Published: 2018-01-05 00:02:41 BdST
The Copernicus Climate Change Service, the first major international weather agency to report on conditions in 2017, said temperatures averaged 14.7 degrees Celsius (58.46 Fahrenheit) at the Earth's surface - 1.2C (2.2F) above pre-industrial times.
Last year was slightly "cooler than the warmest year on record, 2016, and warmer than the previous second warmest year, 2015", it said. Temperature records date back to the late 19th century.
"It's striking that 16 of the 17 warmest years have all been this century," Jean-Noel Thepaut, head of Copernicus, told Reuters, adding there was overwhelming scientific consensus that man-made emissions were stoking the warming trend.
The Copernicus study is in line with a projection by the UN World Meteorological Organization (WMO) in November that 2017 would be second or third warmest behind 2016.
In 2016, an extra dose of heat came from El Nino, a natural event that releases heat from the Pacific Ocean every few years.
But last year was the hottest year without an El Nino, according to Copernicus, run by the European Centre for Medium-Range Weather Forecasts.
It pointed to a retreat of sea ice in the Arctic and prolonged dry conditions in southern Europe that helped trigger wildfires in Portugal and Spain in 2017 as examples of the sort of disruptions that are becoming more frequent in a warming climate.
US President Donald Trump, who doubts that climate change has a human cause, tweeted on Dec. 29 about bone-chilling cold in the United States and cast doubt on the need for action to limit emissions.
"Perhaps we could use a little bit of that good old Global Warming that our Country, but not other countries, was going to pay TRILLIONS OF DOLLARS to protect against. Bundle up!" he wrote.
Trump plans to quit the 2015 Paris Agreement, which has the backing of almost 200 nations and seeks to limit the rise in temperatures to "well below" 2 degrees Celsius (3.6 F) above pre-industrial times, ideally 1.5 C (2.7 F).
High winds and heavy show barrelled into the US northeast on Thursday, closing schools and government offices and disrupting travel.
Data on Thursday compiled by the University of Maine and the Climate Change Institute showed temperatures in the eastern United States, Greenland and parts of central Asia were indeed colder than usual, while most of the rest of the world was warmer.
Earlier on Thursday, German reinsurer Munich Re said insurers would have to pay claims of around $135 billion for 2017, the most ever, following a spate of hurricanes, earthquakes and fires in North America.
Thepaut said rising sea levels and higher temperatures that can produce more rainfall may have aggravated Atlantic hurricanes, even though it was hard to detect links between individual storms and man-made climate change.
The WMO will publish its review of 2017 temperatures, also drawing on Copernicus and other US, British and Japanese data, in about two weeks.