Global average surface temperature anomalies during the month of September. Image: Japan Meteorological Agency
It’s virtually certain that in January 2016, the planet will set a new record for the warmest calendar year on record. A key data set that tracks global average surface temperatures, which comes from the Japan Meteorological Agency, shows a huge jump in temperatures in September as compared to average. Related data compiled by NASA and analyzed using different methods shows that September was most likely the second warmest such month on record, and that there is at least a 93% likelihood of setting the record for the warmest year this year. The data from the Japan Meteorological Agency is striking, since it shows that September 2015 blew the previous record for the warmest such month out of the water by 0.15 degrees Celsius (0.27 degrees Fahrenheit). September had a temperature anomaly of 0.50 degrees Celsius (0.9 degrees Fahrenheit), compared to the 1981-2010 average. The previous record-holder for the warmest September since such data began in 1891 was last year, September 2014. This may seem like quibbling over very small differences, but consider that the discrepancy between the planet we know today and a planet with virtually zero ice cover in Greenland and Antarctica is about 10 degrees Fahrenheit, for a global average.
In short, big changes can occur as a result of relatively small differences in global average temperatures. Typically, global average temperature records — whether they’re months or years — are exceeded by far smaller margins. For example, the difference between the third warmest September and the fourth warmest September in the data set was just 0.1 degree Celsius (0.18 degrees Fahrenheit)….