Blair, vowing Britain would seek to reduce its emissions of harmful carbon dioxide by 60 percent by 2050, said President Bush was wrong to claim fighting warming will slow economic growth.
The prime minister, Bush's closest overseas ally since the Sept. 11 attacks on America, said world leaders must not let the crisis in Iraq and the fight against terrorism distract them from long-term but equally important environmental problems like global warming.
"The only answer is to construct a common agenda that recognizes both sets of issues have to be confronted for the world's security and prosperity to be guaranteed," Blair said. "There will be no genuine security if the planet is ravaged by climate change."
"We will continue to make the case to the U.S. and to others that climate change is a serious threat that we must address together as an international community," he said. "We in Britain have shown that it is possible to break the relationship between economic growth and ever-rising pollution."
Environmentalists praised Blair's new initiative — which includes a planned shift away from reliance on nuclear power — but said they would be watching to see if the lofty words were followed up with concrete steps.
The government promised hundreds of millions of pounds to boost energy efficiency and the use of renewable power sources like wind and waves.
It said it would tighten energy efficiency standards for new homes and appliances and encourage energy companies to help consumers make homes more efficient.
The government also plans a carbon trading system, to come into effect around 2005, in which companies that emit excess carbon dioxide — one of the "greenhouse gases" blamed for warming the earth — will be able to buy credits from companies that are below their limits.
The Kyoto treaty, rejected by Mr. Bush as too costly to the U.S. economy, required industrial countries to reduce greenhouse gas emissions to below 1990 levels by 2012, which Blair said amounted to a 2 percent cut.
He said he embraced instead a recommendation by the Royal Commission on Environmental Protection that a 60 percent cut by 2050 was necessary to stop warming.
Blair said he and Swedish Prime Minster Goeran Persson had written to Greek Prime Minister Costas Simitis, whose country holds the rotating European Union presidency, calling on other European countries to adopt the 60 percent goal.
"It is clear Kyoto is not radical enough," Blair told a conference of the Sustainable Development Commission in London.
Blair said extreme weather such as floods and storms caused by global warming had already caused enormous damage around the world and would only get worse if politicians did not muster the will to limit emissions.
The government rejected arguments from the nuclear industry that atomic energy, which produces no greenhouse gases, was a smart way to reduce emissions.
Its official energy white paper, which sets out Britain's energy strategy, includes no plans for new nuclear power plants but did not rule out ever building more. It said nuclear power was too expensive and that the nuclear waste issue had yet to be resolved.
Last September the government agreed to increase and extend an emergency loan of 650 million pounds ($1.01 billion) to nuclear operator British Energy PLC, raising questions about atomic energy's affordability.
Tim Yeo, trade spokesman for the opposition Conservative Party, said backing away from nuclear energy while cutting down on fossil fuels would leave Britain short of energy.