The three hottest years on record—2014, 2010 and 2005—have occurred in the last 10 years. The odds of that happening randomly are 3,341 to 1, calculated John Grego of the University of South Carolina. Kai Zhu of Stanford University, Robert Lund of Clemson University and David Peterson, a retired Duke statistician, agreed.

Nine of the 10 hottest years on record have occurred in the 21st century. The odds of that being random are 650 million to 1, the statisticians said.

Thirteen of the 15 the hottest years on record have occurred in the last 15 years. The odds of that being random are more than 41 trillion to 1, the statisticians said.

All 15 years from 2000 on have been among the top 20 warmest years on record. They said the odds of that are 1.5 quadrillion to 1. A quadrillion is a million billion.

And then there's the fact that the last 358 months in a row have been warmer than the 20th-century average, according to NOAA. The odds of that being random are so high—a number with more than 100 zeros behind it—that there is no name for that figure, Grego said.