WASHINGTON — America set an off-the-charts heat record in 2012.
A brutal combination of a widespread drought and a mostly absent winter pushed the average annual U.S. temperature last year up to 55.32 degrees Fahrenheit, the government announced Tuesday. That's a full degree warmer than the old record set in 1998.
Breaking temperature records by an entire degree is unprecedented, scientists say. Normally, records are broken by a tenth of a degree or so.
It was off the chart, said Deke Arndt, head of climate monitoring at the National Climatic Data Center in Asheville, N.C., which calculated the temperature records.
Last year, he said, will go down as a huge exclamation point at the end of a couple decades of warming.
Last week, The National Weather Service office in Binghamton, N.Y., reported that 2012 was the warmest year on record for Northeastern Pennsylvania. At a daily average of 53 degrees, 2012 was the warmest year on record at the Wilkes-Barre/Scranton International Airport, breaking the mark of 52.4 degrees set in 1921, according to data from the weather-service office.
The National Climatic Data Center's figures for the entire world won't come out until next week, but through the first 11 months of 2012, the world was on pace to have its eighth warmest year on record.
Scientists say the U.S. heat is part global warming in action and natural weather variations. The drought that struck almost two-thirds of the nation and a La Nina weather event helped push temperatures higher, along with climate change from man-made greenhouse gas emissions, said Katharine Hayhoe, director of the Climate Science Center at Texas Tech University. She said temperature increases are happening faster than scientists predicted.
These records do not occur like this in an unchanging climate, said Kevin Trenberth, head of climate analysis at the National Center for Atmospheric Research in Boulder, Colo. And they are costing many billions of dollars.
Last year was 3.2 degrees warmer than the average for the entire 20th century. Last July was the hottest month on record. Nineteen states set yearly heat records in 2012, though Alaska was cooler than average.
U.S. temperature records go back to 1895, and the yearly average is based on reports from more than 1,200 weather stations across the Lower 48 states.