In a statement released at international climate talks in Qatar, the World Meteorological Organization said the "alarming rate" of the Arctic melt highlights the far-reaching changes caused by global warming.
"Climate change is taking place before our eyes and will continue to do so as a result of the concentrations of greenhouse gases in the atmosphere, which have risen constantly and again reached new records," WMO Secretary-General Michel Jarraud said.
The WMO said global temperatures rose after initial cooling caused by the La Nina weather oscillation, with major heat waves in the U.S. and Europe. Average temperatures in January-October were the highest in the continental U.S., and the ninth highest worldwide, since records began in 1850.
Cyclone activity was normal globally, but above average in the Atlantic, where 10 storms reached hurricane strength, including Sandy, which wreaked havoc across the Caribbean and the U.S. East Coast.
Sandy wasn't the strongest cyclone, though. That was Typhoon Sanba, which struck the Philippines, Japan, and the Korean Peninsula, "dumping torrential rain and triggering floods and landslides that affected thousands of people and caused millions in U.S. dollars in damage," the WMO said.
Related: Permafrost melt needs to be factored into talks, experts say
Droughts impacted the U.S., Russia, parts of China and northern Brazil. Nigeria saw exceptional floods, while southern China saw its heaviest rainfall in three decades.
But of all the weather events in 2012, the most ominous to climate scientists was the loss of ice cover on the North Pole. In September, scientists at the National Snow and Ice Data Center in Colorado said Arctic Sea ice measured 1.32 million square miles — which is 18 percent less than the previous record low, set in 2007. Records go back to 1979 based on satellite tracking.
The scientists said their computer models predict the Arctic could become essentially free of ice in the summer by 2050, but added that current trends show ice melting faster than the computers are predicting.
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