There have been a number of news articles that claim that a global average surface temperature trend (i.e. “global warming) explains the extreme cold weather and snow that has occurred recently; e.g. see
Comment On The CBS News Article “Is Extreme Weather a Result of Global Warming?”
In this post I want to illustrate why it is the location of the westerlies that determine areas that have extreme cold weather and snowstorms.
The first image below presents the heights of the 500mb pressure surface and the temperatures at 850mb from the ECMWF analysis for January 28 2011 at noon GMT.
The 500mb level is used as it is about halfway through the depth of the atmosphere. The distances between the lines of equal height are proportional to the speed of the winds at that level. Since, in the Northern Hemisphere, winds blow counterclockwise around regions of lower heights, the wind field (not shown) is predominately westerly. This is why the middle and higher latitudes are often referred to as the “westerlies”. Winds at this spatial scale blow almost parallel to lines of constant height. When the height contours are close together, we refer to the higher winds that result as the “polar jet stream”.
Clearly evident in the example below is the progressively cooler 850mb temperatures and lower 500mb heights as one progresses to higher latitudes. Also, clearly seen are the regions of colder air (and corresponding lower heights) that extend towards lower latitudes. When these large equatorward excursions of the westerlies occur, extreme cold weather often happens. On the east side of these cold pockets, where there is a strong contrast with warmer air to the east, winter storms occur. If the temperatures are cold enough, precipitation can fall as heavy snow. These large excursions of the westerlies explains why there have been several extreme snowstorms in the eastern USA and western Europe in recent months.
To illustrate the dynamic character of the westerlies, I have presented below the ECMWF 500mb height and 850mb temperature forecast for next Friday [February 7 2010]. Compare the above figure with the one below. Note, for example, the large excursion of cold air and, therefore, westerlies southward to over the central USA. If this forecast verifies, it will be an extreme cold outbreak with considerable snow (and ice storms) on the southeast flank of this cold region.
It is not scientifically accurate to attribute “global warming” of a few tenths of a degree to explain these extreme weather events.
Moreover, in the latest measurements, the lower tropospheric temperatures are actually cooler than the long-term average! [e.g. see
UAH prelim – January temp may be below normal globally.
For other excellent discussions of the recent extreme winter weather, see the posts by Joe Daleo; e.g.
Another Eastern Snow – Brutal Winter Assault Continues
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“Moreover, in the latest measurements, the lower tropospheric temperatures are actually cooler than the long-term average! [e.g. see”
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Precisely!!! I am glad that someone has pointed out this particular and important fact which seems to have been repeatedly overlooked when there have been discussions of extreme winter conditions this year.
And further there was never any plausible explanation as to why and how a small increase in temps of fractions of a degree could be the cause of the widespread present disruption (as they like to call matters now). It is merely weather, not climate change.
mods–check the date. Next Friday is Feb 11, 2011, not Feb 7, 2010. Not sure what dates he is talking about, but the image is dated Monday, Feb 7, 2011.
Starzmom: who has not used a prior year when writing a date in January? He was writing about a forecast so 99.9% of us understand the reason for the minor gaffe.
“These large excursions of the westerlies explains why there have been several extreme snowstorms in the eastern USA and western Europe in recent months.”
This seems a perfectly reasonable explanation (although I am no a meteorologist, so I don’t have any particular expertise in the field).
The next question, of course, is “why are we experiencing large excursions of westerlies?” Weather events don’t just happen on their own with no cause. If (and this is a large “if”) the change in westerlies can be attributed to “a global average surface temperature trend”, then both of these could be called a cause of the the event:
“A” causes “B” which causes “C”.
“It is not scientifically accurate to attribute “global warming” of a few tenths of a degree to explain these extreme weather events.”
From a purely logical (rather than scientific) point of view, this statement is too strong. Consider an analogy: when the front tires of my car turn to the right, the car will veer to the right. But something else might in turn be causing the tires to turn to the right (ie I turn the steering wheel to the right). No one would say “It is not scientifically accurate to attribute “hand movements” of a few inches to explain these extreme driving events.”
I have no reason to say a priori that global warming IS the cause, but there is also no reason to say a priori that it is NOT the cause. It is certainly possible that temperature trends of a few tenths of a degree are “driving” the westerlies.
Then comes the REAL challenge. Are the westerlies this year truly out of the ordinary? Is there a scientific explanation of why they might be unusual that does not involve recent temperature trends? Is there a better scientific explanation of why they might be unusual that DOES involve recent temperature trends?
Saying “we have unusual storms because we are having large excursions of westerlies” is a lot like saying “we have unusual weather because we are having unusual weather”! I want to see the NEXT step — WHY are the arctic winds behaving unusually?
Anyone who has taken even a Meteorology for non-major’s class can understand the argument that Global Warming leads to a higher saturation vapor pressure and the increase in moisture in turn causes more powerful storms is flawed on every level. Do people like Kaku and Gulledge actually believe that the increased moisture (which they assume, but where is the timeseries showing increased water vapor as the global average saturation vapor pressure has increased) will lead to more powerful storms? Water vapor concentration is extremely dynamic, and ranges from what, slightly above 0% to 4% globally? So with a 0.5 C rise in global temperature, the dynamic range of water vapor might increase to slightly above 0% to 4.001%? Is all of this extra water vapor going to somehow concentrate itself into all of these disturbances to make them more powerful?
This reasoning shows and extremely poor understanding of meteorology. Take the recent East Coast (US) snow storms. When the surface lows develop across Texas, they have VERY LITTLE moisture. As the move across the Gulf states and then redevelop along the East Coast, they are acquiring moisture from the ocean. THIS IS WEATHER and has NOTHING TO DO WITH CLIMATE. In case anyone cares, or bothers to look, Gulf and Atlantic SSTs off the eastern seaboard have been 2-3 C BELOW normal, so they cannot even argue that ocean temps have been higher and led to increased evaporation and moistening. So would they suggest there is some increase in the ambient water vapor as the lows intensify that somehow allow these storms to grow powerful? Would they have any idea how stupid that sounds? It’s as if these people are outright lying, to give the carbon control AGW freaks who know nothing about weather/climate, talking points to brag about at their next hippie elitist “farm to table” dinner. Gah!
starzmon – Thanks! I corrected.
Considering the error bands on surface measured temperature, +/- 1C, then 0.1C is as read off a calculator not any accurate change of temperature. We can all get these high ‘accuracy’ levels without any thought.
Tim Folkerts says:
January 30, 2011 at 7:13 am
“Saying “we have unusual storms because we are having large excursions of westerlies” is a lot like saying “we have unusual weather because we are having unusual weather”! I want to see the NEXT step — WHY are the arctic winds behaving unusually?”
Wow! The trolls are really struggling these days. Grasping at the word ‘unusual’. What can be the cause? I believe he is using what I call “The Trenberth Gambit” in which one cleverly tries to reverse the burden of proof.
To address the troll’s point, the claim that “we have unusual storms because we are having large excursions of westerlies” is to be understood as “ONCE AGAIN, we have unusual storms because we are having large excursions of westerlies.” In other words, large excursions of westerlies causing unusual storms is part of our past experience. In other words, any meteorologist who has been around a while will recognize this pattern as part of natural variation. In fact, ordinary folk such as myself recognize that the last four winters are entirely within normal range and would occasion no comment at all except for the fact that AGW propaganda has created expectations of mild winters with little snow.
I really hope that we can keep the trolls under control on this website. This website is a delight and a valuable resource for science, but here I find myself taking the time to respond to yet another bit of AGW propaganda.
OT – but excellent round up of thermometer sighting and adjustment issues.
——————————–
Is It Really The Warmest Ever?
By Joseph D’Aleo – Jan. 28, 2011
http://www.energytribune.com/articles.cfm/6440/Is-It-Really-The-Warmest-Ever
The trolls are starting to intensify their efforts. Just think how bad it’s going to be when this congress eliminates their government science jobs. I mean, why do we need several thousand scientists, with their minds already made up, pretending to study settled science.
Tim Folkerts says:
January 30, 2011 at 7:13 am
“These large excursions of the westerlies explains why there have been several extreme snowstorms in the eastern USA and western Europe in recent months.”
“This seems a perfectly reasonable explanation (although I am no a meteorologist, so I don’t have any particular expertise in the field).”
“The next question, of course, is “why are we experiencing large excursions of westerlies?” Weather events don’t just happen on their own with no cause. If (and this is a large “if”) the change in westerlies can be attributed to “a global average surface temperature trend”, then both of these could be called a cause of the the event:
“A” causes “B” which causes “C”.”
This is an example of trying to reverse the burden of proof, aka “The Trenberth Gambit.” In science, the fact that some event B could be attributed to some cause A provides no reason for believing that A causes B. The reason is that science accepts only physical hypotheses in explanations and physical hypotheses must be reasonably well-confirmed through their use to predict events of the kind B. As is well known, there are no physical hypotheses about global average surface temperature trends that can be used to predict the large excursions of westerlies that we are now experiencing.
There is another way to say the same thing. The claim that “These large excursions of the westerlies explains why there have been several extreme snowstorms in the eastern USA and western Europe in recent months” could be more clearly written as “ONCE AGAIN these large excursions of the westerlies explains why there have been several extreme snowstorms in the eastern USA and western Europe in recent months.” In other words, this behavior of the westerlies and the resulting cold winters are things that have occurred many times before and, for that reason, are part of natural variation. What can be explained by natural variation has no need of explanation by appeal to AGW.
I remember being disgusted by people who would look at x-ray crystal structures of proteins and think these were absolutely rock-solid descriptions of reality. The truth was far different. Crystallographers would have to try to fit the main chain into murky electron density, with the help of some heavy-atom derivatives. The point is, they could make mistakes even at that level. Then you have the side chain positions. Furthermore a crystal structure is not necessarily the solution structure.
The point is, people look at computer-generated images and seem to think it comes straight from God. Well, look at that! It came from the computer! It must be very accurate. The truth is, computers only do what they are told, and fallable people tell computers to do wrong things all the time.
Models are just guesses. At least with some experimentation, we were able to correct some wrong crystal structures (and that was a huge scientific-political mess). With climate, you don’t get the chance to do many experiments. You have to wait for natural variations to discover the truth about your models. Meanwhile, on the political side, the rascals in charge are using poor science to justify their power-hungry scheming. And in the end, as always, we are forced to pay for it.
Thanks to WUWT for sheding light on the dark places where the scientific and regulatory cockroaches run.
If you’re one of the trolls flooding this site (many while on the science payroll of the taxpayer), you should read the article at the link provided by Jimbo, and be ashamed.
Jimbo says:
January 30, 2011 at 8:15 am
OT – but excellent round up of thermometer sighting and adjustment issues.
——————————–
Is It Really The Warmest Ever?
By Joseph D’Aleo – Jan. 28, 2011
http://www.energytribune.com/articles.cfm/6440/Is-It-Really-The-Warmest-Ever
Thanks for the sanity break.
It is not scientifically accurate to attribute “global warming” of a few tenths of a degree to explain these extreme weather events.
I agree: the polar view maps above, showing the heights of the 500mb pressure surface, have more in common with the Earth’s magnetic field intensity distribution, as shown in here:
http://www.vukcevic.talktalk.net/NFC1.htm
than with any of ‘clapped-out’ (falling to pieces) CO2 hypothesis.
mike g says…
and jimbo says…
================
OT but also appropriate here is E.M. Smith:
http://chiefio.wordpress.com/2009/03/05/mr-mcguire-would-not-approve/
But it has long been known that the westerlies (inhabitants of Kalifornica with the exception of Tony) and the easterlies (inhabitants of Messachewsetts where I live) have long been responsible for most of the problems. This is nothing new.
Tim Folkerts says:
January 30, 2011 at 7:13 am
“Consider an analogy: when the front tires of my car turn to the right, the car will veer to the right. But something else might in turn be causing the tires to turn to the right (ie I turn the steering wheel to the right). No one would say “It is not scientifically accurate to attribute “hand movements” of a few inches to explain these extreme driving events.””
Under your analogy there is a clearly understood mechanism of how turning the tyres to the right makes the car go right.
There is no such mechanism identified for linking global warming to these wind patterns.
I’m rather glad the AGW folks have dropped the term climate change.
In the 80’s and 90’s we encountered climate change as the planet warmed slightly. Now the climate is changing a few tenths of a degree colder.
The folks who claimed skeptics to be deniers of climate change when they disagreed about the cause of the slight rise in temperatures, now deny the truth of the shift in the direction of climate change.
Cyclical phenomena can such fun!
In the SH hemisphere the polar frontal jet has not contracted below 60s in the austral summer,bringing colder temperature excursions at height in dec and jan.As these excursions reduced the heat capacity of the atmosphere,heavy rains resulted,
Theo Goodwin says:
January 30, 2011 at 7:59 am
No, Theo M. Folkerts is right. I am a scientist donc skeptic and as such I MUST agree with the Monsieur because Joe has not gone to the source of the change, he has merely cited a symptom. ‘most volitile westerlys ‘. I find this form of science is rampant in climate technology (it’s not science). If this were an electrical circuit and there was a light in the circuit which was suddenly extinquished do you assume that the fault is the bulb or do you go to the source of power first and ensure that the circuit is connected with ample supply? Do you see what is meant?
Before recently, I had never found a copy of the following:
Leroux, Marcel (1993). The Mobile Polar High: a new concept explaining present mechanisms of meridional air-mass and energy exchanges and global propagation of palaeoclimatic changes. Global and Planetary Change 7, 69-93.
http://ddata.over-blog.com/xxxyyy/2/32/25/79/Leroux-Global-and-Planetary-Change-1993.pdf
Quite stimulating.
It has been nearly 2 decades since the publication. Surely there has been some criticism? If anyone is aware of any major criticisms leveled at the paper (or even minor ones), please share! (This could be quite important.)
Skepticism means being skeptic of all science. Until someone comes up with a scientific quality proof for whatever then the hypothysis is invalid, ego AGW and Non-AGW. Global warming there has been ( maybe but temperature measurement is chaotic worlwide), globaling cooling there maybe ( we don’t have enough data to determine), climate change there is, that’s certain.
As a non scientist I am confused and concerned about something. Also, I live in North Alabama where we have had an exceptional winter season so far.
Does the forecast above mean that for the week of February 6-12 we can expect another sever winter weather event here in North Alabama?
With all due respect Professor Pielke, I have difficulty with using “extreme” to describe relatively normal winter weather. Yes it is a bit colder this winter, and yes as a result we are seeing more snow, but it certainly isn’t extreme, is it? We have had cold winters like this many times before. -20 with regular snow falling in Los Angeles would be extreme. Maybe next year?
But thanks for this informative and edifying essay!