The World Meteorological Organization’s (WMO) statement on the status of the global climate says that 2013 was one of the warmest years on the earth since the late 1800s, when global recordkeeping began. The Status of the Climate Report also says the 14 warmest years on record have all occurred in the 21st century, and each of the last three decades has been warmer than the previous one. NOAA made similar observations in its 2013 global analysis. The WMO report is based on an analysis of three datasets, including two maintained by NOAA’s National Climactic Data Center and NASA’s Goddard Institute for Space Studies.
In a press release, WMO Secretary General Michel Jerraud said, “Naturally occurring phenomena such as volcanic eruptions or El Niño and La Niña events have always contributed to frame our climate, influenced temperatures or caused disasters like droughts and floods. But many of the extreme events of 2013 were consistent with what we would expect as a result of human-induced climate change.”
The report also includes a case study of Australia’s record 2012-2013 summer temperatures comparing climate model simulations with and without human factors. The case study concludes it is “five times as likely” that the record heat was a result of human-induced climate change.