Another “Hottest Month on Record” Claim

It’s official. Or, at least official enough for NPR to report it with zero reference to contrary data: “July Was The Hottest Month In Recorded Human History“!

Now, I’ve never been quite sure why “recorded human history” should be such a prominent concern. What about before recorded human history? Historical climatology tells us there were times, before historical recording began but while people were going around doing things people do, that were definitely significantly warmer than the present, like the Holocene Climate Optimum (about 7,000 to 3,000 B.C.), graphed below and discussed by climatologist Judith Curry here, which consisted of “increases of up to 4 °C near the North Pole (in one study, winter warming of 3 to 9 °C and summer of 2 to 6 °C in northern central Siberia).” And, mirabile dictu, humanity survived those times, even though our survival techniques were far less sophisticated than today’s.

But leave that aside for now.

Was this July really “the hottest month in recorded human history”? NPR’s report reproduces, without question, a press release from the National Oceanic and Atmospheric Administration titled “It’s official: July was Earth’s hottest month on record.” (Notice, by the way, NOAA’s failure to qualify the claim by limiting it to “recorded human history.” The folks there undoubtedly know there were much warmer periods in Earth’s history. One can’t help wondering why they chose this false but alarming language.) The press release states:

  • Around the globe: the combined land and ocean-surface temperature was 1.67 degrees F (0.93 of a degree C) above the 20th-century average of 60.4 degrees F (15.8 degrees C), making it the hottest July since records began 142 years ago. It was 0.02 of a degree F (0.01 of a degree C) higher than the previous record set in July 2016, which was then tied in 2019 and 2020.
  • The Northern Hemisphere: the land-surface only temperature was the highest ever recorded for July, at an unprecedented 2.77 degrees F (1.54 degrees C) above average, surpassing the previous record set in 2012.
  • Regional records: Asia had its hottest July on record, besting the previous record set in 2010; Europe had its second-hottest July on record—tying with July 2010 and trailing behind July 2018; and North America, South America, Africa and Oceania all had a top-10 warmest July.

But those data are suspect, because they depend on surface temperature readings compromised by urban heat island effect, unrepresentative spatial distribution, and other problems that compromise their reliability.

More credible are satellite global temperature readings, because they’re not subject to any of those problems. They’re truly global and deal with all altitudes. And those say something quite different. July was not the hottest month in recorded human history, or even close to it.

The graph above, from Dr. Roy W. Spencer’s blog (and Spencer and colleague John Christy are in charge of collecting and archiving the satellite data) shows the actual monthly temperature anomalies. (Full disclosure: Dr. Spencer is a Senior Fellow and Member of the Board of the Cornwall Alliance.) As you can see, almost every month from 2016 to now was warmer than July, and plenty of months in other years from 1998 onward were, and one in late 1987 or early 1988 was.

Trouble is, the satellite data—the most reliable—don’t support the alarmist claims of the UN Intergovernmental Panel on Climate Change and the UN Framework Convention on Climate Change (FCCC), which have the task of getting the world to embrace extremely expensive policies to fight global warming, the next round of such efforts coming up in November at COP26 (26th Conference of the Parties to the FCCC) in Glasgow. So, NPR and lots of other media (here and here and here and here and here and …) dutifully go with the alarming data.

Welcome to “follow the Science”!