"First I want the G8 to secure an agreement as to the basic science on climate change and the threat it poses," Blair said, on the occasion of the 10th anniversary of the Prince of Wales environment programme.

"Second I want the G8 to secure agreement on a process to speed up the science, technology, and other measures necessary to meet the threat," he said, adding that the G8 accounted for some 50 percent of greenhouse gas emissions.

Thirdly, Blair stressed the need to engage with countries such China and India on how to meet their growing energy needs sustainably, and how to adapt to the adverse impact of climate change.

"I am sure that it is the time now to sound the alarm firmly, to put it on the agenda and at least have an open and serious debate" about climate change, said the prime minister.

Blair also said his government may turn to nuclear energy as a way to keep within allowable greenhouse gas emissions.

Leaders of the world's top industrialised nations are to convene at a resort in Scotland on July 6-8 next year, when Britain will holds the G8 presidency as well as the rotating presidency of the European Union from July.

The G8 comprises Britain, Canada, France, Germany, Italy, Japan, Russia -- which will become a full member in 2006 -- and the United States.

Environmental issues have tended to be avoided or subsumed into economic questions during G8 meetings, and commitments obtained from members are often littered with conditional clauses.

The group's only notable green achievements have been to provide financial help to make the Chernobyl nuclear plant safer and a push that helped launch the United Nations's Kyoto Protocol on global warming in 1997.

But US President George W. Bush reiterated at this year's G8 summit in Savannah, Georgia, that Washington was against signing the Kyoto Protocol.

Kyoto's champion is the European Union, which offered huge concessions to Japan, Canada and Russia to save Kyoto from the scrap heap after Washington's pullout.

But Russia has yet to ratify and appears reluctant and divided about wanting to do so, reviving fears that the complex accord to trim greenhouse-gas emissions would be consigned to limbo.

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