It amplifies, to deafening pitch, fears that the reckless burning of fossil fuels is driving the Earth's climate system towards breakdown, with the potential for mass hunger, flooding and homelessness, all of them powerful sources of conflict.

And it comes in the runup to a make-or-break meeting in December on how to tackle this peril.

"It is a confirmation of the role of climate change as an international issue and particularly the future of climate change as an issue for peace," Thomas Downing, director of the Oxford Office of the Stockholm Environment Institute, told AFP.

Former US vice president Gore, who won an Oscar for his documentar on climate change, "An Inconvenient Truth," shares the coveted prize with the Intergovernmental Panel on Climate Change (IPCC), the respected scientific committee that assesses the evidence for global warming and its impact.

In a landmark report this year, the IPCC said it was now more than 90 percent sure that greenhouse-gas emissions were to blame for the perceptible warming of Earth's atmosphere in the past few decades.

It added that there were signs that this warming was already beginning to affect the climate, as seen through melting Arctic ice, shrinking glaciers and retreating permafrost.

By the century's end, temperatures could rise by 1.1-6.4 degrees Celsius (1.98-11.52 degrees Fahrenheit), fuelling the risk of drought, flooding and violent storms. Millions of people face a heightened danger from hunger and homelessness, the assessment said.

The IPCC report is the product of an exhaustive review process and is indirectly endorsed by governments through the officials that are named to the panel.

As a result, it is considered the benchmark of a neutral assessment -- and gives reluctant politicians very little "wriggle room" to deny or duck the realities of climate change.

Gore's biggest contribution has been in his own country, helping to engineer a shift of opinion about climate change in the United States, which with a quarter of all global emissions is the world's No. 1 carbon polluter.

His campaigning, combined with action at state level and the return of a Democratic majority in Congress, has helped to propel proposed measures on emissions caps that President George W. Bush has always bitterly fought.

As a result, climate has surged up the political agenda. The European Union (EU) this year set a target of reducing its own emissions by 20 percent by 2020, and offered to deepen this to 30 percent if other parties followed suit.

Under intense pressure at home and abroad, Bush agreed to a Group of Eight (G8) summit communique in June by which the G8 committed itself to "substantial" cuts in global carbon emissions and vowed to "seriously consider" Europe's aim of halving this pollution by 2050.

In September, the UN hosted a special summit on climate change, which was followed by Bush's own initiative, a forum of the world's 16 major emitters, accounting for around 80 percent of global pollution.

The Nobel award will undoubtedly give this momentum a powerful extra shove.

It helps reduces the clout of the once-monolithic lobby climate skeptics to that of an angry vocal rump.

And it will strengthen the hand of campaigners and politicians who are clamouring for urgent action.

When Gore and IPCC chairman Rajendra Pachauri step up to get their award in Oslo on December 10, a key UN conference will be taking place in Bali, Indonesia.

These talks are tasked with setting a negotiation roadmap for a new deal on deepening emissions cuts when commitments run out under the Kyoto Protocol in 2012, the UN climate pact that was badly damaged after it was abandoned by Bush in 2001.

Steve Sawyer, secretary general of the Global Wind Energy Council, a lobby group in Brussels for the wind energy industry, said the double award recognised action on the public stage and action in the wings.

"Al Gore has done great things in the public realm in the last couple of years. One only wishes that he had done more when he was in office," said Sawyer.

"The IPCC, of course, deserves the recognition as the pre-eminent scientific body which has over the years consistently brought this to our attention. And now it seems that people are paying attention."