Negotiators arrive in Copenhagen Monday amid rising optimism that a global deal is within reach to reduce greenhouse gases sufficiently to avert the worst ravages expected from climate change.
United Nations officials said that developed and developing countries have already promised 80 per cent of the emission reductions by 2020 that climate scientists say are needed to limit the damage from global warming.
That still leaves a significant gap to be closed during the summit, and UN climate chief Yvo de Boer said countries must be prepared to embrace somewhat more ambitious targets if it is to be closed.
Many countries have made their commitments conditional on negotiating partners doing more, particularly demands from emerging economies that the developed world must provide massive financing to help poorer countries achieve their targets.
Negotiators also face significant challenges in translating a political accord into a binding treaty to be signed some time next year. And, as Canada showed after ratifying the 1997 Kyoto Protocol, promising emission reductions is one thing, achieving them quite another.
Still, Mr. de Boer said he is hopeful that the 192 nations can reach a political agreement on key planks of a global treaty - including ambitious emission targets and a $30-billion (U.S.), three-year fund to help finance climate action in developing countries.
In the face of pressure from the United Nations, the provinces and federal opposition parties to adopt more ambitious targets, Prime Minister Stephen Harper has held firm, saying there is little scope for Canada to do more unless the United States agrees to do so.
Mr. de Boer welcomed as a positive sign the decision by U.S. President Barack Obama to change his plans and meet with other global leaders - including Mr. Harper - at the end of the conference. Mr. Obama - who faces a tough fight to win passage of climate legislation in Senate next year - had originally been scheduled to visit Copenhagen this week, on his way to Oslo to receive the Nobel Prize.
"I'm happy he is coming toward the end of the conference," the head of UN Climate Change Secretariat told a news conference in the Danish capital yesterday.
"I hope that, as part of the negotiating process, he comes with ambitious American targets and strong financial support to reach out to developing countries."
Mr. de Boer said countries must be prepared to go further than the commitments that are currently on the table. He noted the UN's scientific panel has said industrialized countries must reduce greenhouse emissions by between 25 per cent and 40 per cent below 1990 levels by 2020 in order to avoid the worst impacts of global warming.
"We are close to that range but we are not in that range, and part of the purpose of Copenhagen is to make sure industrialized countries do get into that range, and that will be the result of a process of negotiation," Mr. de Boer said.
The 2020 targets are medium-term goals, with the ultimate aim of cutting emissions by 50 to 80 per cent by 2050.
Using the upper range of commitments made by developed and developing countries, the United Nations Environment Program calculates that the gap between what has been promised and what is required is 80 per cent closed.
"Reaching the target ... will require governments over the next two weeks and over the next few years to match words with deeds and ambition with action," said Lord Stern of Brentford, the former British government climate adviser who worked with UNEP officials on the report.
"If they do, we could embark on the most dynamic and creative period of the world's economic history, a new energy and industrial revolution."
Mr. Obama has indicated the United States will commit to reduce emissions by at least 17 per cent below 2005 levels, which is equivalent to 3 per cent below 1990 levels. A climate change bill that passed the House of Representatives includes that 17 per cent target, while legislation now before the Senate would reduce emission by 20 per cent below 2006 levels.
However, it remains uncertain whether the Senate will actually pass the legislation early next year, as proponents hope, or what the targets will be.
The White House also indicated U.S. support for a $10-billion (U.S.) per year fund provided by developed countries to the developing world to finance emission reductions and efforts to adapt to looming climate change.
The Canadian government has committed to cutting emissions by 20 per cent below 2006 levels by 2020 - which also equates to a 3 per cent cut from 1990 levels. Ottawa has faced broad censure in the international community because Canada agreed under the Kyoto Protocol to reduce emissions by 6 per cent from 1990 levels by 2012, but will come nowhere near meeting that pledge.
Environment Minister Jim Prentice says that he won't be stampeded by the "hype and drama" surrounding Copenhagen to make a deal that would damage the Canadian economy.
"If we do more than the U.S., we will suffer economic pain for no real environmental gain - economic pain that could impede our ability to invest in new, clean technologies and other innovative solutions to climate change," Mr. Prentice said in a Montreal speech Friday. "But if we do less, we will risk facing new border barriers into the American market."
NDP leader Jack Layton said he does not expect Canada's climate change negotiators to be anything but a drag on the talks. "They will leave their foot on the break as long as they can," he said in an interview Friday. "They will wait to see what Obama will do. They will protect the oil sands as long as possible."
Mr. Layton said he is going to Copenhagen in to inform the delegates from the 192 countries attending the summit that "majority of the members of the House of Commons have a different view" than the ruling Conservatives on the dangers of climate change and the urgency to reduce greenhouse gas emissions.
Canada has been called "the dirty old man" of the industrialized countries because its greenhouse gas emissions have soared since it agreed to the Kyoto Protocol in 1997, and because of the rapid expansion of the Alberta oil sands.
With a report from Eric Reguly in Rome