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Posted at 11:00 AM ET, 10/25/2010

Arctic sea ice loss linked to severe U.S. winters

By Andrew Freedman

* Warm, a bit showery: Full Forecast | The Mall in fall *

Arctic sea ice extent at the end of the 2010 melt season (solid white) was 22 percent below the 1979-2000 average (red outline) and the third-lowest in the satellite record.

Last winter's record wallops of heavy snow had many in the mid-Atlantic wondering what happened to global warming. If the planet were warming as scientists say it is, shouldn't we be receiving less snow? (Not necessarily, I reported at the time). Now comes word that, paradoxically, cooler winters with heavier snowfall in regions such as the mid-Atlantic may be connected to rapid warming and sea ice loss in the Arctic.

In other words, Arctic climate change, which studies have concluded is likely due in part to human activities, could favor cooler and snowier winters in places far removed from the far north.

Of course, this would not hold true in every winter, since multiple natural climate factors, such as El Nino in the Pacific Ocean and the North Atlantic Oscillation (NAO) in the Atlantic, compete for influence over the region's weather, in addition to longer-term climate change. But a new "Arctic Report Card" released last week by the National Oceanic and Atmospheric Administration (NOAA) and prepared by an international team of researchers contains curious insights into how Arctic climate change, which may at first seem disconnected from events here at home, may be influencing weather patterns in the northern mid-latitudes.

As Nick Sundt reports on the WWF climate blog, the Report Card discusses the aptly named "Warm Arctic-Cold Continents" pattern that existed last winter, and ties it in part to sea ice loss from a warming climate.

In the atmosphere section of the lengthy report, the authors write: "There is evidence that the effect of higher air temperatures in the lower Arctic atmosphere in fall is contributing to changes in the atmospheric circulation in both the Arctic and northern mid-latitudes. Winter 2009-2010 showed a new connectivity between mid-latitude extreme cold and snowy weather events and changes in the wind patterns of the Arctic; the so-called Warm Arctic-Cold Continents pattern."

Two of the three authors of the atmosphere section of the report - Jim Overland of NOAA and Muyin Wang of the University of Washington - published a study last year on changes in atmospheric circulation related to Arctic warming and sea ice loss that came to similar conclusions, but without the benefit of observations during the anomalous winter of 2009-2010.

As detailed in the Report Card, a key reason why Arctic air temperatures have warmed in the fall and winter is because of greater sea ice loss during the summer melt season. Sea ice is white in color, and therefore it efficiently reflects incoming solar radiation, cooling the ocean and lower atmosphere. But when sea ice melts, the darker ocean waters are exposed to the sun, which boosts both water and air temperatures. This phenomenon is known as "Arctic amplification."

The ensuing warming raises the height of atmospheric pressure surfaces (known to meteorologists as "geopotential heights") over the North Pole. In fact, the report notes that the winter of 2009-2010 featured "one of the three largest Arctic high-pressure events since 1850." The higher pressure surfaces are thought to change large-scale wind patterns and can lead to bouts of severe winter weather in the eastern United States and East Asia.

Possible impacts of sea ice loss on atmospheric circulation in the northern mid-latitudes. Credit: NOAA.

A related NOAA website states: "Although progress towards a comprehensive understanding of the connection between Arctic sea ice and climate has been slow, sea ice has been recognized as the primary means by which the Arctic can impact the global climate."

Arctic sea ice at the end of the 2010 melt season was the third-lowest in the satellite record, which dates back to 1979. In a study published in June researchers used "proxy" records, such as sediment cores, to extend the record of sea ice extent much further back in time, and found that recent ice loss is unmatched over at least the last few thousand years. The causes of sea ice loss include both warming related to emissions of greenhouse gases as well as natural variability.

The Report Card appropriately cautions that Arctic warming is just one factor influencing U.S. and Eurasian weather, but it notes that it may become a more prominent driver in coming years if recent warming and melting trends continue. It states:

"While individual weather extreme events cannot be directly linked to larger scale climate changes, recent data analysis and modeling suggest a link between loss of sea ice and a shift to an increased impact from the Arctic on mid-latitude climate. Models suggest that loss of sea ice in fall favors higher geopotential heights over the Arctic. With future loss of sea ice, such conditions as winter 2009-2010 could happen more often. Thus we have a potential climate change paradox. Rather than a general warming everywhere, the loss of sea ice and a warmer Arctic can increase the impact of the Arctic on lower latitudes, bringing colder weather to southern locations."

The Arctic Report Card contains richly detailed information on all aspects of the rapidly changing Arctic environment, including updated data on the melting of Greenland's ice sheet. It is well worth reading in order to understand the profound, and potentially irreversible, transformation taking place at the top of the planet.

The views expressed here are the author's alone and do not represent any position of the Washington Post, its news staff or the Capital Weather Gang.

By Andrew Freedman  | October 25, 2010; 11:00 AM ET
Categories:  Climate Change, Freedman  
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Global Warming.....another day, another excuse.

Posted by: MMCarhelp | October 25, 2010 11:49 AM | Report abuse

Isn't this interesting. Just from a lay perspective ... I bet what would happen with this is having all the arctic air in over us will keep us colder than "normal," meaning where before we'd get mix events, we're more likely to get all snow. So anytime we get a big storm that would have mixed, we're more likely to get snow than to get rain.

And I'd also be willing to bet that it'll happen in a North Carolina-like pattern where, say, the farther west you happen to be of 95 the more snow you get with amounts lessening toward the bay.


Are there any models of this nature locally?

Posted by: AdmiralX | October 25, 2010 12:02 PM | Report abuse

Hi Andrew

Nice report. From an atmospheric dynamicists perspective, this argument has always made good sense. Back-of-the-envelope reasoning could go as follows:

Warmer Poles lead to weaker jetstreams (assuming everywhere else doesn't warm at the same rate). These weakened jets allow for larger wave amplitudes (wave activity), which in turn foster more blocking. These blocking patterns (like we saw much of last winter) are associated with *reversals* of the typical north-south temperature gradient (which is cold in the north/warm in the south in the NH), thereby allowing unusually cold air to visit southern latitudes.


Posted by: gregpostel | October 25, 2010 12:08 PM | Report abuse

Showing the ice extent at the end of melt season is odd because it has nothing whatsoever to do with arctic ice and temperatures in the winter. When we had our severe weather here last winter, there was plenty of ice in the arctic. The arctic didn't "remember" that it had less ice the previous summer.

Greg, you should probably consider that the blocking patterns are much more a factor of lowered UV from the sun. See Lockwood for reference 25 and others in that article.

In general though, this is another alarmist tempest in a teapot, trying to attribute natural variations to manmade causes. There are many more natural factors that the authors refuse to consider because they already have the answer before they start the research.

Posted by: eric654 | October 25, 2010 12:37 PM | Report abuse

eric564: No, it's not odd to show Arctic sea ice extent and then discuss winter weather patterns, and this is evident in my discussion and in the NOAA materials & peer-reviewed literature. Arctic sea ice loss during the spring and summer adds warmth to the Arctic climate (primarily by heating the ocean waters), and this heat dissipates slowly in the fall/winter as it released into the air. Fall and wintertime Arctic warming has been much larger than in the summer months, actually, and this is partly due to sea ice loss.

Posted by: afreedma | October 25, 2010 12:45 PM | Report abuse

I don't buy it - yet. I certainly believe that changes in the arctic sea ice are likely to eventually effect overall climate in some way.

But to me the evidence for the the the linkages and mechanisms regarding the arctic and winter storms as described ("Warm Arctic-Cold Continents", etc) is rather tenuous; too much so to generalize from events of recent years, data sparcity, and model simulations.

My feelings are best described by the summary at the end of the referenced NOAA site.

Posted by: SteveT-CapitalWeatherGang | October 25, 2010 12:49 PM | Report abuse

This argument was advanced as a cause for the Ice Ages when I was young...when there was no ice in the Arctic Ocean more moisture evaporated into Arctic air masses and fell as snow over the continents during the winter. During a succession of mild winters and cool summers more snow fell than could melt during the summer. This snow recrystallized into glacial ice and began moving southward as continental glaciers.

Nowadays the theory behind Ice Ages tends to involve several factors, among them changes in the Earth's orbit, changes in the Earth's inclination towards the Sun [the Tropics of Cancer and Capricorn tend to move closer to and further from the Equator on a regular cycle] the precession cycle, possible shifts in polarity of the magnetic poles, the Milankovitch cycle, continental drift and possibly even changes in solar energy output. It is still possible, though, that a string of "warm Arctic/cold continent" winters, coupled with cool summers, could be the trigger that sets an Ice Age in motion when the other factors are already in place. As far as geologic epochs are concerned, we may still be in the "Pleistocene" epoch [barely a million years old]; most geologic epochs last ten to three hundred million years--thus the "Holocene" and "Anthropocene" are but subdivisions of the current epoch as may be the "Pleistocene" as currently defined.

Posted by: Bombo47jea | October 25, 2010 12:56 PM | Report abuse

Hi eric564

No. Blocking occurs all the time, around the world on timescales less than a week, in ways effectively immune to changes in the solar forcing. Bigtime cyclogenesis events can create blocks. So can the fluxes of potential vorticity (PV) associated with anomalous heating in the tropics (e.g., a hurricane). Don't look now, but there's anomalous anticyclonic flow near the pole as I write this. The redistribution of the gradients of PV which are associated with blocking occurs for *many* reasons. And, warming the poles is one of them.

The article you mentioned talks about a slow-manifold modulation of blocking frequency in association with solar changes, which in turn, *could* modify the propagation patterns of the cross-tropopause wave activy fluxes in a way that changes the blocking patterns. That may be true, but it has nothing to do with the modulation of the wave activity patterns associated with warming poles. ZERO.

Kinda reminds me of an argument that some pose regarding global warming ... i.e., that we'll be in an ice age in 10k years. Right. But that has nothing, *nothing* to do with the feedback from anthropogenic forcing on timescales of a human generation.

My Ph.D. was founded on the understanding of blocking in geophysical flows.

greg postel

Posted by: gregpostel | October 25, 2010 1:25 PM | Report abuse

Hi eric564

The last line of the 1st paragraph in my response to you should be, "warming the poles *could be* one of them". I'm not arguing for the case that the poles are in fact warming ... I'm discussing how blocking configurations are borne and that the physical line of reasoning of warming poles is *consistent* with more of them.

sorry for the confusion


Posted by: gregpostel | October 25, 2010 1:33 PM | Report abuse

We are not supposed to refer to global warming deniers, but referring to "alarmists" is OK???

In the arctic winter of 09/10 was the ice thin enough to let an appreciable amount of heat flow from the ocean to the atmosphere? Do we know? Was the ice more porous than normal?

If the Arctic was warmer due to some reason, I do think that would tend to force positive height anomalies there and negative height anomalies in midlatitudes. But why would it be warmer in winter now?

I would like to see evidence of a mechanism.

As for solar-weather connections....
I have much less confidence in such mechanisms.

Posted by: Dadmeister | October 25, 2010 1:38 PM | Report abuse

On a simple note, how sad is it that supposedly grown adults could not discern the difference between *temperature* and *precipitation*? We got a lot of snow this past winter, and the deniers like Jim DeMint were jumping up and down that it was evidence that the *temperature* (globally, no less, based on our local experience) couldn't be going up. How sad is it that that passes for human cognition here in 2010?

Posted by: B2O2 | October 25, 2010 2:14 PM | Report abuse

First question Greg, since "Blocking occurs all the time, around the world on timescales less than a week, in ways effectively immune to changes in the solar forcing" why isn't blocking effectively immune to the increase in Arctic temperature also? Can you explain the difference between "slow-manifold modulation of blocking frequency" and "modulation of the wave activity patterns associated with warming poles"? Final question, is there a measurable difference between blocking patterns in the warming Arctic and those in SH winter in the cooling Antarctic.

Andrew, well sort of. Clicking through the yearly graphs here I see some warming in some winters against the average. The fluctuations seem like a more dominant factor to me, both above and below the average (way above in some cases). Do you know if those upward anomalies are associated with blocking? I suppose a graph of blocking index could be generated to look for a correlation although that would not prove causation.

Posted by: eric654 | October 25, 2010 2:27 PM | Report abuse

Hi eric654,

First of all, sorry if I sounded like a jerk in my prev. response. I didn't mean it to be that way, there were other things going on at the time here.

OK, this hopefully helps: *Individual* events are effectively immune to those, too. Blocking can and does occur with frequencies much faster than those of the environment within which it resides (and to some degree controls it). An analogy: capillary wave action superposed on a big swell.

What is not true is your assertion: "... the blocking patterns are much more a factor of lowered UV from the sun." This is what I was addressing.

Changes in the basic state flow (the environment that houses these events) can change the *statistics* of the events. As I said, it may be true that the solar forcing can alter these. But I also said that regardless, a physical mechanism by which a warming of the Poles would do that too can be addressed independently. In my first response to Andrew's article, I was trying to outline a line of physical reasoning why a warming of the poles -via a change in the statistics of blocking- could make the midlatitudes cooler.

Regarding Southern hemi vs. Northern hemi blocking stats ... I'm not sure.


Posted by: gregpostel | October 25, 2010 2:59 PM | Report abuse

Paper: Current Arctic Sea Ice is More Extensive than Most of the past 9000 Years

Abstract: Cores from site HLY0501-05 on the Alaskan margin in the eastern Chukchi Sea were analyzed for their geochemical (organic carbon, d13Corg, Corg/N, and CaCO3) and palynological (dinocyst, pollen, and spores) content to document oceanographic changes during the Holocene. The chronology of the cores was established from 210Pb dating of nearsurface sediments and 14C dating of bivalve shells. The sediments span the last 9000 years, possibly more, but with a gap between the base of the trigger core and top of the piston core. Sedimentation rates are very high (*156 cm/ka), allowing analyses with a decadal to centennial resolution. The data suggest a shift from a dominantly terrigenous to marine input from the early to late Holocene. Dinocyst assemblages are characterized by relatively high concentrations (600– 7200 cysts/cm3) and high species diversity, allowing the use of the modern analogue technique for the reconstruction of sea-ice cover, summer temperature, and salinity. Results indicate a decrease in sea-ice cover and a corresponding, albeit much smaller, increase in summer sea-surface temperature over the past 9000 years. Superimposed on these long-term trends are millennial-scale fluctuations characterized by periods of low sea-ice and high sea-surface temperature and salinity that appear quasi-cyclic with a frequency of about one every 2500–3000 years. The results of this study clearly show that sea-ice cover in the western Arctic Ocean has varied throughout the Holocene. More importantly, there have been times when sea-ice cover was less extensive than at the end of the 20th century.

Posted by: orkneygal | October 25, 2010 4:17 PM | Report abuse

I too have researched and written papers on atmospheric blocking.

One thing is manifestly clear: blocking is incredibly complex involving dynamical and physical processes within and between scales of atmospheric circulation from global to mesoscale.

As such there is no conceivable way the miniscule energy associated with changes in solar activity can affect the evolution of any given or series of blocking episodes.

Not incidentally the complexity of blocking explains the extreme difficulty in reliably predicting the onset (or demise) of blocks. But, once established, they tend to persist and remain nearly stationary for at least several days, such that associated weather is generally more predictable than average.

The same is relevant to the high latitude blocks associated with the NAO and, thereby, to the odds and predictability of snowstorms such as we had last winter.

Posted by: SteveT-CapitalWeatherGang | October 25, 2010 4:20 PM | Report abuse

Hi SteveT-CapitalWeatherGang

I think the whole solar forcing issue has to do with a year-to-year modulation of wave guides and critical layers. We know solar forcing is too small to affect individual events. The argument, I think, instead refers to the long term statistics of blocking patterns. I don't know if it has any merit. But I do know, that if you change the basic-state jetstream patterns, the blocking will be different. And a warming of the Poles in the mean is physically consistent with a change in both.

greg postel

Posted by: gregpostel | October 25, 2010 4:36 PM | Report abuse

Thanks for the answers Greg. The paper I saw with Antarctic and Arctic blocking trends (sorry can't locate it now) showed an uptick in Antarctica but less of a linear trend from 1958-2007 (IIRC). The arctic linear trend over the interval was higher (perhaps due in part to warming). But what was interesting was an uptick at both poles in recent years. That suggests that a worldwide factor other than warming has increased the blocking.

Steve, the UV argument is not an energy argument (TSI or just UV). Certainly UV represents a small amount of energy, but its affect on stratospheric temperatures (one of the factors in blocking) is quite significant. I would not simply dismiss it.

Posted by: eric654 | October 25, 2010 4:59 PM | Report abuse

One thing I should add is that if it is true that warming poles means more blocking, then that would be (another) example of weather being a negative feedback. This is because more blocking on a worldwide average basis means cooling (or less warming from increased CO2 than there would otherwise be). The essential mechanism is the uneveness of water vapor. As the weather patterns stop, then the dry areas get drier and the wet areas get wetter both on the ground and in the atmosphere.

I also agree with what Steve says which is that blocking is a complex phenomenon which also means that climate sensitivity as it is affected by blocking is also complex.

Posted by: eric654 | October 25, 2010 5:18 PM | Report abuse

I agree that any effect of changes in solar activity on blocking (or anything else) would be sytematic over the long term, not affecting individual events. However, some seemingly reputable scientists appear to be saying just that (e.g., here).

In any event, to the best of my knowledge, there is no demonstratable evidence there has been any change in the basic state of jet stream patterns. If there were, there is no reason a priori to believe it would be a significant function of solar activity. It might be demonstrated so in the future (I doubt it), but anything more for now is just reasoable conjecture.

I know it's not an energy thing with UV - just used this term (not wisely) for simplicity. Stratospheric warming is one (and only one) factor in blocking, but have no reason to believe it's a necessary ingredient. I'd be pleased to know if you have any evidence otherwise.

Posted by: SteveT-CapitalWeatherGang | October 25, 2010 5:38 PM | Report abuse

Some of you are missing the real point. The CAGW folks have been forecasting warmer winters and less snow for some time. With the Pacific Ocean (PDO) turning cold after decades of warming influence, and the Atlantic (AMO) probably about to turn cold, they need a way to keep the global warming hysteria going as we experience probably thirty years of cold and colder winters.

This is just more gravy train protection for the CAGW warmist crowd. Otherwise colder weather several years in a row would call into question their passionate belief that the world is warming, the ice is melting, etc.

Posted by: AGWsceptic99 | October 25, 2010 6:13 PM | Report abuse

I have no evidence of a cause-effect relationship from stratospheric warming to blocking. There seems to be a correlation in some cases. It's interesting that stratospheric temperatures drop with increased CO2. If that in turn causes less blocking then there is more global warming: a positive feedback.

But we are also just coming out of the low point of the solar cycle so UV has been low for that reason. So the stratosphere should be cooler. Ozone decreases also decrease stratospheric temperatures. But this simulation of the Maunder minimum shows that ozone increased, but stratospheric temperatures cooled. The interesting part of that study was that the model runs produced relatively negative AO and NAO during the Maunder minimum. So perhaps more negative AO like last winter is in our future supplemented with blocking caused by the Arctic warming.

Posted by: eric654 | October 25, 2010 7:25 PM | Report abuse


Yeah, perhaps, maybe, possibly, could, might, may, etc....concerning connections to AO/NAO. I see what you are saying, but again it's simply conjecture without sufficent support to take seriously, at least not yet.

BTW: The model used in the simulation (2002 vintage) you reference is not one I would place much confidence.

Posted by: SteveT-CapitalWeatherGang | October 25, 2010 8:30 PM | Report abuse

Global warming is going to freeze us to death!

Posted by: Tom8 | October 26, 2010 12:57 AM | Report abuse

is the ice in winter in the Arctic significantly lower now than before?
Is it significantly thinner so that significantly more heat can escape from
the ocean to the atmosphere?

If not, then I don't see what insitu forcing would make the Arctic temperatures warmer now in the middle of winter and I would question that this mechanism is responsible for the past winter.

In the future when warming does cause winter ice to be less and/or enough thinner to increase the oceanic heat flux to the atmosphere, then the mechanism is quite believable and would make midlatitude heights and temperatures lower than they would be otherwise. Since global warming would be occuring in midlatitudes as well, they might not be lower than the average now, just lower than they would be otherwise.

There has been a lot of work done on solar-weather relationships over the last 50 years and my impression is very little has been found. My impression is that some people try too hard to find any explanation
other than anthropogenic global warming.

Posted by: Dadmeister | October 26, 2010 10:14 AM | Report abuse

is the ice in winter in the Arctic significantly lower now than before?
Is it significantly thinner so that significantly more heat can escape from
the ocean to the atmosphere?

If not, then I don't see what insitu forcing would make the Arctic temperatures warmer now in the middle of winter and I would question that this mechanism is responsible for the past winter.

In the future when warming does cause winter ice to be less and/or enough thinner to increase the oceanic heat flux to the atmosphere, then the mechanism is quite believable and would make midlatitude heights and temperatures lower than they would be otherwise. Since global warming would be occuring in midlatitudes as well, they might not be lower than the average now, just lower than they would be otherwise.

There has been a lot of work done on solar-weather relationships over the last 50 years and my impression is very little has been found. My impression is that some people try too hard to find any explanation
other than anthropogenic global warming.

Posted by: Dadmeister | October 26, 2010 10:15 AM | Report abuse

Global Warming this, Global Warming of our esteemed bloggers here put it best last year - it doesnt need to be THAT cold to snow a lot here in the Mid-Atlantic; it just needs to be cold ENOUGH.

Posted by: DullesARC | October 26, 2010 10:40 AM | Report abuse

Arctic Ice Rebound Predicted

Man is not the primary cause of change in the Arctic says book by Russian scientists

“…scientists have predicted a significant decrease in sea-ice extent in the Arctic and even its complete disappearance in the summertime by the end of the 21st century. This monograph presents results of studies of climatic system changes in the Arctic, focussed on ice cover, that do not justify such extreme conclusions.” “Many studies and international projects, such as the Arctic Climate Impact Assessment (ACIA), attribute the air temperature increase during the last quarter of the 20th century exclusively to accumulation of greenhouse gases in the atmosphere. However these studies typically do not account for natural hydrometeorological fluctuations whose effects on multiyear variability, as this monograph shows, can far exceed the anthropogenic impact on climate.”

Posted by: orkneygal | October 28, 2010 6:14 PM | Report abuse

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