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If you fancy a chilly dip

07 Apr 2021 | OP ED Watch

Roy Spencer reports that “The Version 6.0 global average lower tropospheric temperature (LT) anomaly for March, 2021 was -0.01 deg. C, down substantially from the February, 2021 value of +0.20 deg. C.” You don’t say. But he does, including a graph that shows that, in what will doubtless be declared the “hottest year ever” long before it ends, it’s currently colder than it was in, um, 1988. Of course some people might express skepticism about the hundredth of a degree and those people would be us. But the point is, if you’re going to take satellite measurements seriously, you have to take satellite measurements seriously even when they don’t say what you wanted them to.

Including the warmer one for February, of course. Which Spencer does. His overall verdict is that “The linear warming trend since January, 1979 remains at +0.14 C/decade (+0.12 C/decade over the global-averaged oceans, and +0.18 C/decade over global-averaged land).” And again one might squirm at the second decimal place, or even the first, although to be fair it is what can happen if you take a number and divide it by another number even if both of them do not have decimal places.

For instance one divided by seven legitimately is .1428571428571429 and then some. So if you had good reason to think the planet had warmed by 1 degree over 7 decades you could claim it had warned 0.14 degrees per decade. And there’s no real issue with seven decades being 70 years. It’s the degree that’s an issue. And if you think it warmed by about a degree, well, saying it warmed about 0.14 degrees per decade is a bit weak.

What’s not an issue, and should be, is that a lot of people really think that satellites are measuring global temperature continuously, exhaustively and accurately. (One angry commentator told us if we doubted it to go and look at Google Earth and we’d find that it had a picture of our back yard. Which it did… except a photo at one moment in time, and in this case years old, is not the same thing as a temperature series over time.) Satellite readings are one of two things people generally point to when they claim we know the planet is warming, along with thermometer data from reliable historical series like those in the United States that is then regrettably massaged by government agencies to show warming where none may exist.

As for satellite data, well, it too involves a lot more steps than just sticking it under Gaia’s tongue, waiting a minute then reading the little red or silver line. The satellites read radiation reaching them up there in space then computers perform complex manipulations to infill, correct and estimate temperatures we are subsequently told are rock-solid approximations. And if you say so when they show warming then, since Spencer’s are among the best out there, you have to believe that temperatures are falling whatever the long term trend may be.

OK, there’s another issue. Temperature could have risen by a degree over seven decades because it went up by roughly the same amount each decade. Or it could be fluctuating wildly in a process that is “a coupled non-linear chaotic system (see page 6 in this document, numbered page 774), and therefore the long-term prediction of future climate states is not possible.” At which point the decimal places cease even to distract. Spencer, for instance, suggests that La Niña is behind this particular drop.

Still, let us try to start with consistency. Do you believe in the satellite readings or not? If you do, March 2021 was chilly. Colder than the 30-year average. And there must be some reason for it.

3 comments on “If you fancy a chilly dip”

  1. Professor Roy Spencer checks satellite measurements against weather balloons to confirm the accuracy of his data.
    When taking hundreds of accurate measurements decimals are certain to occur.
    This is confirmed in his peer reviewed paper.
    Michael Mann, of course, claimed, in an interview, that this paper had been debunked. NOT TRUE.

  2. “The linear warming trend since January, 1979 remains at +0.14 C/decade (+0.12 C/decade over the global-averaged oceans, and +0.18 C/decade over global-averaged land).” Ummm... Wasn't there a cooling trend from the 1940s to the 1970s that had people believing a new ice age was imminent? Pardon me if I'm suspicious of a 'trend' that begins in 1979.

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