This year is expected to be one of the three hottest years on record after 2015 and 2016, the World Meteorological Organization (WMO) warned on Monday.
"High-impact" events including heatwaves, droughts, hurricanes and floods could all worsen as the planet heats up, the body said, as a U.N. climate change conference got underway in Bonn, Germany.
"Long-term indicators of climate change such as increasing carbon dioxide concentrations, sea level rise and ocean acidification continue unabated.
"Arctic sea ice coverage remains below average and previously stable Antarctic sea ice extent was at or near a record low," the WMO said in a statement.
According to WMO data, the average global temperature from January to September 2017 was approximately 1.1C (33.9F) above the pre-industrial era.
"As a result of a powerful El Nino, 2016 is likely to remain the warmest year on record, with 2017 and 2015 being second and/or third. 2013-2017 is set to be the warmest five-year period on record," the WMO said.
Worldwide, 23.5 million people were displaced during weather-related disasters in 2016.
Parts of southern Europe, North Africa, parts of eastern and southern Africa and the Asian part of Russia experienced record temperatures.