The UN's weather and climate agency say 2017 is set to become the hottest year on record aside from those impacted by the El Nino phenomenon.
The World Meteorological Organisation also says 2017 is already on track to be one of the three hottest years of all time, after 2015 and 2016, which were both affected by a powerful El Nino effect, which can contribute towards the higher temperatures.
2016 set a record for the Earth's average global temperature. The warning was timed for Monday's start of the latest UN climate change conference, hosted this year by Bonn, Germany.
25,000 odd scientists, envoys, lobbyists and environmental activists have descended on the city for two weeks of trying to figure out how to turn the goals of the 2015 Paris climate change accord into reality.
Key indicators of climate change – such as rising carbon-dioxide concentrations in the atmosphere, rising sea levels and the acidification of oceans – "continue unabated" this year, says the WMO.
The global temperature from January to September 2017 is about a half-degree Celsius warmer than the 1981-2010 average, which was estimated to be 14.31 degree Celsius.
2017 has been marked by higher-than-average rainfall in places like China, southern South America and the contiguous United States. It has also been marked by lower-than-average coverage areas for Arctic sea ice.