Guest essay by Linnea Lueken

NewScientist, a publication dedicated to popularizing science, recently published a post titled “Extreme winter weather isn’t down to a wavier jet stream,” reporting on a new study that shows, the jet stream is not getting wavier in winter months due to climate change. This is true, and it has been evident for some time, but runs counter to assertions commonly made by climate alarmists.

NewScientist writes that “[i]ncreasingly erratic winter weather in the northern hemisphere isn’t a result of the polar jet stream getting more wavy, according to new research . . ..”

Although the vast bulk of the article is devoted to insisting that climate change is causing worsening winter and summer weather, claims regularly debunked at Climate Realism, the publication deserves some credit for reporting the study’s results concerning the jet stream, which was, in fact, the focus of the research itself.

The new reports findings are not actually that “new,” in the sense that Climate Realism has reported on research that came to the same conclusion several times in the past few years, here, here, and here, for instance. There is copious evidence showing that not only are cold snaps not uncommon, but that the jet stream’s (and more specifically, polar vortex) influence on extreme winter weather has been acknowledged since at least 1853. Years of studies looking at the frequency of and intensity of polar vortex events have found no consistent trends. As pointed out by my colleague Anthony Watts in this post on the subject, “a 2021 study in the journal Geophysical Research Letters found no statistically significant increase in jet stream waviness or meandering in recent decades,” and he explains there has never been a consensus among scientists when it comes to the issue of polar vortex/jet stream behavior.

The post at NewScientist goes on to explain the new study, saying “recent erratic behaviour isn’t out of the ordinary,” and that the jet stream has been both wavier and less wavy than it is today.

Unfortunately, that is where the NewScientist and the authors of the paper it was discussing ceased to follow the evidence. One of the study’s authors reassured NewScientist that climate change is still “affecting extreme weather events in all sorts of really important ways,” and that the jet stream is actually becoming wavier in the summertime, “where it is getting slower, with bigger waves, which leads to things like big heatwaves, drought, and wildfires.”

This would be compelling if existing data backed up the claim, but, in fact, big heatwaves, drought, and wildfires have not become more frequent or severe in recent decades. Heatwaves were much more severe in the earlier decades of the 20^th century, and overall drought has been declining while precipitation increases. Now that it is summer, many outlets are attempting to claim that hot weather is driven by climate change. In doing so they almost always ignore where heat records are being set, as it is often at airports and other heat-absorbing locations, and ignore historical records that show hot summers are not unprecedented.

Similarly, data shows that wildfires were worse in the past with research from NASA and the European Space Agency showing that acreage lost to wildfires has declined markedly over the past few decades.

The NewScientist, and the AGU study it references, should have quit when they were ahead. They should have published their unalarming findings about climate change’s lack of an impact on the winter jet stream without then assuring people that despite their study’s findings, they really are true believers and climate change is making weather worse. The latter point is refuted by real world data.