April 11 (Bloomberg) -- California Governor Arnold Schwarzenegger, seeking U.S. permission to limit carbon dioxide in automobile exhaust, said Detroit's carmakers must get off their ``butt'' on so-called greenhouse gases.

``I say, Arnold to Michigan: get off your butt and join us,'' Schwarzenegger said today at an environmental conference in Washington. ``California may be doing more to save U.S. automakers than anyone else. We are pushing them to make changes. If they don't change someone else will.''

Schwarzenegger is stepping up pressure on General Motors Corp., Ford Motor Co. and DaimlerChrysler AG as he seeks a waiver from U.S. pollution rules to implement carbon-dioxide curbs he signed into law in 2004. The governor met today with Stephen Johnson, who leads the U.S. Environmental Protection Agency.

California's plan would force a cut of as much as 30 percent in carbon dioxide and other gases linked to global warming. The U.S. Supreme Court said last week that the EPA is authorized to regulate CO2 emissions, as California has sought.

Automakers led by Detroit-based GM, Dearborn, Michigan- based Ford and Japan's Toyota Motor Corp. are suing California in federal court to block the program. A similar trial began yesterday in Vermont, which also wants to adopt those curbs.

Detroit's Savior

``Only technology will ultimately save Detroit,'' Schwarzenegger said at the Global Environment Conference at Washington's Georgetown University. ``If they don't change, someone else will, the Japanese will, the Chinese will, the South Koreans will.''

Schwarzenegger's jab at the automakers echoed a gibe at the Hollywood actor-turned-governor by U.S. Representative Joe Knollenberg, a Michigan Republican who paid to erect a billboard in metro Detroit that says, ``Arnold to Michigan: Drop Dead!''

Knollenberg has said Schwarzenegger's proposals to cut tailpipe emissions and increase fuel-economy standards for vehicles in California would cost the U.S. automakers $85 billion.

``We are standing up and we are innovating like we never have before,'' said DaimlerChrysler spokesman Jason Vines. `` U.S. technology has been there; it's there today and will be there tomorrow. It will be back.''

`Broad Strokes'

Schwarzenegger's ``broad strokes aimed at Michigan-based automakers are misinformed, given all we're doing and planning to do promote fuel efficiency and cleaner alternatives,'' said Greg Martin, a Washington-based GM spokesman.

GM currently has 23 vehicles with highway fuel economy of 30 miles per gallon or better, the most of any automaker, and the most vehicles capable of running on biofuel such as ethanol, Martin said.

The company will have 10 hybrid-electric models available by year end, and is developing fuel-cell autos and plug-in hybrids for the consumer market, he added.

EPA Administrator Johnson said at a press conference yesterday that his agency is ``evaluating the Supreme Court decision, evaluating our options and looking at what actions we might take.''

California ``cannot go ahead until our evaluation,'' Johnson told reporters in Washington.

Schwarzenegger, 59, helped popularize the Hummer brand in the 1990s, sport-utility vehicles targeted by environmental groups as gas guzzlers. GM bought the marketing rights to Hummer in 1999.

He said today that one of his Hummers runs on biofuel and another runs on hydrogen. ``That's the change we have to make, instead of getting rid of Hummers,'' Schwarzenegger said.

Last September he signed a greenhouse gas law seeking a 25 percent cut in such emissions from industrial and other sources by the year 2020. He appears on the cover of Newsweek magazine this week as the ``Green Giant,'' balancing the Earth on his fingertip.

To contact the reporter on this story: Alan Ohnsman in Los Angeles at aohnsman@bloomberg.net; Gopal Ratnam in Washington at gratnam1@bloomberg.net

Last Updated: April 11, 2007 21:40 EDT