A weaker, wavier jet stream allows Arctic air to spill south to midlatitudes. NASA/GODDARD SPACE FLIGHT CENTER SCIENTIFIC VISUALIZATION STUDIO

Landmark study casts doubt on controversial theory linking melting Arctic to severe winter weather

From Science

Every time severe winter weather strikes the United States or Europe, reporters are fond of saying that global warming may be to blame. The paradox goes like this: As Arctic sea ice melts and the polar atmosphere warms, the swirling winds that confine cold Arctic air weaken, letting it spill farther south. But this idea, popularized a decade ago, has long faced skepticism from many atmospheric scientists, who found the proposed linkage unconvincing and saw little evidence of it in simulations of the climate.

Now, the most comprehensive modeling investigation into this link has delivered the heaviest blow yet: Even after the massive sea ice loss expected by midcentury, the polar jet stream will only weaken by tiny amounts—at most only 10% of its natural swings. And in today’s world, the influence of ice loss on winter weather is negligible, says James Screen, a climate scientist at the University of Exeter and co-leader of the investigation, which presented its results last month at the annual meeting of the European Geosciences Union. “To say the loss of sea ice has an effect over a particular extreme event, or even over the last 20 years, is a stretch.”

The idea that Arctic sea ice loss could influence midlatitude winter weather first gained traction in 2012, in a paper by two climate scientists, Jennifer Francis, now at the Woodwell Climate Research Center, and Stephen Vavrus at the University of Wisconsin, Madison. It started with a simple observation: The Arctic is warming nearly three times faster than the rest of the world. At the time, sea ice loss was thought to be the primary accelerant for this amplification: As bright, reflective ice is replaced by dark, sunlight-absorbing water, the Arctic heats up, causing more ice loss, and more warming in turn.

The warming, Francis and Vavrus proposed, would inflate the height of the polar troposphere—the lowest layer of the atmosphere and home to its weather. That would decrease the pressure differences between polar and midlatitude air that drive the polar jet stream, which separates the air masses and keeps cold air collared around the pole. The jet would grow weaker and wavier, allowing cold air to intrude farther south. In their paper, Francis and Vavrus argued such a trend was visible in weather records and worsening with Arctic warming and ice loss.

A lot has changed since then, Francis now says. “Like all things, as you dig into them, they become more complicated.” Most significantly, the 25-year trend that she and others had identified in observations from the late 1980s to early 2010s has weakened after another decade of observations. Although sea ice loss has continued, there are few signs of colder winters in Eurasia or North America, more cold extremes, or more frequent weakening or waviness in the jet stream. The new computer modeling matches the observations, says Doug Smith, a climate scientist at the United Kingdom’s Met Office and another co-leader of the modeling effort. “There’s not an inconsistency.”

In the yearslong investigation, called the Polar Amplification Model Intercomparison Project (PAMIP), researchers ran more than a dozen climate models 100 times each. One set of model runs simulated the Arctic atmosphere without pronounced sea ice loss, using ocean temperatures and sea ice extent from 2000. The other kept the ocean temperatures the same, but reduced the ice coverage to the extent expected decades from now, after 2°C of global warming, when the Arctic could be ice free in the summer. Keeping the oceans the same should highlight the influence—if any—of sea ice loss.

In addition to finding only a tiny effect of sea ice loss on the polar jet stream, the models also found no coherent sign of a second proposed effect of reduced sea ice: more frequent disruptions of the stratospheric polar vortex—a second set of swirling winds, much higher up. Such disruptions, which occur every 2 years on average, ultimately allow cold air lower in the atmosphere to spill southward, causing extreme winter storms, including the cold that gripped Texas this past winter.

Full article here.

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May 13, 2021 2:26 am

How can we move things forward without depending on models. Models are so often wrong, that we can’t really rely on them for anything. Even if we “like” a model’s “findings”, that doesn’t make them right.

David Guy-Johnson
Reply to  Mike Jonas
May 13, 2021 3:01 am

Models are virtually 100% reliable when you understand what you are modelling. As we don’t fully understand how our atmosphere works……………. I leave you to complete the sentence

Reply to  David Guy-Johnson
May 13, 2021 5:01 am

Even if you could say we understood the atmosphere as well as possible it would be impossible to accurately model the climate. The evidence comes from climate science itself.

Edward Norton Lorenz postulated chaos theory as a result of his observation that the climate is so exquisitely sensitive to initial conditions that the slightest change in the inputs to a climate model completely change the model’s output. It’s called the Butterfly Effect.

Reply to  commieBob
May 13, 2021 8:19 am

In this case, they aren’t modeling the climate, just trying to model how the atmosphere flows around the artic over short periods of time. Still a complex problem, but a lot simpler than trying to model the entire climate.

Alan M
Reply to  David Guy-Johnson
May 13, 2021 6:06 am

Wow that leaves a lot open. Having worked in the resources industry modelling geological deposits for over 30 yrs I’m not really sure how to answer that. However we always followed the premise that ” All models are wrong, but some are useful” and I think I’ll stick with that

Reply to  David Guy-Johnson
May 13, 2021 12:39 pm

The generic term ‘Model‘ can apply to many things tbh (Conceptual Disparities).
I authorise different models for my job & after tasking a modeller decades ago he asked what output did I want or expect; every time since then I am wary of all modes.
George Box attributed quote: All models are wrong” is a common aphorism in statistics; it is often expanded as “All models are wrong, but some are useful“, and I’ve added ‘…and some are dangerous“!
Recently we are doing modelling of equipment support, and looking at the input the modeller started with reminded me also of: Garbage in, Garbage Out (GIGO) the concept that flawed, or nonsense input data produces nonsense output or “garbage“. Sometimes Rubbish In, Rubbish Out (RIRO) is used.
So we’ve been amending the input, but being a complex system I’m talking about, this model can be improved but never be 100% (even just MTBF is a calculation & rarely we’ve found match reality well) in the timescales we have.
But customers love them & my modeller this time who said before joining us he helped in some of the current world scenario agreed, even if you write in a presentation & in flashing lights ‘This Model is Preliminary‘ analysis ‘no one’ remembers and consider the model(s) correct!
They can be reliable yes, but also they can be reliably wrong! …unless you fully under the system you are modelling & have ‘infinite’ resources to keep refining the model.

William Capron
Reply to  Mike Jonas
May 13, 2021 6:25 am

Every time I see “model say” I think of “ancient alien theorists say” and the gag-reflex kicks in.

Reply to  William Capron
May 13, 2021 8:21 am

Every time I hear the word “model”, I think of Christie Brinkley, and I end up ignoring the rest of what you have to say.

Jon R
Reply to  William Capron
May 14, 2021 5:01 pm

Hey watch out there Ancient Aliens is my favorite show buddy.

Reply to  Mike Jonas
May 13, 2021 8:38 am

The US State Department, under John Kerry and Antony Blinken, have developed a model of how the world is supposed to work politically… and usher in the Great Reset. And political scientists have determined that Climate Hysteria is the control knob. The climate model, CMIP6, is tied directly into this State Department political model and it is called PIMP6. 🙂

Clyde Spencer
Reply to  Mike Jonas
May 13, 2021 9:39 am

These models are computer implementations of complex hypotheses. The Scientific Method requires that falsifiable hypotheses be validated against reality, specifically attempting to invalidate the null-hypothesis. If the model is found to be wrong, it needs to be rejected and either completely replaced, or modified to correct the problem(s). Computer modelers seem to pay little attention to this crucial step! To move forward, modelers have to have their feet held to the fire of validation!

Reply to  Mike Jonas
May 13, 2021 10:08 am

The only models worth looking at are the ones with arms, legs, etc. and I don’t listen to most of them either.

T Gannett
Reply to  Mike Jonas
May 13, 2021 2:22 pm

All models are false, some are useful.

Reply to  Mike Jonas
May 13, 2021 5:36 pm

“…One set of model runs…”


Bernard Anderson
May 13, 2021 2:40 am

I think that when cold air flows out of the Arctic it is replaced by warmer air which may melt more ice than otherwise. So it is cold weather down south that leads to more melted ice.

Gerald Machnee
Reply to  Bernard Anderson
May 13, 2021 6:11 am

In the winter it is not cold enough to melt the ice.

May 13, 2021 2:46 am

Which brings us back to my long standing proposition that the changes in jet stream meridionality are solar induced as a result of varying solar effects on the ozone creation/ destruction balance in the stratosphere and mesosphere.
I was an early critic of the theory from Jennifer Francis et al.

Gerry, England
Reply to  Stephen Wilde
May 13, 2021 6:25 am

HH Lamb pointed out that the meridional jet stream occurs during solar minimums back in the 1950s.

Reply to  Gerry, England
May 13, 2021 7:20 am

Yes, and he was right.

Joseph Zorzin
May 13, 2021 2:50 am

“researchers ran more than a dozen climate models 100 times each”
Maybe if they run the models 1,000 times they’ll find the truth!

Richard (the cynical one)
Reply to  Joseph Zorzin
May 13, 2021 5:36 am

After running a particular model more than once (and finding the same wrong answer each time), maybe running 100 models more than a dozen times, and creating an consensus of 97% of them would give a result more in line with the desired outcome.

Timo, not that one
Reply to  Richard (the cynical one)
May 13, 2021 12:23 pm

would give a result more in line with the desired outcome.”

lyn roberts
Reply to  Joseph Zorzin
May 13, 2021 4:02 pm

Definition of insanity by Einstein is “doing the same thing over and over and expecting different results”, I think fits. 1000 times something wrong here. Ever heard of involuntary commitment.

May 13, 2021 3:05 am

Hot weather: evidence of Global Warming.

Cold weather: also evidence of Global Warming.

Pull the other one, it’s got bells on.

Reply to  Graemethecat
May 13, 2021 4:34 am

Pull the other one, it’s got bells on.

Also evidence of global warming

May 13, 2021 3:07 am

All to no avail. Mention this to a libtard, and their only question these days is: “…but, but, but what about the Polar Vortex!?” Gods only know where they even get that term, because they certainly have no idea where it comes from, so it must be global warming’s fault.
Sometimes I think everybody should just shut up, and leave science to those who bother to go look for themselves, the population has half-assed understanding of the half-assed interpretation that urinalists give to half-assed theories thunk up by wide-eyed students under the influence of wide-eyed ‘professors’ pushing their half-assed agenda on a wide-eyed public, a public with no real interest in understanding anything that does not fit into a video full of wide asses hanging half in the open.
Sometimes I think everyone should carry a soapbox, to be erected every time some half-ass starts spouting fear porn, to shout them down and expose their stupidity wide in the open.
Then I remember the new laws on disagreeing with ‘consensus’ modelling. I shall go now…

Peta of Newark
Reply to  paranoid goy
May 13, 2021 3:45 am

The ‘wide-eyed’ term is insightful and what I’ve been raving about (here) since forever as an explanation of the Junk Science

People have ‘wide eyes’ (dilated pupils) for 2 possible reasons:

  1. They fancy you sexually
  2. They are chemically depressed (classically: drunk)

That is what got me wondering because, Global Warming Paranoia seems to be a particularly ‘Western’ affliction.
The theory appealed because Western Societies consume vastly more alcohol that most everyone else
With one notable exception, USSR or Russia.
Thus, as per Feynman, my beautiful theory bit the dust

Until it dawned that sugar, in all its manifestations as sucrose, dextrose, lactose and glucose, is also a chemical depressant.

Thus, all you need do is find out what the teacers, scientists, lecturers and politicians (yes Lardy Ass Dipsomaniac Boris Johnson, I’m looking at you) have for their breakfast and lunch.
And they cannot lie can they –
Q: What is THE solution for Climate Change?
A: Plant based diet. i.e. one that is not only low in actual nutrition but entirely made out of sugar. There is nothing else in there for the Lipivores ## that we are.
Bit like ‘Stepford Wives innit’, ‘take this pill and you’ll understand/feel better

## No. Not esp Carnivores. The meat is useful food in small amounts but mostly, it carries around/delivers what we want and need. The fat.

And its easy to tell who consumes the most sugar – They Are Fat/Overweight/Obese and spend vast amounts of money on healthcare.

There you go Data Miners – correlate:
National Obesity
National Climate Hysteria
National (per capita) Health Expenditure
National (per capita) Covid, Cardio-Vascular and Dementia fatalities

Also, the average height of the citizens…
Beyond bizarre is that eating fat during your formative years (age 2 thro 12) makes you tall and slim – as you will remain for the rest of your life.

Eating a diet revolving around carbohydrate (sugar) make you short and fat

And it was young girls in our past that caught the brunt of the Low-Fat diet:
Because the lo-fat hi-carb diet landed them with:

  • Short legs (boys don’t like girls taller than they are)
  • Phat arses (boys do like that)
  • Quite perfectly trashed their ability to deliver babies – all that fat got in the way and it ki11ed not only them but also their child.
Clyde Spencer
Reply to  Peta of Newark
May 13, 2021 9:44 am

Or, 1 and 2 simultaneously.

Reply to  Peta of Newark
May 13, 2021 10:33 am

Wide eyes also refers to the lids being pulled back.

Smart Rock
Reply to  Peta of Newark
May 13, 2021 11:34 am

Peta – this is a true story I will share with you, and just this once I will try not to make fun of you.

It was 1949, I was 5 years old and I was in hospital for observation because I was suspected of having appendicitis. This was in the suburbs of London, where I grew up. After my overnight stay, a nurse brought me breakfast, it was one fried egg and 2 rashers of bacon, with a lot of melted bacon fat on the plate. I was balking at eating it because (like most kids) I didn’t like eating fat, plus I’d never eaten bacon or fried egg before. The nurse came round again and urged me to eat it up and I even remember the words she used: “Look at that lovely fat, eat it up, it’s good for you”.

Most of my adult life, I’ve been hearing that animal fat is bad for you.

I draw no conclusions whatever from this story.

OTOH, your rants about sugar are somewhat misplaced. Our great ape ancestors were mainly fruit eaters, and because of that, we are genetically programmed to like sweet things. The problem with modern society is that sugar is too widely available, thanks to sugar cane, sugar beet and corn syrup. Plus there’s too much bread, and cakes, and pies around, and all that wheat flour turns to sugar while you’re eating it.

Bears like sweet things too. They eat a lot of fruit, and they will go to great lengths to get at honey. I’ve read that if you make sugary foods freely available to a bear, it will eat nothing else, and become sick. Bears, being bears, have no self control. Whereas humans ……. oh, right.

Reply to  Smart Rock
May 13, 2021 2:13 pm

Whats about salt ?
Same, lot of people die because of to much salt, without, you die too.

Zig Zag Wanderer
Reply to  Smart Rock
May 13, 2021 2:19 pm

Whilst I tend to ignore Peta’s rants, I must agree that carbs are our enemy. It started with the ‘war on fat’ which appears to have been started by the cornsugar industry. Basically ‘reduced fat’ foods need something to make them taste good, and sugar works. It also causes obesity and diabetes, hence the current epidemics of same.

In my experience, fat satisfies much better than carbs of any kind. I tend to eat a bowl of muesli, with added nuts for fat and protein, and a small steak or fish, say 200g, cooked in butter, and vegetables each day. That’s enough for me, and I’m a big lad at 6′ 3″ and 110kg.

Unfortunately, I also drink a lot of beer, because that makes me happy. I’d much rather be happy than right!

Ron Long
May 13, 2021 3:16 am

Atmospheric winds move from higher pressure to lower pressure, with modification of the Coriolis Effect. Hotter or warmer effects can greatly influence atmospheric pressure, but the air still moves based on pressure gradients. So why study sea ice loss to understand wind movement? Study pressure gradients through time and then, and only then, go looking for influences.

Reply to  Ron Long
May 13, 2021 8:32 am

The article makes the claim that the loss of sea ice affects the height of the troposphere which in turn affects the pressure gradient.

May 13, 2021 4:16 am

Personally I’m extremely sceptical that an allegedly warming Arctic makes [UK] winters colder. In my experience it doesn’t.

I remember the 1960s and 1970s and the ice age scare. The Arctic, as far as I know wasn’t melting away then.

Somebody please tell the climate sceantists that unless you fully understand something you cannot successfully model it.

May 13, 2021 4:36 am

Just checked NSIDC image and SHAZAM! Arctic is still covered with ice. Imagine that.

Reply to  2hotel9
May 13, 2021 9:34 am

Yesterday’s sea ice extent hasn’t been posted yet (presumably they still have some issues), but on the 11th, it was above the same day in a number of previous years, including 2006.

They (the climate liars) talk about the temperature anomaly in the Arctic as if it reflects the same energy content as in the lower latitudes. Some of them probably even believe it.

Reply to  philincalifornia
May 13, 2021 11:19 am

I used to just post the image of ice extent, then NISDC changed somethings around and it is much harder to just get the image. Almost like they don’t want people doing that. Weird.

Reply to  2hotel9
May 13, 2021 2:15 pm

Here you are

and the data are complete, they came a bit later, an hour or two.

Reply to  Krishna Gans
May 13, 2021 7:31 pm

Yeah thanks. I really like the interactive site at:


They do run a good site, that’s for sure.

Reply to  philincalifornia
May 14, 2021 4:21 am

Graphs just don’t convey the reality as well as the image, the whole “picture is worth 1000” blahblah.

Reply to  Krishna Gans
May 14, 2021 4:21 am

Yea, links. Actually putting the image in people’s faces gets it across much better. Can’t remember exactly when they changed it, used to be you just cut&paste it right into comment threads.

Joel O’Bryan
May 13, 2021 5:13 am

In toto, The loss of Arctic Sea ice increases annual heat loss to outer space. 3 months of low angle summer sunlight warming can’t offset 6 months of near total dark and open water heat release.

Clyde Spencer
Reply to  Joel O’Bryan
May 13, 2021 9:48 am

And, the Arctic is notoriously cloudy, which is why Vikings depended on something called a Sun Stone to locate the position of the the sun. Thus, the potential for heating the water is reduced significantly because of the high albedo of the clouds.

Steve Case
May 13, 2021 6:03 am

IPCC TAR Chapter 14 Page 773 Paragraph 14.2.2 Predictability in a Chaotic System

In climate research and modelling, we should recognise that we are dealing with a coupled non-linear chaotic system, and therefore that the long-term prediction of future climate states is not possible.

Tom Abbott
Reply to  Steve Case
May 13, 2021 7:30 am

Yes, they say that, and then they go to making long-term predictions.

Reply to  Tom Abbott
May 13, 2021 8:15 am

If they left it at “not possible”, their pay stubs would start reading zero rather quickly thereafter.

Jim Clarke
May 13, 2021 6:58 am

Over the next 30 years we will most assuredly have increasing sea ice in the arctic, as the AMO goes through its cooler phase. the the very premise of decreasing sea ice in the model is false. Why do we even need to try and model the future, when we have excellent data concerning the last 30 years while Arctic sea ice was reducing? Did we see an increase in severe weather in the last 3 decades? No! Severe weather actually decreased, just as one would expect after passing am introductory course in basic meteorology.

The threat of man-made climate change due to CO2 emissions has always been one of H. L. Menken’s imaginary hobgoblins, along with all of its derivatives.

Tom Abbott
Reply to  Jim Clarke
May 13, 2021 7:32 am

“Did we see an increase in severe weather in the last 3 decades? No! Severe weather actually decreased, just as one would expect after passing an introductory course in basic meteorology.”

That is absolutely correct.

Richard M
Reply to  Jim Clarke
May 13, 2021 7:52 am

There may be another effect to consider besides the AMO. Increasing ocean salinity as described here.


More saline water reduces evaporation which allows the oceans to warm. As this water is transported into the Arctic we get more melting. Humans have been adding to ocean salinity in the last century via water treatment, road deicing and agriculture.

In addition, micro-plastic pollution of the oceans has a similar effect and has been going on for the last 60 years. It has an added warming effect because the plastic is a solid and can intercept high energy solar SW radiation which would normally penetrate deeper into the oceans.

Zig Zag Wanderer
Reply to  Richard M
May 13, 2021 2:24 pm

I have to disagree. I don’t believe that the miniscule effects of our salting the roads or plastic can change anything significantly. To believe so is hubris imo.

Heck, next you’d be believing that adding 1 or 2 parts per million of anything to the air would cause catastrophic warming!

May 13, 2021 7:33 am

I’ll remember once more: TCI, the influence of low solar activity, reduced UV radiation, cooler, shrinking thermosphere, cooler winter.

Sweet Old Bob
May 13, 2021 7:45 am

” It started with a simple observation: The Arctic is warming nearly three times faster than the rest of the world. ”

Not in summer !

Ocean and Ice Services | Danmarks Meteorologiske Institut

And , who cares if winter is warmer ?

May 13, 2021 8:17 am

How many times does the claim that loss of sea ice is a strong positive feedback have to be refuted, before climate scientists stop using it?

Reply to  MarkW
May 13, 2021 10:11 am

If they understand it, I doubt, they don’t 😀

Bruce Cobb
May 13, 2021 8:28 am

“Like all things, as you dig into them, they become more complicated.”
“More complicated” = climate-speak for “we haven’t figured out yet how to climate-splain this yet, but we will”.

May 13, 2021 9:21 am

Not to worry, that idiot John Holdren has safely moved on to his next con job.

May 13, 2021 9:24 am

It really makes you wonder what quantum computing will do for climate science–good and bad at the same time for a net zero impact, until politicos tip the scale.

Clyde Spencer
May 13, 2021 9:31 am

As bright, reflective ice is replaced by dark, sunlight-absorbing water, the Arctic heats up, causing more ice loss, and more warming in turn.

Note that the reason the Arctic water typically looks dark is because there is so little in the way of sediment or phytoplankton to cause diffuse reflectance from under the surface, and there is very little light that enters the water. Thus, almost all of the reflectance is specular reflectance from the surface, and can only be observed from the correct viewing geometry — looking towards the sun (which is typically low on the horizon) — because virtually all the light is in a narrow band leaving the water surface at the same angle as the sun’s rays impinge on the surface.


May 13, 2021 2:59 pm

lts not sea ice loss that changes the jet stream, but rather its looking like its extended low sun spot activity that can lead changes in the jet stream that can effect the global climate. Am now convinced that it was this that lead to the LIA and the current state of the jet stream is opening a window to what was going on during the LIA.

Paul Redfern
May 13, 2021 8:50 pm

Tim Ball had an article about Rossby waves. Here is an excerpt. The link doesn’t work anymore.

As the world cools because of decreasing solar activity the dome of cold polar air expands. The mean position of the Polar Front is closer to the Equator, but it doesn’t expand evenly.
The pattern of Rossby Waves changes from zonal to meridional because the cold dense air pushes further south. Of course there’s a balance as warm air pushes toward the Pole. 

Tom McQuin
May 13, 2021 11:54 pm

If GW was the cause of cold air blasting south, surely that should also have been a characteristic of the Medieval and Roman warm periods? From a quick squiz at some info, it is said Medieval had warm summers and mild winters, and the Tiber froze once in 179BC, in the 700 yr warm period..

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