This year is likely to be the hottest ever, according to the World Meteorological Organisation (WMO).
Human-induced global warming and the strong El Nino in the Pacific mean the average surface temperature of the earth in 2015 is likely to be the warmest on record.
The organisation announced that temperatures are now one degree higher than they were, compared to pre-industrial levels, describing the change as "all bad news for the planet".
The warning comes ahead of landmark climate talks in Paris at the end of this month, when world leaders are expected to agree on measures to stop temperatures rising beyond key measures.