"We are now trying to find a portfolio in which three words are important, technology, technology, technology," US President George W. Bush's chief environment adviser James L. Connaughton told BBC radio.

The Kyoto Protocol on cutting emissions of greenhouse gases came into force in February but is still shunned by the world's biggest emitter, the United States, and puts scant limits on China as it rises fast up the pollution ranks.

Senior officials from both countries are at the London meeting, whose main goal is how to achieve the environmental Holy Grail of sustainably growing non-polluting economies.

Liu Jiang, leading the Chinese delegation, said China would invest heavily in nuclear technology in order to reduce its heavy reliance on major polluter coal. He urged developed nations, which had a virtual monopoly on green technology, to make it more readily available.

KILIMANJARO

Focusing their minds will be photos that include Tanzania's Mount Kilimanjaro burned almost bare of its 11,000-year-old icecap by global warming, and coastal defences in the Marshall Islands threatened with swamping from rising sea levels.

The London meeting is part of the agenda of Britain's presidency of the Group of Eight rich nations which Prime Minister Tony Blair has vowed will make progress on climate change and African development.

"Today at the start of the 21st century, co-operation internationally is the only way forward ... not just for this generation but for generations to come," British finance minister Gordon Brown told the meeting.

A senior official at Britain's Department of the Environment, Food and Rural Affairs, which is co-organising the unique meeting, said the aim was to find common ground between developed and developing nations.

"This is a chance for people to get together and by not forcing them to negotiate a very concrete outcome ... allow them to explore common interests," she said.

"There are plenty of technologies out there which we can deploy which can help ... straight away. We know that energy efficiency can already deliver huge carbon savings at a net benefit to our society," she told Reuters.

But environment pressure group Greenpeace said the issue was a minefield.

"It is very sensitive given that the developing countries are trying to climb the development curve and the developed countries must not be seen to be doing anything to hold them back," a spokeswoman told Reuters.

British think-tank the Institute for Public Policy Research has proposed a multi-tiered approach, calling for progressively deeper cuts in greenhouse gas emissions by rich nations allied with more flexible commitments from the developing world.