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Earth extended a decades-old hot streak in 2014 with a new temperature record, topping previous marks set in the last decade and a half with warm spots recorded around the globe.
The global average land and sea temperature for the year was 0.69 degrees Celsius (1.24 degrees Fahrenheit), over the 20th century average of 13.9 Celsius (57 degrees Fahrenheit), researchers at NASA and the National Oceanic and Atmospheric Administration (NOAA) reported Friday.
That tops the previous high marks set in 2010 and 2005 by about 0.04 degrees Celsius and knocks 1998 — the year climate-change deniers say global warming stopped — back to fourth on the list of the hottest years. And unlike 1998, this year's record was set without the boost from the Pacific Ocean warming pattern known as El Nino.
"Some regions were much cooler than average, but that was overwhelmed by the far greater proportion of land area and ocean that was warmer than average or had record temperatures," said Thomas Karl, the head of NOAA's National Climactic Data Center.
"Every continent had some aspect of record high temperatures," he added.
The year 2014 now ranks as the warmest on record since 1880, according to an analysis by NASA scientists. (Video by NASA)
Scientists point to the buildup of carbon dioxide and other industrial emissions in the atmosphere as the source of the warming trend. Gavin Schmidt, the director of NASA's Goddard Institute for Space Studies, said natural changes can't account for the steady increase in global temperatures seen since the mid-20th century.
"If you try and break out which parts of the human forcings are contributing the most to that trend, the figure shows quite clearly that it is the greenhouse gas trends," Schmidt told reporters Friday. Since that trend is still going up, "we may anticipate further record highs in the years to come."
Friday's figure is 0.9 degrees Celsius (1.6 degrees Fahrenheit) over pre-industrial temperatures, Schmidt said. Nine of the 10 hottest years in a record going back to 1880 have occurred since 2000, and December marked the 358th consecutive month that the global average temperature was warmer than that 20th century benchmark.
"If you're under 29.8 years old, you haven't lived on a planet cooler than average relative to the 20th century," Marshall Shepherd, the head of the atmospheric science program at the University of Georgia and former president of the American Meteorological Society, told VICE News.
The announcement had been expected as scientists watched monthly temperature records falling over and over again during 2014. The announcement had been expected as scientists watched monthly temperature records falling over and over again during 2014. Japan's Meteorological Agency reported similar findings Thursday, and Britain's Met Office is expected to reach the same conclusion shortly.
While annual averages bounce up and down, the overall trend has been toward hotter and hotter years each decade since the middle of the 20th century.
"Multiple data sets from across the globe continue to validate each other and highlight the long-term trends that we are seeing," Rick Spinrad, NOAA's chief scientist, told reporters Friday.
"Viewed in context, it underscores the undeniability that we are witnessing, before our eyes, the effects of human-caused climate change," Penn State climate scientist Michael Mann told VICE News. "It is exceptionally unlikely that we would be seeing a record year, during a record warm decade, during a multi-decadal period of warmth that appears to be unrivaled over at least the past millennium, if it were not for the rising levels of planet-warming gases produced by fossil fuel burning."
Without action to reduce emissions, scientists project a future of rising sea levels and more intense storms and droughts. The United Nations has called on countries to find ways to limit warming to two degrees Celsius (3.6 degrees Fahrenheit) over pre-industrial levels by 2100 — a difficult prospect for both advanced, carbon-intensive economies like the United States and Europe and rapidly developing nations like China and India.
Sierra Club's Michael Bossie told VICE News that the new data "should be adding impetus to all sorts of efforts we could be taking to push for clean energy." That could fuel even more interest in technologies like wind and solar power, which are already seeing a boom.
"There's a perception that in order to address something like climate disruption, you have to take an economic hit," said Bossie, the environmental group's Deputy National Program Director. "But the fact is there are a lot of benefits to taking action to address climate disruption."
Despite the broad scientific consensus, the subject remains controversial politically — especially in winter, when every blizzard seems to bring a new round of jokes from those who deny climate change.
"There are going to be some who are tempted to say, 'What are they talking about? It's cold where I live,' " Shepherd said. "That's like saying just because you're out of ketchup in your refrigerator, the entire neighborhood is out. It's not called 'where you live warming,' it's global warming."
Friday's announcement delivers a new blow to what has become a common talking point among opponents of reining in carbon emissions — that the globe hasn't warmed since 1998. Scientists have long said that argument was based on cherry-picking data while ignoring the long term upward trend.
Both Mann — a frequent target of critics of the science — and Shepherd said they hoped Friday's news would sink that claim. But Shepherd said he wasn't expecting miracles.
"I think the people who say that are going to continue to say that," he said.
The Heartland Institute, one of the most outspoken opponents of climate action, immediately dismissed the findings and accused NASA and NOAA of ignoring satellite data that points to a third-place finish for 2014. The group previously won notoriety for renting billboards to compare climate scientists to killers like Charles Manson and "Unabomber" Ted Kaczynski in 2012.
"It is not surprising that some agenda-driven NASA employees with a vested interest in keeping their global warming-related budgets at record levels would seek to distort the raw data and falsely claim record warmth in 2014," James Taylor, the group's senior fellow for environment and energy policy, said in a written statement to VICE News. Even if Friday's milestone were true "in some alternate universe," the temperature record is so short that it makes the increase "of little significance," he added.
But Spinrad said satellite observations were included in the data that researchers used to assess 2014. And Shepherd, who worked for NASA before taking his teaching post, told VICE News that he considers ground-based temperature gauges more accurate than satellite readings.
"Clearly, we've seen a run of very warm temperatures in the past several years that challenge this idea that there hasn't been warming," he said. Most of the heat is being absorbed by the oceans, "and there's no pause there." And he said focusing on the relatively small margins in global averages ignores the long-term effects on the climate.
"I put it in terms of a child running a one-degree fever for a year," he said. "Those are things people can perceive."
Follow Matt Smith on Twitter: @mattsmithatl