defended the decision of his EPA administrator.

"Is it more effective to let each state make a decision as to how to proceed in curbing greenhouse gases? Or is it more effective to have a national strategy?" he said.

Citing the new energy law -- which sets a fuel economy standard for the whole country -- Bush said Johnson "made a decision based upon the fact that we passed a piece of legislation that enables us to have a national strategy."

But Schwarzenegger said he would like to set a higher standard for California. "Anything less than aggressive action on the greatest environmental threat of all time is inexcusable," he said. Watch Schwarzenegger slam the Bush administration for denying California the waiver »

The new federal law will increase fuel efficiency standards by 40 percent by 2020, requiring automakers to bring their fleets to an average of 35 miles per gallon.

The California plan, however, would cut emissions by nearly 30 percent by 2016, raising fuel efficiency standards in the state to 43.7 miles per gallon for passenger cars and some SUVs and trucks, while larger vehicles would need to reach 26.9 mpg by that year.

In all, 16 states had either adopted California's tough standards or announced plans to do so.

A top aide to Schwarzenegger said the governor has been frustrated with the White House over emissions standards, and was very exasperated after a February meeting with Johnson.

EPA officials say they went the extra mile with Schwarzenegger, even taking the unusual step of holding a second hearing in California on emissions. They say they're sorry he's upset, but they believe a national standard on emissions is going to be more effective.

A White House official would only react to Schwarzenegger's frustration by saying the administration "looks forward to working with him on a variety of issues."

In the ebb-and-flow relationship between Schwarzenegger and Bush, sources close to the governor say this is a low point.

"It's never been a warm, throw-your-arms-around-the-shoulders kind of relationship," said former Schwarzenegger adviser Joel Fox. "Even during the re-election campaign for the president, he would come to California and the governor wouldn't always be there to greet him."

Fox said Schwarzenegger and Bush have cooperated on issues like immigration, but the two have differed on several issues, including stem cell research funding, the expansion of the State Children's Health Insurance Program and climate change.

"He's got a pretty strong personality, the governor has, and wants to get things done. If the federal government is one of those obstacles, then he'll run that tank he has over it. It's not particularly anything personal, I think."

Schwarzenegger is much closer -- personally and politically -- to the president's father, former President George H.W. Bush, another aide said. E-mail to a friend

From CNN's Brian Todd and Dugald McConnell.

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