Climate Letter #1868

In yesterday’s letter I delivered my own explanation of how the breakdown of the polar vortex in the stratosphere over the North Pole could translate into severe deformation of the high-altitude air pressure configuration (HAPC) that exists in the upper part of the troposphere. A map of the HAPC revealed how badly splintered it has actually become. In fact if you refer back to letters of a month or two ago, before the vortex breakdown occurred, you can find imagery of a much more compact sort. You can also refer to the Weather Maps website and check out the current HACP in the SH, which has loosened up a little because of a modest level of summer warmth, and see how compact the image is at that end of the world. (For a still different perspective, go back to some of last year’s letters composed when it was summer in the NH and compare the HAPC maps of those times to the summer-SH maps of today. Bear in mind that vortex breakdown is only a wintertime phenomenon. Something else, most likely due to extreme and persistent heating of surface air, was needed to explain the exceptional HAPC deterioration in the NH last summer.)

Yesterday I also delivered a quick summary, absent any illustrations, describing the ordinary processes through which the splintering of the HAPC is likely to be translated step-by-step into an array of severe temperature anomalies at Earth’s surface, as illustrated. Variations in the local level of high-altitude precipitable water (PW) was named as the key factor behind the expression of both hot and cold anomalies at the surface. Those local variations in PW readings were said to be the result of a haphazard jetstream formation that was in turn governed by the pattern of air pressure gradients as they actually existed while slowly changing. Many recent letters explain these processes more fully, with detailed illustrations, which I promise will continue.

Last year I used the same processes as a way of explaining summer heatwaves occurring in Siberia, persistent heating of temperatures over the Arctic Ocean in the fall, and many other anomalies of various sorts, often referring to water vapor as the primary producer of greenhouse effects rather than more broadly-based PW.  The latter is now standard, based on the practical aspects of combining the greenhouse effects of water vapor with those of cloud bodies into a single unified force.  Doing so takes advantage of the existing long-term database of PW measurements that is updated daily and all mapped out, allowing simple comparisons to be made with temperature anomaly data provided in the exact same mode of reference. A surprising amount of consistency is the result, enabling certain rules to be spelled out with reference to observed changes in PW, by doubling for example.

One might now be asking, how scientific is this explanation?  What do scientists have to say, for instance, when identifying and appraising a variety of factors behind the amplified warming commonly experienced in the Arctic?  A new study has just been published by a leading journal, Nature Climate Change, which deals directly with this subject. According to a review and commentary of the study, available at this link, https://phys.org/news/2021-02-arctic-amplified.html, no reference is made to either water vapor or PW, or to any of the high-altitude processes I have described. The study itself, or abstract alone, is not yet available for reading but the review seems to cover everything the authors wanted to spotlight.   You should read it and see how far apart these views are from mine, and I believe they are typical of the science community at large. I don’t think they are wrong, as far as they go, just missing a big part of the story.

Carl