It's official: 2016 was the hottest year on record in 122 years of record-keeping, according to independent analyses by NASA and the National Oceanic and Atmospheric Administration.
The 1.78-degree jump over the mid-20th-century average marks the third year in a row that global temperatures have reached record-shattering levels.
Earth's average surface temperature has risen about 2 degrees since the late 19th century, about the time when such records were first kept, scientists with NASA and NOAA said.
"It was really global warmth that we saw in 2016," Derek Arndt, chief of the monitoring branch at NOAA's National Centers for Environmental Information, said in a news briefing.
The findings were not exactly a surprise _ scientists had predicted that 2016 might turn out to be even hotter than the previous year's record-breaking temperatures, and data through November seemed to be bearing that out. But the announcement cemented for many researchers the worrying reality that global temperatures are continuing their inexorable upward climb.
The announcement follows NOAA's findings earlier this month that 2016, with an average temperature of 54.9 degrees, was the second-hottest year in the United States since records began in 1895 (and second only to 2012). 2016 was also the 20th year in a row that the average annual temperature exceeded the average temperature.
Thanks in large part to human activity, unprecedented amounts of carbon dioxide have been released into the atmosphere since the Industrial Revolution. The potent greenhouse gas has warmed the Earth and acidified the oceans _ leading, among other things, to the bleaching of coral reefs and the destruction of the ecosystems they support.
The rising temperatures have also contributed to the melting of polar ice reserves, causing sea levels to rise _ which, according to a recent study, could cause flooding that would affect 13.1 million people living along U.S. coastlines.
Weather events, thanks to climate change, have also become more extreme _ and NOAA's data from the United States seems to bear that out. The U.S. experienced 15 weather-related disasters last year, including drought, wildfire, flooding, severe storms and a hurricane, which together resulted in losses of $46 billion and the deaths of 138 people.
