Last year was the second or third warmest on record behind 2016, and the hottest without an extra dose of heat caused by an El Nino event in the Pacific Ocean, the United Nations said on Thursday.
Average surface temperatures in 2017 were 1.1 degree Celsius above pre-industrial times, creeping toward 1.5 degree, the most ambitious limit for global warming set by almost 200 nations under the 2015 Paris climate agreement.
The agreement has been weakened by a plan by U.S. President Donald Trump, who doubts mainstream scientific findings that warming is driven by man-made greenhouse gases, to pull out.