WEIRD WINTER: The record-breaking snowfalls of 2009-10 in the eastern U.S. resulted from the combination of two periodic weather phenomena, experts say.
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Just six months ago residents of the eastern U.S. were shoveling themselves out of the snowiest winter ever—weather that prompted mockery of global warming among some people. Now, scientists have a new explanation for why such anomalous snowstorms can coexist with global warming: The storms were kicked up by the convergence of two natural, large-scale weather patterns.
In order to better understand possible triggers of last year's media-dubbed "snowmaggedon," a team of scientists from Columbia University's Lamont–Doherty Earth Observatory analyzed more than 50 years of snow data as well as measurements of atmospheric pressure and sea-surface temperatures. They found that a combination of El Niño (periodic sea-surface warming in the tropical Pacific Ocean) with an unusual period of decreased variability in atmospheric pressure across the North Atlantic (known as the North Atlantic oscillation, or NAO) frequently results in a pile-up of snow in the mid-Atlantic region.
The NAO is a fluctuating pattern of air-pressure, extending from an area of low pressure that hovers over Iceland to a high-pressure region near the Azores, which helps to control the strength and direction of winds and storms across the Atlantic. When the NAO enters a negative phase, as it did last winter, the Icelandic low and the Azores high do not reach their respective pressure extremes. This causes freezing Arctic air to descend along North America's east coast. The researchers suggest that when those colder temperatures combined with the increased moisture delivered by El Niño, a greater amount of the precipitation in the area fell as snow.
The researchers were also able to use the atmospheric data to compute expected snowfalls for the 2009–10 winter, and found that their calculations matched well with what actually occurred.
A record-breaking 141.9 centimeters of snow buried Washington, D.C., last year, compared with the long-term average of 38.6 centimeters for the region.* Parts of Baltimore and Philadelphia were blanketed with more than 175 centimeters. Northwestern Europe was also cold and particularly snowy.
"What happened this past winter has nothing to do with climate change," says Richard Seager, senior research scientist and lead author of the study, which was published online July 26 in Geophysical Research Letters. He explains that although he does not doubt that human activity is altering the climate, individual weather events like last winter's blizzards cannot be used to make arguments for or against the reality of climate change.
Mark Serreze, director of the National Snow and Ice Data Center at the University of Colorado at Boulder who was not involved in the study, agrees. "What we saw last winter was just weather. The current heat wave is also weather," he says. He explains that although we have global warming, superimposed on the long-term warming trend are fluctuations in short-term weather patterns. "The NAO naturally varies between positive and negative phases, but last year it got stuck in a negative phase for a good part of the winter," Serreze says. "That was part of why it was so unusual."
Unfortunately, scientists will not be able to use this information to anticipate when massive snowstorms are likely to occur. Seager explains that El Niño events are predictable up to year in advance, because they are related to slowly evolving sea-surface conditions over the Pacific Ocean. By contrast, the NAO is primarily an atmospheric phenomenon, and is only predictable to the same extent as weather forecasting.
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25 Comments
Add CommentAs we all already know, wheather is one thing, climate something else. Because this is so by definition there could not be too many views of this.
Reply | Report Abuse | Link to thisWe also know wheather can be cold one year and hot next year as a natural variation in long term trends which has been warmer and warmer since the 15th century.
What we don´t know is why climate is warmer than the trend app. 30 years and then cools down the next 30 years.
That is why the AGW was accelerating from late 70´s untill
some 7 years ago. Now there is no wariming trend so there is much to explain to the "scientists" and will be until 2030-2035. "AGW is having a pause" will not do as an scientific explanation any more.
There is a curious thing in this article: "A record-breaking 141.9 meters of snow buried Washington, D.C., last year..."
Reply | Report Abuse | Link to thisI surely hope it was not METERS but centimeters.
If it was meters I think I have go from being sceptic to being absolutly convinced that the science is corrpupted.
(of course I am joking)
I have the most respect for scientists quoted in this article, but they are insisting in speaking in the language of Science to an audience that mostly only know the language of English, and as such are contributing to the ongoing public confusion about global warming, climate change, and weather.
Reply | Report Abuse | Link to thisTo say any one particular weather event has "nothing to do with climate" is nonsensical in lay discussion. Weather events are an expression of the climate. And extreme events such as heat wave are part of the long-term trend in more frequent heat waves brought on by climate change.
To carry this logic to the extreme we could be having multiple killer heatwaves every year, but we would have to insist on note talking about climate change during any particular heat wave because that heat wave might have been the one that would have happened in absence of global warming.
To apply this logic in another realm where science has informed intense public debate, we would have to refuse any discussion of the risks of tobacco whenever a smoker died from lung cancer.
There are other serious substantive issues with this stance as well. To be absolutely rigorous, ALL weather events are now connected to climate change, because the fundamental character of the background condition that give rise to all weather patterns and events has changed, i.e. the atmosphere and oceans have warmed globally.
Further, to say that the event was caused by "weather patterns" not climate change, is to refuse to acknowledge that climate change has had an impact on weather patterns.
For more a detailed discussion of the science that illuminates the connections between climate change and weather events, see http://climateprogress.org/2010/07/27/snow-storms-consistent-with-global-warmin/
"Now there is no warming trend" ?
Reply | Report Abuse | Link to thisPlease crawl out of your hole now and then to look around.
The FACTS are simply overwhelming that the Earth is warming.
Now the East coast is sweltering in a heatwave. Weather and temperature have become irratic. Get used to it. I think it will get worse.
Reply | Report Abuse | Link to this""AGW is having a pause" will not do as an scientific explanation any more. " - Kookamunga
Reply | Report Abuse | Link to thisGiven that the first half of this year was the warmest ever recorded I have to agree with that statement.
The so called "pause" exists only in the tiny, polluted minds of those who can't seem comprehend the distinction between climate and weather.
You know the type of losers I am referring to. Right?
I think sometimes we get so caught up in the now we forget that there were other times that we had snowy winters. I remember snow up to my adult thighs in the 70's, 80's and 90's. Sadly I do believe because of our greed, we have trashed our envoronment and the weather is one of the results. Also we must remember the devices we used to track weather has changed, even in just a few short years.
Reply | Report Abuse | Link to thisOkay... EVEN IF last winter wasn't a random fluctuation it in no way stands as disproof of global warming.
Reply | Report Abuse | Link to thisFor starters, one of the predictions of potential consequences of global warming is the interruption of the conveyor currents. These currents moderate climate in places like Virginia, and Washington DC. Without them, over all warmer globe or not, Virginia winters would be more like Boston winters. Weather and climate are not the same things and if the general population thinks so then they need to do a little leg work and figure it out.
Yes Scientists would do well to engage the general public in a manner they find more accessible. Please bear in mind though that they are already using facts to fight people using rhetorical tricks and often losing. Simplifying the science only makes it easier for the rhetoric mill to mislead. So as usual in a relatively democratic government the public is going to have to shoulder some of the work in understanding this. If they fail to do so only a tiny share of the onus falls on scientists. The rest falls squarely on us.
It would be nice if we could streamline policy making and the legislative process to the point where the public could easily spot conflicts of interest. However that will not happen without some serious political will. We are letting the fox guard the henhouse and have only ourselves to blame.
Yes, it's complicated out there! All the more to question those who think they have all the answers on global warming. I don't think we have all the answers yet.
Reply | Report Abuse | Link to thisI don't think anyone sane thinks science has all the answers. Scientists certainly don't. Science is a tool (a whole kit really but lets pretend it's just one for a moment). It's not a perfect tool anymore than a hammer is perfect for driving in nails. Pointing out the shortcomings of a hammer when everyone else is trying to use marshmallows to drive nails is a bit of a stretch though.
Reply | Report Abuse | Link to thisjarmo says, "Now there is no wariming trend so there is much to explain to the "scientists" and will be until 2030-2035. "AGW is having a pause" will not do as an scientific explanation any more."
Reply | Report Abuse | Link to this*****************
Hmmm....you're definitely a denialist, not a skeptic, since the past decade was the warmest on record, and this year is on track to be the warmest year since records have been kept.
http://content.usatoday.com/communities/sciencefair/post/2010/05/2010-is-warmest-year-on-record/1
We've had 8 to 10 consecutive years of general cooling globally and you continue to talk about global warming. Most of your colleagues have changed their mantra to "climate change" so it will include cooling once the general public figures out that someone's trying to cook the books on weather issues, which equate nicely to big bucks for some and fewer bucks for the many.
Reply | Report Abuse | Link to thisYou have your facts twisted:
Reply | Report Abuse | Link to this> http://www.isthereglobalcooling.com/
> http://wattsupwiththat.com/2010/01/11/ipcc-scientist-global-cooling-headed-our-way-for-the-next-30-years/
> http://www.foxnews.com/scitech/2010/05/19/global-cooling-scientists-warming/
> http://www.dailytech.com/Temperature+Monitors+Report+Widescale+Global+Cooling/article10866.htm
> http://wmml.info/gkwp/?p=197
Global warming is about "carbon taxation" and nothing more. The same "scientist" that sounded the "global cooling" call in the 70s also sounded the "global warming" call in the 90s. Odd, no?
well, stan, sounds like you're one of those in line for "fewer bucks." but then, anyone whose understanding comes from foxnews deserves the misinformation.
Reply | Report Abuse | Link to thisThanks for the reply. Why am I not surprised that you only cited the FoxNews item, not the other half dozen or more? I'm a journalist, but I don't participate in imaginary tales of woe for profit. I'll leave that to those who continue to promote this global warming, now climate change ruse.
Reply | Report Abuse | Link to thisRight. I love post hoc explanations from scientists employed by the global warming socio-polital complex.
Reply | Report Abuse | Link to thisGary L Wade, MD
If you're a journalist, I'm the pope. Possibly "Journalist?" Journalist's check their sources and fairly report both sides, and they try never to caught up in looney conspiracy theories.
Reply | Report Abuse | Link to thisFrankly, I've read some information that blames the amount of snowfall last winter on the greater amount of water vapor in the atmosphere from the last ten years of warming? Not a contributing factor?
The cause of long term global warming is still scientifically just a theory. Since it has been revealed that over 8,000 temperature monitoring stations in cooler climates have been eliminated from the statistical data base, while many other monitoring stations have been located in warmer spots strongly influenced by external forces, such as air conditioning units exhaust blowing their air on the measuring devices. There is much theory about the impact of sunspots and their influence upon the earths weather, but since it does not FIT the emotional thoughtlessness, it is largely ignored by most media, teachers, and those ever political correct, (to keep their grants coming in) scientists.
Reply | Report Abuse | Link to thisSo, there you have it.
It is interesting that these scientists explain the recent past, but reiterate their inability to predict the future, except to say the earth is warming.
Reply | Report Abuse | Link to thisThe earth is warming, no question. The point made about individual stations having a local heat effect is very important; chopping down trees and installing a new runway will greatly affect the local climate for a weather station near an airport, for example.
The earth has a 1,400 year cycle of warming and cooling and coincidentally (or more likely not coincidentally), the global warming doom-mongers chose to date their assertion of man-made global warming from 1750, the lowest point of "the Little Ice Age".
Is man contributing to glabal warming? Maybe, but very slightly. It is most likely that the warming we are now seeing is a chiefly caused by natural events.
Try reading "The Chilling Stars" by Henrik Svensmark and Nigel Calder for a challenging hypothesis that explains why the global temperature changes on a regular 1,400 year cycle. The crux of this hypothesis is that cloud cover is very important to the global climate and clouds may be seeded by sub-atomic particles from outer space. From time to time, the earth's orbit around the sun oscillates away from a zone where the sun's magnetic field reduces the number of cloud-seeding sub-atomic particles, and this may explain the regular mini ice ages and intervening warm periods. (My apologies to the authors for any disservice by this very brief summary of their theory).
However, cloud cover records are almost non-existent, and they are very vague. Hopefully cloud-cover data will improve with satellites recording the weather.
Then you're the Pope.
Reply | Report Abuse | Link to thisGlobal warming probably does increase the amount of water in the atmosphere, so it's not surprising that when air lowers its temperatures during winter, the amount of snowfall is greater, as there was more water in the air to be transformed into snow. Also, all kinds of cyclonic weather, from depressions, to hurricanes are expected to increase, because heat produces atmospheric movements, the effect being more noticeable in the times of highs in the solar cycle. A high was expected around this year, but for unknown reasons, the sun is quieter and cooler than foreseen. The Iceland volcano eruption had also a cooling effect in the global warming, as dust storms from Sahara had in the birthplace of hurricanes. Providence really exists.
Reply | Report Abuse | Link to thisI continue to struggle to understand why so much attention is focused on "warming". It's clear that our atmosphere is indeed accumulating energy faster than it is dispelled. In human terms, a more energetic atmosphere does not automatically translate to warming, even though the long term effect results in a somewhat warmer atmosphere.
Reply | Report Abuse | Link to thisHas everyone forgot the gas laws?
Our atmosphere is expressing much of that added energy by becoming more rambunctious. If I had to make a prediction about the effects this may have on the weather, I'd have to simply say that the weather will become ever more unpredictable.
Add a degree or two to the over all average global temperature, and we all yawn, but having a storm hang your car in the neighbors tree will for certain get your attention.
The planet has a temper.
Who knew?
I love the way you said 'global warming is just a theory' in exactly the same way people say 'evolution is just a theory'. And you're mistaken for exactly the same reason, mainly that you don't know what 'theory' actually means for a scientist.
Reply | Report Abuse | Link to thisThe word you're looking for is 'hypothesis'; it's just too bad that that word doesn't apply, and your assertion is bunked before it even got off the ground.
Jgrosay, are you stating scientific fact?
Reply | Report Abuse | Link to thisjgorsay says:"Providence really exists."
Reply | Report Abuse | Link to thisThat's not science.
It's true though, and that matters.
You nailed it.
You also stated that: "Global warning probably does increase the amount of water in the atmosphere...."
Of course. It's a gas solution and it's lowering it's pressure in response to an increase in energy. Every living pilot knows that wet air is less dense than dry air. It's spending some of that energy putting more water vapor in solution, and it's not a giant surprise that more of it wrings out in suspension, ie, the difference between clear skies and clouds.
Good job!
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