In a report released today, the intergovernmental body said the average global surface temperature from January to October this year was around 0.73°C above the 1961-1990 average of 14.0°C, and around 1°C above the pre-industrial period of 1880-1899.
The estimate for the year to date is based on data gathered from measuring centres around the world, and has led the researchers to predict a “record year”.
“2015 is likely to be the hottest year on record, with ocean surface temperatures at the highest level since measurements began,” said WMO secretary-general Michel Jarraud, explaining that a number of factors have combined to cause the temperature peak.
Levels of greenhouse gases in the atmosphere reached new highs and in the Northern hemisphere spring 2015 the three-month global average concentration of carbon dioxide crossed the 400 parts per million barrier for the first time.
China is having its warmest year on record, as is most of Asia and South America. Africa and Europe are having their second hottest years.
In addition to expecting 2015 to be the warmest year ever recorded, the WMO found that the period from 2011 to 2015 would likely be the hottest five years in history, with average temperatures about 0.57°C higher than the 1961-1990 reference point. Jarraud puts this down to a series of extreme weather events, such as heatwaves, and he expects the temperature rise to continue into 2016:
We are witnessing a powerful El Niño event, which is still gaining in strength. This is influencing weather patterns in many parts of the world and fuelled an exceptionally warm October. The overall warming impact of this El Niño is expected to continue into 2016.