Two bloggers have made a stunning claim that has spread like wildfire on the Internet: They say the Northern Hemisphere jet stream, the high-altitude river of winds that separates cold air from warm air, has done something new and outrageous. They say it has crossed the equator, joining the jet stream in the Southern Hemisphere. One said this signifies that the jet stream is ‘wrecked’, the other said it means we have a “global climate emergency”.
But these shrill claims have no validity — air flow between the hemispheres occurs routinely. The claims are unsupported and unscientific, and they demonstrate the danger of wild assertions made by non-experts reaching and misleading the masses.
The two bloggers who have perpetuated this misinformation are Robert Scribbler, who describes himself as “a progressive novelist, non-fiction writer and emerging threats expert,” and Paul Beckwith, who is working on a PhD with “a focus on abrupt climate system change” at the University of Ottawa.
Scribbler says the cross-equator flow is a manifestation of man-made global warming, supported by the hypothesis that disproportionate heating of the Arctic is destabilizing the jet stream. “The Hemispherical Jet Streams have moved out of the Middle Latitudes more and more,” he writes. “More and more it has invaded regions both within the Polar zone and within the Tropics. Now, it appears that the old dividing lines are so weak that flows of upper level air between Hemispheres can be exchanged.”
He concludes that this “violation of dividing lines” is “a kind of weather weirding that we are not at all really prepared to deal with”.
Beckwith writes that the jet stream behaviour is “unprecedented” and represents “climate system mayhem”: “Our climate system behaviour continues to behave in new and scary ways that we have never anticipated, or seen before. . . . We must declare a global climate emergency.”
I reached out to several atmospheric scientists, who have graduate degrees and are trusted sources in the profession, for their reaction to these claims. Without exception, they said air flow between the hemispheres is not at all uncommon.
“This is total nonsense,” said Cliff Mass, a professor of meteorology at the University of Washington. “Flow often crosses the equator.”
Mass added that the cross-equator flow identified by Scribbler and Beckwith is not between mid-latitude jet streams, as claimed. “The analysis is making mistakes that even one of my junior undergrads would not make,” Mass said.
Ryan Maue, a senior meteorologist with a doctoral degree who works at WeatherBell Analytics, agreed with Mass that the cross-equator flow is totally normal and not evidence of a joint hemispheric jet stream. “Cross-equatorial flow at both upper and lower levels is part of the seasonal transition of the Western Pacific monsoon through boreal summer,” he said.