Addressing a meeting in London of 30 environment and energy ministers from 20 of the world's biggest polluters, Gordon Brown warned that failure to develop environmentally-friendly energy policies would pose economic obstacles.

"If our economies are to flourish, if global poverty is to be banished, and the well-being of the world's people enhanced... we must make sure we take care of the natural environment and resources on which our economic activity depends," Brown said in a speech opening the two-day conference.

"Environmental issues -- including climate change -- have traditionally been placed in a category separate from the economy and from economic policy. But this is no longer tenable," the British chancellor of the exchequer said.

It was clear that economic activity not only caused environmental problems but that "these problems in themselves threaten future economic activity and growth," he said.

The informal debate on climate change in London aims to lay the groundwork for a summit of the Group of Eight (the United States, Canada, Britain, Japan, Russia, Germany, France and Italy) scheduled to take place at Gleneagles, Scotland in July.

British Prime Minister Tony Blair holds the G8 presidency for 2005 and has set two priorities for his tenure -- climate change and development in Africa.

But the success of the environmental challenge will depend heavily on whether Britain can convince its US ally, the world's biggest polluter, to change its stand on global warming initiatives.

Hoping to lead by example, Brown outlined steps that Britain has taken to meet a goal under the Kyoto Protocol on climate change to reduce greenhouse gas emissions by 12.5 percent by 2012 through market-based policies.

He also discussed Britain's self-imposed target to lower carbon dioxide emissions by 20 percent by 2010 and by 60 percent by 2050.

"But at the same time we have to acknowledge that no country can solve this problem on its own," Brown said, noting that Britain was only responsible for two percent of global emissions of greenhouse gases.

"We will need a comprehensive global response."

Greater use of nuclear power would help to reduce carbon dioxide emissions, France's Industry Minister Patrick Devedjian told the meeting, which was attended by fellow G8 representatives as well as other industrialised nations such as Australia, Spain and Poland.

"Nuclear power can play an essential role in the sustainable development of energy," Devedjian said.

Nuclear power stations already in existence cut 2.2 billion tonnes in carbon dioxide emissions compared with the 24 billion tonnes released worldwide, he said.

"That is more than two times the reduction demanded of developing countries by the Kyoto Protocol for the period 2008-2012," the minister said.

For his part, Claude Mandil, director of the Paris-based International Energy Agency who is also at the gathering, noted that stabilising the use of carbon dioxide was a formidable task with no simple solution.

In the long term, technological breakthroughs will become essential but it is important not simply to "cross our arms and wait for them," he told AFP.

The guests at the meeting -- which also include rapidly developing states from the southern hemisphere such as China, India and Brazil -- are the countries which will have the highest energy needs for the next 30 to 40 years.

They will also be the countries pumping the largest amounts of carbon dioxide into the atmosphere, mainly from the burning of fossil fuels.

Fossil fuels remain the main source of global energy and their use typically increases at pace with economic growth in a country.

The British government proposes to accelerate the use of so-called clean fuels and industrial processes already on the market which make the use of fossil fuels cleaner.

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