Why Climate Change is Bringing the Polar Vortex South

By Jennifer Francis, Rutgers University | January 29, 2019 3:54 pm
freezing conditions

(Credit: Vladimir_Sotnichenko/Shutterstock)

A record-breaking cold wave is sending literal shivers down the spines of millions of Americans. Temperatures across the upper Midwest are forecast to fall an astonishing 50 degrees Fahrenheit (28 degrees Celsius) below normal this week – as low as 35 degrees below zero. Pile a gusty wind on top, and the air will feel like -60 F.

This cold is nothing to sneeze at. The National Weather Service is warning of brutal, life-threatening conditions. Frostbite will strike fast on any exposed skin. At the same time, the North Pole is facing a heat wave with temperatures approaching the freezing point – about 25 degrees Fahrenheit (14 C) above normal.

weather forecast

Predicted near-surface air temperatures (F) for Wednesday morning, Jan. 30, 2019. Forecast by NOAA’s Global Forecast System model. (Credit: Pivotal Weather, CC BY-ND)

What is causing this topsy-turvy pattern? You guessed it: the polar vortex.

In the past several years, thanks to previous cold waves, the polar vortex has become entrenched in our everyday vocabulary and served as a butt of jokes for late-night TV hosts and politicians. But what is it really? Is it escaping from its usual Arctic haunts more often? And a question that looms large in my work: How does global warming fit into the story?

temperature anomalies

Predicted near-surface air temperature differences (C) from normal, relative to 1981-2010. (Credit: Pivotal Weather, CC BY-ND)

Rivers of Air

Actually, there are two polar vortices in the Northern Hemisphere, stacked on top of each other. The lower one is usually and more accurately called the jet stream. It’s a meandering river of strong westerly winds around the Northern Hemisphere, about seven miles above Earth’s surface, near the height where jets fly.

The jet stream exists all year, and is responsible for creating and steering the high- and low-pressure systems that bring us our day-to-day weather: storms and blue skies, warm and cold spells. Way above the jet stream, around 30 miles above the Earth, is the stratospheric polar vortex. This river of wind also rings the North Pole, but only forms during winter, and is usually fairly circular.

Polar Vortex

Dark arrows indicate rotation of the polar vortex in the Arctic; light arrows indicate the location of the polar jet stream when meanders form and cold, Arctic air dips down to mid-latitudes. (Credit: L.S. Gardiner/UCAR, CC BY-ND)

Both of these wind features exist because of the large temperature difference between the cold Arctic and warmer areas farther south, known as the mid-latitudes. Uneven heating creates pressure differences, and air flows from high-pressure to low-pressure areas, creating winds. The spinning Earth then turns winds to the right in the northern hemisphere, creating these belts of westerlies.

Why Cold Air Plunges South

Greenhouse gas emissions from human activities have warmed the globe by about 1.8 degrees Fahrenheit (1 C) over the past 50 years. However, the Arctic has warmed more than twice as much. Amplified Arctic warming is due mainly to dramatic melting of ice and snow in recent decades, which exposes darker ocean and land surfaces that absorb a lot more of the sun’s heat.

Because of rapid Arctic warming, the north/south temperature difference has diminished. This reduces pressure differences between the Arctic and mid-latitudes, weakening jet stream winds. And just as slow-moving rivers typically take a winding route, a slower-flowing jet stream tends to meander.

Large north/south undulations in the jet stream generate wave energy in the atmosphere. If they are wavy and persistent enough, the energy can travel upward and disrupt the stratospheric polar vortex. Sometimes this upper vortex becomes so distorted that it splits into two or more swirling eddies.

These “daughter” vortices tend to wander southward, bringing their very cold air with them and leaving behind a warmer-than-normal Arctic. One of these eddies will sit over North America this week, delivering bone-chilling temperatures to much of the nation.

Deep Freezes in a Warming World

Splits in the stratospheric polar vortex do happen naturally, but should we expect to see them more often thanks to climate change and rapid Arctic warming? It is possible that these cold intrusions could become a more regular winter story. This is a hot research topic and is by no means settled, but a handful of studies offer compelling evidence that the stratospheric polar vortex is changing, and that this trend can explain bouts of unusually cold winter weather.

Undoubtedly this new polar vortex attack will unleash fresh claims that global warming is a hoax. But this ridiculous notion can be quickly dispelled with a look at predicted temperature departures around the globe for early this week. The lobe of cold air over North America is far outweighed by areas elsewhere in the United States and worldwide that are warmer than normal.

world temperatures

Predicted daily mean, near-surface temperature (C) differences from normal (relative to 1979-2000) for Jan. 28-30, 2019. Data from NOAA’s Global Forecast System model. (Credit: Climate Reanalyzer, Climate Change Institute, University of Maine., CC BY-ND)

Symptoms of a changing climate are not always obvious or easy to understand, but their causes and future behaviors are increasingly coming into focus. And it’s clear that at times, coping with global warming means arming ourselves with extra scarfs, mittens and long underwear.The Conversation


Jennifer Francis, Visiting Professor, Rutgers University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

CATEGORIZED UNDER: Environment, Top Posts
  • http://www.mazepath.com/uncleal/EquivPrinFail.pdf Uncle Al

    And pushing the Equator into Antarctica! Rumor has it that Chicago snowballs are frozen so hard they will not melt – being sold as souvenirs to tourists. “Deep Freezes in a Warming World” Do you touch kitchen appliances with those fingers?

    … Hiring diversity is like eating your own snot. It attracts a crowd. So what?

  • Nom de Plume

    Amazing. I remember these cold snaps before fifty years ago. My father remembered them further back that I. His parents took a loss growing cabbage due to a cold snap about a century ago. Want to talk about the Great Blizzard of 1888? How about the one that took a huge toll on cattle in 1886? How about 1857, when it hit -20 in Petersburg, Virginia?

    This is why it’s hard to take “climate change” seriously. Blaming dips in the Jet Stream to “climate change” may impress the younger folks, but not those of us old enough to have a longer baseline of memories and who know some history.

    Want to sell “climate change?” Here’s a suggestion: stick to actual science. “Will become a more regular winter store?” News-flash: they already are, and have been long before any of us were born. When you see stories like this, it’s like someone using current events to argue for astrology. It’s like they’re afraid someone will lose “faith.”

    Here’s a suggestion: Since Discover is supposed to be a science magazine, can you please stick to science? I’m sure you can find all the real “climate change” stories you could possibly wish to run without sinking to dubious hyperbole.

    Now let the howls of “denier” or “heretic” or whatever floats your boat begin.

    • Douglas Thorburn

      This is science and totally science based and your whole argument is antidote which is not science. .. look it up … I feel you lack education and love living in willful ignorance.
      Have a nice day.

      • Nom de Plume

        A predictable response. Tell us: you’ve never lived through a cold snap before? Ever? Are you older than 50 and remember those that happened before the time frame in the article? You’ve never heard of the Great Blizzard of 1888? Of the cold snap that devastated the cattle industry in the western US in 1886? Never heard of it being -20 below in Virginia in 1857?

        These are data points.You can’t verify the loss my family took in farming a century ago due to that cold snap, but you can every other data point I’ve mentioned. To refute my argument, all you have to do is show cold snaps never occurred prior to the 50 year window given in the article.

        • Douglas Thorburn

          a predictable response from someone trying to remain willfully ignorant and continuing to push his antidotes. I’m much older than 50 and also understand science. Obviously you don’t.
          Your straw man arguments are worthless to real science.

    • Erik Bosma

      Over 99% of scientists polled believe in man-made climate change. I’d call that science.

      • Nom de Plume

        Argument by assertion. Tell us who ran the poll and the methodology.

      • Darren Man

        Actually that’s a lie…I call that facts

    • http://mywebsiteweb.com/MySite/pmwiki.php?n=MotherGooseMob.MotherGooseMob Jagtig

      I rely on a long memory store, and support the science of climate change as a result. I have seen where a local lake has gone from where you could drive a car on the ice to where it barely freezes over, while the adjacent canal freezes not at all, anymore.

      I remember cool weather beginning at the end of August when weekly fronts stemming from cooling air over Canada were signaled by thunderstorm activity. These are gone completely, now. The air remains warm into October and the leaves fall from genetic memory, not actual cooling.

      The winter begins with expanding buds, as a result, and there is even Spring blooming before Christmas as a result of a quick cool-down followed by a warm December.

      I’ve watched the weather here in Central New Jersey since I was a kid, and am 68 going on 69, now.

  • Kurt Stocklmeir

    polar vortex does not have any thing to do with cold weather around the U.S. – any changes of the climate do not have any thing to do with a polar vortex moving south – there are an almost infinite number of things that influence the weather – how much dirt from space ends up in air around the earth – how much cold water at bottom of ocean goes to the surface of the ocean – how many waves there are in the ocean moving warm water to north pole – how much wind there is making waves in the ocean – direction of wind all over the earth – direction of wind over the ocean moving water to north pole – wind over ocean making currents moving water around – mixing warm air around surface of earth and cold air high above the earth – how many plastic bags end up in the ocean – how fast plastic bags break down – little pieces of plastic all over the ocean – cutting down trees – how many high pressure areas there are – how many low pressure areas there are – what high pressure areas and low pressure areas are going – how much snow there is around the world – roads and buildings absorb energy of the sun as compared to trees and snow Kurt Stocklmeir

    • Douglas Thorburn

      smoke some more and write a short story.

    • Kurt Stocklmeir

      there is a lot of dirt in the air – it stops clouds from being made – it stops rain – water in the air absorbs energy from the sun – temperature increases – because temperature increases more water goes into the air – this water absorbs energy of the sun – temperature increases – people are cutting down a lot of trees – a lot of things like roads building and cars are absorbing energy from the sun – people are putting a lot of things in the ocean like plastic bottles rubber glass metal food and paper – if paper breaks down a lot of chemicals are in the ocean – carbon associated with the paper is in the ocean – bacteria and plants use food that people put in the ocean – bacteria and plants make ocean more dark and this makes ocean absorb a lot of energy from the sun – if more air gets to the north pole – there is a lot of high pressure more wind around the north pole – the wind makes cold water from north pole move south – this lets warm water move to north pole – warm water melts ice at north pole – low pressure areas and high pressure areas go over the U.S. – when they are over the Atlantic ocean they make warm water move north and cold water move south – temperature and speed of wind together are important – cold air and a lot of wind can make up for a lot of hot air – jet stream messes up low pressure areas and high pressure areas – a lot of cold air that moved to the U.S. 2 days ago ended up in the jet stream Kurt Stocklmeir

    • Kurt Stocklmeir

      if I put an almost infinite amount of cherry pepsi in the ocean I will make the ocean more dark – the ocean will absorb more energy of the sun – people put a lot of liquids in the ocean – this makes the ocean more dark – this makes the ocean absorb more energy of the sun – a lot of chemicals go in the ocean – this makes the ocean more dark – food fertilizer waste products grass leaves go in the ocean – this makes the ocean more dark – bacteria and plants use the food fertilizer waste products grass leaves for food – the ocean ends up with more bacteria and plants – this makes the ocean more dark – people put a lot of things in the ocean – this makes the ocean more dark – a lot of things like plastic rubber paper grass leaves wood break down – all of it ends up all over the ocean – this makes the ocean more dark – the ocean will absorb more energy of the sun – the temperature of the water will increase – water a little more warm than normal can get around the north pole and south pole – this can cause trouble for ice around the north pole and south pole – people need to stop cutting down trees – people need to stop eating fish – people need to stop putting things in the ocean – it is ok if all the kids at the beach let the ocean have their waste products – if I had an almost infinite amount of cherry pepsi I would drink it jump in the ocean letting the ocean have it – God liked the ocean when God created it Kurt Stocklmeir

  • Unbeliever

    The climate explainers are out in full force: global warming is causing global cooling. If we were having record high temperatures, I am sure that could come up an explanation that suits their climate change agenda.
    Try this for a possibility: The climate is supposed to change, its unpredictable and we have no control over it.

    • OWilson

      Two old jokes, one told by my Grandfather have come to pass! :)

      “One day the politicians will find a way to tax the air we breath!” – 1948

      And a later one from 1990:

      “One day they’ll tell us that colder weather is actually Global Warming!”


    • Disa


    • Douglas Thorburn

      you are kind of right … we do not have control of it … but we are effecting it …. and yes its always changing but never so fast and in the opposite direction to where the planetary cycle should be taking it. Get into actually looking into the science of it or STFU.

      • Unbeliever

        Exactly how fast and in what direction should the planetary cycle be taking it? How do we “effect” it to get back to your alleged normal cycle?

        • Douglas Thorburn

          Exactly how lazy are you? Look it up … learn some climate science and geological history. Its all available with a little effort. We don’t get it back even if we shut down all of industry. Things have changed.

          • Unbeliever

            ((They)) don’t know what the climate is supposed to be doing because nature doesn’t follow a set course decided by a consensus of scientists. ((They)) cannot predict the future of the climate because it’s unpredictable. And “things” have always changed…..it’s normal to change and ((They) have no control over that. Somethings don’t need to be “looked up”. Try using some common sense once is a while.

          • Douglas Thorburn

            Such a good excuse to be lazy and try to b.s. everyone with non sequitur and straw man arguments. Enjoy your ignorance.

  • Mike Richardson

    It’s amazing to see climate change deniers disputing science when we are able to observe in real time with satellites the warming poles, and how this is causing the polar vortex to dip south. Even when it is explained and shown to them, the default reaction seems to be “nope, it’s cold outside, so no global warming.” Like Sen. James Inhofe bringing a snowball inside the Capitol during winter and insisting that disproved climate change. This is honestly getting to the point of trying to have a discussion with flat earthers or creationists.

    • http://epxhilon.blogspot.com.au Rusdy Simano

      It’s computer animated, not real! The actual earth is flat!! :)

      • Mike Richardson

        LOL! Don’t give them ideas. I’m just surprised chemtrails haven’t been brought into the discussion yet.

  • Bolide

    Hey!! Did you know that it’s warmer in Antarctica than it is in the midwest!!!! The NEWS said so!!! Antarctica!!!! Is it CLIMATE CHANGE coming to KILL us?!!! Or is it that it’s actually summer right now in the southern hemisphere and that the average temp for February at the Wellington base is 17.1 C where at the same time in Duluth MN it’s -14.4……….average…..without the vortex……..science……
    Sorry my point is that when you hear something research it out a little, don’t believe someone just because they support your beliefs.


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