COPENHAGEN, Denmark – This decade is on track to become the warmest since records began in 1850, and 2009 could rank among the top-five warmest years, the UN weather agency reported yesterday on the second day of a pivotal 192-nation climate conference.

In central Africa and southern Asia, this will probably be the warmest year, but overall 2009 probably will be “about the fifth-warmest year on record”, said Michel Jarraud, secretary-general of the World Meteorological Organisation.

Only the United States and Canada experienced cooler conditions than average, it said, although Alaska had the second-warmest July on record.

The agency also noted an extreme heat wave in India in May, and a heatwave in northern China in June. It said parts of China experienced their warmest year on record, and that Australia so far has had its third-warmest year. Extreme warm events were also more frequent and intense in southern South America.

The decade 2000-2009 “is very likely to be the warmest on record, warmer than the 1990s, than the 1980s and so on”, Jarraud told at a news conference, holding up a chart with a temperature curve pointing upward.

The decade has been marked by dramatic effects of warming.

In 2007-2009, the summer melt has shrunk the Arctic Ocean ice cap to its smallest extent ever recorded. In the 2007-2009 International Polar Year, researchers found that Antarctica is warming more than previously believed. Almost all glaciers worldwide are retreating.

Meanwhile, such destructive species as jellyfish and bark-eating beetles are moving northward out of normal ranges, and seas expanding from warmth and glacier melt are encroaching on low-lying island states.

If 2009 ends as the fifth-warmest year, it would replace the year 2003. According to the US space agency NASA, the other warmest years since 1850 have been 2005, 1998, 2007 and 2006. NASA says the differences in readings among these years are so small as to be statistically insignificant.

The UN agency reported that the global combined sea surface and land surface temperature for the January-October 2009 period is estimated at 0.44 degrees C (0.79 degrees F) above the 1961-1990 annual average of 14 degrees C (57.2 degrees F), with a margin of error of plus or minus 0.11 degrees C. Final data will be released early in 2010.

The data were released as negotiators at the two-week talks in Copenhagen turned Tuesday to “metrics”, “gas inventories” and other dense technicalities, as delegates worked to craft a global deal to rein in carbon dioxide and other greenhouse gases and stem climate change.

Governments, meanwhile, jockeyed for position leading up to the finale late next week, when more than 100 national leaders, including President Barack Obama, will converge on Copenhagen for the final days of bargaining.

Scientists say without an agreement to wean the world away from fossil fuels and other pollutants to greener sources of energy, the Earth will face the consequences of ever-rising temperatures: The extinction of plant and animals, the flooding of coastal cities, more extreme weather, more drought and the spread of diseases.

In Britain, Prime Minister Gordon Brown urged fellow Europeans to raise their bid on reducing greenhouse gas emissions to pressure the US and others to offer more at Copenhagen.

“We’ve got to make countries recognise that they have to be as ambitious as they say they want to be. It’s not enough to say ‘I may do this, I might do this, possibly I’ll do this.’ I want to create a situation in which the European Union is persuaded to go to 30 per cent,” Brown was quoted as saying by Britain’s Guardian newspaper.

The European Union has pledged to reduce greenhouse gas emissions by 20 per cent by 2020, compared with 1990, and is considering raising that to 30 per cent if other governments also aim high. EU leaders will have an opportunity to make such a move at an EU summit this Thursday and Friday in Brussels.

On Monday, when the climate conference opened, the Obama administration gave the talks a boost by announcing steps that could lead to new US emissions controls that don’t require the approval of the US Congress.

The US Environmental Protection Agency (EPA) said scientific evidence clearly shows that greenhouse gases “threaten the public health and welfare of the American people” and that the pollutants — mainly carbon dioxide from burning fossil fuels — should be reduced, if not by Congress then by the agency responsible for enforcing air pollution.

As Congress considers the first US legislation to cap carbon emissions, the EPA finding will enable the Obama administration to act on greenhouse gases without congressional action, potentially imposing federal limits on climate-changing pollution from cars, power plants and factories.

Yvo de Boer, UN climate chief, said yesterday the EPA finding gives Obama “something to fall back on.”

“I think that will boost people’s confidence” at the Copenhagen talks in the Americans’ ability to offer more, he said.

The European Union had called for a stronger bid by the Americans, who thus far have pledged emissions cuts much less ambitious than Europe’s. The US has offered a 17 per cent reduction in emissions from their 2005 level — comparable to a three to four per cent cut from 1990 levels.

“This is meaningful because it is yet a sign that the Americans have more to offer. My evaluation is that the US can offer much more,” EU environment spokesman Andreas Carlgren told reporters yesterday in Stockholm.

Whether the prospect of EPA action will satisfy such demands — and what China may now add to its earlier offer — remains to be seen. And success in the long-running climate talks hinges on more than emissions reductions. Most important, it requires commitments of financial support by rich countries for poor nations to help them cope with the impact of a changing climate.

Swedish negotiator Anders Turesson yesterday said the US 17-per cent reductions “are insufficient and we hope more would come out of that”.

He suggested the US buy more carbon credits on the international market, where emissions reductions by developing countries can be credited and sold to the industrialised world.