The main purpose of this ongoing blog will be to track planetary extreme, or record temperatures related to climate change. Any reports I see of ETs will be listed below the main topic of the day. I’ll refer to extreme or record temperatures as ETs (not extraterrestrials).😉
Main Topic: Planetary Wave Changes Linked to Wild Summer Weather Have Tripled Since 1950, Study Finds
Dear Diary. If you have been following me along for the last few years, you will note that I produce a lot of posts delving into planetary resonance or warm ridge/cold trough patterns in association with the jet stream as it is influenced by climate change. During the summer we are tending to get a wavier jet stream with stronger and more persistent ridges or heat domes, which lead to extreme heatwaves. This is Dr. Michael Mann’s current area of work. On the periphery of heat domes we are witnessing more flooding, such as the awful July 4th Texas floods. During the winter we see this effect as well, but here at least for the next couple of decades more warmth from lower latitudes will be interacting with what is left of the polar vortex, so occasionally we see strong amplification that can lead to mega cold outbreaks from the Arctic. This is Dr. Jennifer Francis’ area of work.
Now a new study has strengthened these hypotheses. Here is more from the Associated Press:
Planetary waves linked to wild summer weather have tripled since 1950, study finds
Survivors wade through water in their Khairpur Nathan Shah, Pakistan, on NOV, 2nd 2010, which is surrounded by floodwaters. (AP photo/Shakil Adl, File)
Updated 4:51 PM EDT, June 16, 2025
WASHINGTON (AP) — Climate change has tripled the frequency of atmospheric wave events linked to extreme summer weather in the last 75 years and that may explain why long-range computer forecasts keep underestimating the surge in killer heat waves, droughts and floods, a new study says.
In the 1950s, Earth averaged about one extreme weather-inducing planetary wave event a summer, but now it is getting about three per summer, according to a study in Monday’s Proceedings of the National Academy of Sciences. Planetary waves are connected to 2021’s deadly and unprecedented Pacific Northwest heat wave, the 2010 Russian heatwave and Pakistan flooding and the 2003 killer European heatwave, the study said.
“If you’re trying to visualize the planetary waves in the northern hemisphere, the easiest way to visualize them is on the weather map to look at the waviness in the jet stream as depicted on the weather map,” said study co-author Michael Mann, a University of Pennsylvania climate scientist.
Planetary waves flow across Earth all the time, but sometimes they get amplified, becoming stronger, and the jet stream gets wavier with bigger hills and valleys, Mann said. It’s called quasi-resonant amplification or QRA.
This essentially means the wave gets stuck for weeks on end, locked in place. As a result, some places get seemingly endless rain while others endure oppressive heat with no relief.
“A classic pattern would be like a high pressure out west (in the United States) and a low pressure back East and in summer 2018, that’s exactly what we had,” Mann said. “We had that configuration locked in place for like a month. So they (in the West) got the heat, the drought and the wildfires. We (in the East) got the excessive rainfall.”
“It’s deep and it’s persistent,” Mann said. “You accumulate the rain for days on end or the ground is getting baked for days on end.”
The study finds this is happening more often because of human-caused climate change, mostly from the burning of fossil fuels, specifically because the Arctic warms three to four times faster than the rest of the world. That means the temperature difference between the tropics and the Arctic is now much smaller than it used to be and that weakens the jet streams and the waves, making them more likely to get locked in place, Mann said.
“This study shines a light on yet another way human activities are disrupting the climate system that will come back to bite us all with more unprecedented and destructive summer weather events,” said Jennifer Francis, a climate scientist at the Woodwell Climate Research Center who wasn’t involved in the research.
“Wave resonance does appear to be one reason for worsening summer extremes. On top of general warming and increased evaporation, it piles on an intermittent fluctuation in the jet stream that keeps weather systems from moving eastward as they normally would, making persistent heat, drought, and heavy rains more likely,” Francis said.
This is different than Francis’ research on the jet stream and the polar vortex that induces winter extremes, said Mann.
There’s also a natural connection. After an El Nino, a natural warming of the central Pacific that alters weather patterns worldwide, the next summer tends to be prone to more of these amplified QRA waves that become locked in place, Mann said. And since the summer of 2024 featured an El Nino, this summer will likely be more prone to this type of stuck jet stream, according to Mann.
While scientists have long predicted that as the world warms there will be more extremes, the increase has been much higher than what was expected, especially by computer model simulations, Mann and Francis said.
That’s because the models “are not capturing this one vital mechanism,” Mann said.
Unless society stops pumping more greenhouse gases in the air, “we can expect multiple factors to worsen summer extremes,” Francis said. “Heat waves will last longer, grow larger and get hotter. Worsening droughts will destroy more agriculture.”
____
The Associated Press’ climate and environmental coverage receives financial support from multiple private foundations. AP is solely responsible for all content. Find AP’s standards for working with philanthropies, a list of supporters and funded coverage areas at ap.org.
Borenstein is an Associated Press science writer, covering climate change, disasters, physics and other science topics. He is based in Washington, D.C.
Here are more “ET’s” recorded from around the planet the last couple of days, their consequences, and some extreme temperature outlooks, as well as any extreme precipitation reports:
Here is More Climate News from Sunday:
(As usual, this will be a fluid post in which more information gets added during the day as it crosses my radar, crediting all who have put it on-line. Items will be archived on this site for posterity. In most instances click on the pictures of each tweet to see each article. The most noteworthy items will be listed first.)