It continues a pattern of high temperatures blamed directly on man-made climate change.
All of the warmest years have been since 1998, and this year once again continues the underlying, long-term trend. The coldest years now are warmer than the hottest years before 1998.
Atmospheric concentrations of carbon dioxide and other greenhouse gases reached new highs in 2012, and are expected them to reach unprecedented levels by the end of 2013.