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
From here, it’s just a small leap to realizing that adding the CO2 molecule that wasn’t there before is an agent of cooling via convection…I’m not worried, you guys will get there.
REPLY: No, it isn’t, and that crap you are spewing comes from John O’Sullivan’s epic misunderstanding of how the thermosphere works. – Anthony
While the post is correct that adiabatic heating is involved in heat waves, this in no way invalidates the greenhouse effect. That’s like saying that has gas pedals disprove combustion. They are different but related events in a system.
REPLY: actually, note that most of the greenhouse effect has to do with CO2 molecules slowing heat transfer to the Top of the Atmosphere, a feature most strong at night due to slowing of LWIR radiating from Earth’s surface to TOA, not daytime when lots of solar shortwave, surface heating, and Tmax occurs.
The four fundamental heat transfer processes are:
Explain how CO2 works in reaching even higher Tmax when advection and convection (far more powerful forms of heat transport in our atmosphere) are muted by that blocking high pattern. Blocking high patterns reduce advection (atmospheric circulation), and vertical convection from thunderstorms which also help transport heat to TOA. CO2 radiative forcing doesn’t even operate in the same orders of magnitude when advection and convection (atmospheric mass transport) are in action or muted. Those that want to equate CO2 as the cause probably don’t understand the difference. -Anthony
I think this summer’s naked alarmism will actually cost them support overall. I know DOZENS of people who turned against AGW last year with a similar campaign and they are even worse this year and there have been FEWER weather events to hype up. Once you lose the confidence of the people, you lose them forever. The global warming movement may be in its death throes.
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, which is an incredible 44F above normal.
Kugluktuk is on the shores of the eastern Beaufort Sea
http://www.wunderground.com/history/airport/CYCO/2013/6/29/DailyHistory.html?req_city=NA&req_state=NA&req_statename=NA
Reply
It’s currently 50 degrees in Kugluktuk, for the rest of the week the highs will be in the mid-to-high 60s. Alarmists are turning into psychotics.
As a fellow environmentalist who made the same journey…..I have been wanting to talk to someone about the way high pressure systems affect the jetstream….given that they are downward directed air masses, and the jetstream is at such a high altitude….can you direct me to an appropriate textbook, if possible with some 3D diagrams of what happens to the airmasses and what generates the vorticies? I can be mailed at peter.taylor(at)ethos-uk.com…..and would very much appreciate the mail as I am not now able to access the blogosphere as often as I once did.
“However nearly every single model driven by CO2 failed to predict the cooling in the eastern Pacific Ocean”
————————————————————————————————————————————
What’s this “nearly every single model” stuff? Did all the models fail or not?
Nobody is arguing that the direct warming of CO2 caused that heat, Anthony. I can’t even imagine what you think climatologists think for that reply to make sense.
REPLY: I never thought of you as a climatologist, just an activist. So of course the reply wouldn’t make sense to you. Many activists (and some scientists that are activists) blame CO2 induced AGW for increasing heat waves. -Anthony
Jim Steele. Excellent post and information.
Warmist will cry a river!!!
Tom Trevor says:
July 1, 2013 at 9:42 am
—
Each model gets about 90% wrong and about 10% right.
What differs between the models is that each one gets a different 10% right.
Just because one of the models got this right in that 10% is not evidence that over all, the model did not fail.
Yesterday, Steven Goddard highlighted EPA data showing more heat waves in the 1930s. My comment: Steven, if my memory serves me correctly you have done some posts showing that perhaps it was hotter in the US, and the world, during the thirties than it is now. And look at your EPA link, it’s like 5 times the amount of heat waves (500%!!) in the 1930s then we have now. http://www.epa.gov/climate/climatechange/pdfs/print_heat-waves.pdf
NSA please pass this on to Obama as a MUST read, maybe his eyes will be opened!!!
One unique feature of Death Valley is that is sits in a triple Mountain Rain shadow. Triple in that there are three mountain ranges which force nearly all the moisture from the weather systems which move in to Death Valley. This is the main reason it is so hot and dry.
Why this is an interesting post, everyone knows that global warming causes weirdness in the jet stream and that leads to these strong high pressures forming. (end sarcasm)
I learned a lot from this article. I read it several times. It seems to me that it covers all of the essential elements of climate for the lower troposphere. Those blocking high pressure regions that sit over the oceans will be important under conditions of quiet sun in winter as they channel cold air southward over the continents.
Master of Space and Thyme says:
July 1, 2013 at 9:14 am
On Earth, 90 minus 58 yields 32, not 44.
Besides which, here are the actual data for today:
http://weather.yahoo.com/canada/nunavut/kugluktuk-23405898/
It should be noted that during the Maunder minimum (1660-1710) the average England’s winter temperatures were about 2.5C colder than the average since 2000 (due to less evaporation and the absence of clouds), while the summer temps were only about 1C lower than those since 2000, mainly due to colder N. Atlantic’s sea surface. Future low solar activity it is likely to be associated with dry climate. Solar cycle SC24 just sailed through its solar max
http://www.vukcevic.talktalk.net/SSN.htm
and despite its meagre sunspot numbers in the last couple of years, it is unlikely that they will be reached again for at least two to three decades.
Anthony’s comment to Ryan above completes the picture. The radiative gasses do their thing in the upper atmosphere, not at the surface.
Master of space and thyme, if you take a look at the humidity as those high temperatures were reached it explains a lot of what was going on that day and this post fills in some of the details. Humidity sure was low for a town on the coast of a sea.
One such model would be the interior of my black Hyundai Santa Fe.
Temperatures rise because the air is compressed and the work involved acts exactly the same as input of heat.
What’s this? Real science?
There is no place for that in climate science!
Very good article
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.
Kugluktuk is on the shores of the eastern Beaufort Sea
Only one problem –
Record high is 36.8C.
http://en.wikipedia.org/wiki/Kugluktuk,_Nunavut#Climate
Paul that number is the “humidex” record high, for the month of June in that same chart it is 88F. So, a new record for that month but not terribly significant.
The statement in the post that the hottest temperatures are all at latitude 30 or higher may be incorrect, if informal measurements by the National Geographic Society and others in the Danakil Depression in Ethiopia are correct. Those ran as high as 145 degrees.
However, even if the Danakil temps are accurate, this does NOT affect the overall conclusion of the article as to the adiabatic processes or the lack of any role for CO2 in heat waves.,
@ Peter Taylor
I will also email you this reply. I recommend one book for general knowledge “Severe & Hazardous Weather: An introduction to High Impact Meterology” . They have a short section on convergence and divergence of air streams that is instructive. I also recommend the CRWS Jet Stream website at http://squall.sfsu.edu/crws/map_info/jetstream_info.html The have archived maps and animations which you can construct to see how the jet streams have been behaving.
Hope this guy has tenure or is retired or he will be unemployed soon
@ Chad Wozniak
Interesting fact. I was unaware of Danakil Depression’s unoffical record heat but it maybe the exception that proves the rule. That region is still about 12 to 14 degrees north of the equator and receives very little rain. Like Death Valley locations below sea level experience higher pressures that trap the heat.
[snip – not interested – Anthony]
@Ryan Spear,
I never suggested adiabatic heating invalidates the greenhouse effect. I argued that the lack of water vapor minimizes the contribution from the greenhouse effect. Strong convection currents naturally short circuit the greenhouse effect by carrying heat directly to the stratosphere. When convection stops temperatures rise far more dramatically than can be possibly explained by added CO2.
Typically due to convection, maximum temperatures represent a well mixed column of air and are a better indicator of the atmosphere’s heat content, whereas there is virtually no convection when minimum temperatures are measured. So minimums are mostly an indication of surface conditions, which is why urban heat islands often amplify the minimum far more than the maximum. This is why CO2 advocates do not like to focus on maximum temperatures.
In addition to reducing the greenhouse effect and amplifying surface temperatures, the lack of moisture also makes it more difficult for convection currents to rise and break through that adiabatic ceiling. When moist air rises the moisture condenses and releases latent heat that provides the necessary energy to maintain the upward motion as observed in thunderstorms and tornados. CO2’s affect on convection is trivial compared to water vapor. You might argue that when CO2 absorbs heat it should augment convection.
“I argued that the lack of water vapor minimizes the contribution from the greenhouse effect.” -Jim
Yes, but that in no way threatens the link between the heat wave and anthropogenic global warming. You’re arguing against CO2 being DIRECTLY responsible for the extra heat that breaks a record. But nobody is claiming that it is DIRECTLY responsible. A hotter planet will mean more records because it adjusts circulation patterns, not because it directly and evenly raises the temperature of the globe by some small increment.
Sorry but although the title is right, a much more comprehensive demonstration was given by Leroux in Dynamic Analaysis of Weather and Climate, Springer 2010.
Meanwhile, here in North Arkansas, we’re enjoying absolutely splendid “weather.” Almost 2:00pm and it still hasn’t reached 80F. Yes, it’s dry as a bone, but the temp just keeps staying so very nice and cool. Cool in July? In Arkansas, one of the leading producers of cotton in the world? Yup. And they’re calling for upper 50s for the next three nights. The climate might be boiling but the weather is fine for many of us in the middle of the country. (condolences to victims of the wildfires. no way is any flippant attitude intended on my part)
“At the equator despite the greatest heating by the sun, convection currents carry away the heat.”
Does the equator receive greater heating by the sun than 32 to 36° North during summer? With the earth tilted toward the sun, the days will be longer at higher latitudes. Wouldn’t that result in greater heating, at least during summer months? I can see where the equator would receive the greatest heating year around, but not during summer months, which is when record temperatures are reached. I just want to make sure I understand what was meant by that statement.
“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.”
But who to teach? Ryan’s right. No-one is saying that CO2 is involved in the mechanics of a heat wave event.
The AGW argument is that anthropogenic GHG’s cause a net radiative forcing of about 1.6 W/m2 (AR4, 2007). That’s far too little to have an effect over a few days. But it accumulates, causing long-term warming. Heatwaves come and go as they always did, with blocking highs and all. But they build on a higher base.
during a dry heat wave, greenhouse gases are reduced, and that fact should alert people that other more critical factors are governing heat waves
Here’s a bit of into on this by Freeman Dyson:
In humid air, the effect of carbon dioxide on radiation transport is unimportant because the transport of thermal radiation is already blocked by the much larger greenhouse effect of water vapor. The effect of carbon dioxide is important where the air is dry, and air is usually dry only where it is cold. Hot desert air may feel dry but often contains a lot of water vapor.
http://www.edge.org/documents/archive/edge219.html#dysonf
In a Greehouse Maximus scenario, the great deserts centered on 25 Deg N would shrink and summers in most places would be moister and rainier. There would be more of the nasty sort of 85/85 type heat and less of the 125/5 type heat.
@ Nick
Where is the “higher base” in Death Valley? See Death Valley’s USHCN temps in the article. The world record in 1913 occurred when there was a much lower base. If your reasoning was correct then we should have shattered the old record years ago.
For most of the USA there has been no higher base in the Maximum temperatures since the 1930s. See Shen (2012) “The twentieth century contiguous US temperature changes indicated by daily data and higher statistical moments.” They looked at weather variability using temperature data that was quality controlled for documented changes but not homogenized. Those temperatures show a cyclical pattern in agreement with the Pacific Decadal Oscillation with maximum annual temperatures never exceeding the 1930s and 40s.
The most reliable models that forecast seasonal heat waves are driven primarily by soil moisture and ocean surface temperatures. If CO2 had any credible link to heat waves, you would first need to prove that rising CO2 has caused more droughts which contradicts Trenberth’ s mantra of a “warmer and wetter” world. El Ninos and La Ninas are much more reliably implicated in droughts, and CO2 models fail miserably at simulation El Nino cycles, often acting in the exact opposite manner than predicted by rising CO2.
For Death Valley, La Nina conditions cool the eastern Pacific and intensify the blocking High causing more drought. More direct human affects have also dried the landscape as we have lost 50% of our wetlands and degraded 99% of our stream channels. Urbanization dries the landscape and shunts water underground into our sewer systems. And the widespread effect of vegetation removal that holds the moisture further dries the soil. The most dramatic evidence of that is the Dust Bowl. Any increase in heat waves would be more realistically correlated with the drying of the land — not rising CO2!
Nick Stokes says:
July 1, 2013 at 12:01 pm
“But who to teach? Ryan’s right. No-one is saying that CO2 is involved in the mechanics of a heat wave event.”
Warmunists are only on the record predicting more extreme heat waves, caused by increased CO2. Now you say, yes, but it is not CAUSED by CO2? That’s what I call a flexible brain.
“The AGW argument is that anthropogenic GHG’s cause a net radiative forcing of about 1.6 W/m2 (AR4, 2007). That’s far too little to have an effect over a few days. But it accumulates, causing long-term warming.”
But I guess we can agree that that long-term warming happens only in the deep oceans.
” Heatwaves come and go as they always did, with blocking highs and all. But they build on a higher base.”
Because of the hotter deep oceans?
The AGW argument is that anthropogenic GHG’s cause a net radiative forcing of about 1.6 W/m2 (AR4, 2007). That’s far too little to have an effect over a few days. But it accumulates, causing long-term warming. Heatwaves come and go as they always did, with blocking highs and all. But they build on a higher base.
jim Steele says: July 1, 2013 at 12:40 pm
Jim, you’re creating a straw man. Try quoting a scientist who says that CO2 is involved in the mechanics of heat waves. Quote what they actually say. Then we could see if heat waves disprove it.
But the fact that it’s getting warmer doesn’t mean that this, or any other heat wave, is guaranteed to break a record. It just means that over time it’s more likely. And getting some very hot weather now certainly isn’t evidence to the contrary.
What’s this? Climate science without the alarmism?
Can’t have that, someone find me a big rug to sweep this under.
Jim Steele
“More direct human affects have also dried the landscape as we have lost 50% of our wetlands and degraded 99% of our stream channels. Urbanization dries the landscape and shunts water underground into our sewer systems”
That’s very interesting. The UHI-effect is primarily concerned with a bias of measuring surface temperatures with thermometers in such regions where people are around to install and read them.
But you suggest another effect om population, namely drier surface conditions due to a much more efficient use of water resources? Both in cities, around rivers and streams and also i though farming and irrigation practices!? At least during daytimes.Is that what you suggest?
It would be interesting to study those numbers. And at least, it is in the northern hemisphere and tempered and populated regions where the warming is recorded (OK, it is hypothesized between surface stationed far apart too, further north. But that’s a different story)
CLEARLY lack of CO2 in Texas is responsible for our nearly-unheard-of cool temperatures this week of early July. 🙂
==============================================================
I noticed you left the “C” off of “AGW”. (as in “Catastrophic Anthropogenic Global Warming”)
If there is no catastrophe on the horizon, why spend trillions or billions (and, perhaps impoverish millions) to try to prevent it?
@ Nick Stokes Jim, you’re creating a straw man. Try quoting a scientist who says that CO2 is involved in the mechanics of heat waves.
As you suggest, I am sure those quotes would be rare. CO2 advocates are careful not to claim CO2 is directly involved in the mechanics of a heat wave. However Trenberth just implies CO2 when he suggests a ” warmer and wetter” world causes everything and you seem to be a disciple of such simplistic weather analyses.
CO2 advocates created the global average as the penultimate strawman. However the global average has nothing to do with local heat waves. To quote the Intergovernmental Panel on Climate Change, The Physical Science Basis, 2007 — “No single location follows the global average”
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. In fact much of the USA has been a warming hole. As Kunkel (2006) in “Can CGCMs Simulate the Twentieth-Century “Warming Hole” in the Central United States?” wrote, “An interesting regional feature of the spatial pattern of temperature trends is the lack of twentieth-century warming in portions of the United States.” Or as Pan (2004) in “Altered hydrologic feedback in a warming climate introduces a ‘‘warming hole.’’ wrote “the central United States had cooled by 0.4-1.4°F during the 20th century. You keeping talking about a nebulous increase in the statistical “base” that means precious little to the areas under discussion.
l don’t think we should get to carried away with these heat waves.
Because what the current jet stream and weather patterns give with one hand it will take with the other. Because with the current jet stream set up, 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.
Note how cool the temps in the Arctic are at the moment. Which risks a forming a very cold Arctic come the winter time. lf the current jet stream/ weather patterns stay in place, a lot of this cold air will be making its way southwards as we move towards winter.
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’s more CO2 backradiation when elevation is lower? Evidence?
There’s obviously less water vapor so that’s not it.
There is greater atmospheric pressure? But its not supposed to make any difference except when the air is sinking/compressing.
I just looked at the Wikipedia chart for Kugluktuk and found an incredible anomaly: the record high temp for December was 81.3 degrees F! The surrounding months have nothing remotely similar, and the only months with warmer maxima were July, August, and perhaps September. Where did that wildly high maximum come from?
About Kugluktuk, July 1989 had three consecutive days warmer than the new June record peaking at 94.8F on the 15th of July. And Coppermine, not far from there, had 87F the 7th of July 1936 and 90F the 9th of July 1964. The 29th of June this year had a reading of 90.1F and another of 90.5F.
Now there is something about greenhouses gases and heatwaves. It seems that greenhouses gases might increase the speed of diffusion of heat within the atmosphere. If you have more greenhouse gases in a warm volume of gases, it means you have more emitters of heat. The emitted heat might be absorbed and emitted back toward the center by other molecules, but only proportionally to the amount of heat emitted by the center.
So it could be different than the problem of transfer of heat between the ground and the atmosphere. The ground needs to get warmer in order to emit more heat. But the atmosphere emits more heat when it contains more greenhouse gases. So the increase in greenhouse gases might increase diffusion in this case.
@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. 🙂
@ 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 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?
@ 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
@ 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?
Is not this apparent from considering deserts and tropical rain forests in the same latitude.
Deserts are arid, dry and hot. The lack of the most dominant green house gas (water vapour) does not result in cooler/less warm temperatures.
tropical rain forests are warm and humid. They are rich in the most dominant green house gas (water vapour) and yet they are not as warm/hot as desets.
This tells you something about the effectiveness of GHGs to raise temperature. This is especially so since outgoing LWIR from the surface is at its peak in equatorial/tropical regions and hence back radiation is also at its peak, yet all that supposedlu enhancing water vapour does not result in extremely hot conditions in tropical rain forests.
[Snip. Russell Seitz is persona non grata here. — mod.]
Copy of an apropos comment from this thread:
http://wattsupwiththat.com/2013/06/30/about-the-record-temperature-in-las-vegas-yesterday-it-wasnt-117f/#more-89013
Ian W says at June 30, 2013 at 11:50 am
“Perhaps someone would check my maths the formula is rather nasty – but I just did a rough comparison –
Florida (Daytona Beach) Temp 25.1C Humidity 83% – Heat Content – 1257.6 Kilojoules/Kilogram
Nevada (Las Vegas) Temp 41.6C Humidity 12% – Heat Content – 307.2 Kilojoules/Kilogram
I was under the impression that green house gases trapped heat – not ‘temperature’. There is more heat on the East coast than there is in Nevada because the enthalpy of the air is higher due to its water vapor content.”
richard verney says:
July 1, 2013 at 6:35 pm
“This tells you something about the effectiveness of GHGs to raise temperature. This is especially so since outgoing LWIR from the surface is at its peak in equatorial/tropical regions and hence back radiation is also at its peak, yet all that supposedlu enhancing water vapour does not result in extremely hot conditions in tropical rain forests.”
Right. Surface moisture is the key. Evaporating water soaks up heat and cools the surface. Then, the low molecular weight of water vapor(18 vs an average weight of dry air of 29) adds buoyancy to the air so that it convects rapidly. Greenhouse effect means little at the surface as you say. Its all about evaporation and moist convection. If you want relief from a heat wave, pray for rain (or head for the beach).
I live on an island in Puget Sound. Humidity is fairly low here in the summer, as is rainfall. Our annual rainfall is about 26″, Much less than Dallas, TX. Proximity to large bodies of water is no guarantee of high humidity.
============================================================
I know this isn’t “global”. It’s just my little spot on the globe. I’d mentioned this before for record highs. I copy/pasted the record temps into Excel in 2007 and in 2012. I compared them. I’d put up the changes made in the record highs. I just now got done comparing the record lows. I did not include records “set” after 2007. I guess records are made to be broken … one way or another. (And to be fair I should note that since I first brought this up here awhile ago some of the past records have been changed again. Some now match the 2007 list.)
Anyway, here’s the comparison of record highs and lows for Columbus Ohio. (Highs first, then Lows. 2012 first, then 2007)
All temps Fahrenheit
Newer-April ’12 Older-’07 (did not include ties)
6-Jan 68 1946 Jan-06 69 1946 Same year but “new” record 1*F lower
9-Jan 62 1946 Jan-09 65 1946 Same year but “new” record 3*F lower
31-Jan 66 2002 Jan-31 62 1917 “New” record 4*F higher but not in ’07 list
4-Feb 61 1962 Feb-04 66 1946 “New” tied records 5*F lower
4-Feb 61 1991
23-Mar 81 1907 Mar-23 76 1966 “New” record 5*F higher but not in ’07 list
25-Mar 84 1929 Mar-25 85 1945 “New” record 1*F lower
5-Apr 82 1947 Apr-05 83 1947 “New” tied records 1*F lower
5-Apr 82 1988
6-Apr 83 1929 Apr-06 82 1929 Same year but “new” record 1*F higher
19-Apr 85 1958 Apr-19 86 1941 “New” tied records 1*F lower
19-Apr 85 2002
16-May 91 1900 May-16 96 1900 Same year but “new” record 5*F lower
30-May 93 1953 May-30 95 1915 “New” record 2*F lower
31-Jul 100 1999 Jul-31 96 1954 “New” record 4*F higher but not in ’07 list
11-Aug 96 1926 Aug-11 98 1944 “New” tied records 2*F lower
11-Aug 96 1944
18-Aug 94 1916 Aug-18 96 1940 “New” tied records 2*F lower
18-Aug 94 1922
18-Aug 94 1940
23-Sep 90 1941 Sep-23 91 1945 “New” tied records 1*F lower
23-Sep 90 1945
23-Sep 90 1961
9-Oct 88 1939 Oct-09 89 1939 Same year but “new” record 1*F lower
10-Nov 72 1949 Nov-10 71 1998 “New” record 1*F higher but not in ’07 list
12-Nov 75 1849 Nov-12 74 1879 “New” record 1*F higher but not in ’07 list
12-Dec 65 1949 Dec-12 64 1949 Same year but “new” record 1*F higher
22-Dec 62 1941 Dec-22 63 1941 Same year but “new” record 1*F lower
29-Dec 64 1984 Dec-29 67 1889 “New” record 3*F lower
Now the Lows
Newer-’12 Older-’07 (did not include ties)
7-Jan -5 1884 Jan-07 -6 1942 New record 1 warmer and 58 years earlier
8-Jan -9 1968 Jan-08 -12 1942 New record 3 warmer and 37 years later
3-Mar 1 1980 Mar-03 0 1943 New record 3 warmer and 26 years later
13-Mar 5 1960 Mar-13 7 1896 New record 2 cooler and 64 years later
8-May 31 1954 May-08 29 1947 New record 3 warmer and 26 years later
9-May 30 1983 May-09 28 1947 New tied record 2 warmer same year and 19 and 36 years later
30 1966
30 1947
12-May 35 1976 May-12 34 1941 New record 1 warmer and 45 years later
30-Jun 47 1988 Jun-30 46 1943 New record 1 warmer and 35 years later
12-Jul 51 1973 Jul-12 47 1940 New record 4 warmer and 33 years later
13-Jul 50 1940 Jul-13 44 1940 New record 6 warmer and same year
17-Jul 52 1896 Jul-17 53 1989 New record 1 cooler and 93 years earlier
20-Jul 50 1929 Jul-20 49 1947 New record 1 warmer and 18 years earlier
23-Jul 51 1981 Jul-23 47 1947 New record 4 warmer and 34 years later
24-Jul 53 1985 Jul-24 52 1947 New record 1 warmer and 38 years later
26-Jul 52 1911 Jul-26 50 1946 New record 2 warmer and 35 years later
31-Jul 54 1966 Jul-31 47 1967 New record 7 warmer and 1 years later
19-Aug 49 1977 Aug-19 48 1943 New record 1 warmer and 10, 21 and 34 years later
49 1964
49 1953
21-Aug 44 1950 Aug-21 43 1940 New record 1 warmer and 10 years later
26-Aug 48 1958 Aug-26 47 1945 New record 1 warmer and 13 years later
27-Aug 46 1968 Aug-27 45 1945 New record 1 warmer and 23 years later
12-Sep 44 1985 Sep-12 42 1940 New record 2 warmer and 15, 27 and 45 years later
44 1967
44 1955
26-Sep 35 1950 Sep-26 33 1940 New record 2 warmer and 12 earlier and 10 years later
35 1928
27-Sep 36 1991 Sep-27 32 1947 New record 4 warmer and 44 years later
29-Sep 32 1961 Sep-29 31 1942 New record 1 warmer and 19 years later
2-Oct 32 1974 Oct-02 31 1946 New record 1 warmer and 38 years earlier and 19 years later
32 1908
15-Oct 31 1969 Oct-15 24 1939 New tied record same year but 7 warmer and 22 and 30 years later
31 1961
31 1939
16-Oct 31 1970 Oct-16 30 1944 New record 1 warmer and 26 years later
24-Nov 8 1950 Nov-24 7 1950 New tied record same year but 1 warmer
29-Nov 3 1887 Nov-29 2 1887 New tied record same year but 1 warmer
4-Dec 8 1976 Dec-04 3 1966 New record 5 warmer and 10 years later
21-Dec -10 1989 Dec-21 -11 1942 New tied record same year but 1 warmer and 47 years later
-10 1942
Sorry the copy/paste didn’t work that well.
For anyone trying to follow it, as I see it on my screen, the end of the longer comments I made for “tied lows” jumped down a line the the “new” records appear with the temperature then the year.
@ Janice Moore .
Florida (Daytona Beach) Temp 25.1C Humidity 83% – Heat Content – 1257.6 Kilojoules/Kilogram
Nevada (Las Vegas) Temp 41.6C Humidity 12% – Heat Content – 307.2 Kilojoules/Kilogram
Excellent post. Perfect example of what a meaningless statistic the global average temperature is. It is a chimera of vastly different quantitites of heat.
Jimbo says:July 1, 2013 at 4:12 pm
” 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?”
In the long run, warmer. As I said above, we can expect the full range of weather – cold spells, heat waves – little different except for the gradual shift in mean. And there is overlaid spatial variation, sometimes from causes. It seems, for example, that melting ice is doing odd things to Arctic circulation patterns.
Not to Antarctic, though. Where I am, it is supposed to be the depths of winter. Right now, 18.7°C and sunny, and we’ve had a two-week spell of this (not always quite as warm, and some frosty mornings). I saw the first Cootamundra wattle flowering about a week ago, at least two weeks early. There’s just a lot of variability.
Anthony obviously does not know the correct explanation for the GHE.
CO2 cannot ”slow” radiation from the surface because ALL radiation travels at the speed of light. Gas molecules in the way have no effect on the speed. The only process that affects heat loss at night is water vapour latent heat surrender as the atmosphere cools.
Anthony explain why a desert, (very dry) is far hotter than a rainforest at the same latitude. Both will have atmospheric CO2 contents the same and the same insolation. If the GHe were true then deserts would be warmer than rainforests.
Eugene WR Gallun says:
July 1, 2013 at 5:19 pm
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
Actually, in recent years the ratio of record high temperatures to record low temperatures across the US has been 2:1, not the other way around.
https://www2.ucar.edu/atmosnews/news/1036/record-high-temperatures-far-outpace-record-lows-across-us
The contradiction is largely a matter of using homogenized versus non-homogenized data. The adjustments procedure commonly dropped high minimum temperatures by several degrees in the early 20th century making it more difficult to register a new low is homogenized data used.
A recent paper looking at climate variability in the USA (Shen 2011) required using non-homogenized data that was only adjusted for documented changes. They concluded, “The conclusion of the reductions in the temperature variability seems counterintuitive since many reports state that climate has become warmer and more violent particularly with stronger cyclones over the ocean” And they also reported “These observations indicate the existence of more cold extremes in all temperatures, but the occurrence of such cold extreme events is more frequent in the maximum temperatures than in the other two.”
Shen, S., et al., (2011) The twentieth century contiguous US temperature changes indicated by daily data and higher statistical moments. Climatic Change Volume 109, Issue 3-4, pp 287-317.
johnmarshall said at July 2, 2013 at 3:32 am: “Anthony explain why a desert, (very dry) is far hotter than a rainforest at the same latitude. Both will have atmospheric CO2 contents the same and the same insolation. If the GHe were true then deserts would be warmer than rainforests.”
The first and last sentences in that paragraph seem contradictory. Perhaps you meant to say that rain forests would be warmer than deserts?
Furthermore, diurnal temperature swings in arid regions tend to be far greater than they are in humid regions at the same latitude. One contributing factor for why this is so is that water vapor “feedback” is probably strongly negative, rather than positive as the IPCC assumes. Which probably helps explain why none of the IPCC climate model temperature “projections” match observations.
@Jonas But you suggest another effect om population, namely drier surface conditions due to a much more efficient use of water resources? Both in cities, around rivers and streams and also i though farming and irrigation practices!? At least during daytimes.Is that what you suggest?
Any practice that reduces the vegetation cover dries the soil and raises surface tempertures. Changing a forest into grassland or a grassland into barren soils can raise temperatures 10 to 30 degrees. Studies of temperatures in Arizona and Mexico have shown that lost vegetation from severe overgrazing and other careless practices had caused the soil surface to dry. This drying process increased temperatures by as much as 7°F compared to adjacent lands that had not been so mistreated.
Thanks, Jim Steele (at 8:56PM on July1). I’m glad that you also thought that Ian W‘s** post was a good one. And, GOOD WORK, here, responding to the comments. It’s always so much better when an author engages in the discussion instead of just doing a post-and-go.
**(just to clear up any possible confusion among WUWT readers as to who wrote that fine post — AS IF I ever could…)
Feedback effects interesting, too. Here in Southern California we’ve had hot mornings, rising air, condensation into clouds, hence less solar radiation reaching the surface, and afternoons cooler than expected. Local weather reports, though, seldom mention the clouds. Effect on human body dramatically different from sun to shade.
jim Steele says: July 2, 2013 at 8:33 am
“The contradiction is largely a matter of using homogenized versus non-homogenized data.”
Do you know that they use homogenized data for daily records? What homogenized daily data could they use?
A “chinook” is a smaller example of a down-welling dry air mass sliding down the eastern slopes of the Rockies in Alberta after its moisture has snowed out (is it called a chinook on the US side?) that occurs in winter. The temperature can vary from above freezing to well below freezing and I was told by a rancher that you could ride on horseback in and out of the two very contrasting air masses at the boundary between “tongues”.
https://www.google.ca/search?q=chinook+winds&client=firefox-a&hs=GtE&rls=org.mozilla:en-US:official&tbm=isch&tbo=u&source=univ&sa=X&ei=S5XTUbn4M4amygGg6YHwDA&ved=0CDYQsAQ&biw=1920&bih=917
@Nick Stokes Do you know that they use homogenized data for daily records? What homogenized daily data could they use?
Your criticism is valid and I do not know. I stand corrected. I made a hasty assumption that all records were similar to USHCN temperatures. Perhaps Anthony or anyone ellse could shed some light on how many records are due to homogenization.
I think there is more valid criticism of those records. They are frequently bandied about as proof of CO2 caused warming. However landscape changes have had an enormous effect, especially on minimum temperatures. Relatively fewer cold record my simply be a reflection of increased urbanization effects.
For example, in 1967 Columbia, Maryland was a newly established, planned community designed to end racial and social segregation. Climate researchers following the city’s development found that over a period of just three years, a heat island of up to 8.1°F appeared as the land filled with 10,000 residents. Although Columbia would be classified as a rural town, that small population raised temperatures five times greater than a century’s worth of global warming.
See Erella, E., and Williamson, T, (2007) Intra-urban differences in canopy layer air temperature at a mid-latitude city. Int. J. Climatol. 27: 1243–1255.
@ Gary Pearse is it called a chinook on the US side?
I have heard friends from the Columbia River area in northern Oregon as well as in southern Idaho refer to the Chinnoks, or “snow eaters.” I think it is commonly used. Your story of ranchers riding in and out of those warm winds is something have felt just hiking in the Sierra Nevada. It opens your eyes to local variability. The most amazing foehn wind reports come from Antarctica. Some studies have shown that even during the dark winter, adiabatic heating from a foehn storm can raise local temperatures by 90°F in a matter of hours.
Lynn Clarke yes sorry, rainforests hotter than deserts. Fingers not working with brain.
Lynn Clark. yes diurnal variations in deserts are far greater due to lack of water vapour and its latent heat. But I thought more information might cloud the issue and start the usual misunderstanding about latent heat. Can’t have dissent.
johnmarshall @ July 3, 2013 at 3:48 am:
The point I was trying to make about diurnal variations in arid regions being larger than in humid regions is that that fact seems to be a clear indication that water vapor “feedback” is strongly negative rather than positive as the IPCC claims. I don’t know if I made that clear. Hopefully, this comment does that.
Thanks Lynn, I think we were both saying the same in a different way. i have asked the desert/rainforest question of warmists before but never received any meaningful answer.