This year is "very likely" to be the hottest on record, the UN said. It marks the third consecutive year that temperature records have been broken, while 16 of the 17 hottest years recorded have been this century.
The UN's World Meteorological Organization (WMO) said Monday that preliminary data through October showed global average temperatures this year were 1.2 degrees Celsius (2.2 degrees Fahrenheit) higher than pre-industrial levels.
The figures are getting close to the limits set by the global climate change agreement adopted by 200 countries in Paris last year. The pact calls on states to limit the temperature rise since the industrial revolution to "well below" 2 degrees Celsius, ideally 1.5 degrees Celsius.
The added heat was stoked this year by an El Nino weather phenomenon and the ongoing burning of fossil fuels. It has led to Greenland's ice caps melting and damaged Australia's Great Barrier Reef.
"The extra heat from the powerful El Nino event has disappeared," WMO Secretary-General Petteri Taalas said. "The heat from global warming will continue."
Parts of Arctic Russia are said to have seen temperatures 6 to 7 degrees Celsius higher than the long-term average, while other Arctic and sub-Arctic regions in Russia, Alaska and northwest Canada were at least 3 degrees Celsius above average.
The most damaging weather events of 2016 were Hurricane Matthew, which killed 500 people in Haiti, and the floods in the Yangtze basin in China, which killed 310 and caused an estimated $14 billion (13 billion euros) in damage.
"Because of climate change, the occurrence and impact of extreme events has risen," Taalas said.
"'Once in a generation' heat waves and flooding are becoming more regular. Sea level rise has increased exposure to storm surges associated with tropical cyclones," he said.
The WMO reported that if 2016 became the hottest year on record, it would mean 16 of the 17 hottest years on record have been this century - the other one was 1998.
Marrakesh: Heading towards decarbonization?
The news comes as climate change talks got under way in Marrakesh, Morocco.
"Another year. Another record," Taalas said as during the talks.
With more than 200 countries in attendance, the conference aims to focus on executing plans and goals outlined in the Paris agreement.
However, the talks have been overshadowed by Donald Trump's election win in the United States. The President-elect has said he is seeking to quickly pull the United States out of the 2015 Paris agreement, which aims to shift the global economy from fossil fuels to renewable energy.
Outgoing US President Barack Obama had identified combating climate change as a key policy of his administration. The US was also a driving force behind the design of the Paris Agreement.
On Monday, the annual Global Carbon Budget report said that carbon emissions from fossil fuels have been almost flat over the last three years - a "great help" but not enough to stave off the dangerous effects of climate change.
Data from the UN refugee agency estimates that 19.2 million people have been displaced by weather, water, climate and hazards, such as earthquakes, in 2015 - twice as many as in conflict and violence.
Food shortages and conflict are also expected to increase as a result of more frequent weather-related disasters.
dm/se (AFP, Reuters, AP)