Sudden Stratospheric Warming and Polar Amplification: How Climate Change Interacts With the Polar Vortex

Over the past few years, the term Polar Vortex has dominated the broadcast weather media — gaining recent notoriety due to increasingly extreme weather events associated with a number of disruptions to Arctic atmospheric circulation patterns. In short, this swirl of cold air over the furthest north regions is being intensely disrupted by warm air invasions — both at the surface and in the upper levels of the atmosphere. A subject that we’ll explore further as part of this analysis.

Take the recent extreme February warming at the North Pole in which temperatures there rose to above freezing even as a major cold snap slammed into Europe this week. We’ve seen such varied headlines as Yes the North Pole is Warmer than Europe Right Now and Arctic Warm Event Stuns Scientists.

When it’s warmer at the pole than in Europe, it’s a sign that the weather is clearly out of whack. Especially when temperatures in a region spanning tens of thousands of square miles over the Arctic rocket to between 40 and 63 degrees Fahrenheit above normal. Scientists are notably concerned. Dr. Michael Mann, one of the world’s foremost experts on climate change characterized the polar warming event as:

…an anomaly among anomalies. It is far enough outside the historical range that it is worrying — it is a suggestion that there are further surprises in store as we continue to poke the angry beast that is our climate.

But what’s driving all this? Dr. Mann gives us a bit of a hint by describing our climate as an angry beast that’s being poked.

(Polar Amplification writ large. The entire region of the Arctic above the 80 degree North Latitude line has been 8.64 degrees Celsius warmer than normal for all of 2018 thus far. This is an extraordinary departure for a region that plays a critical role in how the Earth’s climate system functions. Image source: DMI.)

Perhaps another way to say it is that it’s a warming atmosphere that’s prodding the Jet Stream to take a chunk out of the Polar Vortex.

How might this work?

First, surface warming in the Arctic caused by increased radiative forcing from rising greenhouse gas levels and by follow-on reductions of Arctic sea ice and snow result in less temperature difference between the Pole and the Equator. This surface warming translates into higher levels of the atmosphere through convection.

Temperature difference is what drives the upper level winds. So a lower difference in temperature causes these winds to slow. When the Jet Stream winds slow, they tend to meander — forming large ridges and deep troughs. The elongated ridges and troughs eventually break like waves — pushing against the circulation of the Polar Vortex.

(NOAA graphic shows how a weak jet stream results in changes in atmospheric circulation and increased disruption of the Polar Vortex.)

When this happens, the speed of the winds that make up the Polar Vortex slow down and sometimes reverse. This results in the collapse of the column of upper level air held aloft by the Vortex’s winds. When the air collapses, it compresses, causing the stratosphere to warm. This falling column of warm air then can end up acting like an atmospheric wedge — driving the Polar Vortex apart and causing it to split.

The split then tends to generate smaller funnels that capture polar air and pull it south. Beneath the funnels, it can be quite cold as Arctic air invades places like North America or the UK (as happened this week). But at the Pole, where the cold air should typically reside, it warms up enormously.

That’s how, under a regime of human-forced climate change, you can end up with periods where temperatures are warmer at the Pole than they are in Europe.

It’s worth noting that Polar Vortex collapse events did occur in the past. But not in such a way that generated the kinds of historically extreme Arctic temperatures we see today. The primary driver for the recently increased extremity of weather driven by Polar Vortex collapse events being human-caused climate change, Polar Amplification, and related influences on the Jet Stream.

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  1. Jim

     /  February 28, 2018

    Great post Robert, and thanks for the explanation of the mechanisms at plan with the jet stream changes. Readers of RobertScribbler will know these changes are due to relentless greenhouse gas emissions – primarily CO2 – warming our world, and the polar amplification that we are presently seeing was predicted by climate models many years ago.

    In contrast, readers of the Washington Post might not even notice the term climate change unless they read the article through to the last attachment, and look at the bio of the author. Those are the only two uses of the term “climate change”. CO2 is never mentioned in the WaPo report at all.

    Instead you’ll see a quote from Kent Moore, professor of atmospheric physics at U of Toronto which states ““I’m surprised how warm it is, but I am not sure why.” The rare reader who follows the link to his paper might understand he is likely referring to the interplay of multiple factors, not presenting doubt about climate change.

    The embedded WaPo produced video, which you get to see after viewing a 15 second Shell advertisement, gives prominent coverage to Donald Trump and Scott Pruitt, while showing selected text from the National Climate Assessment, before finishing with a statement from White House spokesperson Raj Shah that the “climate has always been changing”.


    • rhymeswithgoalie

       /  March 1, 2018

      Here’s a Japanese scientist from 30 years ago (1 minute into video):

    • Thanks for the kind words, Jim.

      Also, thanks for the discussion with regards to WaPo climate coverage. Maybe a letter to the editor might help them a bit?

      I suppose I tend to add my own internal narrative when I read articles from sources like WaPo. So I may not miss as much as a person who might not be as informed RE climate change. However, when I write a post, I have a number of standards for points that I try to hit. Primarily:

      1. Causes — fossil fuel burning and greenhouse gas emission.
      2. The use of the term — human-caused climate change.
      3. The use of the term — warming.
      4. The identification of low-hanging fruit systemic solutions — renewable energy (wind, solar, batteries).

      I get the most negative response from the trolls, harassers, and bots when I do this. So I figure this is the right messaging.

      Of course, the overall goal is to educate and inform based on facts. Education, in this sense, requires repeating an accurate message in a way that is as easily understood as possible given the complex nature of human-caused climate change and related systemic solutions.

      • Jim

         /  March 1, 2018

        I’ll bet dealing with the trolls is almost a full time job. I’d need to up my blood pressure medication to handle the task, so I’m appreciative of your work moderating this site 🙂

        What’s interesting and underappreciated by most people is that personal changes to reduce their CO2 footprint also increasingly are the most economical.

        In much of the US, residential PV solar is already cheaper than grid electricity, with a 6-7 year total cost payback for a 20-25 year system life. Free electricity for 14-19 years is pretty nice.

        Similarly the “fuel” costs to power an EV are about 70% cheaper than gasoline for a 25mpg ICE vehicle. Throw in lower maintenance and longer vehicle life, and you’ve got a very compelling economic argument.

        Surprisingly, residential battery storage using Tesla’s battery pricing, is currently at, or close to, grid parity in some utility regions that charge by Time of Use. And battery prices are still dropping fast.

        So thanks for the increased posting on your item 4 above: low hanging solutions. We’ve got more changes in how we use energy coming together at the same time – batteries, electrified transportation, PV solar, wind, energy efficiency – than any time in recent history. And the forces that be will be telling us “we can’t afford it”, or “we need a clean bridge fuel”, or that it’s all a “Chinese Hoax” to make us uncompetitive. Wrong, wrong, and WRONG. SO SAD!

        ~ Jim

  2. Jim

     /  February 28, 2018

    Typo at end of first line should read “play” not “plan”.

  3. Vaughn An

     /  February 28, 2018

    Point of understanding:

    In Warming, Northern Hemisphere is Outpacing the South
    By Andrew Freedman in Climate Central April 9, 2013

    In 2013 it looks like the the Northern Hemisphere has warmed about 1.0 C and the Southern Hemisphere has warmed about 0.5 C for a global average warming of 0.75 C. So, the north has warmed on a ratio of about 2:1 compared to the south. Since then additional warming has pushed the average global temperature to about 1.0 C above long term averages . Let’s say for this point of understanding that the ratio to north/south warming has continued at this rate since 2013 for a northern average temperature of +1.3 C and a southern average temperature of +0.7 C.

    So, does this mean that the Northern Hemisphere is already operating in a +1.3 C world as described by the conditions we would expect in a +1.3 C world due to the isolation of southern and northern air circulation?

    Or, are we operating at +1.0 C global conditions as to what would be expected at +1.0 C?

    If we really are operating at +1.3 C in the northern hemisphere, then we are perilously close to the +1.5 C where the problems associated with these temperatures will occur with much more frequency.

    According to the Climate Reanalyzer:

    as of February 28, 2018 the global temperature anomaly was +0.7 C. The northern hemisphere was +1.2 C and the southern hemisphere was +0.1 C.

    It looks to me like we are already operating somewhere in a +1.0 C to +1.5 C world in the northern hemisphere if we look at weather events over the past year. So, on February 28, 2018 was the northern hemisphere operating in a +0.7 C world or are we already in +1.2 C world?

    • Kiwi Griff

       /  March 1, 2018

      As far as I know the map you are looking at and the temperatures at the bottom giving global northern and southern hemispheres are based on the anomaly from1979 to 2000 temperatures.

      The term temperature anomaly means a departure from a reference value or long-term average. A positive anomaly indicates that the observed temperature was warmer than the reference value, while a negative anomaly indicates that the observed temperature was cooler than the reference value.

      We exceeded 1.5C globally from pre industrial temperatures in February 2016

      The threshold talked about in the Paris agreement are for global temperatures not hemispheric ones. 1.5 C is an arbitrary limit
      Temperatures for the northern hemisphere will be much warmer than 1.5 C when globally we do exceed 1.5C on a yearly basis.

      The impact is not liner we can expect more impact for the change from 1.5 to 2 C than we see from 1. to 1.5C.

      • Vaughn An

         /  March 1, 2018

        Kiwi, so are we already feeling the impact of +2.0 C in the northern hemisphere. My question is more about the effects of temperature in each hemisphere. Should we separate the conditions in each hemisphere to determine potential effects of temperature in each hemisphere separately or should we average the temperatures of both hemispheres out and look at the average to determine the potential effects for each hemisphere as a whole?

        • The effect is systemic. 2 C warming will produce further effects in the N Hemisphere environment. So the answer to this question is: No. 1.1 C global warming produces the effect of 1.1 C global warming in every hemisphere despite the fact that the intensity of warming in each region may vary.

          What is relevant is where the warming is occurring and how this will impact specific regions. However, we should not necessarily expect that warming acceleration in the Arctic will continue without responses in other regions as well. Nor should we discount the likely roles that ice sheet melt in that region will begin to play — both with respect to ocean heat uptake and surface temperatures in the region.

          To reiterate, the 2 C number is global and systemic. The effect of that warming is on a global scale. Some regions may experience more warming or less. But it is the systemic effects that increase the risk of damage at this threshold.

      • Correct:

        “Climate Reanalyzer uses a 1979-2000 climate baseline derived from the reanalysis of the NCEP Climate Forecast System (CFSR/CFSV2).”

        That period was already about 0.5 C warmer than 1880s. So you can add that number to daily anomalies given at the global scale.

        With regards to the 1.5 C departure, let’s be careful not to cherry pick. In other words, a monthly departure does not represent base climatology as we understand climate thresholds:

        Though we experienced one month at a 1.5 C peak anomaly reading during 2016, this is not reflective of base climatology as we typically define thresholds. Present multiyear global averages are in the range of 1.1 C above 1880s and the peak year is presently 2016 at 1.2 C above 1880s.

        We are approaching the 1.5 C threshold and will likely experience a single year temperature that exceeds 1.5 C before 2030 with multiyear averages in that range soon to follow.

        A single month excession does, however, show that we are approaching that threshold and that individual base conditions within certain regions and at certain times may provide hints of the more severe conditions that are to come with future warming.

        The only safe ways to mitigate future warming is to reduce carbon emissions as swiftly as possible and to attempt to remove some of the carbon from the atmosphere. The swiftest and least disruptive methods for reducing carbon emission involve replacing fossil fuel burning with renewable energy sources (which is most effective due to the low and falling cost of wind, solar, batteries, and EVs) and other clean energy sources while prioritizing the closure of carbon emitting plants. These activities will have the best cumulative impact if the push to increase efficiency continues and so long as efficiency is not seen as a replacement for a necessary energy transition. The most effective methods for carbon removal from the atmosphere involve improved land management and related changes to agriculture as well as attempting to further advance atmospheric carbon capture technology.

        But we should note that atmospheric carbon capture systems are difficult to produce at scale due to expense or potential externalities (in some cases). Other renewable energy technologies may assist in reducing atmospheric carbon emissions, as could nuclear. However, these systems are also more expensive than wind and solar + batteries and some (nuclear) do not possess the positive learning curves provided by wind, solar, and batteries. Furthermore, these systems increase civilization resiliency to climate change even as they work synergistically in an electricity based energy system that adds both simplicity and ease of scaling.

        Attacks on renewable energy are attacks on climate change response and should be viewed as such. But they are prevalent, cynical, and come from all quarters. This is due to the fact that the present economic power of fossil fuel industries is able to manipulate media to provide a false narrative. A narrative aimed primarily at dividing clean energy supporters and removing confidence in our ability to establish a clean energy future.

        This assault comes alongside and coincides with climate change denial. But those who attack renewable energy are courted and cultivated on all sides of the present media debate. Targeted with messages aimed at their specific ideological vulnerabilities and sympathies.

        As with any just cause that threatens people in power, those of us who support responses to climate change should keep our eyes clearly focused on the cause — a world with zero carbon emissions — and the path — building the clean and renewable energy systems that will achieve that helpful end. Those who do this will be attacked from every quarter. Smeared and bullied and character assassinated. But we should understand that the standing of the individual here does not matter. That the cause of preventing civilization collapse through renewable energy transition is more important than our own petty standings, page views, or ranks within the present media environment.

        • Vaughn An

           /  March 1, 2018

          Robert, thanks for your clear reply. I had been wondering about that for awhile.

  4. bostonblorp

     /  March 1, 2018

    “anomaly among anomalies” and yet likely destined to become the norm.

    I don’t know why but I’ve been thinking a lot recently about what surprises we’ll get when the next strong El Nino comes rolling in. It’s just a silly gut feeling but I think it will shake us from our slumber.

    • Andy_in_SD

       /  March 1, 2018

      I 100% agree with you. If we received the equivalent of the 97 El Nino, what would it look like now?

  5. Loni

     /  March 1, 2018

    bostonblorp, , one would have thought that Puerto Rico and Houston et. al. would have been slumber disturbing, but alas, we stir not.

  6. Andy_in_SD

     /  March 1, 2018

    Thanks for the very clear explanation of the jet stream breakdown, cause etc… Robert. It certainly helped fill in areas and portions of the subject I did not know.

    As I was reading I was thinking (I’m always pondering, wish I could just stop that).

    I wonder if anyone has calculated the delta for absorbed energy due to open water versus ice pack cover (from former ice cover) during periods of sunshine and it’s effect on the following melt season and refreeze. That would be interesting as it would give one a tool to quantify the cumulative effect over multiple seasons. That could then be graphed season to season as a trend line providing an input for projections.

  7. Spike

     /  March 1, 2018

    Nice concise explanation Robert, intelligible to an educated layman. It’s a shame that this isn’t widespread in the media, although today’s Guardian takes a few more respectable steps in that direction.

  8. Spike

     /  March 1, 2018

    Katharine Hayhoe speaking wisely again:

    • Spike

       /  March 1, 2018

      From the paper linked to: “We should entertain the possibility that the inertia in global systems is the reason why we are not witnessing significant changes in response to the forces and shocks imposed by human activity. It is not because they are resilient, but because system inertia simply means that the reaction to our action has just not arrived yet, failure could be coming. Here it is the multiple temporal scales that is significant, failure could be occurring on a different temporal scale to human life. For decades the composition of the atmosphere has been changing, and for decades very little seemed to be happening. Only now are we starting to see the system react as average surface temperatures have started to change (Mann et al., 2008), potentially therefore it is happening at a different temporal scale. We could easily be seeing the very beginning of the reaction to our action, and that reaction could massively accelerate in future decades.”

    • Spike

       /  March 1, 2018

      And: “The nature of our response to the possibility of a given systemic failure would appear to be more dependant on ideology than systemic thinking, and in the case of climate change this could prove catastrophic. The possibility of severe changes in our climate should not be dismissed as ‘fake news’, a hoax, or conspiracies against economic development, and the fact that it is could prove to be a contributing factor in the failure of the climate system. From the point of view of a systemic response to the possibility of climate change, the paralysis in the political system could constitute a systems failure in its own right. A failure in the political system would feedback into the climate system. Could that result in a cascade failure of both systems?”

    • Thanks for this, Spike. Excellent statement here by Katharine and a much-needed report given the present time and the difficulties we face.

  9. kassy

     /  March 1, 2018

    One for the Californians:

    California AG’s soft approach toward Exxon’s climate deception could cost him his job

  10. kassy

     /  March 1, 2018

    An interesting story on supercapicitors:

    A fluke breakthrough could be the missing link for an electric car age

    Soft contact lens technology could link renewables and the grid and make electric cars better

  11. kassy

     /  March 1, 2018

    This is pretty bad:

    Brazil’s top court approves controversial forestry law

    Brazil’s supreme court has upheld major changes to laws protecting the Amazon rainforest, delivering a blow to environmentalists.

    The revision of the 2012 law includes an amnesty programme that scraps penalties for landowners who have cut trees down illegally in the past.

    Environmentalists say it will make illegal deforestation of the world’s largest rainforest acceptable.

    Farmers say the changes give producers confidence to grow the economy.

    The Amazon rainforest is the largest tropical rainforest in the world and home to plant and animal species that are still being discovered by scientists.

    Most of its millions of square kilometres are inside Brazil, where under laws dating back to 1965, landowners must keep a percentage of their terrain forested.

    That percentage ranges from 20% in some parts of the country to 80% in the Amazon.

    But the supreme court’s decision eases that rule. Attorney General Grace Mendonca has defended the change saying it struck a balance between environmental protection and economic development.

    The revised rule will reduce the amount of land that should be restored by 112,000 sq miles (290,000 sq km) – an area the size of Italy.

    It also provides an amnesty from fines owed for illegally clearing trees before July 2008, although larger landholders would have to replant most of the cleared area or preserve the same amount of land elsewhere.

    Environmentalists say the revised laws will reward those who have deforested in the past.

    Speaking to Reuters, Nurit Bensusan from the non-governmental organisation Instituto Socioambiental said: “With this amnesty you create a climate that invites deforestation in the future. It creates the impression that if you deforest today, tomorrow, you are handed an amnesty.”

    Under the new bill, farmers will be able to cultivate land closer to hilltops and riverbanks, which are especially vulnerable to erosion if trees are chopped down.

    Farmers and Brazil’s powerful agriculture lobby argue that the new laws allowed for continued growth of a key sector of the Brazilian economy without hindering it by dealing with crimes from the past.

    Whatever happens to the Amazon is important to all of us but it is of extra importance to the other counties in South America since it has an important role in cloud seeding. I haven’t seen a mention of any of them objecting to this or urging Brazil to reconsider.

    It is somewhat similar to a neigbouring country damming the rivers your country depends on and that has lead to tensions between Egypt and Sudan.

  12. Excellent article.

  13. Hi Robert, this is an excellent read and one I’ve used to explain the recent conditions in Norfolk, UK, to friends. It also motivated me to write this: Please keep up the good work! James

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