OSLO (Reuters) - Awarding the Nobel Peace Prize to former U.S. Vice President Al Gore and the U.N. climate panel widens a definition of peacemaking and will raise pressure for the world to agree a new deal to combat global warming.

"I hope this will enhance further a sense of urgency," said Yvo de Boer, the head of the U.N. Climate Change Secretariat who wants governments to set an end-2009 deadline to work out a new long-term plan to fight global warming.

The secretive Nobel committee, making a first award clearly linking climate change to peace since the prize was set up in 1901, said on Friday: "Action is necessary now, before climate change moves beyond man's control."

The prize to Gore and the U.N.'s Intergovernmental Panel on Climate Change (IPCC) which has issued reports this year outlining risks of global warming, partly targets the world's environment ministers who will meet in Bali from December 3-14.

The United Nations and the Group of Eight industrialized countries want them to agree a 2-year negotiating mandate to broaden the U.N.'s Kyoto Protocol, the main plan for curbing warming, to outsiders such as the United States and China.

By coincidence, the Nobel Prize will be handed out in a ceremony in Oslo on December 10 -- and so gives both Gore and Rajendra Pachauri, chairman of the IPCC, new authority to urge action. Both Pachauri and Gore were already due to visit Bali.

U.S. President George W. Bush decided not to implement Kyoto -- favored by Gore -- in 2001 when he decided that its curbs would cost U.S. jobs and that it unfairly omitted 2012 targets for developing nations. Until now he has favored voluntary measures.

"I call on all our partners to take this Nobel Peace Prize as an encouragement to approach this challenge even more swiftly, and decisively," said European Commission President Jose Manuel Barroso.

Broadening a definition of peace, the Nobel Committee said "there may be increased danger of violent conflicts and wars," because of tensions over ever scarcer resources caused by more floods, droughts, desertification and rising seas.

Such theories are not universally accepted, especially in the United States.

"I am...happy that the committee has not come up with a very strong link between climate change and armed conflict because that is something we know very little about," said Stein Toennesson, head of the International Peace Research Institute in Oslo. "It could just as well lead to more cooperation."

Gore, who has campaigned for more action to safeguard the environment since he was beaten by Bush in a narrow 2000 presidential election, said on Friday that he was honored and that: "we face a true planetary emergency".

Many experts say that creeping desertification, linked to climate change, is an underlying spur to the conflict in Darfur, Sudan, where 200,000 people have died.

"The Nobel Peace Prize Committee has today made it clear that combating climate change is a central peace and security policy for the 21st century," said Achim Steiner, head of the U.N. Environment Program.

The IPCC said this year that it was "very likely" or at least 90 percent certain that humanity was to blame for global warming, mainly by burning fossil fuels. And it said time was running short for action that would have moderate costs.

The secretive five-strong committee made a first environmental award in 2004, to Kenya's Wangari Maathai for leading a campaign to plant 30 million trees across Africa.

"Now, we have started a small road, a path when it comes to environment," committee chairman Ole Danbolt Mjoes said, noting that the prize had been widened to new areas such as human rights over the years.

(With additional reporting by Wojciech Moskwa and Aasa Christine Stoltz in Oslo, Jeremy Lovell in London)