Move Over Polar Vortex: A Tale of Two Extreme Storms

By Tom Yulsman | February 14, 2014 3:40 pm

Nature has really been dishing out the misery to millions of people on opposite sides of the Atlantic in the past few days.

It might be tempting to conclude that the cold and snow that has reached from Mississippi to Maine this week (as seen in the animation of satellite images above), and the extreme storms that have caused devastating flooding in the United Kingdom, each are separate examples of the kind of weather mayhem that just happens to occur from time to time. But this winter, these events have not been a time-to-time phenomenon. The cold and snow on one side, and intense wind and rain storms on the other, have come one after the other, starting in late December.

So how unusual is that, and what’s going on?

If a new scientific analysis is correct, the repeated bouts of extreme weather on either side of the Atlantic are indeed unusual — and both are manifestations of a chain of climatic “teleconnections” that reach half way around the globe and all the way to the tropics.

According to the new analysis, produced this week by the U.K.’s Met Office, they are tied together by a distorted and, in some places, unusually fast jet stream, abnormally warm sea surface temperatures in the West Pacific, and by a particularly intense polar vortex — not a weak one, as has been widely reported before.

And the analysis does not stop there. It also raises the possibility that the extreme weather may have gotten a boost from us, through human-caused climate change.

The report itself was cautious in its conclusions about climate change links, pointing out possible connections and saying that more research is necessary. But the head of the Met Office, Julia Slingo, went a little further. Here’s what she told reporters at a press briefing on Feb. 10 about what’s been happening (as quoted in the British newspaper the Independent):

“Is it consistent with what we might expect from climate change? Of course, as yet there can be no definitive answer on the particular events that we have seen this winter, but if we look at the broader base of evidence then we see things that support the premise that climate change has been making a contribution.”

Her comments are in contrast to what five prominent climate scientists have to say in a paper published today in the journal Science. They conclude that the recent discourse focusing on the possible connections between winter weather and climate change distracts from the bigger issue: that is, regardless of extreme winter weather, climate change is undoubtedly real, and that harsh winters are not what we really need to be concerned about going forward as the climate continues to change.

To this I might add a more down to Earth reaction: When you’ve just developed a sore throat, and then you sneeze, you don’t need to spend that much time wondering whether that particular sneeze is the result of the cold coming on, or perhaps a momentary allergic reaction to the cat that has just walked in the room. You’re getting a cold, and you know that means you’re going to be sneezing a whole lot more in coming days.

It is undeniably interesting to know whether these particular storms are connected to climate change. And it is without question important to pursue the question scientifically so that we might get a better idea of the types of things that could be headed our way — for planning on things like re-construction of sea walls in the U.K. But we don’t need to answer the question to know that the climate system has the equivalent of a cold, and that if we don’t take care, it could develop into pneumonia.

I’ll delve more deeply into these issues in a bit. But first, some details on what’s been happening, and how they may actually be linked together.

On Wednesday, the latest wintry mix of cold, ice and snow in the U.S. left Atlanta coated in ice. Throughout the Southeast, more than 600,000 people lost power. And then the misery spread northeast, leaving a region from Mississippi to Maine afflicted by cold, ice and snow.

Again.

U.K. extreme storms

On Wednesday, NASA’s Aqua satellite captured this dramatic image of the powerful cyclonic storm pushing across Ireland and into England, Wales and Scotland. (Image: NASA)

Meanwhile, across the Atlantic, the United Kingdom was hammered Wednesday by a powerful storm that brought 100 mile per hour gusts in places, torrential rain, and further devastating flooding. To make things even worse, a new deluge of a month’s worth of rain is forecast for some areas through the weekend — on top of record and near-record rains that have already fallen in January and February.

Scotland, for example, had its wettest December and southern England its wettest January since record keeping began in 1910. Moreover, this may have been one of the most exceptional periods of winter rainfall in England and Wales in 248 years or more.

The duration of this stormy weather “and the clustering of deep depressions has been a notable feature of this winter,” according to the Met Office report. Moreover, that astonishing storminess “was part of a hemispheric pattern of severe weather. More specifically, it has happened concurrently with the outbreaks of bitter, arctic cold across Canada and large parts of the United States, which have affected more than 200 million people.

The Met Office report documents in detail how the events on either side of the Atlantic have been connected — through strange twists and turns of the jet stream, and conditions half a world away in the tropics, where sea surface temperatures have been running anomalously warm.

abnormal jet stream extreme storms

Source: U.K. Met Office

You can see the contortions of the jet stream during January in this image from the Met Office report. The arrows show the direction of the winds in the upper troposphere, and the colors show their speeds in meters per second.

The red streak in the western Pacific is part of the Asian-Pacific jet stream. Follow it across the ocean and you’ll note a sharp upward buckling toward Alaska. This is a significant departure from the normal pattern. It contributed to exceptional warmth in Alaska in January.

Meanwhile, the downward buckling over the U.S. midsection allowed bitter cold to spill south.

Now, keep following the jet. It turns to the northeast, tracking up the U.S. East Coast, and then heads out over the North Atlantic. Here, it is known as the North Atlantic jet.

As it turns out, cold air from arctic outbreaks in the United States was able to enter this part of the jet stream — with dramatic effects. The temperature differential this introduced caused the jet to strengthen by as much as 30 percent, according to the Met Office report. And this, in turn, enhanced the formation of cyclonic storms, the very ones that have been pummeling the U.K.

But what’s the connection to the western Pacific Ocean? Check out this graphic:

precipitation anomalies extreme storms

Source: U.K. Met Office

Both show how the rate of precipitation varied from the long-term average during December (on the left) and January (on the right). Take a look at the western Pacific above Australia. Those purple areas indicate above normal rainfall rates.

That’s the area of the Pacific that has also been experiencing higher than average sea surface temperatures, and not just this winter but for the better part of a decade. There is a connection between warmer surface waters and enhanced precipitation: The warmth leads to greater evaporation and, as a result, more water vapor in the atmosphere. This provides more moisture for storms.

Now, go back to the maps and follow those curving dashed lines in each one. They trace areas of disturbances associated with precipitation across the Pacific, the Gulf of Mexico, up the Eastern Seaboard of the United States, out across the North Atlantic, and all the way to…

The United Kingdom.

The connections aren’t as simple and straightforward as these graphics and my shortened explanation might imply. Suffice it to say that the rainfall patterns seen in December and January in the western Pacific and eastern Indian Ocean are known to enhance the movement of disturbances in the Pacific. And in the eastern part of the ocean, they became entrained in the deep downward buckle of the jet stream this winter, which helped propel them up the east coast of the U.S. and then out across the Atlantic.

According to the Met Office report, once there the disturbances got a boost from the faster jet stream, and also from another source: a stronger than normal polar vortex — not a weaker one, as has been reported recently. This, in turn, helped whip up the succession of storms that have been battering the United Kingdom, the report says.

What’s the explanation for the discrepancy between what the Met Office is saying about the polar vortex and what other scientists have previously said? I’m not sure. I’m trying get some insight into that from Julia Slingo, head of the Met Office. When I learn something, I’ll update this post.

What about possible connections to climate change, particularly the storminess in the U.K.? The report cautiously points out that attributing changes in storminess and rainfall intensity to human-caused climate change will require development of climate models with the ability to simulate weather at the resolution of individual storms. But it also notes that models like this are just coming into use, so more definitive science on climate change connections to events such as these may be on the way soon.

With that caveat, the report notes a number of observations related to climate — the “broader base of evidence” that Slingo referred to in her press briefing — including these:

  • The persistence of the recent storminess is unusual, “and although clustering of storms is quite common, the continued run of deep depressions, through December, January and on into February, is not.”
  • Although the number of strong cyclonic storms in winter in the North Atlantic has not increased since 1871, the mean intensity of very strong cyclones has risen by quite a lot.
  • There is evidence that rainfall in the United Kingdom has been increasing in intensity. And globally, there’s “robust evidence” for an increase in the frequency and intensity of extreme rainfall events.
  • North Atlantic storms that take a relatively southerly track — typical of those that have battered the U.K. this winter — have been getting more intense.

And then there is the question of whether the strange contortions of the jet stream are related to a changing climate. From the report:

The persistence of the weather patterns affecting both the UK and also the US, where abnormally cold conditions have continued to affect the eastern and southern states through January, has raised questions about whether the jet stream is making greater excursions, north and south, and whether these waves in the jet stream are becoming more locked in one position. This is a critical question because it raises the possibility that disruption of our usual weather patterns may be how climate change may manifest itself.

What to make of all this?

Slingo told reporters that what we’ve been seeing is “consistent” with our understanding of the physics of climate change. On its surface, that seems reasonable. But dig deeper and its significance begins to weaken a bit.

As my colleague here at the University of Colorado, Roger Pielke, Jr., has tried to help me understand, if you think about it, just about everything is consistent with climate change. A day when it does not rain buckets is consistent with climate change. A week when the jet stream is not weirdly contorted and weather patterns appear more “normal” is also consistent with climate change. The sun shining, the clouds rolling in, the wind whipping the trees around my house right now — all of it is consistent with climate change.

How’s that? As Kevin Trenberth of the National Center for Atmospheric Research (and an author of the Science paper) has said on a number of occasions, all weather events are now taking place against the backdrop of a climate system that we’ve altered. So on some level, however small, climate change is involved in some way in all of them. But if all weather events have some sort of nudge from a changed climate system, then they’re all “consistent” with climate change.

So making the consistency argument for one particular set of events doesn’t really say very much. What we really want to know is how particular aspects of a changing climate system are contributing to particular kinds of weather events.

In their technical report, U.K. Met Office scientists did their best to help us with that. For example:

The climatological context discussed earlier was unusual, with the Atlantic jet stream being more intense and reaching further back into the tropical East Pacific than normal. Those factors in themselves would allow warmer and moister air to enter the storm systems. It is also the case that the sub-tropical Atlantic is now warmer than it was several decades ago and that too would act to enhance the moisture content of the storms.

My translation — with additional elaboration: We know that global warming can theoretically contribute to storminess by heating up the surface of the seas, which leads to increased evaporation and thus more water vapor available in the atmosphere to form storms. We also know that a warmer atmosphere can carry more moisture to begin with.

Now, combine that with a jet stream set up in a pattern that would shunt warmer and moister air from the western Pacific into developing storm systems. Then guide those storms along an abnormal path that winds up targeting parts of the U.S. as well as the United Kingdom. That is what the Met Office is saying we’ve seen this winter.

So there are plausible ways that climate change could have played an important role in both storms specifically. But “could” doesn’t mean “did.” So can scientists say definitively whether climate change acted in that way? The answer is no.

Perhaps more important, at least for me (because I don’t need yet another example of the impact of climate change to convince me that action is prudent), these two storms should tell us something about how we interpret our experiences of a world that is changing.

If the Met Office scientists are right, what we’ve been experiencing in the U.S. and U.K. are linked through a series of complex climatic teleconnections that span more more than half the globe. This reminds me that the weather I will experience when I step out the door in a little while is not some isolated event. Rather, it may well be the result of a chain of countless complex interactions spanning every latitude and every longitude, and across many different timescales ranging from seconds to decades. It’s all connected, all part of a living, breathing planet.

It also makes me see the wisdom of the “butterfly effect,” at least metaphorically. That’s the idea that in a non-linear system, the origins of hurricane in, say, the Atlantic Ocean, can actually be found in the flapping of a butterfly’s wings somewhere on the other side of the globe. In this case, the butterfly is that patch of warm water in the Pacific.

I also draw another lesson from the Met Office Report: that Earth scientist Wally Broecker of Columbia University’s Earth Institute was very wise when he said, “The climate system is an angry beast and we’re poking it with sticks.”

The thing about an angry beast is that it can surprise you. It might actually do something unexpected, something unbeastly. It might, for example, cower for a bit behind a tree. It might even run away. But then it may suddenly rise up with fury and swat you down.

Metaphorically, again, I get a sense that this is what we’re seeing with the climate system. That isn’t an expert scientific assessment. It’s coming from both my knowledge of climate science and from intuition. So take it for what its worth.

 

  • http://blogs.discovermagazine.com Longmire

    Somehow yours was more emotional but not sure on length.

  • Cheralynne T Kastner

    It’s not nice to fool with Mother Earth.

    She’s begun to change in earnest. She will do it because She makes the rules here.

    We once believed that spirits held sway. We believed our Mother provided for us when we did things the right way. We believed She punished us for breaking Her rules.

    We grew and learned to protect ourselves from the vagaries of the Earth. We moved water and mountains to accomadate US and forgot how harsh the earth actually is. We belived we had harnessed Her and She would do OUR biding.

    It is only humans who suffer from the hubris of believing that WE can control our enviroment and, by extension, the Earth’s.

    The punishment of drought and heat, of bitter cold in the wrong places, of raging wildfires and mega storm driven surges will seem all most mundane.

    She lives, She breathes.

    Surrender back Her fossil fuels, let her forests grow back to clean Her waters. Help Her replenish Her oceans

    Allow her to nuture all of the lives on this planet. Earth will continue no matter what WE do.

    • Buddy199

      how exactly do we surrender back fossil fuels?

      • Cheralynne T Kastner

        Stop using fossil fuels.
        We are addicted.
        Fossil Fuels Annonymous.

        • Buddy199

          Travel on donkeys and windmill powered jets.

          Live in teepees.

          Great plan.

    • Cheralynne T Kastner

      Yes, I use similtudes.

      Water is her blood.
      Her atmosphere her breath.
      Her body is the ground where we walk.

      If we continue to ignore the physics we will have only ourselves to blame.

      Physics does not care if we understand. The winds will blow for another 100 million years. The question is what kind of species will feel the wind.

  • http://blogs.discovermagazine.com Jennifer Mason

    Would that dogleg in the jet stream around Alaska also be responsible for the drought in California?

  • http://www.mazepath.com/uncleal/qz4.htm Uncle Al

    Would Jamestown, VA having a string of -40 degree winters indicate Climate Change? Would the Hudson River freezing three feet thick indicate Climate Change? If so, then we are returning to normal climate, 1600s through 1900.

    • guthrie

      Except that it is a lot warmer already than it was then. And it depends on the reason for it being so cold. If it is because everywhere was cooler, but today’s cold is due to climate change related changes in the jet stream moving colder arctic air further south, then we certainly aren’t returning to a ‘normal’ climate.

      • http://www.mazepath.com/uncleal/qz4.htm Uncle Al

        You are talking weather, I am talking climate. What you say has no bearing on my trending.

        • guthrie

          IN that case you’re making no sense, which is climate and which is weather? What trending are you talking about, given that the climate is definitely warmer on a global scale than the 1600-1900 period?

          • http://www.mazepath.com/uncleal/qz4.htm Uncle Al

            Exactly. Enviro-whinerism is criminal opportunism.

          • Tom Yulsman

            Uncle Al: As I’ve said before, if you want to be taken seriously, be serious. I welcome serious and well-argued debate here. But no ad homs and elementary-school name calling. And implying that an another commenter is an “enviro-whiner” and is guilty of “criminal opportunism” falls in those categories.

            It seems that it is difficult for you to resist that. So let me give you an incentive: If you keep doing it, you will be banned from the site. We’ll start at a week and see if that works.

            I value your contributions here when they stick to reasonable and rational debate. Please keep it to that.

  • Lorraine Surringer

    This is nothing to do with God, or Mother Nature, or ‘Global Warming’ – but it is everything to do with man-made intervention in the climate – geoengineering and HAARP – please look into these – as I have been monitoring the sky for the past 18 months and this is going on – fact- and admitted to in the House of Commons Report on the Regulation of geoengineering 2010. http://www.publications.parliament.uk/pa/cm200910/cmselect/cmsctech/221/221.pdf

  • Buddy199

    Just one question.

    What exactly would disprove the theory of AGW?

  • Jody Schmidt

    I will now attempt to track the number of articles, editorials and studies that claim that warming is causing cooling. There are many shades to this connection, but one way or another, it all boils down to the Arctic tundra you are witnessing out your door, and what seems like the ice age is upon us, is really caused by a warming planet.

    Within the past week alone I have come across the following:
    i. Trade winds are burying all that supposed extra heat in the ocean depths
    ii. Especially warm temperatures in the Arctic region are allowing a meandering jet stream and prolongation of winter in the temperate latitudes.
    iii. This article: Warm pacific waters are somehow causing this year’s brutal arctic blasts and endless blizzards

    There are dozens more just like this if I go back a year or two, that make the connection between global warmth causing global frigid.

    Note, it’s more of a word frequency study than an exact science study. More an indicator of bias than hard science – somehow, some way, something ‘warm’ is causing something ‘cool.

    This is almost certainly happening so that the global warming crowd doesn’t lose the million skeptics on the fence leaning toward denying it after experiencing one of the most brutally cold winters ever, over much of the northern hemisphere. It boggles the mind to consider how an increase in warmth could cause such an absence of heat over such a large area.

    • Tom Yulsman

      Thank you for these thoughtful comments Jody. I appreciate it.

      I think one lesson to draw from this is that any connection between global warming and extreme winter weather — if one exists — is a question at the cutting edge of science. Which means there are great uncertainties.

      I’d also emphasize what I said in the story, and what some leading climate scientists wrote in a commentary last week: Regardless of whatever connection may or may not exist, going forward more intense winter weather is probably NOT something we need to be concerned about above other impacts. The projected impacts from climate changes, and many of those already documented, fall in other areas. So, for example, I’m more concerned about the impact of heat on water resources and wildfire where I live here in Colorado. And if I lived in Miami, I’d be concerned about sea level rise — which is already causing big problems there.

  • Bella

    So much information! There is no doubt that this has been an intense, extreme winter for most of the country. There will likely always be debate as to what causes it–global warming, climate change, etc. –but that is one of the great things about science; debating, challenging the norms, and constantly searching for answers.
    http://www.orionweblog.com

  • james

    Just great! Now global warming “experts” are telling us a colder and more stormy than normal winter is caused by global warming. And the comments related to the southeast U.S.. are ludicrous. We have always had our share of winter storms.

NEW ON DISCOVER
OPEN
CITIZEN SCIENCE
ADVERTISEMENT

Discover's Newsletter

Sign up to get the latest science news delivered weekly right to your inbox!

ImaGeo

ImaGeo is a visual blog focusing on the intersection of imagery, imagination and Earth. It focuses on spectacular visuals related to the science of our planet, with an emphasis (although not an exclusive one) on the unfolding Anthropocene Epoch.

About Tom Yulsman

Tom Yulsman is Director of the Center for Environmental Journalism and a Professor of Journalism at the University of Colorado, Boulder. He also continues to work as a science and environmental journalist with more than 30 years of experience producing content for major publications. His work has appeared in the New York Times, Washington Post, Audubon, Climate Central, Columbia Journalism Review, Discover, Nieman Reports, and many other publications. He has held a variety of editorial positions over the years, including a stint as editor-in-chief of Earth magazine. Yulsman has written one book: Origins: the Quest for Our Cosmic Roots, published by the Institute of Physics in 2003.

ADVERTISEMENT

See More

ADVERTISEMENT
Collapse bottom bar
+

Login to your Account

X
E-mail address:
Password:
Remember me
Forgot your password?
No problem. Click here to have it e-mailed to you.

Not Registered Yet?

Register now for FREE. Registration only takes a few minutes to complete. Register now »