Earth Had Its Hottest Year on Record in 2015, Says NASA, NOAA

Both agencies calculated a spike in Earth's average temperature.

— -- It's official: 2015 was Earth's hottest year on record.

NOAA reported last year's average temperature for the Earth as a whole was 58.62 degrees Fahrenheit -- that's 0.29 degrees higher than the previous year. NASA also calculated a temperature increase of 0.29 degrees over the previous year.

While both agencies agree 2015 was the hottest year on record and use much of the same raw data, the differences in their data sets can be accounted for, NASA said, because NOAA scientists use different methods to analyze Earth's polar regions and global temperatures.

"It's getting to the point where breaking record is the norm," Katharine Hayhoe, a climate scientist at Texas Tech, told the Associated Press. "It's almost unusual when we're not breaking a record."

With the large spike this year, NASA said it could call 2015 the hottest year on record with 94 percent certainty -- that's double the certainty they had the previous year when 2014 was announced as a record.

Since the beginning of modern record keeping, Earth's temperature has risen about 1.8 degrees Fahrenheit, according to NASA, which attributed the change to "increased carbon dioxide and other human-made emissions into the atmosphere."

The Associated Press contributed to this report.