The string of especially hot years observed by scientists over the past decade is almost certainly the result of human-caused climate change, a team of meteorologists reported on Monday.
Thirteen of the 15 hottest years on record have occurred since 2000, and according to a study published Monday, the odds of that happening by natural means is between 1 in 5,000 and 1 in 170,000.
They found the probability of those happening due to global warming to be “overwhelmingly” high, though not as high as has been previously reported.
Previous studies put the likelihood of natural record warmth at 1 in 27 million; this report concluded it was between 600 and 130,000 more likely to have occurred due to man-made climate change.
"Natural climate variability causes temperatures to wax and wane over a period of several years, rather than varying erratically from one year to the next,” Michael Mann, the director of Penn State’s Earth Systems Science Center, said in a statement.
The team's report concluded: “While considerably greater than cited in some recent media reports, these odds are low enough to suggest that recent observed runs of record temperatures are extremely unlikely to have occurred in the absence of human-caused global warming.”
Federal officials announced last week that 2015 was the warmest year on record, a conclusion echoed Monday by the World Meteorological Organization.
Scientists predict 2016 will break last year’s mark. Never since record-keeping began in 1880 have three straight years set a temperature record, but officials said that is likely; they, too, attributed it to climate change.