As world governments begin meeting in Poland they are predicted to make only modest progress in reaching a 2015 deal to fight climate change.
For many countries concern over economic growth is at least partially eclipsing scientists’ warnings of rising temperatures.
“We can’t expect a grand agreement that solves the problems in one fell swoop,” said Elliot Diringer, executive director of the Centre for Climate and Energy Solutions, a United States think-tank.
Reuters Newsagency reports he said the best hope was for a 2015 accord in which countries would agree limits on emissions of greenhouse gases with a mechanism to compare and strengthen them over time.
The outline of a deal, to be discussed by negotiators in Warsaw from November 11-22, is emerging that will not halt a creeping rise in temperatures but might be a guide for tougher measures in later years.
Environmentalists warned about the dangers of delaying action to avert more floods, heatwaves and rising sea levels.
They point to super typhoon Haiyan, which killed more than 10,000 people in the Philippines last week, as a reminder of the risks of extreme weather.
A United Nations scientific panel says cyclones may become more intense in some regions by 2100 as the planet warms.
Reuters reports global average temperatures have risen by 0.8 degrees Celsius since the Industrial Revolution and are set to exceed two degrees Celsius, a target ceiling agreed at a previous UN summit, on current trends, despite a hiatus in the pace of warming so far this century.
In September, the UN panel of climate experts raised the probability that mankind is the main cause of recent warming to 95 per cent or “extremely likely” from 90 per cent “very likely”.
The World Meteorological Organisation said this month atmospheric volumes of greenhouse gases reached a new record in 2012, driven up by growth in emerging economies led by China.
Reuters reports developed nations are putting most emphasis on spurring economic growth after the financial crisis, rather than making big investments in renewable energies such as wind or solar power.
Economic slowdown has, at least temporarily, cut greenhouse gas emissions in many nations.
The US shale boom helped push US carbon emissions to an 18-year low last year, but also shifted cheap, polluting coal into Europe where it is used in power stations.
Many governments, especially in Europe, are concerned climate policies, such as generous support for renewable energy, push up energy bills for consumers, a major political issue in countries such as Britain.
Reuters reports the Warsaw meeting will also seek ways to raise aid to help developing nations cope with climate change.
They have been promised $100 billion a year by 2020, up from $10 billion a year from 2010-12.
Meanwhile, aid charity Oxfam has estimated that climate aid totalled between $7.6 billion and $16.3 billion in 2013, but said “murky accounting and a lack of transparency by rich countries” made it hard to know.
Christiana Figueres, the UN climate chief, said Warsaw was a “pivotal moment” when it was still possible to limit rising temperatures to two degrees Celsius above pre-industrial times.
“Global greenhouse gas emissions need to peak this decade,” she said.
Summit hosts Poland said a climate deal should allow countries to define their own emissions targets, from power plants, factories and cars, rather than try to impose them in a global diktat.
“We need flexibility between the countries, that they will promote their own strategies, their own goals,” Environment Minister Marcin Korolec said.
Poland uses coal to generate 90 per cent of its electricity and has upset some delegates by planning a “world coal summit” about how to cut emissions from coal during the climate talks.
Environmental group Greenpeace projected messages on six Polish coal-fired power plants before the summit saying: “Climate change starts here!” and “Storms start here!”.
