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Declining arctic snow cover is bad news for polar vortex

The views expressed are those of the author and are not necessarily those of Scientific American.


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As many in North America are learning, the health of the arctic affects weather in warmer, southern parts of the continent. Mark Fischetti does a great job explaining the “polar vortex” and how the belt that essentially keeps cold air tucked away up in the arctic is loosening, resulting in the historic and extreme cold snap we’ve all been tweeting about:

The polar vortex is a prevailing wind pattern that circles the Arctic, flowing from west to east all the way around the Earth. It normally keeps extremely cold air bottled up toward the North Pole. Occasionally, though, the vortex weakens, allowing the cold air to pour down across Canada into the U.S., or down into other regions such Eastern Europe. In addition to bringing cold, the air mass can push the jet stream—the band of wind that typically flows from the Pacific Ocean across the U.S.—much further south as well. If the jet stream puts up a fight, the moisture it carries can fall out as heavy snow, which atmospheric scientists say is the circumstance that caused the February 2010 “snowmageddon” storm that shut down Washington, D.C.

But we’ve seen that the jet stream isn’t putting up as much of a fight lately. The reason, is that arctic sea ice is melting. Another factor is the role of snow in reflecting sunlight back to the atmosphere and strengthens the jet stream. As with sea ice, snow cover has been declining. NASA’s Earth Observatory illustrates how snow cover is changing relative to historical averages:

In the image above, blue regions indicate more snow fall than historical records while brown regions indicate less snow cover:

In spring 2013, snow covered less area than the historical mean, with a new record low set in May in Eurasia, according to NOAA’s Arctic Report Card. The images above show snow day anomalies in April, May, and June; that is, they depict the percentage of days that snow cover was above or below the long-term average (1981-2010). Fewer snow days are represented in brown, while more snow days are shown in blue. The images are based on the weekly NOAA snow cover data records.

April had more days with snow cover than average because melting started late in northwestern Europe. However, once the melting started, it occurred rapidly, as shown in the May and June images. Eurasia reached a record low in May, and the snow cover extent in North America was at its fourth lowest in June. This lack of snow occurred because snow melted quickly, not because less snow fell during the winter.

But perhaps more striking is a look at the overall trend. A look at snow cover over several decades shows a warming trend (again from NASA where blue means higher than average snow cover; brown means less):

Trends in both arctic sea ice and snow are worrisome from a climate perspective, especially if the trends continue.

Top image courtesy NOAA Climate.gov based on data from the Rutgers Snow Lab; Bottom image by Robert Simmon, using data from the Rutgers University Global Snow Lab.

David Wogan About the Author: An engineer and policy researcher who writes about energy, technology, and policy - and everything in between. Based in Austin, Texas. Comments? david.m.wogan@gmail.com Follow on Twitter @davidwogan.

The views expressed are those of the author and are not necessarily those of Scientific American.





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  1. 1. Giulio 7:52 pm 01/7/2014

    I remember much colder and snowier winters as a child. Christmas was almost always white. Blizzard conditions were common. I live in the northeast US. But lately, the past 20 years or so, I became so use to winters that were not really winter-like. I’m not a climate scientist, but I listened to their claims and attributed the climate change to… well, climate change. Whether it was man-made or not didn’t seem to matter anymore. It was here. The last cold spell like this one hasn’t been seen since ’93. But now I come to find out that the polar vortex is loosening, bringing back the cold weather we use to see regularly decades ago. Huh? And this is climate change too? Wow, let’s just blame every weather pattern and event going forward on global warming. They got us comin’ and goin’. No matter what happens, it’s climate change. Kinda sounds like weather forecasting. Partly cloudy, mostly sunny, chance of rain. Just cover all the bases and you can’t go wrong.

    I think if you want to convince more people of anthropogenic climate change, you should pick and choose your fights. This polar blast, I’m sure, is a short term weather pattern. Unlikely to reoccur again for perhaps decades or more. And I’m sure this story about the polar vortex loosening will never be heard from again.

    Come on guys/gals, quit kidding around.

    Link to this
  2. 2. m 10:03 pm 01/7/2014

    At Giulio

    Reposting the same thing on every article does not make you right.

    Link to this
  3. 3. rkipling 10:32 am 01/8/2014

    Thanks for the link back to Fischetti’s article. It is no longer shown on the Energy and Sustainability list.

    Link to this
  4. 4. Sisko 11:28 am 01/8/2014

    David Wogan writes- “the jet stream isn’t putting up as much of a fight lately. The reason, is that arctic sea ice is melting. Another factor is the role of snow in reflecting sunlight back to the atmosphere and strengthens the jet stream.”

    David Wogan- you might want to write that someone believes that is the cause but there are certainly climate scientists with other theories. Have you read the stadium wave paper by Wyatt? There is much to learn and despite those like you who seem sure of the cause the truth comes out over time

    Link to this
  5. 5. Squish 11:54 am 01/8/2014

    The natural variation vs. anthropogenic climate change is a reasonable area for debate.

    What I think is often overlooked is that base conditions have changed on which to expect variation. An analogy to this is that the NYSE can be up 20% over the year before but still have daily ups and downs. A record high is not solely attributable to daily fluctuations, but also based on the long-term trend. Or to use an increasingly popular metaphor: a baseball player may only get hits at a random rate, but steroid use will increase the likelihood that each hit makes it out of the park.

    The baseline that is often overlooked when commenters post about conditions from decades ago is that the arctic is much warmer today. Deniers need not disparage science, just look at business: look at Maersk’s evolving strategy for Arctic shipping, or the US Naval Institutes assessment for increased Arctic shipping; look at the increase in lobbying for Arctic oil exploration (Shell began exploration in 2012); look at how reinsurance companies are making new models to forecast the new risks involved in a warmer arctic. Or just watch Chasing Ice.

    http://www.ft.com/intl/cms/s/0/f44bd53a-2e74-11e3-be22-00144feab7de.html#axzz2ppJhjTbv

    Doesn’t it seem that the current variability is pegged around a new baseline – one empirically established by physical data, sound theory, and supported by government and business decisions alike – including oil?

    Link to this
  6. 6. Sisko 12:16 pm 01/8/2014

    Squish
    When you write- “Deniers need not disparage science”– what in your opinion is a “denier”???

    There are many differing opinions amoung climate scientists. Will more atmospheric CO2 warm the planet if other conditions remain unchanged? Answer- yes, but the debate is over how much and whether it will result in better or worse conditions for humanity–and where. The truth is that nobody knows the answers to those questions with sufficient fidelity to give a creditable answer.

    The margin of error for temperature change ranges from a rate of no significant concern to one of concern, and there is no reliable data to tell us if other conditions will change in a positive or negative manner due to any warming that does occur.

    Link to this
  7. 7. cjschnurr 12:31 pm 01/8/2014

    You know, I’d accept the data as presented if it went further back than the beginning of the global cold spell that had everyone yammering about global cooling. Showing snow cover in decline from the beginning of this same cold spell is grossly misleading and dishonest. Of course it will be in decline from the record cold in the 70s. Show me arctic snow/ice cover beginning from 1900 forward.

    Link to this
  8. 8. cjschnurr 12:34 pm 01/8/2014

    I’ll also add, if declining ice is the cause of this so-called polar vortex, please explain the temperature records broken from the 1940s in terms of cold. Was global warming the cause of similarly cold temperatures in the 1940s?

    Link to this
  9. 9. sault 2:06 pm 01/8/2014

    Sisko,

    This is an incorrect statement:

    “Will more atmospheric CO2 warm the planet if other conditions remain unchanged? Answer- yes, but the debate is over how much and whether it will result in better or worse conditions for humanity–and where. The truth is that nobody knows the answers to those questions with sufficient fidelity to give a creditable answer.”

    We do know that CO2 traps heat and that extra heat is changing the climate. There are a range of estimates concerning how bad or how quickly that warming will happen, but those estimates range from bad to catastrophic. However, as we continue to emit CO2 without care, the odds for catastrophic climate change become higher and higher.

    It’s like the dangers of a poor diet, low activity level and / or smoking. We don’t know EXACTLY which twinkie will give somebody diabetes or a heart attack, or EXACTLY which cigarette will give somebody lung cancer, but we DO know that continuing to live an unhealthy lifestyle increase the odds and severity of a wide range of health problems. It’s better to cut down on the causes of a problem ahead of time instead of dealing with the consequences later on, don’t you think? It’s just like how toothpaste and good brushing habits are a lot cheaper and easier than a dozen root canals, right?

    Besides, all the nasty pollution that comes off of fossil fuels BESIDES CO2 costs our economy hundreds of billion$$$ every year. In terms of direct subsidies to fossil fuels, and indirect subsidies like dealing with the property damage / healthcare costs / reduced worker productivity / premature death that fossil fuel pollution causes, the IMF recently determined that all this adds up to $1.9 TRILLION a year:

    http://www.washingtonpost.com/blogs/wonkblog/wp/2013/03/27/imf-want-to-fight-climate-change-get-rid-of-1-9-trillion-in-energy-subsidies/

    I just wish global energy would operate by free market principles instead of getting led astray by unfair government policies that favor one group of technologies over all others…

    Link to this
  10. 10. singing flea 4:23 am 01/9/2014

    Sisko posed the question of what is a denier of AGW. The answer is deceptively simple. It has nothing to do with politics or carbon credits. It is all about simple math. Either you can do the math or you can’t. The average 6th grader can do simple averaging equations. What does this say about the average Republican?

    Its not rocket science or Google level computing power to calculate an average. Even easier is just looking around. When 95% of the worlds glaciers have shrunk and only 5% have grown, it’s getting warmer, not colder on the average. Pointing to a cold snap on 10% of the earths surface, or a ship stuck in the ice in a frozen sea does not mean the rest of the world is cooling down. If you can’t figure out why, then you fall into that half of the population that is below average intelligence. On a political level it’s easy to figure out which half that is too.

    Link to this
  11. 11. Sisko 10:16 am 01/9/2014

    Saulty

    You wrote- “There are a range of estimates concerning how bad or how quickly that warming will happen, but those estimates range from bad to catastrophic.”

    LOL– Wrong again!!!

    There are also many estimates that the changes will be so gradual that the are easily adapted to and will result in benefits for much of the planet. Only in your religious like belief system must any change be negative. The climate has always been changing and humans can and will adapt.

    Link to this
  12. 12. sault 10:58 am 01/9/2014

    Sisko,

    And you FAIL to provide any links to these “estimates” once again! Could it be that you don’t want to get caught peddling lies for the fossil fuel industry again?

    Link to this
  13. 13. Sisko 12:12 pm 01/9/2014

    Sault

    You are an idiot- Try reading outside of Skeptical Science. http://judithcurry.com/2014/01/08/the-fundamental-uncertainties-of-climate-change/

    http://judithcurry.com/2014/01/06/ipcc-ar5-weakens-the-case-for-agw/

    http://judithcurry.com/2013/08/13/impact-of-climate-population-and-co2-on-water-resources/

    http://ca.answers.yahoo.com/question/index?qid=20130902031202AAp02J2

    David Wogan

    It looks like you have been described as a media idiot.
    http://judithcurry.com/2014/01/07/is-global-warming-causing-the-polar-vortex/

    Link to this
  14. 14. Sisko 12:16 pm 01/9/2014

    http://www.nybooks.com/articles/archives/2012/aug/16/climate-contrarians/?pagination=false

    Link to this

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