This year has a decent shot at becoming No. 1 in records dating to 1880, based on U.S. data.
Last month was the warmest August on record worldwide – temperatures were 1.35 degrees above the 20th Century average of 60.1 Fahrenheit – according to the National Climatic Data Center. (The NCDC margin of error = plus or minus 0.22 degrees.)
Thus, the first eight months of 2014 moved into third place among all December-August periods over the past 135 years, by the NCDC's count.
Through August, the 2014 global temperature was about 58.5 degrees, or 1.22 above that 20th Century average, or 0.04 degrees shy of the eight-month co-leaders, 1998 and 2010.
In the government database, 2010 went on to become the warmest year, despite the fact that an El Nino, the large-scale warming of surface waters in the tropical Pacific, gave way to La Nina, or cooling.
The warming pace did slow down later that year, and the Sept. 1-Dec. 31 period was only the ninth-warmest such period on record.
As a result, the year finished at 1.19 degrees above the annual average, a figure technically called "the anomaly."
As for 1998, after a record El Nino dissipated, the last four months came in at a tepid No. 15, and the year finished at No. 3. That allowed 2005, with the warmest last four months on record, to sneak in to No. 2.
For 2014 not to become the new champ, the warming rate will have to slow some, and the September-December numbers will have to drag down the annual anomaly by 0.04 degrees.
Such change is certainly possible, but it has happened in only about one-third of the years in the period of record.
And if the forecasts calling for the likelihood of El Nino work out, however, that's unlikely to happen this year.
The list of the top 30 warmest years is utterly dominated by the modern era, but that shouldn't be too surprising given the generally plodding pace of global temperature change.