We recently turned the calendar over to a new year, which provides us an opportunity to analyze last year’s climate rankings. According to Dr. Roy Spencer, a renowned climate researcher at the University of Alabama in Huntsville (UAH), the temperature of the lower troposphere in 2017 registered a positive anomaly of 0.38°C. This measurement originated via satellite recordings that began in the 1970s and uses 1981-2010 as a baseline. According to Spencer, at +0.38°C, 2017 ranks as the third-warmest year (2016 and 1998 were both higher).

Similarly, the California-based Remote Sensing Systems company, whose niche is “specializing in satellite microwave remote sensing,” says based on its analysis that “the lower troposphere [in] 2017 was the second warmest recorded since satellite observations began in 1979.” Both the UAH and RSS computations take into account a 39-year satellite history. This is very important, as we’ll explain.

On Thursday, NASA asserted that “Earth’s global surface temperatures in 2017 ranked as the second warmest since 1880.” More specifically, “Globally averaged temperatures in 2017 were 1.62 degrees Fahrenheit (0.90 degrees Celsius) warmer than the 1951 to 1980 mean.” Strangely, even the libertarian site Reason ran with the headline, “2017 Was the Second Hottest Year Since 1880, Says NASA.” It’s true that the NASA ranking is similar if not identical to the satellite reports, but it’s incredibly deceptive to pretend they mean the same thing.

It’s one thing to compare more modern satellite temperatures and quite another to make concrete claims that are heavily dependent on logs from 100-plus years ago. Satellite measurements — the most reliable tool we have — went into commission in the late 1970s. On the other hand, NOAA is taking us all the way back to 1880, when satellite data was nonexistent. Anyone who claims that global climate data from then up until the satellite era is anywhere close to factual is delusional. Moreover, NASA is utilizing revisionist temperature data along with very spurious methodology. So next time you hear “It’s the hottest year since…” remember, it’s all relative. And if government data is involved, it’s most likely based on highly unsubstantiated claims.