Tony Blair has made a pact with Californian governor Arnold Schwarzenegger that commits Britain to work with the US state to reduce greenhouse gases and develop energy efficient technologies.
The agreement between the prime minister and the governor follows a climate change meeting between the two men and leading businessmen in Long Beach yesterday as part of Mr Blair's tour of the US.
The statement endorsed by both Mr Blair and Mr Schwarzenegger binds the UK and California to "urgent action to reduce greenhouse gas emissions and promote low carbon technologies".
"California and the UK recognise the links between climate change, energy security, human health and robust economic growth," the statement said.
"Working together, California and the UK commit to build upon current efforts, share experiences, find new solutions and work to educate the public on the need for aggressive action to address climate change and promote energy diversity."
A spokesman for Mr Blair said that both parties would consider whether they could co-operate on an emissions trading scheme, such as that recently adopted by the EU. He added that officials would even look at whether California could be included in the EU's own programme, under which companies trade the right to emit carbon dioxide using a permit system.
Commenting on the need to tackle global climate change, Mr Blair told business leaders, including BP chief Lord Browne and Virgin boss Richard Branson, that "the answers to this will come in the end by the development of the right science and technology".
"This is something that can't be done just by governments doing it," the prime minister added.
"We need a joint framework, we need it to incorporate all the main countries in the world and we need not just your commitment but also your expertise," he said
Mr Schwarzenegger, whose strong environmental agenda as Californian governor contrasts with that of US president George Bush, who refuses to sign the international Kyoto protocol on global warming, criticised the lack of leadership shown by the White House in tackling climate change.
"We see that there is not great leadership from the federal government when it comes to protecting the environment, so this is why we as a state move forward with it, because we want to show leadership," said Mr Schwarzenegger.
California has a population of 37 million, with a GDP comparable to leading world economies such as Italy and China.