DOHA, QATAR-- An area of Arctic sea ice bigger than the United States melted this year, according the U.N. weather agency, which said the dramatic decline illustrates that climate change is happening "before our eyes."

In a report released at U.N. climate talks in the Qatari capital of Doha, the World Meteorological Organization said the Arctic ice melt was one of the myriad extreme and record-breaking weather events in 2012, including the drought and heat waves that hit the United States.

But it was the ice melt that dominated the annual climate report, with the United Nations concluding ice cover had reached "a new record low" around the North Pole and that the loss from March to September was a staggering 4.57 million square miles -- bigger than the United States.

"The alarming rate of its melt this year highlighted the far-reaching changes taking place on Earth's oceans and biosphere," WMO Secretary-General Michel Jarraud said. "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."

The dire news -- following a report Tuesday that melting permafrost could significantly amplify global warming -- comes as delegates from nearly 200 countries struggled for a third day to lay the groundwork for a deal that would cut emissions in an attempt to ensure that temperatures don't rise more than 3.6 degrees over what they were in preindustrial times. Temperatures have already risen about 1.4 degrees, according to the latest report by the IPCC. Discord between rich and poor countries has kept the two-decade-old U.N. talks from delivering on that goal.

ASSOCIATED PRESS