CANCUN, Mexico (AP) — A scorching summer that killed thousands in Russia and exceptionally mild winters in the Arctic were among extreme weather events that have put 2010 on track to be one of the three hottest years on record, U.N. experts said Thursday.
The data from the World Meteorological Organization show that the last decade was the warmest ever, part of a trend that scientists attribute to man-made pollution trapping heat in the atmosphere.
Europeans and some Americans may think it was chilly this year, but their unusually cold winters were more than balanced by searing temperatures from Canada to Africa and the Indian subcontinent, said Michel Jarraud, WMO’s secretary-general.
Parts of Greenland, where glaciers are threatened with summer melt, had an annual average temperature of 5.4 degrees Fahrenheit (3 degrees Celsius) above normal, said the WMO’s preliminary report, released on the sidelines of a 193-nation U.N. conference on climate change.
Moscow had 33 consecutive days when the thermometer topped 86 degrees Fahrenheit (30 Celsius) and one day when it cracked 100 (38.2 Celsius), a new record. Russian officials ascribed 11,000 excess deaths to the heat wave and the peat fires that raged on the capital’s outskirts.
The WMO said the same extreme weather event that suffocated Russia also caused the floods that submerged a fifth of Pakistan, killing 1,700 people and displacing 20 million. The year also witnessed heavy rains that lashed Australia and Indonesia, flooding in Thailand and Vietnam, and drought in the Amazon basin and southwest China.
‘‘The year 2010 is almost certain to rank in the top three warmest years since the beginning of instrumental climate records in 1850,’’ the WMO said.
Recent anecdotal evidence reinforces the science. Northern permafrost is thawing underneath buildings in Alaska, northern Canada and Siberia, causing them to tilt and crack. Children are swimming in normally frigid waters in the Arctic Ocean and American robins have appeared in Canada’s far north for the first time. Sea ice has retreated north of Russia, opening the possibility of a summer passageway for shipping.
Natural disasters or individual weather events cannot be directly traced to climate change, Jarraud said. But the long-term trend leaves little doubt the Earth is warming in ways that cannot be explained by nature and is almost certainly caused by man-made pollution that traps heat, he said.
‘‘If you don’t include the human emissions you cannot reproduce what you observe,’’ he said. ‘‘That’s why we feel that we can attribute a significant part of what we observe to man-made emissions.’’
Activists at the climate talks seized on the report to berate the negotiators.
‘‘This is yet another warning from the planet that it is feeling the heat. Will governments take this warning and take the opportunity to act? Or will they continue to delay action and accept more warming, year after year?’’ said Wendel Trio of the Greenpeace environmental group.
Warming temperatures are ‘‘making it harder for people to survive,’’ said Oxfam International. In the first nine months of this year, 21,000 people died due to weather-related disasters — more than twice the number for the whole of 2009.
Jarraud said temperatures through October were at near-record levels this year. Data for November and December will be analyzed early in 2011 but are expected to be slightly colder than normal because of the late-year La Nina, a cooling effect on Pacific sea temperatures.
Still, ‘‘there is a significant possibility 2010 could be the warmest’’ year on record, Jarraud told reporters.
Cold winters in northern Europe — not counting the early snow and freezing temperatures now gripping Britain and parts of the continent — meant it was the coolest year in that region since 1996, Jarraud said. But that ‘‘did not reflect the global average,’’ he said.
The two other extraordinary years were 1998 and 2005. Jarraud said those two steaming years and 2010 were all within a fraction of a degree of each other.
The conference, which ends Dec. 10 with a meeting of scores of ministers and about 25 heads of state, is seeking agreement on a narrow package of measures to help poor countries prepare for changing climate conditions. Key among them is to set up an organization to govern $30 billion in emergency climate funds through 2012, and $100 billion a year starting in 2020.