U.S. Climate Headed for Record Year
PHOTO: A man walks past a holiday window display during unseasonably warm weather at the Penn Security Bank & Trust building on Spruce Street in downtown Scranton, Pa., on Dec. 4, 2012.

A man passes a holiday display in Scranton, Pa., Dec. 4, 2012. (Butch Comegys/The Scranton Times-Tribune/AP Photo)

The nation's climate in 2012 is on track to be the warmest and most extreme ever. And scientists tell us we should get used to it.

"It appears virtually certain that 2012 will surpass the current record (1998, 54.3 degrees F) as the warmest year for the nation," NOAA said today in its monthly analysis of the nation's climate.

"We have a clear signal for rising temperatures for the contiguous U.S. and the globe," said Jake Crouch, a climate scientist at the NOAA's National Climatic Data Center in Ashville, N.C. "If this trend continues, we will be breaking records and be near record-breaking warm more often in the future."

Scientists say the number of climate extremes, such as high daytime and nighttime temperatures as well as the amount of drought, heavy rain and even cyclones so far this year, is unprecedented.

"The percent of the U.S. experiencing extremes is twice what we'd expect. And that is a record," Crouch told ABC News.

A stubborn drought is taking the biggest toll, with 2012 so far ranking as the 12th-driest ever recorded.

"We have been really warm but we've also been really dry," said Crouch. "And that's having real-world impacts on people."

Climate scientists around the world warn the extreme trends will continue as long as humans continue to pump heat-trapping greenhouse gasses into the atmosphere.

The news comes as nations are feuding over how to best tackle the effects of rising global temperatures at the United Nations climate talks underway in Doha, Qatar.

New scientific studies show human-caused global warming is helping melt ice sheets around both poles. Melting land ice has helped raise sea levels by about half an inch since 1992, and scientists say that amount probably made flooding from October's Superstorm Sandy even worse.

In a new NOAA sea level report released today, scientists said they have "very high confidence" that global sea levels will rise at least eight inches, and no more than 6.6 feet, by 2100. The report presents four scenarios, including an "intermediate-high" scenario that predicts a 3.9-foot sea level rise by 2100 by taking into account ocean water that expands as it warms, as well as the loss of ice sheets.

"If the trend of warming temperatures continues into the future," Crouch said, "we would expect more years to be like 2011 and 2012."

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