One of the prime minister's closest allies has called on next week's G8 summit to "respond positively and constructively to the climate change challenge".
Former Cabinet minister Stephen Byers said on Wednesday that the Gleneagles gathering of the leaders of the world's richest countries must do more than merely agree a package of voluntary measures on technology.
The Newcastle MP is the joint chairman of the International Climate Change Taskforce, established by the Institute of Public Policy Research think tank.
Along with his co-chair, US Republican senator Olympia Snowe, he said the forthcoming summit under Britain's presidency was a crucial opportunity to get to grips with global warming.
But although Tony Blair has made the environment one of Britain's two key G8 priorities, the meeting could be hampered by American opposition to any pressure to reduce carbon emissions.
The White House disputes the science linking emissions to climate change and has refused to sign up to the Kyoto agreement.
And while reports have suggested that the US is interested in investing in new technologies in order to reduce its reliance on foreign oil, the taskforce argued that the summit must go much further.
Urgency
Byers and Snowe said agreement must also be reached on the urgency of the problem, that all leaders should acknowledge that it is man made, that commitments should be made on adopting mandatory cap and trade schemes for greenhouse gas emissions and that existing commitments be met.
"People throughout the world know that something strange is happening to the weather and they are worried," the MP said.
"They know that our climate is changing and that they are witnessing the often devastating effects of global warming. We are running out of time.
"Action to tackle climate change can be delayed no longer. That is why it is so important for the G8 to respond positively and constructively to the climate change challenge that we issue today."
Snowe added that opinion is shifting across the Atlantic.
"As the US Senate officially recognised for the first time last week, there is no doubt that greenhouse gases are irrevocably impacting our climate and that mandatory caps on greenhouse gas emissions are necessary," she said.
"This truly global problem requires solutions based on co-operation and consensus.
"As the world's economic leaders and largest emitters of greenhouse gases, the G8 countries have a responsibility to address this problem.
"The G8 summit in Scotland must be used as a forum to reach agreement on practical and reasoned solutions to confront climate change, setting the stage to bring the developing world to the table."
