2015 was almost certainly the hottest year since we began keeping records, according to data released Wednesday by NASA and the National Oceanic and Atmospheric Administration. In a press release Wednesday, NASA stated that it was 94 percent confident that last year was the warmest since 1880.
http://www.citylab.com/weather/2016/01/confirmed-2015-was-the-hottest-year-on-record/424875/
http://www.citylab.com/weather/2016/01/confirmed-2015-was-the-hottest-year-on-record/424875/