Essay by Jim Steele, Director emeritus, Sierra Nevada Field Campus, San Francisco State University
The heat wave and near record-breaking temperatures in Death Valley provides a superb teaching moment to show why CO2 has nothing to do with heat waves whether the record is ever broken or not.
- Most heat waves are associated with dry conditions. Water vapor contributes between 80 and 94% of the greenhouse effect. But during a dry heat wave, greenhouse gases are reduced, and that fact should alert people that other more critical factors are governing heat waves. The dryness lowers the soil’s heat capacity and allows temperatures to rise more rapidly. The dryness also creates clear skies that increases incoming solar radiation. The winter drought set the stage for this west coast heat wave as well as Europe 2003 and Russia 2010.
- All heat waves are caused by stationary high pressure systems. Always! High pressure systems are driven dry descending air currents. In addition to the dryness amplification mentioned above, Highs cause two other critical weather events.
2.1 High pressure systems force the jet stream northward and prevent cooling air from moving southward.
2.2 Most importantly descending air currents adiabatically generate a thermal ceiling that prevents rising convection currents from carrying away surface heat. Models have demonstrated that if convection stops the global temperature could rise by 100° F. Adiabatic heating means no heat is added. Temperatures rise because the air is compressed and the constrained molecular motion releases heat. Many cultures in southeast Asia used fire pistons to start fires by simply squeezing air in a tube. When that adiabatically heated air reaches the ground we get foehn storms, when it hovers a few hundred feet above the ground we get heat waves. Air only rises if it is warmer than its surroundings. When rising air reaches a layer of adiabatically heated air the rising convection currents stop and the surface heat is trapped just like the raised windows in your car trap the heat.
Descending air currents of High pressure systems are also the reason we have deserts and why the world’s records for hottest temperatures on each continent are not at the equator but about 32 to 36° North.
The reason for this pattern is the Hadley Cells. At the equator despite the greatest heating by the sun, convection currents carry away the heat. Those rising currents are balanced by descending currents that are most powerfully focused in the regions that hold the world’s records. Those dry descending currents also cause the pattern of the world deserts. Those descending currents also create the quasi permanent high pressure system in the Pacific and the Bermuda High in the Atlantic.
Finally heat waves are caused by stationary blocking highs and all research shows that blocking highs are most common during the cool phase of the Pacific Decadal Oscillation or North Atlantic Oscillation. The PDO cool phase occurred from about 1900 to 1920, again from 1946 to 1976, and we have currently been in the cool phase since about 2003. I bet most heat wave records for the western half of the USA occurred during those time periods. Death Valley’s record was 1913. However nearly every single model driven by CO2 failed to predict the cooling in the eastern Pacific Ocean
The CO2 advocates simply predicted heat waves in the future, but anyone can do that and be right eventually. However, the mechanisms of every heat wave contradict nearly every aspect of the global warming theory. They cannot even argue that it is more likely because its warmer. Death Valleys maximum temperatures have not exceeded the 1930s. These heat waves are good examples of how weather dynamics cause extreme heat independently of the sun or CO2.
This article is adapted from Landscapes & Cycles: An Environmentalist’s Journey to Climate Skepticism
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@taxed “l can see winter coming in hard and early over the N H. With eastern Canada and northern central Asia looking the most at risk.”
I agree. Heat waves are just temporary reductions in cooling convection. When the High pressure caused melting over Greenland I posted that it was more than likely that the following winter would be brutal. And it was. Likewise 1913 set the record for both the hottest and coldest temperatures in Death Valley. Maybe NIck Stokes can explain the mechanism by which the CO2 base causes both a hotter summer and a colder winter.
Paul Homewood says, on July 1, 2013 at 10:25 am in part:
“”This is how you break a record! the record broken was by 15 degress F, which occurred Saturday in Kugluktuk, NU Canada. It reached 91.5 F, (or 33C) or which is an incredible 44F above normal.”
Only one problem – Record high is 36.8C.
http://en.wikipedia.org/wiki/Kugluktuk,_Nunavut#Climate”
That link says the alltime record humidex is 36.8 C, and the alltime record temperature is 34.9 C. The record that was broken was probably for the date.
Been wondering myself what a previous high record in 1913 means for the CO2 = warming theory generally, specially in the aftermath of this paper: http://arxiv.org/PS_cache/arxiv/pdf/0707/0707.1161v4.pdf
And this follow-up comment to the attempt by Halpern et al to contradict the paper: http://arxiv.org/abs/1012.0421
Yeah, the consequences of real science in the face of alarmism are never pretty for the alarmists, are they? I have to admit: I had a big Schadenfreudian smile on my phiz when I read “tentatively maybe kinda-sorta tied the 100-year old record” today. 🙂
@ur momisugly Dr. John M. Ware
It is an error. From the official site, the record for December is said to be 27.4C on the 19th of December 1999. But the daily record shows -27.4C.
jim Steele says: July 1, 2013 at 1:28 pm
“It is the local and regional maximums that are important. Again in Death Valley and the USA in general, there is no increased base since the 30s.”
I can’t see what you’re proving here. Death Valley hasn’t warmed, and there wasn’t a record in 2013? OK. The USA actually has warmed, though the 30s were an earlier peak, and this heat wave extended far beyond Death Valley.
A rise in the global average doesn’t mean that everywhere has got warmer. But it means a lot of places have.
On the effects of a general warming trend, a lot was made on a thread a few days ago about how, while Australia’s last summer was its hottest recorded, this was not true of any of the states. This is shown in a table here.
But the fact is, most of those State hottest summers are also recent. Qld, 1938-9 is the oldest, and then NT 85-86. But then WA 97-98, SA and Vic 00-01, NSW 05-06. Tas is not recorded there. That’s the pattern of fluctuations on a warming trend.
The Graphic needs updating to 2013 least we commit the alarmist sins.
Bob Tisdale another project!
Bill Illis says: I would still like to see a scientific explanation for why the hottest places on the planet are mostly those that are below sea level.There is greater atmospheric pressure? But its not supposed to make any difference except when the air is sinking/compressing.
I am only giving you my opinion but I suspect it is partly a coincidence that many of the lowest elevation sites are also located in a broad region affected by most by descending currents of the Hadley cell. Those descending currents shift with the season and there has also been an observed 100-year periodicity as the width of the Hadley cell was greatest in 1875, shrunk to its narrowest in the 1920’s and has now been expanding. So I suspect the descending currents get focused in different place over a relatively wide region.
In South America Valdes Peninsula is considered one of the lowest spots but it is about 42 S south, and does not claim to be the hottest spot in South America.
The lower elevation definitely adds to the pressure and depending on the season it would make a difference. Death Valley’s extremes typically occur around the summer solstice when the Hadley Cell has shift farthest north.
@Nick Stokes
So would you agree then that where ever the temperatures have not risen above the 1930’s then due to that lower base then we can not implicate CO2 for the heat waves in those regions?.
Nick Stokes says:
July 1, 2013 at 12:01 pm
Except there’s no evidence of this base building when you compare today’s warming to tonight’s cooling. All of the papers on diurnal temps are about today’s min and today’s max, no one compares how much of today’s heat is lost tonight.
http://wattsupwiththat.com/2013/05/17/an-analysis-of-night-time-cooling-based-on-ncdc-station-record-data/
Jim Steele, not only heat wave records for the western U.S. have occurred during the periods that you mentioned in your second to last paragraph but down here in Oceania the all time heat record of 42.4 C was set on Feb 7th 1973 in two locations, Rangiora in Canterbury and Jordan in Marlborough, both in the South Island of New Zealand. The North Island record of 39 degrees C was also set on that day. Conditions were very much as you describe with the foehn winds blowing across the Southern Alps and the northern dividing ranges with heated air fed directly by the jet stream from the heart of the Australian continent.
jim Steele says: July 1, 2013 at 2:24 pm
“So would you agree then that where ever the temperatures have not risen above the 1930’s then due to that lower base then we can not implicate CO2 for the heat waves in those regions?.”
A whole lot of warm air blew in to the Western US. This was forecast days ahead, and is what caused temperatures to rise in Spokane, LV, Death Valley etc. There wasn’t a different cause for different places.
The AGW logic is simple. GHG’s cause gradual warming. Warm days get warmer. Cold days get warmer. Heat waves get warmer. There can be wrinkles on how much. Maybe minima rise more than maxima. And you get local effects like where a whole lot of ice melts. But basically that’s all they are saying. A warmer world (from whatever cause) will have hotter heat waves.
Thank you for a very clear explanation of heat waves. One thing. One question. You say “…and why the world’s records for hottest temperatures on each continent are not at the equator but about 32 to 36° North.” I know you know this but the two tropics should get a mention as the equator in terms of the surface being perpendicular to that sun wanders either side of the geographic equator totaling some 50 degrees, so that during each hemisphere’s summer the desert regions are almost at an ‘equator’. In addition it is interesting that Venus has only two Hadley cells. A north and a south, which I guess is because of that planets slow rotation and heavy atmosphere?
What about the Siberian High which is responsible for both extreme clod and extreme high pressure? I would have thought this is an example of how week the Arctic sun is because the slow cold descending air and clear skies give plenty of opportunity for the sun to heat the surface?
What does a record heatwave in Death Valley have to do with global warming? What did record cold in the interior of Alaska have to do with global cooling.? We must insist, just like Warmists a few years back, that ‘GLOBAL’ is what we want, not a valley in a country that is just a small percentage of the Earth surface. The Earth is slightly cooling so what the heck doe Death Valley have to do with it?
http://wattsupwiththat.com/2013/05/01/record-cold-in-interior-alaska-heading-into-the-usa-agriculture-at-risk/
But CO2 adds a little bit of warming and a little bit more CO2 adds a little bit more warming so over all Heatwaves don’t validate sceptics all they do is demonstrate that heatwaves have little to do with CAGW.
Nick Stokes says “The AGW logic is simple. GHG’s cause gradual warming. Warm days get warmer. Cold days get warmer. Heat waves get warmer.”
Your AGW logic is way toooooo simple to be seriously considered. Ask any university ecology professor how the would treat any undergraduates’s term paper that argued wildlife died from overheating due to the the rise in global average. They would thrash and trash it. Global averages do not explain local climate not its effects. The global average is a chimera of local temperatures compiled from regions affected by vastly different.
If you look at neighboring USHCN temperatures at Battle Mtn, NV and Winnemucca NV, at Battle Mtn there is a cooling trend in maximums similar to all the stations in the Sierra Nevada. In between those 2 stations just 45 miles from Battle Mtn is Winnemucca which exhibits a steep warming trend. Such different trends can only be explained by local landscape effects. Water diversions turned Lake Winnemucca into a dry lake.
The Bering Sea and Alaska experience one of the most rapidly rising temperatures on earth during the PDO warm phase. Since the PDO went negative, it is one of the most rapidly cooling places, despite your “AGW simple logic” that it should be getting warmer. Only natural ocean cycles can explain those contradictory trends. You blurr and obscure all the local dynamics by persistently touting a chimeric global average and that helps no one understand and prepare for climate change.
@Stephen Fisher Skinner
I can only offer some general observations because pressure systems are complicated. They are a function relative differences caused the major circulation cells, temperature contrasts and momentum from local convection and subsidence. There are quasi-permanent pressure systems associate with the Hadley, Ferrel and Polar circulation cells. However the oscillate with the seasons. In general during a hemisphere’s summer the continental land mass experiences lower pressure systems while cooler oceans experience higher pressures. The summer monsoons are caused by the continental low pressure. That changes in the winter when the land cools much more quickly than the oceans due to differences in heat capacity. The Siberian High strengthens in the winter.
The El Nino Oscillation causes pressure systems to change in part by altering the location of warm and cool ocean surfaces. EL Ninos warm the eastern Pacific and weaken the Pacific High allowing more rains to reach the American Southwest. La Ninas and the negative PDO cool the eastern Pacifc and strengthen Pacific HIgh causing droughts in the southwest.
The oscillations of these major pressure systems during a El Nino event are transmitted worldwide. El Ninos enhance the Icelandic Low causing a cooling effect on western Greenland and the Baffin Bay. Researchers found sea ice in Baffin Bay increased during El Ninos.
Finally pressure systems are affected by the jet stream and the divergence and convergence of upper air streams.
But whatever happened to global warming? There is slight global cooling at the moment, so AGW logic is correct as usual. Global warming or cooling is caused by global warming. How do you look at yourself in the mirror each morning Nick?
@ur momisugly son of mulder says Heatwaves don’t validate sceptics all they do is demonstrate that heatwaves have little to do with CAGW.
I agree my title was a bit of a reach but it validates the skeptic argument that heatwaves have little to do with CAGW.
Thanks for the article, Jim Steele. I bought your book as a result, and ordered the one about severe weather you suggested to another reader.
Nick Stokes, I am sure you remember when we were told to expect warmer winters in Western Europe and the USA (don’t worry if you can’t remember I will provide you with many quotes from the fairy tale tellers). Can you let me know whether Western Europe and the USA should expect colder or warmer winters as a result of Co2 caused global warming? Finally, what would disprove AGW logic in your mind?
Past warmer winter projections (early Spring too).
The wonderful effects of global warming.
And you may wonder why I will not buy CAGW fairy tales. The world either warms or cools, that’s it. That’s all that matters, that’s the bottom line and so far it’s not looking good for your religion.
Anthony Watts has done a great job in the last few days dispelling much of the ‘record’ heatwave rubbish. However, I just feel he should mention ‘global’ and ‘global warming’ in his posts more often. Warmists used this very tactic with me some years back quite reasonably. And they were right as they should be right today. 😉
jim Steele
Yes what some over look is the fact that what can cause a heat wave over the summer, can also cause bitter cold during the winter. A example here in the UK was the hot summer of 1976, which was mainly caused by a blocking high sat over the UK. But it was also a blocking high sat over the UK during mid December of 2010 which help to give England its coldest December since 1890.
Neil Stokes July 1 303pm
The AGW logic is simple. GHG causes global warming. Warm days get warmer. Cold days get warmer. Heat waves get warmer.
If i am not mistaken more record cold days have been recorded in the US in recent years than record hot days — by a large margin. Your logic is simple — simple minded. So can you admit that the logic of AGW is flawed?
Eugene WR Gallun
@ur momisugly Louis, Does the equator receive greater heating by the sun than 32 to 36° North during summer?
You are right. The equator only receives the most direct heat during an equinox. The tilt of the earth’s axis is a little more than 23 degrees, so during the solstice in late June the sun is over the Tropic of Cancer 23.5 degrees North. Accordingly the Hadley cell shifts northward. The Death Valley record was July 10, and this recent heat wave is within that same temporal window. However the exact location of the Hadley Cells and the location of the greatest rising currents (called the Intertropical Convergence Zone,or ITCZ) and the focus of its descending currents, are also affected by surface temperatures.
From a seasonal perspective, the summertime heating of the Asian landmass has the greatest effect, moving the ITCZ over the Himalayas, much further north than predicted by the sun’s relative location. See wikipedia’s graphic of the locations of the ITCZ. It is the shifting location of the ITCZ.
On decadal time scales EL Ninos and the Pacific Decadal Oscillation effect ocean surface temperatures causing a shift. It is not clear why the width of the Hadley cell expands and contracts although the strength of the sun is likely invovled, but it appears to exhibit a ~100 year periodicity, but that may be a function of the study’s start point in the 1870s.
On a millennial timescales, the tilt of the earth’s axis changes by 2 degrees and the wobbles as well. Two thousand years ago we had a different “North Star” due to this wobble. Six thousand years ago the Sahara was a green savannah but the axis wobble caused the Hadley cell to shift southward, and northern Africa was increasingly subjected to a greater proportion of dry descending currents. The Green Sahara was then transformed into the greatest desert on earth.
Thank you Jim Steele.
The article was very cogent and informative. The discussion amplified it and I appreciate that the warmists are actually engaging in discussion. ITS ABOUT TIME.
Presumably there is at least the possibility creeping into some minds that AGW (with or without the Catastrophe) might be a bit of crap theory.
If they get to this point the continuing hysterical spending of taxpayer money for chimeras (eco crucifixes, solar panels, et al) should be stopped, right?