From the Institute of Physics
Cold winters caused by warmer summers, research suggests
Scientists have offered up a convincing explanation for the harsh winters recently experienced in the Northern Hemisphere; increasing temperatures and melting ice in the Arctic regions creating more snowfall in the autumn months at lower latitudes.
Their findings may throw light on specific weather incidents such as the extremely harsh Florida winter of 2010 which ended up killing a host of tropical creatures, as well as the chaos-causing snow that fell on the UK in December 2010.
Published today, Friday 13 January, in IOP Publishing’s journal Environmental Research Letters, this new research suggests that the trend of increasingly cold winters over the past two decades could be explained by warmer temperatures in the autumn having a marked effect on normal weather patterns, causing temperatures to plummet in the following winter.
The strongest winter cooling trends were observed in the eastern United States, southern Canada and much of northern Eurasia, which the researchers, based at Atmospheric and Environmental Research (AER), the University of Massachusetts and the University of Alaska Fairbanks, believe cannot be entirely explained by the natural variability of the climate system.
Their results showed strong warming throughout July, August and September in the Arctic, which continued through the autumn and, according to their observational data, appeared to enhance the melting of sea ice.
This warmer atmosphere, combined with melting sea ice, allows the Arctic atmosphere to hold more moisture and increases the likelihood of precipitation over more southern areas such as Eurasia, which, in the freezing temperatures, would fall as snow. Indeed, the researchers’ observations showed that the average snow coverage in Eurasia has increased over the past two decades.
They believe the increased snow cover has an intricate effect on the Arctic Oscillation – an atmospheric pressure pattern in the mid- to high-latitudes – causing it to remain in the “negative phase”.
In the “negative phase”, high pressure resides over the Arctic region, pushing colder air into mid-latitude regions, such as the United States and northern Canada, and giving the observed colder winters.
The lead author of the study, Judah Cohen, said: “In my mind there is no doubt that the globe is getting warmer and this will favour warmer temperatures in all seasons and in all locations; however, I do think that the increasing trend in snow cover has led to regional cooling as discussed in the paper and I see no reason why this won’t continue into the near future. Also if it continues to get much warmer in the fall, precipitation that currently falls as snow will fall as rain instead, eliminating the winter cooling.”
It is also deduced that one of the main reasons conventional climate models fail to pick up on this observed winter cooling is their failure to account for the variability of snow cover, which, as demonstrated in this study, can greatly improve the accuracy of seasonal, and lengthier, forecasts.
“We show in the paper how using the snow cover in a seasonal forecast can provide a more skilful or accurate forecast. Without correctly simulating the coupling of winter climate patterns and the variability of snow fall, the models currently used by Government centres miss an important influence on winter and will therefore continue to be deficient in predicting winter weather on seasonal time scales, and even longer decadal time scales,” continued Cohen.
Tim Ball says
The cause of the current pattern is changes in the Rossby Waves in the Circumpolar vortex from zonal, with few low amplitude Waves, to Meridional with more higher amplitude
———-
So my question is what causes the change in Rossby waves, if this in fact what is happening?
There is a cause and effect problem here. What exactly is the ultimate cause as distinct from a secondary cause.
Check fig 4 of this recent article at Jo Novas:
http://joannenova.com.au/2012/01/does-the-pdo-drive-global-temps-and-is-there-a-siberian-connection/
From “the Siberia-Pacific climate pendulum”.
It shows quite clearly, that cold around Pacific equator is followed by cold in Siberia and vice versa.
Not the other way around.
K.R. Frank
If it HAD been constantly warming, would they have come out and said something was wrong – that some cooling should have occurred? SURE they would have.
Their findings may throw light on specific weather incidents such as the extremely harsh Florida winter of 2010 which ended up killing a host of tropical creatures, as well as the chaos-causing snow that fell on the UK in December 2010.
———-
I have a very simple hand waving argument for these cold winters.
AGW is stronger in the tropics since greater water vapour feedbacks are in effect there. So the heat credit there has to move from the equator to the poles. Hence more equator to pole circulation.
Rather like applying more heat to a boiling kettle more hot weather systems move to the poles displacing cold air that moves towards the equator.
The consequence is that the Poles get warmer and mid latitudes get big snow dumps as cold and warm/moist weather systems pass in the night.
Obviously this description is so simple its not likely to be true. Feel free to poke holes in it.
You could start with:
1. Is the radiation budget in credit at the equator and in deficit at the poles!
2. Is this difference increasing?
3. Are there measurements that justify the claim that north south circulation of air is increasing?
4. Is there any evidence that there is greater alternation between hot and cold weather conditions?
And so on. This is a falsifiable hypothesis. No magical Rossby waves in sight.
You mean they don’t model snowfall at the moment??????
Had to wipe the coffee off the laptop, is it April already? Its still snowing outside.
That snow is sure having “an important influence” on Vancouver, with the usual rear-enders, flipped cars and blocked highways. 15 cm more tonight and another system coming on Wednesday – satellites not models. Its always the satellites proving the models wrong.
I guess the throw-away comment by the Met Office UK, a few winters ago, that snow “will be a rare and exciting event” was because thats how the models are written.
“We show in the paper how using the snow cover in a seasonal forecast can provide a more skilful or accurate forecast. Without correctly simulating the coupling of winter climate patterns and the variability of snow fall, the models currently used by Government centres miss an important influence on winter and will therefore continue to be deficient in predicting winter weather on seasonal time scales, and even longer decadal time scales”
Facepalm.
It rained all night the day I left
The weather it was dry
The sun so hot, I froze to death
Susannah, don’t you cry.
This is so obvious that my kids know it. If you have a warm winter, you will have a cool summer – so that the average remains about even. And vice-versa.
To me, it is fair proof that the earth has a massive feedback mechanism that keeps the average temperature stable. Our puny efforts at pumping out carbon dioxide are minor. The sun controls the temperature of the earth.
not feeding the troll…
And there you have it! Religion!
DaveE.
Bottom line is however, that the planet continues to warm and arctic sea ice continues to melt. Look at mid troposphere temps and cryosphere today for verification of this. While some contributors here insist on blanking any research that doesn’t fit the belief system, let’s just keep half an eye on the facts & the continuing trend. AGW will not be “dead in the water” until the warming TREND is reversed. It has not reversed and while I accept it may be reaching the top of its cycle, the trend line of mid troposphere temps, since 1960 would suggest otherwise. The same is true of arctic sea ice since 1979. The odd few cold winters here and there are simply not enough to offset the current trend, so I wait with baited the breath the loudly trumpeted signs of negative phase PDO etc, etc being realised.
In the same way that warmists have no right to claim that Australian floods and Russian heat waves have anything to do with AGW, we have no right to point to a few cold winters in various locations as being evidence of a cooling trend. When and only when a cooling trend shows up clearly on a decadal basis can we start to really expect researches of orthodox view AGW to pull their heads out of the sand and more importantly, for the media and the politicians to take any real notice.
Philip Bradley says:
“Of interest, is that we don’t know why increasing snow cover doesn’t cause runaway cooling and a ‘snowball’ earth.”
I think it was the “Science Channel” had a program on the theory on snowball Earth that involved the continental drift interupting the oceanic conveyor which circulates warm southern waters to the north and returns colder water to the south. At some point the continental drift blocked this system and caused the freeze up of everything. I do believe that it is theorized that glaciations are contributed to by the continuous build up of snow and the increasing reflection of sun light this causes which also would have contibuted to snow ball Earth. All theory (conjecture?), of course, even the idea that there ever was a snow ball Earth.
I’ve got Just one or two problems with that nonsense, the one that stands out is this,
During the winter of 2010 – 2011 the largest lake in the whole of Ireland and the UK froze over, due to prolonged record breaking freezing temperatures.
I knew this confident rubbish was coming someday and I told others about it before it happened. With more grant-funded research they will close the loop on any and all variances from whatever they say and do. The explanation of more or less hurricanes from the thought police is next. The brown shirts will be replaced by the smart green shirts.
The lead author of the study, Judah Cohen, said: “In my mind there is no doubt that the globe is getting warmer and this will favour warmer temperatures in all seasons and in all locations; however, I do think that the increasing trend in snow cover has led to regional cooling as discussed in the paper and I see no reason why this won’t continue into the near future. Also if it continues to get much warmer in the fall, precipitation that currently falls as snow will fall as rain instead, eliminating the winter cooling.”
Perhaps this is clarified in the original, but increased snowfall in the Northern Hemisphere winter due to warmer, wetter air from the Arctic, does not imply decreased spatio-temporal average temperature over the same area and time span. So what the author said may not be false or self-contradictory. He is surely correct that, if the warming Arctic produces more snow, then continued warming will eventually cause rain in its place. This is true whether or not CO2 accumulation is the cause of the warming.
However, it is also not necessarily true that net global heat accumulation will result in every region having a warmer climate, so that part does not follow.
The Northern Hemisphere temperatures and the CET have high degree of correlation. By looking at the CET summers and winters it is obvious that there is no correlation:
http://www.vukcevic.talktalk.net/CET-SW.htm
The CET summers and winters oscillate at different rate and often out of phase; it would be surprising if the Northern Hemisphere did behave differently, considering high degree of correlation.
Further more, as it can be concluded from the above link summer temperatures have hardly changed in the last 350 years, while all the temperature increase is due to the rise in the winter temperatures.
m.vukcevic
There has been no warming since the late 1990’s.
No warming means that if increased winter “severity” is a result of warming, then the “severity” resulting from warming will stop increasing also. So has it stopped? When is it going to stop? Did it stop in 1998?
I am unconvinced that severity is increasing.
This is the sort of rubbish you get if you give people to many grants for research. Black is White, Hot is Cold, Up is Down, and the money is ours.
@Ken bellet, which warming trend are you talking about?
http://www.woodfortrees.org/plot/rss/from:2001/plot/hadcrut3vgl/from:2001
Steve Goddard already debunked this on his site.
http://www.real-science.com/anchorage-water-vapour-year
I don’t see indications in their paper that they examined what happened in the 1960s or 1940s. Most of their pretty pictures start in 1988, and they mention 1973 in snow hindcasting. Their models don’t know history.
LazyTeen writes: “Rather like applying more heat to a boiling kettle more hot weather systems move to the poles displacing cold air that moves towards the equator.”
LOL dense colder air being displaced by hot less dense air… a new physics paradigm!
To all concerned including the authors of this sad, really sad paper, recommended reading: Leroux, Dynamic Analysis of Weather and Climate” Springer-Praxis 2010 2nd edition.
Richard Craniums the lot of ’em
This reminds me of an old gentleman that I encountered at my first job back around 1980. Having just moved from the west coast to the east coast I asked about how hot or cold the summers and winters were. He said the temperatures always seem to average out the same but if you had cold winter it would lead to a hot summer while a mild winter would lead to a mild summer. Later on I thought about his generalization in terms of the jet stream. If you have zonal flow, generally from west to east, temperatures in summer and winter will moderate. However, if the jet stream had a large north south component to it, a lot of cold could be brought down from the arctic in the winter and the summer jet could summon flow from the tropics. I also thought that most of the changes in the jet stream were a result of the state of the oceans (PDO, ENSO) but will acknowledge the arctic oscillation can certainly make itself felt in the winter, like it did in Feb. 2010 in DC.
LazyTeenager says: “What it does prove is that they don’t know everything and they are constantly looking to expand their understanding and so now they know more than they did before.”
But the problem is not what they don’t know; it’s what they do know that ain’t so.
“Their results showed strong warming throughout July, August and September in the Arctic, which continued through the autumn and, according to their observational data, appeared to enhance the melting of sea ice.”
At DMI they have an archive of Arctic temps going back to 1958
http://ocean.dmi.dk/arctic/meant80n.uk.php
Admittedly these are ERA40 modeled estimates, but since there never has been much in terms of actual empirical temperature observations for the Arctic, they probably constitute the BAG ( Best Available Guess) for that history. I don’t know if it’s just me, but having clicked through the entire series, I can’t say I see any evidence of this “strong warming throughout July, August and September in the Arctic”. 1958 appears almost identical to 2011.