Mainstream media the world over breathlessly report that scientists say July 2016 was the “hottest” month in the global temperature record stretching back to 1880 (or as CNN wrongly reported, “ever”)! And future Julys will only become hotter! Repent, the end is near!
Or maybe not. Consider:
First, for most of the world, whether land or sea, raw data were nonexistent for most of the period before, roughly speaking, the 1960s, making precise claims about global temperature before then tenuous.
Second, from then until 1979, when satellite measurements became available, for most of the world, land or sea, raw data were not geographically randomly distributed and therefore not statistically representative, making the claims still more tenuous.
Third, NOAA and NASA have been busily “homogenizing” raw data over the last few years, the rather suspicious result of which is an almost universal lowering of older readings and raising of later readings, augmenting the apparent rise in temperature. That homogenizing has resulted, for instance, in masking the fact that the raw data show that in the continental U.S. the 1930s were significantly warmer and had far more record high temperatures than the present (and data for most of the rest of the world are far less comprehensive and accurate than the [still not very comprehensive and accurate] data for the U.S.).
Fourth, according to the satellite data—our most comprehensive and least subject to contamination—the claim is false.
The claim is that July was the “hottest month”—not just the hottest July—on record, going all the way back to 1880. That’s much more expansive and therefore much easier to refute than the claim that it’s the hottest July since 1979, so if the latter’s false, the former must be, too.
Here are the July temperature anomalies (departures in ˚C from the 1981–2010 average) according to the UAH satellite data for the period:
So July 2016 isn’t even the warmest July on record, even stretching back only to 1979. The record month was July 1998—in a year made abnormally warm by the same thing that’s making 2016 abnormally warm, an abnormally strong El Niño.
All those caveats aside, I have no objection to granting the claim that July 2016 was the warmest July, or even the warmest month, since records began in the 1880s, but that’s really not significant. Why?
- In the early 1800s the world started rising out of the Little Ice Age, and when one climbs for a while and reaches a plateau, it’s mathematically certain that one’s altitude (or in this case temperature) will remain at or around that plateau until one either resumes ascending or begins descending, so record highs are no big surprise.
- The margin by which July 2016 is warmer (a more realistic term than “hotter”) than the near runners-up is so tiny as to be utterly without impact on human or other life on earth.
- The entire spread between the “hottest” and “coldest” Julys in the satellite record is 1.2˚C, and I dare you to find someone who will step from a room at 15˚C (59˚F) to a room at 16.1˚C (60.98˚F) and, unrehearsed, say “Ugh, this room is hotter!” (as distinct from mildly warmer). So much of this controversy is rooted in overblown rhetoric!
- And the difference between July 2016 (0.39˚C) and the next- (meaning third-) hottest July (2010) is only 0.06˚C. That’s indiscernible to humans and, for that matter, not really measurable—though calculable, but well under the measurement margin of error—for the globe as a whole.
Ah, but scientists say future Julys will only become hotter!
So what? Either they have a crystal ball, or they claim divine inspiration (which might be a little difficult for the atheists among them), or they’re talking through their hats.
Nobody knows what future temperatures will be. Even the Intergovernmental Panel on Climate Change said in its Third Assessment Report, “The climate system is a coupled non-linear chaotic system, and therefore the long-term prediction of future climate states is not possible” (emphasis added).
“Future Julys will only become hotter”? That means the ups and downs evidenced in the 37-year satellite record will stop. How likely do you think that is? It means we’ll get only ups—every single year, on into the indefinite future. There will be no more “little ice ages” driven by solar minima, or glacial periods driven by Milankovich cycles, or any other such thing. How likely do you think that is?
We’re not done yet. How does July’s temperature anomaly (Can you imagine how much less alarming these announcements would be if couched in such language?) fit into the broader history of global temperature?
It depends on how far back you want to go. For the satellite record, you’ve got the entire record for Julys above, and you can see for yourself: it’s hardly significant. For the land and sea surface temperature record back to 1880, sure, maybe it’s warmer, by perhaps 1˚C, than at the start of the period (not than the next-warmest month), but so what? Temperature changes by ten or twenty times that from low to high on any given day in many locales around the world, and by sixty to eighty times that from winter low to summer high.
Since the end of the last glacial period (~18,000 years ago), it’s much warmer than at the start (thank God!), but much cooler than the Holocene Climate Optimum (~9,000–5,000 year ago) and probably cooler than the Minoan (~3,000 years ago) and Roman (~2,000 years ago) warm periods and almost certainly cooler than the Medieval Warm Period (~950–1250 a.d.).
Finally, in the debate over the magnitude of the human contribution to global warming, this is utterly irrelevant. A 0.06˚C difference is a 0.06˚C difference whether caused by turning on an electric stove burner a half second ago or natural solar and ocean cycles over thousands or millions of years or adding CO2 to the atmosphere for the last two centuries.
To argue, “If doubling atmospheric CO2 concentration raises global average temperature by x˚C over 100 years then July 2016 should be 0.06˚C warmer than July 2010; July 2016 is 0.06˚C warmer than July 2010; therefore doubling atmospheric CO2 concentration raises global average temperature by x˚C over 100 years” is to commit the fallacy of affirming the consequent (if x, then y; y; therefore x). That’s a fallacy because there could be other causes of y than x. And in this case we know for sure from long-term temperature history that there are plenty of causes for y (global warming) other than x (rising atmospheric CO2 concentration).
So cool it, folks. Don’t get sucked in by the rhetorical hype. Enjoy a mint julep, hug your kids, and get on with life, remembering God’s promise: “While the earth remains, seedtime and harvest, cold and heat, summer and winter, day and night, shall not cease” (Genesis 8:22).