Last year was the second hottest worldwide on record, just behind a sweltering 2016 with signs of climate change ranging from wildfires to a thaw of Arctic ice, a European Union monitoring centre says.
The Copernicus Climate Change Service, the first major international weather agency to report global 2017 temperatures, said they averaged 14.7degC or 1.2degC 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", the report said. Temperature records date back to the late 19th century.
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The measurements back up a projection by the UN World Meteorological Organisation (WMO) in November that 2017 would be second- or third-warmest behind 2016, as part of a long-term trend driven by manmade greenhouse gases.
Sweltering temperatures in 2016 were also boosted by a natural El Nino event that happens every few years and releases heat from the Pacific Ocean.
Last year was the warmest year on record without the influence of an El Nino, according to Copernicus, run by the European Centre for Medium-Range Weather Forecasts.
In the Arctic, "sea-ice cover was... below average, especially during the cooler months at the beginning and the end of the year"..
"Meanwhile, southern Europe was hit hard by prolonged dry conditions from late spring into the autumn months. The dry conditions led to water shortages in many areas and facilitated the spread of wildfires on the Iberian Peninsula."
The WMO will publish its review of 2017 temperatures, also drawing on US, British and Japanese data, in about two weeks.