Cold snaps like the ones that hit the eastern United States in the past winters are not a consequence of climate change. Scientists at ETH Zurich and the California Institute of Technology have shown that global warming actually tends to reduce temperature variability.
Repeated cold snaps led to temperatures far below freezing across the eastern United States in the past two winters. Parts of the Niagara Falls froze, and ice floes formed on Lake Michigan. Such low temperatures had become rare in recent years. Pictures of icy, snow-covered cities made their way around the world, raising the question of whether climate change could be responsible for these extreme events.
It has been argued that the amplified warming of the Arctic relative to lower latitudes in recent decades has weakened the polar jet stream, a strong wind current several kilometres high in the atmosphere driven by temperature differences between the warm tropics and cold polar regions. One hypothesis is that a weaker jet stream may become more wavy, leading to greater fluctuations in temperature in mid-latitudes. Through a wavier jet stream, it has been suggested, amplified Arctic warming may have contributed to the cold snaps that hit the eastern United States.
Temperature range will decrease
Scientists at ETH Zurich and at the California Institute of Technology, led by Tapio Schneider, professor of climate dynamics at ETH Zurich, have come to a different conclusion. They used climate simulations and theoretical arguments to show that in most places, the range of temperature fluctuations will decrease as the climate warms. So not only will cold snaps become rarer simply because the climate is warming. Additionally, their frequency will be reduced because fluctuations about the warming mean temperature also become smaller, the scientists wrote in the latest issue of the Journal of Climate.
The study’s point of departure was that higher latitudes are indeed warming faster than lower ones, which means that the temperature difference between the equator and the poles is decreasing. Imagine for a moment that this temperature difference no longer exists. This would mean that air masses would have the same temperature, regardless of whether they flow from the south or north. In theory there would no longer be any temperature variability. Such an extreme scenario will not occur, but it illustrates the scientists’ theoretical approach.
Extremes will become rarer
Using a highly simplified climate model, they examined various climate scenarios to verify their theory. It showed that the temperature variability in mid-latitudes indeed decreases as the temperature difference between the poles and the equator diminishes. Climate model simulations by the Intergovernmental Panel on Climate Change (IPCC) showed similar results: as the climate warms, temperature differences in mid-latitudes decrease, and so does temperature variability, especially in winter.
Temperature extremes will therefore become rarer as this variability is reduced. But this does not mean there will be no temperature extremes in the future. “Despite lower temperature variance, there will be more extreme warm periods in the future because the Earth is warming,” says Schneider. The researchers limited their work to temperature trends. Other extreme events, such as storms with heavy rain or snowfall, can still become more common as the climate warms, as other studies have shown.
North-south shift makes the difference
And the jet stream? Schneider shrugs off the idea: “The waviness of the jet stream that makes our day-to-day weather does not change much.” Changes in the north-south difference in temperatures play a greater role in modifying temperature variability.
Schneider wants to explore the implications these results have in further studies. In particular, he wants to pursue the question of whether heatwaves in Europe may become more common because the frequency of blocking highs may increase. And he wants to find why these high pressure systems become stationary and how they change with the climate.
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http://www.freesmileys.org/smileys/smiley-shocked032.gif
that far? 🙂
“…not only will cold snaps become rarer simply because the climate is warming..”
Well we may be getting back to the original AGW ideas.
Thanks, Anthony.
ETH Zurich and CalTech seem to agree with Dr. Roy Spencer in this matter: Global warming brings less extreme weather.
The study was not referring to less extreme weather in general.
“… less frequent cold outbreaks in Northern Hemisphere winter …”
A simplified climate model?
There are no conclusions in this paper that cannot be arrived at through application of Stefan-Boltzmanm Law. It is some of the most basic physics. Plenty of physicists have been saying this for a very long time. Must be nice to get paid to regurgitate known physics and dress it up as something new.
Unless their model captures the motion of Rossby waves and shows how their amplitude changes and how they are blocked and unblocked, they missed the whole ballgame.
Really? So are they saying strong storms won’t become stronger and weak storms weaker? The hell you say. Lol.
The arrogance of anyone predicting climate beyond a few days ( either warmer or colder ) is like a mosquito on his back, floating down the river and shouting: “Open the draw bridge.”
Oh he was funny.
Even warmists have very different views on what, how much and where, which are the three necessary components of a successful prediction. So many of them will be dead wrong and I don’t believe in averaging the predictions – nor in taking the extremes as the basis of climate politics.
“And the jet stream? Schneider shrugs off the idea: “The waviness of the jet stream that makes our day-to-day weather does not change much.” Changes in the north-south difference in temperatures play a greater role in modifying temperature variability”
=========================================
I am not so certain this is supportable. What drives jet streams is up for discussion and research. Yet loopy jet streams certainly have consequences, bringing North cold further south, and vice versa. (N.H.)
The stability of the polar vortex is directly proportional to solar activity, specifically plasma penetration events. The more plasma entering our system the more stable the vortices and, therefore, the more stable the jet stream.
The converse of this is also true.
Thanks for that insight.
I guess I’ll just bend to Her wishes.
Philp B, it may well be. You make this sound like a proven fact?
Duh. Cold is crazy, warm is sane.
“My research is very robust and it tells me that most prostitutes are employed as streetwalkers. […]Believe me, the computer models I’ve been staring … I mean looking at, have indicated that this research is very robust.”
You worried me. For a moment there, I thought you were actually trying to use data to support your hypothesis. I am glad that you stuck with the purity of the models – untainted by laymen, derived by mathematics and not samples, safeguarded by the Authority.
Models refuting models…..meh.
Some kind of infarction so trying this again. Cold is crazy, warm is sane.
The key word here is MAY. It may increase if it is a linear trend. If it is cyclical, it may increase and then decrease just like the previous cycles. He is hoping to get a decade or so of grants to find out.
Isn’t climate change great? The market’s wide open!
Yawn…..ahhhhwh… another computer modeling study.
If this had been published in 2002, it would be plausible.
Translation from ‘climate speak’ to standard English.
Record observed cold temperatures in the eastern United States and eastern Canada in the last two winters are not the consequence of global warming. Record sea ice in the Antarctic for all months of the year, staring in 2012, and the recovery of Arctic sea ice is not caused by global warming. The sudden and unexplained outbreak of record cold temperatures both poles is early indication that global warming is over. A sudden increase in snowfall on the Greenland ice sheet and cooling on the Greenland Ice sheet is not due to global warming. The planet is cooling.
What we will experience (significant abrupt cooling) has happened before when the sun changes from the most active in 8000 years to a weird type of Maunder minimum state. There are cycles of warming and cooling in the paleo record. In the last 10 years the geomagnetic specialists have determined using multi proxy analysis techniques that the geomagnetic field for unknown reasons suddenly drops intensity and that significant planetary cooling occurs when the geomagnetic field intensity drops.
A observational hint that something weird is happening is the fact that the geomagnetic field intensity started to drop in intensity at 5%/decade (the geomagnetic field intensity was dropping intensity a 5%/century prior to the mid 1990s) starting in the mid 1990s which is roughly ten times faster than believed possible if the origin of the geomagnetic field is movement of magma in the earth core.
There is no explanation as to why there would suddenly in the mid 1990s be a massive movement of the magma in the earth’s core. Even if there was some mechanism to cause massive movement of magma in the earth’s core starting in the mid 1990s, a back emf is generated, if the magma change did occur, that resists fast and large changes to the earth magnetic field. The only physically possible method for a change as large as observed and as rapid as observed is a surface change of electrical charge.
Although we need observations to confirm, it is likely the cooling will be similar to the 8200 BP event. Significant abrupt cooling will be a big surprise, a big media event. During the last two decades we have been told almost daily that the science is settled, all of the warming in the last 50 years is due to the increase in atmospheric CO2. Furthermore we have been told that we must spend trillions and trillions of dollars on green scams that do not work to ‘save’ the planet from dangerous warming. Abrupt significant cooling is only possible if everything we have been told by the IPCC for the last two decades is incorrect.
http://www.geo.arizona.edu/palynology/geos462/8200yrevent.html
I still think that I got it right here:
http://joannenova.com.au/2015/01/is-the-sun-driving-ozone-and-changing-the-climate/
and here:
http://www.newclimatemodel.com/new-climate-model/
I await hearing of any new observations that do not fit.
And I await your giving concrete real-life observations that do fit your qualitative model, Mr Wilde. Mucho data from over the recent past two winters do reveal the solar influence on ozone, stratospheric warming events, offset polar vortex activity, and therefore the wavy jetstream action we’ve experienced. The data is out there, and I suggest you collect it and use it to demonstrate your model, please. Help yourself.
No need, Bob. It is all pretty obvious and should already be obvious to most professionals in the field.
I’m content to let the planet do the proving.
It isn’t at all obvious to everyone. If you were correct that it’s obvious to most professionals in the field, every time there’s a SSW, someone in the field would make a point of it – something that doesn’t happen, and it would be common knowledge, which it isn’t. Can anyone name one well-known person in the field who does that?
If it were common knowledge, people like Piers Corbyn, who regularly predicts solar-induced SSWs and the weather effects of SSWs, would not be vilified by people who obviously don’t understand what is happening or what he does or says.
If it were common knowledge, our friend ‘ren’ probably wouldn’t feel the need to regularly post graphics that illustrate what is happening as it happens wrt the polar vortex.
If it were common knowledge, you wouldn’t need to keep coming back proclaiming your ‘new climate model’, as it would have been accepted long ago, and it would be an “old” climate model by now, and furthermore, it wouldn’t be ‘your’ model anymore, would it?
How can it be ‘your’ model anyway? What makes it a model? Where’s the rigor?
You’re a nice guy, non-confrontational, persistent, but you don’t supply much in the way of evidence or examples when you could very easily do that. For example, what particular solar event(s) triggered the latest polar vortex displacements? What happened, and how did it happen? Show us you know the particulars and aren’t hand-waving.
I wish I could get away with doing next to nothing to prove my points.
Bob,
I note your frustration.
It is only obvious to someone prepared to go out and see how well my conceptual ‘model’ fits new observations as they come in.
As for SSWs they occur all the time whether the system is warming or cooling. My contention is that over decades and centuries the net interplay between the sun from above and the oceans from below gradually affects the average length and frequency of SSW events. Greater frequency and persistence gives more clouds and global cooling and vice versa.
Real world observations of past climate regimes is not detailed enough to rebut or prove my hypothesis so I have to rely on new observations as they arise and then point out how they fit into my proposed scenario.
Don’t get me wrong, I do generally agree with what you’re saying. There is actually so much data to collect, one could spend a lot of their time getting and presenting it coherently, regularly.
really? this will be?
i am waiting eagerly for a new study with opposite conclusions.
but may be as a conséquence of global warming the rate of publication of studies with “opposite” conclusions will slow.
and well if you behead all the people who disagree with agw..i guess well this rate might actually slow.
I quote “It has been argued that the amplified warming of the Arctic relative to lower latitudes in recent decades has weakened the polar jet stream, a strong wind current several kilometers high in the atmosphere driven by temperature differences…”
Horsefeathers. First, this is not Arctic amplification at work, Polyakoff went looking for Arctic amplification in person and could not find any sign of it, Arctic warming today is caused by warm Gulf Stream water, carried into the Arctic ocean by North Atlantic currents. It started suddenly at the turn of the twentieth century, before which there was nothing but slow, linear cooling for two thousand years. There was a a thirty year pause in mid-century but the warming resumed in 1970 and kept on going. Most observations start about 1980 and they have no idea of what happened before this, Carbon dioxide as a cause of warming is completely ruled out because laws of physics do not allow this, In order to start carbon dioxide greenhouse warming youmust put new carbon dioxide into the air. What istgere already is in use and does not count. The Keeling curve shows that no no carbon dioxide wasadded to the atmosphere when the warminh bega. For ffurther details, read E&E 22(8):1069-1083(2011).
From the article:
“And the jet stream? Schneider shrugs off the idea: “The waviness of the jet stream that makes our day-to-day weather does not change much.” Changes in the north-south difference in temperatures play a greater role in modifying temperature variability.”
Perhaps you need to understand Meteorology to twig this logical/scientific fail. I do.
They are saying on the one hand that the DeltaT twixt Equ and Pole is decreasing but also that the PJS waviness does not change much.
Sorry, it has to, and if readers doubt this, with a bit of effort you can demonstrate this to yourself using a water filled dish in the centre of a turntable. Put drops of ink in the water. Gently heat the rim of the dish with (say) a hair-drier. Rotate the turntable. Observe. Now place an ice-cube in the centre of the dish. Again observe. You will see a much wavier stream of inky water in the region of greatest deltaT in the water (akin PJS) without ice than with. Basic thermodynamics. If a wave gets stuck in one region (eg E US this winter and last) then “severe weather” results.
Also a “simple model” will not simulate local changes in heat transport which can set up planetary waves in early winter. eg open Arctic seas feeding more moisture into Eurasia to allow a quicker build up of snow field) This factor is known to favour harsher European winters.
Tony said:
“If a wave gets stuck in one region (eg E US this winter and last) then “severe weather” results.”
That block seems to be due to a west-east SST difference across the north Pacific. A defined north-south SST gradient would tend to force a zonal atmospheric pattern.
It may have been … or it may not. My point is that a “stuck” trough north of a meridionally plunging PJS will necessarily produce severe cold in the NH in winter. The E US has more than most of these instances due the Rockies diverting the PJS southwards to it’s lee. If you look up the IA ice sheet geography you will see this pattern reflected in that. Basic Rossby wave/vorticity theory.
I would first look at the jet stream pattern when the north Pacific SST pattern is the reverse with a warm west and cold east, and see if that block still occurred there.
Note where the colder air is . Note the air circulation change . Warm air is being sucked into the high Arctic and the North Pole region. Cold air gets pushed out over North America . Changes in global air circulation could be behind these steady SSW events that now last the entire winter instead of just a few during a typical previous winter. But cooling started already in 1995 for the Northern Hemisphere but the alarmists were in a denial mode about cooling of any kind . North Atlantic has also been cooling as the AMO has been dropping since 2003 and the index is almost 0.
http://earth.nullschool.net/#current/wind/surface/level/overlay=temp/orthographic=277.78,71.44,397
Evidence of a cooling Northern Hemisphere winters
http://icecap.us/images/uploads/COOLING_OF_NORTHERN_HEMISPHERE.pdf
HH Lamb was telling us the same thing 30 yrs ago.
Taliking about the little cooling period after the war, he comments:
Over the years since the 1940’s, it has become apparent that many of the tendencies in world climate which marked the previous 50 to 80 years or more have either ceased or changed…. It was only after the Second World War that the benign trend of the climate towards general warming over those previous decades really came in for much scientific discussion and began to attract public notice.
VARIABILITY INCREASES
Such worldwide surveys as have been attempted seem to confirm the increase of variability of temperature and rainfall [since 1950].’’
In Europe, there is a curious change in the pattern of variability: from some time between 1940 and 1960 onwards, the occurrence of extreme seasons – both as regards temperature and rainfall has notably increased…..
These variations, perhaps more than any underlying trend to a warmer or colder climate, create difficulties for the planning age in which we live. They may be associated with the increased meridionality of the general wind circulation, the greater frequency of blocking, of stationary high and low pressure systems, giving prolonged northerly winds in one longitude and southerly winds in another longitude sector in middle latitudes.
Over both hemispheres there has been more blocking in these years… The most remarkable feature seems to be the an intensification of the cyclonic activity in high latitudes near 70-90N, all around the northern polar region. And this presumably has to do with the almost equally remarkable cooling of the Arctic since the 1950’s, which has meant an increase in the thermal gradient between high and middle latitudes.
And he did not even need a computer model!
https://notalotofpeopleknowthat.wordpress.com/2014/12/02/11646/
JC reflections
“I REALLY object to President Obama’s ‘denier’ hunt, and insistence on the 97% scientific consensus in support of his policies. The extreme scientization of the political debate by President Obama is absolutely pernicious to academic freedom and and is hampering scientific progress in understanding this complex problem.”
http://judithcurry.com/2015/03/24/the-stupid-party/#more-18191
“Using a highly simplified climate model, they examined various climate scenarios to verify their theory. It showed that the temperature variability in mid-latitudes indeed decreases as the temperature difference between the poles and the equator diminishes. Climate model simulations by the Intergovernmental Panel on Climate Change (IPCC) showed similar results: as the climate warms, temperature differences in mid-latitudes decrease, and so does temperature variability, especially in winter.”
Increased forcing of the climate produces a more zonal northerly circulation pattern, and increases the temperature difference with Arctic. As through the last couple of years, and the trend from 1979 to 1995:
http://snag.gy/mfOI7.jpg
UK winters cooled from 1925 with a warm AMO mode, then warmed from 1965 with a cold AMO mode, then leveled from 1995 with a warm AMO mode, and started falling again from 2009.
http://www.metoffice.gov.uk/pub/data/weather/uk/climate/actualmonthly/16/Tmax/UK.gif
Some of the warmer UK winter variability during warm AMO modes (and associated north Pacific) effects, is winter blocking locking the Arctic incursions during negative AO episodes into e.g. the northeast U.S., while tipping the NAO the other way and making it mild wet and stormy in the UK. As in early 2014.