COPENHAGEN (AP)

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.

Only the United States and Canada experienced cooler conditions than average, the World Meteorological Organization (WMO) said, although Alaska had the second-warmest July on record. In central Africa and southern Asia, this will probably be the warmest year, but overall, 2009 will "be about the fifth-warmest year on record," said Michel Jarraud, secretary general of the WMO.

The agency also noted an extreme heat wave in India in May and a heat wave 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. Extremely warm weather was 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 a news conference, holding a chart with a temperature curve pointing upward. The second warmest decade was the 1990s.

The current decade has been marked by dramatic effects of warming.

In 2007-2009, the summer-melt reduced 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 United States 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° C (0.79° F) above the 1961-1990 annual average of 14.00° C (57.2° F), with a margin of error of plus or minus 0.11 degrees C. Final data will be released early in 2010.Negotiators at the two-week talks in Copenhagen turned yesterday 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.

In a series of reports, the Intergovernmental Panel on Climate Change, a United Nation-sponsored scientific network, has warned that unless the world is weaned away from fossil fuels 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 tropical diseases.

Some governments have reacted slowly to the warnings because of concerns over the cost to business and consumers of converting economies to new energy sources, the influence of "old energy" industries on policy, and the reluctance of societies to change.