The average annual U.S. temperature last year reached 55.32 degrees, the National Climatic Data Center announced Tuesday. The new record was a full degree higher than the old one, set in 1998.
Breaking a record by so much is unprecedented, scientists say. Typically, a tenth of a degree or so separates a new record from an old one.
"It was off the chart," said Deke Arndt, head of climate monitoring at the climatic data center. Last year, he said, will go down as "a huge exclamation point at the end of a couple decades of warming."
The center's assessment of global temperatures is not expected until next week. Based on first 11 months of 2012, the world was on pace to log average temperatures that are eighth warmest on record.
In Utah, the annual average temperature was 51.6 degrees, which broke a record set in the Dust Bowl year of 1934. In Salt Lake City, the average annual temperature was 56.6 degrees, a sweltering 3.8 degrees higher than normal.
Jim Steenburgh, a member of the Utah Governor's Blue Ribbon Advisory Council on Climate Change and professor of atmospheric sciences at the University of Utah, called the latest statistics "a reflection of a trend."
"This is not your grandparents' climate," he said, noting that warming will continue into the future, making it highly unlikely we'll see record-cold years again.
"I don't see anything slowing it down."
A common question is, "What do the latest numbers say about climate change?"
Steenburgh said both natural variability and human factors are at work. Looking beyond last year's record, the many types of evidence point to the importance of human influences in the trend.
"It's global warming," he said. "We're pumping a lot of greenhouse gases into the air and those gases are warming the planet."
Rob Davies at Utah State University agrees that the trend suggests something more is at work than the natural rhythms of climate. He notes that 19 of the past 19 years in Utah have been above average, and the probability that natural variability is the cause is "very unlikely."
"Roughly speaking, assuming no underlying trend such as climate change any given year is as likely to be above the average as below," he said.
"We've just flipped 19 heads in a row," he said using a coin toss analogy in referring to the above-normal temperatures of the past 19 years. "From a random variability standpoint, the odds of this are about two chances in a million."
Vicki Bennett, director of Salt Lake City's Sustainability programs, was not surprised the city saw its temperature record broken. Her office has focused on adapting to the climate changes ahead, preparing for stresses on water, energy and weather-related disasters that are expected as the climate warms.
"I hope this opens more people's eyes to the fact that we are having climate issues that need to be addressed," she said.
The National Oceanic and Atmospheric Administration noted 2012 had the second-most weather extremes on record since hurricane-heavy 1998, based on a formula that factors in temperature records, drought, downpours and land-falling hurricanes.
Ranked second after 2011, last year logged 11 different disasters that caused more than $1 billion in damage, including Superstorm Sandy and the drought, NOAA said.
Randy Parker, director of the Utah Farm Bureau Federation, agreed that last year was a difficult one for many farmers and ranchers.
"It was a tough year because it was hot; it was a tough year because it was dry,'' he said. "But those things are cyclical. They happen."
A member of the 2007 Utah climate change panel, he disputed that global warming is happening because of humans.
"I'm in total agreement the climate is changing that's a natural process," he said. "The debate is how much" humans can be blamed.
A variety of lines of scientific evidence point to the burning of fossil fuels coal, oil and natural gas as the primary driver of rapid climate change that is being observed.
Heat-trapping gases, such as carbon dioxide, get into the air and change the climate, scientists say.
The Associated Press contributed to this article.
2012 climate by the numbers:
9.2 million • Acres burned in wildfire in the contiguous U.S.
16 • Consecutive months with contiguous U.S. temperatures above the long-term average the longest such streak on record.
1993 • The last time Utah had a colder than normal year.
+3.8 °F • Departure from the average temperature last year in Salt Lake City, making it the city's warmest year on record.
51.6 • Average annual temperature in Utah last year, a record high at 3.7 degrees above normal.
Source: National Climatic Data Center.