Residents of San Francisco give their views on climate change

In pictures



After a week-long battle, firefighters have finally subdued the worst blaze to hit California's Lake Tahoe region in a century.

But to Linda Adams, who heads California's Environmental Protection Agency, it is only a sign of things to come.

"We can expect a lot more of this. More fires, more drought. This is global warming," says Ms Adams.

While the administration of President George W Bush has been accused of wilfully ignoring climate change, the State of California has already taken unilateral action.

Governor Arnold Schwarzenegger has charged Ms Adams with implementing what she calls "the most comprehensive law in the world to reduce greenhouse gas emissions".

She is referring to Assembly Bill 32 (AB32), or the Global Warming Solutions Act, passed last year by California's Democratic-led assembly, with the backing of the governor, a Republican.

Trading emissions

The legislation obliges California to cut emissions back to 1990 levels by 2020. Work has begun on quantifying the level of emissions, after which a cap will be enforced, and industries will be able to buy and sell permits allowing a certain amount of pollution.

CALIFORNIA ACTS ON CLIMATE 2002 law on vehicle emissions cuts copied by 10 other states 2006 law AB32 demands cut in emissions to 1990 levels by 2020 $3bn programme to install solar panels on a million roofs Power generators must source 20% from renewable sources by 2010 Power firms rewarded if customers decrease energy use State suing six car makers for damage to climate

But Ms Adams says it will be better, using a "unique" combination of incentives, regulation and market forces.

"We're using probably all the tools in the toolbox to address the problem," she says.

She recently visited Europe to examine its system. Many acknowledge it is far from perfect. The price of carbon credits dropped to virtually nothing after the EU handed them out far too generously, critics say.

"Europe will admit that in their trial period the market collapsed - we went to find out why, to avoid the same mistakes," she says.

Applying pressure

While California's law has yet to be implemented fully, it is already being used as a template for nationwide action that American environmentalists hope will turn their country from a laggard on climate change, to a leader.

Fabian Nunez, the speaker of California's state parliament, says that was exactly the intention.

The Democrats are leading a push for greater use of ethanol

"The intent for us when we passed AB32 was not only our commitment to California; there is a sense of state activism.

"When you look around and see that our president has essentially turned a blind eye to the issue of climate change, it raises a lot of concerns. So we wanted to help put the pressure on the federal government, and we think that's worked quite well thus far."

Indeed, the dominoes have started falling across the country.

Washington converts

Nine north-eastern states have committed to their own carbon trading scheme, and more than 400 mayors have pledged their cities to reduce emissions.

A lot of countries have resentment towards the US because we've turned a blind eye to global warming

Fabian Nunez

speaker of California's state parliament

The speaker of the House of Representatives, Nancy Pelosi, has pulled together a raft of different measures, being considered by 11 different congressional committees, under the banner of "energy independence".

Many of the measures - which include new energy efficiency standards for appliances, increased use of ethanol to power vehicles, and long-term financial incentives for renewable power - tie in with President Bush's call to reduce America's dependence on foreign oil.

But they are also explicitly presented as a way of combating climate change, in language - "requiring federal government operations to be carbon-neutral by 2050", for instance - that could not have emerged from the White House or the previous Republican-led Congress.

Senator Barbara Boxer has taken over the Environment and Public Works Committee from Republican James Inhofe, who memorably declared global warming to be "the greatest hoax ever perpetrated on the American people".

She has approved efforts by two senators to produce a bill, along the lines of California's AB32 law, which would introduce a greenhouse gas emissions cap and trade system nationwide.

It is expected within months.

President Bush has recently changed tack on climate change, saying in May that he wanted America to be part of a global deal, and inviting the world's heaviest emitters for talks.

The move was welcomed by some, including Britain's leader at the time, Tony Blair, as a significant change of attitude.

Environmentalists, however, said it was a "delaying tactic", and that the US would only make a real impact on climate change when there was a change at the top.

Election issue?

That is why next year's presidential election is being eyed keenly and apprehensively.

Although climate change has not been a dominant theme of the early presidential campaign, many of the candidates, whether Democrat or Republican, have indicated they will go further on climate change than the current president.

Speaker Nunez sees the 2008 election as a watershed not only for global warming but for America's reputation in the world.

"A lot of countries have resentment towards the US because we've turned a blind eye to global warming," he says.

"And for us to not act, for us to play a wait-and-see strategy, is not only an incorrect way but it sends a message of arrogance to the rest of the world.

"I believe that the next president of this country will indeed take a leadership role on this issue."