Hottest September on Record Basically "Locks In" 2016 as Hottest Year: NASA

Last month was the hottest September on record, which means 2016 is all but locked into being the hottest year on record, according to new NASA statistics released Tuesday.

"With data now available through September, 2016 annual record (~1.25oC above late 19th [century]) seems locked in," tweeted Dr. Gavin Schmidt, director of NASA's Goddard Institute for Space Studies.

By a narrow 0.004deg C, last month beat out September 2014 to be the hottest September in 136 years of record-keeping, NASA said, in addition to being .91degC warmer than the month's mean temperature from 1951-1980.

It follows several consecutive record-setting periods, including August tying July for hottest month since reliable temperature-measuring instruments started being used, and is also notable for the fact that September is usually the year's low point for carbon emissions--but not this year.

"The record-warm September means 11 of the past 12 consecutive months dating back to October 2015 have set new monthly high-temperature records," a NASA blog post explains, excepting last June, which was initially believed to be the warmest on record but was adjusted to being the third-warmest after additional data came in from Antarctica.

But the run of hot months also includes an unusually warm February, when temperatures were 1.34degC above normal, which, as Climate Central pointed out Monday, is "the closest the world has come to the 1.5degC threshold, which is viewed as an important threshold for the continued existence of a number of small island states."