This year is set to be the hottest year ever recorded globally, beating 2015's record temperatures, the World Meteorological Organisation has said.
Global temperatures this year are approximately 1.2C (2.16F) above pre-industrial levels and 0.88C (1.58F) above the average for 1961-1990, which the WMO uses as a reference period, provisional figures show.
As a result, 2016 is on track to be the hottest year in records dating back to the 19th century, and 16 of the 17 hottest years on record will have occurred in the 21st century.
WMO secretary-general Petteri Taalas said: "Another year, another record. The high temperatures we saw in 2015 are set to be beaten in 2016."
The provisional assessment by the WMO has been released to inform the latest round of UN climate talks in Morocco which are focusing on implementing the world's first comprehensive climate treaty, the Paris Agreement.
It comes as a study suggests carbon emissions have seen "almost no growth" in the past three years, marking a break from rapidly rising output in the previous decade and raising hopes that emissions may have peaked.
But the election of Donald Trump as the next US president has raised concerns about the international fight against climate change, which he has previously described as a hoax created by the Chinese to make American manufacturing uncompetitive.
The WMO assessment, which uses several international datasets including one from the Met Office and the University of East Anglia's Climatic Research Unit, showed global temperatures for January to September 2016 were 0.88C above the 14C (57.2F) average for 1961-1990.
A powerful climate phenomenon in the Pacific known as El Nino, which pushes up global temperatures, led to a spike in temperatures in the early months of the year.
But preliminary data for October suggests temperatures remain high enough for 2016 to be on track for the title of hottest year on record, beating 2015.
This year has also seen record-breaking concentrations of greenhouse gas carbon dioxide in the atmosphere, as well as melting ice, coral reefs bleaching in the face of hot oceans, above-average sea level rise and extreme weather.
Prof Taalas said: "The extra heat from the powerful El Nino event has disappeared. The heat from global warming will continue.
"In parts of Arctic Russia, temperatures were 6C to 7C above the long-term average.
"Many other Arctic and sub-Arctic regions in Russia, Alaska and north-west Canada were at least 3C above average.
"We are used to measuring temperature records in fractions of a degree, and so this is different."
Professor Peter Stott, of the Met Office, said: "Three record-breaking years for global temperature would be remarkable. The year 2015 was exceptionally warm and, like 2016, was influenced by the warm El Nino circulation in the tropical Pacific.
"As the El Nino wanes, we don't anticipate that 2017 will be another record-breaking year in the instrumental record."
But 2017 was still likely to be warmer than any year prior to the last two decades because of the underlying extent of man-made global warming due to increasing levels of greenhouse gases in the atmosphere, he said.
The warning that it is set to be a record warm year comes after an analysis by the WMO that the global climate had seen its hottest five-year period on record between 2011 and 2015, with temperatures 0.57C (1.03F) above the 1960-1991 average.
Man-made climate change is driving extreme weather, with more than half of 79 studies published between 2011 and 2014 by the Bulletin of the American Meteorological Society finding global warming contributed to individual extreme events, the WMO said.
Responding to the announcement on 2016's record temperatures, Friends of the Earth's head of campaigns Andrew Pendleton said: "This is an urgent memo from the planet to President-elect Trump, Theresa May and any other leaders that think tackling climate change isn't important.
"While Trump denies the existence of climate change, and May approves fracking and Heathrow expansion, our planet is warming fast and time for action is ticking down.
"It's still possible to stop the worst effects of climate change, but it requires us to stop using coal, oil and gas in less than a generation - and put growingly affordable renewable energy in their place."