DANA PERINO, WHITE HOUSE SPOKESWOMAN

"We welcome effective state action to complement over 60 regulatory, incentive, and voluntary federal programs working to achieve the president's goal of reducing national greenhouse gas intensity by 18 percent by 2012. Of concern would be any program that moves jobs and increases emissions in other states or other countries -- an open question for California's proposed legislation."

TOM GRAFF, CALIFORNIA DIRECTOR OF ENVIRONMENTAL DEFENSE

"Today California's leaders showed that global warming is so important that addressing it rises above personal differences, partisan politics and special issues. California is filling a void created by inaction and gridlock in Washington."

US SEN. JAMES INHOFE, OKLAHOMA REPUBLICAN AND CHAIRMAN OF SENATE ENVIRONMENT AND PUBLIC WORKS COMMITTEE

"Californians suffer from the worst air pollution in the country, killing thousands every year because of the state's failure to address this real and serious problem. If California was sincere about improving public health and the environment, they would clean up their air instead of passing feel-good legislation to appease liberal special interest groups simply for political profit."

STEVE SAWYER, CLIMATE POLICY DIRECTOR, GREENPEACE ENVIRONMENTAL GROUP

"We could look back on this as the day the tide turned in the United States. For California, which has the world's number eight economy, this is huge.

I am sure that there will be problems with implementation but it's a real sharp stick in the eye to the Bush administration and all the climate change deniers. Many people say that industry will move to China or North Carolina but I don't think so. California's just too important a market."

STEVEN DRUMMOND, MANAGING DIRECTOR OF CO2E, A GREENHOUSE GAS EMISSIONS BROKER

"It looks like a very strong step forward, and the legislation goes further perhaps than was expected." (Unlike the European scheme, for instance, the California scheme covers car makers)

A SPOKESMAN FOR THE UK DEPARTMENT FOR ENVIRONMENT, FOOD AND RURAL AFFAIRS

"The UK welcomes Californian leadership on climate change under Governor Schwarzenegger, and recognizes the importance of such a large and powerful state showing real commitment to tackling an equally substantial problem. The UK hopes to build on the partnership established during the Prime Minister's visit in July and plans to work together with California on areas such as technology research. The UK and EU believe that market-based systems play an important role in efforts to tackle climate change." (Schwarzenegger agreed to a global warming deal with British Prime Minister Tony Blair in July).

ABYD KARMALI, SENIOR VICE-PRESIDENT AT ICF CONSULTING, CARBON MARKET EXPERTS