As delegates gathered in the Danish capital, newspapers from 45 countries argued in an unprecedented joint appeal that leaders have two weeks to save the world from being ravaged by climate change.
The summit is aimed at forging a new pact to tackle greenhouse gas emissions after the Kyoto Protocol´s requirements expire in 2012, and will be attended by US President Barack Obama among other world leaders.
Delegates have to craft a blueprint for tackling manmade "greenhouse" gases blamed for trapping solar heat and disrupting Earth´s climate system.
They must also put together a funding mechanism for helping poor nations most exposed to the potential catastrophic effects of climate change, from drought to floods, vicious storms to rising seas.
Negotiators from 192 countries were to embark Monday on a gruelling round of talks under the aegis of the UN Framework Convention on Climate Change (UNFCCC) before around 100 leaders attend a summit on December 18.
"Negotiators now have the clearest signal ever from world leaders to craft solid proposals to implement rapid action," said Yvo de Boer, the UNFCCC´s executive secretary.
"Never in 17 years of climate negotiations have so many different nations made so many firm pledges together.
"So whilst there will be more steps on the road to a safe climate future, Copenhagen is already a turning point in the international response to climate change."
Further negotiations are expected to take place in 2010 to fill in the details of whatever is agreed at Copenhagen. If all goes well, a legally binding treaty would take effect from the end of 2012.
Analysts, though, stress the deep gap between the demands of developing countries and the willingness of rich countries to dig both into their pockets and into their carbon emissions.
China Monday called anew for developed nations to provide funding to help poorer countries fight climate change.
"It is obvious that the planet is everyone´s, and although poor countries must bear responsibility, poor people must not pay a price... that exceeds their own abilities," the state-run Beijing News said.
Obama is hoping to push through a new deal after the United States -- the world´s biggest economy -- rejected Kyoto under his predecessor George W. Bush.
But the US Congress is still hammering out legislation to cut emissions and his opponents have been emboldened by a scandal over leaked emails from academics that they say raises questions on the science behind climate change.
Across the globe, 56 newspapers published the same editorial telling their leaders to agree on action to limit temperature rises to 2.0 degrees Celsius (3.6 degrees Fahrenheit) or risk seeing climate change "ravage our planet".
"We call on the representatives of the 192 countries gathered in Copenhagen not to hesitate, not to fall into dispute, not to blame each other but to seize opportunity from the greatest failure of modern politics," the editorial said.
And a poll of more than 24,000 people worldwide found that 64 percent believe climate change is a "very serious" problem that their governments must tackle, although it showed concern had dropped in the United States and China.
"The poll shows strong worldwide support for action on climate change, in spite of the recession," said Doug Miller, chairman of GlobeScan, which conducted the poll for Britain´s BBC World Service.
Antonio Hill of British development charity Oxfam said anger and suspicion among poorer countries could be eased by a big show of financial goodwill.
"The price of success in Copenhagen is 200 billion dollars (per year)," he said.
"We need to see this figure sparkling overhead in Christmas lights by the end of the summit. It´s peanuts compared to the 8.4 trillion dollars we found to save drowning banks."
The Copenhagen conference venue has been declared UN territory, with about 15,000 delegates, journalists and observers from grass-roots organisations attending.
More than half of all of Denmark´s police force has been deployed to the capital and police warned they would act swiftly to quell any violent protests.
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