UN Secretary General Ban Ki-Moon speaks during the opening of the World Climate Conference at the World Meteorological Organization headquarters in Geneva in September 2009. (Martial Trezzini/Associated Press)

An upcoming international conference on climate change is looking less likely to produce a new treaty to slow global warming, says a United Nations official.

Janos Pasztor, director of the secretary general's Climate Change Support Team, said Monday a number of factors are making it less likely that climate talks in Copenhagen in December will produce a deal to replace the Kyoto Protocol.

"It's hard to say how far the conference will be able to go," said Pasztor, particularly because the United States has yet to approve legislation that would cut greenhouse gas emissions by 80 per cent over the next 40 years.

The 1997 Kyoto Protocol only required 37 industrialized nations to cut emissions, and the lack of participation of the United States and China — the two largest emitters of greenhouse gases in the world — helped undermine its effectiveness. United Nations officials have been hoping the U.S. under President Barack Obama would not only join a new agreement, but also help lead the way for others to participate.

"Secretary General [Ban Ki-moon] sees U.S. engagement as vital for a climate change deal," said Pasztor. "He stated that we cannot afford another period where the U.S. stands on the sidelines."

But enthusiasm about U.S. involvement has begun to wane, as the Obama administration has made health care a priority. As a result, a Senate bill imposing emission guidelines is not expected to pass before the Copenhagen conference and likely would not happen until next year at the earliest, according to Senate Democrats.

Belief in climate change declines: poll

Popular support for climate change as a political issue is also declining in the United States, according to a Pew Research Centre poll reported last week.

The poll of 1,500 adults found just over half of Americans favoured setting limits on carbon emissions and making companies pay for their emissions, while 56 per cent supported U.S. participation in international agreements.

But more alarming, said Pasztor, was that the poll found only 57 per cent of Americans believe there is strong evidence that the Earth has grown hotter in the past few decades, down from 77 per cent in 2006.

In Canada, the New Democratic Party had tried to push through a private member's bill on greenhouse gas emission targets before Copenhagen, but was denied when the House of Commons environment committee received an extension to study the legislation further.

Bill C-311 would have called for Canada to cut greenhouse gas emissions to 25 per cent below 1990 levels by 2020 and 80 per cent below 1990 levels by 2050.

Earlier this month, Environment Minister Jim Prentice said it was doubtful that the international community would be able to reach an agreement at the Copenhagen conference.

Pasztor said there was "tremendous activity by governments in capitals and internationally to shape the outcome" of the Copenhagen conference. But two unresolved issues are emission reduction targets for industrialized countries and how to finance actions by developing countries to limit their emissions growth and adapt to the effects of climate change, he said.

With files from The Associated Press