UN agency: 2012 year of extremes and above average temperatures despite La Nina

The U.N. weather agency says despite early cooling from La Nina, 2012 is on track to become one of the top 10 hottest years on record, with the United States experiencing extreme warmth and Arctic Sea ice shrinking to its lowest extent.

The World Meteorological Organization on Wednesday said the "alarming rate" of Arctic melt highlights the changes caused by global warming.

At the international climate talks in Qatar, the WMO says global temperatures rose after initial cooling caused by the La Nina weather oscillation, with major heat waves in the U.S. and Europe.

Average January-October temperatures were the highest on record in mainland U.S. and the ninth highest worldwide. Cyclone activity was normal globally, but above average in the Atlantic, where 10 storms, including Sandy, reached hurricane strength.