Brown warned that "the earth itself will be at risk" unless a conference in Copenhagen in December -- which aims to strike a new agreement on rolling back global warming -- reaches a strong accord.

"If we are to achieve an agreement in Copenhagen, I believe we must move the debate from a stand-off over hypothetical figures to active negotiation... and an urgent recognition of the needs of the poorest and most vulnerable countries," Brown said in a speech at London Zoo.

"Today I propose we take a working figure for this purpose of around 100 billion dollars (70 billion euros) per annum by 2020."

Last month, a study from the Global Humanitarian Forum headed by former UN chief Kofi Annan said climate change is responsible for the deaths of 300,000 people every year, with 325 million of the poorest suffering most.

Brown's call for a new fund, worth over 70 billion euros annually, was welcomed by environmental activists Greenpeace.

"By becoming the first major leader to put a figure on how much money is needed, (Brown) has shown signs of leadership on climate change that have so far been sorely lacking," its chief scientist Doug Parr said.

"At last a G8 leader is talking about the right order of magnitude... without these kinds of sums, there won't be a deal in Copenhagen and without a deal, the world faces a grave future."

All rights reserved. © 2005 Agence France-Presse. Sections of the information displayed on this page (dispatches, photographs, logos) are protected by intellectual property rights owned by Agence France-Presse. As a consequence, you may not copy, reproduce, modify, transmit, publish, display or in any way commercially exploit any of the content of this section without the prior written consent of Agence France-Presse.