2011 is tied for the 10th hottest year since records began in 1850, the office said in its annual assessment of average global temperatures. The Arctic sea ice has also shrunk to record-low volumes this year, it said. The 13 hottest years on the books all have occurred in the last 15 years.
“The science is solid and proves unequivocally that the world is warming,” said R.D.J. Lengoasa, deputy director of the International Meteorological Organization, and human activity is a significant contributor.
“Climate change is real, and we are already observing its manifestations in weather and climate patterns around the world,” he said on the sidelines of the UN climate conference under way in South Africa.
The IMO’s preliminary report, based on the first 10 months of the year, was released in Geneva and at the UN climate talks in South Africa. It provided a bleak backdrop to negotiators who are seeking ways to limit pollution blamed for global warming.
2011 has been a year of extreme weather, the weather service said. Parching drought in East Africa has left tens of thousands dead, and there have been deadly floods in Asia, and 14 separate weather catastrophes in the United States with damage topping $1 billion each.
Climate negotiators have set a goal of keeping temperatures from rising more than 3.6 degrees Fahrenheit (2 degrees Celsius) above preindustrial levels. They already are 1.4 F (0.8 C) above the 1750 average.
Small islands want that target reset at 2.3 F (1.5 C), saying their very existence is threatened by rising sea levels.
Michel Jarraud, IMO’s secretary-general, said the 2.3 F target already is out of reach.
“Forget about it. It’s too late,” he told The Associated Press in Geneva, adding that 3.6 F (2 C) is now a very challenging target. “Technically, if action is to be taken quickly, 2 degrees is reachable.”
Record high concentrations of greenhouse gases in the atmosphere are fast approaching levels consistent with another 3.3 F (2.4 C) rise in average global surface temperatures, “which scientists believe could trigger far-reaching and irreversible changes in our Earth, biosphere and oceans,” he said.
The IMO report said high temperatures saturated the Earth despite a La Niña event, when low surface temperatures in the equatorial Pacific Ocean has a cooling effect on the entire globe.
In an exhaustive study of extreme weather, the authoritative Intergovernmental Panel on Climate Change reported this month that such events will increase in frequency and intensity as the Earth continues to warm.
The IMO said the extent of Arctic sea ice in 2011 was the second-lowest on record, and its volume was the lowest. Scientists see the Arctic as the planet’s most sensitive region and a barometer of the future.
The largest departure from the norm occurred in northern Russia, where thermometers soared and average 7.2 degrees Fahrenheit (4 degrees Celsius) above average in some places, and some stations reporting spring weather 16 degrees Fahrenheit (9 degrees Celsius) above normal.
The Russian Arctic and most of Siberia hold massive amounts of methane locked into the permafrost, carbon-rich soil that never thaws. Warmer summer temperatures mean a deeper thaw of permafrost and greater release of methane, a gas with a global warming potential 23 times more powerful than carbon dioxide.
The report came on the second day of the two-week conference in this South African coastal city attended by 192 parties seeking agreement on future action to curb climate change.
The talks will determine whether industrial countries will renew and expand their commitments under the 1997 Kyoto Protocol to reduce their greenhouse emissions and whether developing countries will accept binding limits on their emissions in the future.
Negotiators also are discussing how to raise $100 billion a year to help poor countries move to low-carbon economies and cope with the effects of global warming.
