Despite early cooling from La Nina, 2012 is on track to become one of the top 10 hottest years on record, with the U.S. experiencing extreme warmth and Arctic Sea iceshrinking to its lowest extent, the U.N. weather agency said Wednesday. 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.