For those still unconvinced about the reality of climate change, the year that just ended should erase any doubt. Climate data from the air, land and water all reveal an indisputable portrait of a warming world.
On Wednesday, the National Oceanic and Atmospheric Administration and NASA jointly announced that 2015 was the warmest year on record for the planet. The previous record, set just 12 months ago in 2014, wasn't merely broken, it was smashed.
There's a saying that numbers numb and stories sell, but the latest climate numbers tell a story that is stunning.
Including 2015, 15 of the 16 warmest years in NOAA's 136-year climate record have occurred since 2000. And 2015 marks the 39th consecutive year, dating to 1977, in which global temperatures have been above the 20th-century average.
In the past two decades, the Earth's temperature has surged to new highs six times - in 2015, 2014, 2010, 2005, 1998 and 1997 - while the last record-cold year was 1908.