2010s hottest decade in history, UN says as emissions rise again (AFP) This decade is set to be the hottest in history, the United Nations said Tuesday [Dec.3rd] in an annual assessment outlining the ways in which climate change is outpacing humanity’s ability to adapt to it. The World Meterological Organization said global temperatures so far this year [2019] were 1.1 degrees Celsius (two degrees Fahrenheit) above the preindustrial average between 1850-1900.