Schwarzenegger unveils global warming plan at UN conference

SAN FRANCISCO — Gov. Arnold Schwarzenegger stole the show at the United Nations environmental conference Wednesday by unveiling a plan to combat global warming by setting goals for reducing California's emissions of greenhouse gases.

At the opening of the UN World Environmental Day Conference, Schwarzenegger signed an executive order that appeared to put the Republican governor on an opposite course from the Bush administration, which has rebuffed international efforts to address climate change.

‘‘Today, California will be a leader in the fight against global warming,'' Schwarzenegger told an international audience of mayors and environmentalists at San Francisco City Hall. ‘‘I say the debate is over. We know the science, we see the threat and we know the time for action is now.''

Schwarzenegger's executive order calls for reducing the state's emissions of such gases to 2000 levels by 2010, 1990 levels by 2020 and 80 percent below 1990 levels by 2050. The secretary of California's Environmental Protection Agency will be charged with overseeing efforts to meet those goals, and will report on the state's progress in January and every six months after that.

Schwarzenegger didn't announce any specific new policies, but said he would move ahead to impose greenhouse gas emissions standards for automobiles, increase use of renewable power and boost energy efficiency in state buildings and vehicles.

The governor said he would work with state lawmakers to enact legislation to meet his ambitious targets. The California Assembly this week overwhelmingly passed a bill to meet international greenhouse gas reduction standards by 2010, which is more aggressive than the governor's 2010 target.

‘‘We have no choice but to meet this challenge,'' Schwarzenegger said. ‘‘We must leave a better world for our children and their children.''

Scientists and environmentalists said they were encouraged by Schwarzenegger's new targets. As the country's largest state and the world's eighth largest economy, California has the clout to influence the national debate over global warming, they said.

‘‘The governor has opened the door to a whole new future for the California economy,'' said Kate Larsen, a policy analyst at Environmental Defense.

But scientists said the state would have to launch more aggressive policies and programs to meet the governor's ambitious goals, such as setting state limits on greenhouse gas emissions and allowing companies to buy and sell permits to release such gases.

‘‘We have to accelerate the policies we already have in place and develop new policies to fill the gap,'' said Jason Mark, California director of the Union of Concerned Scientists.

Schwarzenegger unveiled his plan at the opening of the five-day international conference, the first ever held on American soil. While no major Bush administration official has announced plans to attend, at least 70 mayors from cities such as London, Rio de Janiero and Shanghai were expected, trading ideas on renewable energy, recycling, public transportation, city parks and clean air and water.

Schwarzenegger has made other attempts to rein in greenhouse gases. His ‘‘hydrogen highways'' program encourages the installation of enough hydrogen fueling stations to enable the use of zero-polluting vehicles across the state, and his ‘‘million solar roofs'' program would subsidize residential solar power installations, jump-starting that industry as well.