2015 was the hottest year in the historical record -- that's the consensus of more than 450 scientists from 62 countries around the world who contributed to an annual State of the Climate report released by the American Meteorological Society.
"The year 2015 saw the toppling of several symbolic mileposts: notably, it was 1.0°C warmer than preindustrial times, and the Mauna Loa observatory recorded its first annual mean carbon dioxide concentration greater than 400 ppm. Beyond these more recognizable markers, trends seen in recent decades continued," said the AMS website.
An El Niño weather pattern in the Pacific Ocean that was among the strongest on record and record levels of greenhouse gases fueled the year's warmth, said the Washington Post. The global temperature beat last year's record by 0.1 degree Celsius.
In addition to record temperatures, the Earth saw record-high sea levels, record ocean surface temperatures, a record number of major cyclones in the northern hemisphere, and low levels of artic sea ice and glaciers, the Post said.
The contiguous United States saw the hottest and wettest December on record, but overall temperatures for the year were the second-warmest on record, The New York Times reported.
"The whole system is warming up, relentlessly," Gerald A. Meehl, a scientist at the National Center for Atmospheric Research in Boulder, Colo., told the Times.
Global warming slowed after the strong El Niño event of 1998, but record temperatures during the past two year suggest the phenomenon may be picking up speed again.
This year is shaping up to eclipse 2015's record temperatures, according to NASA's midyear climate analysis.
"Each of the first six months of 2016 set a record as the warmest respective month globally in the modern temperature record, which dates to 1880," NASA said on its website last month, adding that the first six months of 2016 were the planet's warmest half-year on record.