The global average surface temperature in 2015 is likely to be the warmest on record and to reach the symbolic and significant milestone of?one degree?Celsius above the pre-industrial era due to a combination of a strong El Ni?o and human-induced global warming, the World Meteorological Organization (WMO) said on Wednesday.

The years 2011-2015 have been the warmest five-year period on record, with many extreme weather events - especially heatwaves - influenced by climate change, according to a WMO five-year analysis.

"The state of the global climate in 2015 will make history as for a number of reasons," said WMO Secretary-General Michel Jarraud, adding that levels of greenhouse gases in the atmosphere reached new highs and in the northern hemisphere spring 2015 the three-month global average concentration of CO2 crossed the 400 parts per million barrier for the first time.

"2015 is likely to be the hottest year on record, with ocean surface temperatures at the highest level since measurements began. It is probable that the?one degree?Celsius threshold will be crossed," said Mr Jarraud. "This is all bad news for the planet."

Greenhouse gas emissions, which are causing climate change, can be controlled. We have the knowledge and the tools to act. We have a choice. Future generations will not."

"Added to that, we are witnessing a powerful El Ni?o 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 Ni?o is expected to continue into 2016," said Mr Jarraud.

WMO issued its provisional statement on the status of the climate in 2015, and an additional five-year analysis for 2011-2015, to inform negotiations at the U.N. Climate Change Conference in Paris.

A preliminary estimate based on data from January to October shows that the global average surface temperature for 2015 so far was around 0.73?degrees above the 1961-1990 average of 14.0 degrees?and approximately 1 degree?above the pre-industrial 1880-1899 period.

This temperature tendency indicates that 2015 will very likely be the warmest year on record. The global average sea-surface temperature, which set a record last year, is likely to equal or surpass that record in 2015. The global average temperatures over land areas only from January to October suggest that 2015 is also set to be one of the warmest years on record over land. South America is having its hottest year on record, as is Asia (similar to 2007), and Africa and Europe their second hottest.

According to preliminary figures as of the end of September 2015, 2011-2015 was the world's warmest five-year period on record, at about 0.57 degrees?above the average for the standard 1961-1990 reference period. It was the warmest five-year period on record for Asia, Europe, South America and Oceania, and for North America.