Johnny Carson of the Tonight Show used to do a schtick called “The Edge of Wetness” which was a parody of a soap opera called “The Edge of Night”
It was he first thing that went through my mind after reading this press release citing a new worry about wet bulb temperature. Apparently it’s not just the heat, but the humidity too.
Researchers find future temperatures could exceed livable limits
This map shows the maximum wet-bulb temperatures reached in a climate model from a high carbon dioxide emissions future climate scenario with a global-mean temperature 12 degrees Celsius (21 degrees Fahrenheit) warmer than 2007. The white land areas exceed the wet-bulb limit at which researchers calculated humans would experience a potentially lethal level of heat stress. (Purdue University graphic/Matthew Huber)
WEST LAFAYETTE, Ind. – Reasonable worst-case scenarios for global warming could lead to deadly temperatures for humans in coming centuries, according to research findings from Purdue University and the University of New South Wales, Australia.
Researchers for the first time have calculated the highest tolerable “wet-bulb” temperature and found that this temperature could be exceeded for the first time in human history in future climate scenarios if greenhouse gas emissions continue at their current rate.
Wet-bulb temperature is equivalent to what is felt when wet skin is exposed to moving air. It includes temperature and atmospheric humidity and is measured by covering a standard thermometer bulb with a wetted cloth and fully ventilating it.
The researchers calculated that humans and most mammals, which have internal body temperatures near 98.6 degrees Fahrenheit, will experience a potentially lethal level of heat stress at wet-bulb temperature above 95 degrees sustained for six hours or more, said Matthew Huber, the Purdue professor of earth and atmospheric sciences who co-authored the paper that will be published in Thursday’s (May 6) issue of the Proceedings of the National Academy of Sciences.
“Although areas of the world regularly see temperatures above 100 degrees, really high wet-bulb temperatures are rare,” Huber said. “This is because the hottest areas normally have low humidity, like the ‘dry heat’ referred to in Arizona. When it is dry, we are able to cool our bodies through perspiration and can remain fairly comfortable. The highest wet-bulb temperatures ever recorded were in places like Saudi Arabia near the coast where winds occasionally bring extremely hot, humid ocean air over hot land leading to unbearably stifling conditions, which fortunately are short-lived today.”
The study did not provide new evaluations of the likelihood of future climate scenarios, but explored the impacts of warming. The challenges presented by the future climate scenarios are daunting in their scale and severity, he said.
“Whole countries would intermittently be subject to severe heat stress requiring large-scale adaptation efforts,” Huber said. “One can imagine that such efforts, for example the wider adoption of air conditioning, would cause the power requirements to soar, and the affordability of such approaches is in question for much of the Third World that would bear the brunt of these impacts. In addition, the livestock on which we rely would still be exposed, and it would make any form of outside work hazardous.”
While the Intergovernmental Panel on Climate Change central estimates of business-as-usual warming by 2100 are seven degrees Fahrenheit, eventual warming of 25 degrees is feasible, he said.
“We found that a warming of 12 degrees Fahrenheit would cause some areas of the world to surpass the wet-bulb temperature limit, and a 21-degree warming would put half of the world’s population in an uninhabitable environment,” Huber said. “When it comes to evaluating the risk of carbon emissions, such worst-case scenarios need to be taken into account. It’s the difference between a game of roulette and playing Russian roulette with a pistol. Sometimes the stakes are too high, even if there is only a small chance of losing.”
Steven Sherwood, the professor at the Climate Change Research Centre at the University of New South Wales, Australia, who is the paper’s lead author, said prolonged wet-bulb temperatures above 95 degrees would be intolerable after a matter of hours.
“The wet-bulb limit is basically the point at which one would overheat even if they were naked in the shade, soaking wet and standing in front of a large fan,” Sherwood said. “Although we are very unlikely to reach such temperatures this century, they could happen in the next.”
Humans at rest generate about 100 watts of energy from metabolic activity. Wet-bulb temperature estimates provide upper limits on the ability of people to cool themselves by sweating and otherwise dissipating this heat, he said. In order for the heat dissipation process to work, the surrounding air must be cooler than the skin, which must be cooler than the core body temperature. The cooler skin is then able to absorb excess heat from the core and release it into the environment. If the wet-bulb temperature is warmer than the temperature of the skin, metabolic heat cannot be released and potentially dangerous overheating can ensue depending on the magnitude and duration of the heat stress.
The National Science Foundation-funded research investigated the long-term implications of sustained greenhouse gas emissions on climate extremes. The team used climate models to compare the peak wet-bulb temperatures to the global temperatures for various climate simulations and found that the peak wet-bulb temperature rises approximately 1 degree Centigrade for every degree Centigrade increase in tropical mean temperature.
Huber did the climate modeling on supercomputers operated by Information Technology at Purdue (ITaP), Purdue’s central information technology organization. Sherwood performed the wet-bulb calculations.
“These temperatures haven’t been seen during the existence of hominids, but they did occur about 50 million years ago, and it is a legitimate possibility that the Earth could see such temperatures again,” Huber said. “If we consider these worst-case scenarios early enough, perhaps we can do something to address the risk through mitigation or new technological advancements that will allow us to adapt.”
Writers: Elizabeth K. Gardner, 765-494-2081, ekgardner@purdue.edu
Greg Kline, 765-494-8167, gkline@purdue.edu
Sources: Matthew Huber, 765-494-9531, huberm@purdue.edu
Steven Sherwood, +61 (2) 9385 8960, s.sherwood@unsw.edu.au
Related Web site:
Matthew Huber’s Climate Dynamics Prediction Laboratory
ABSTRACT
An Adaptability Limit to Climate Change Due to Heat Stress
Steven C. Sherwood, Matthew Huber
Despite the uncertainty in future climate change impacts, it is often assumed that humans would be able to adapt to any possible warming. Here we argue that heat stress imposes a robust upper limit to such adaptation. Peak heat stress, quantified by the wet-bulb temperature Tw, is surprisingly similar across diverse climates today. Tw never exceeds 31C. Any exceedence of 35C for extended periods should induce hyperthermia in humans and other mammals, as dissipation of metabolic heat becomes impossible. While this never happens now, it would begin to occur with global-mean warming of about 7C, calling the habitability of some regions into question. With 11-12C warming, such regions would spread to encompass the majority of the human population as currently distributed. Eventual warmings of 12C are possible from fossil fuel burning. One implication is that recent estimates of the costs of unmitigated climate change are too low unless the range of possible warming can somehow be narrowed. Heat stress also may help explain trends in the mammalian fossil record.
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Our local steam room runs at 150 F, and humidity of 80% and so far as I know nobody has died of this ‘massive heat stress’!
I suggest we stick Huber and his mates in a room set at the temperature/humidity he suggests is possible for a few hours and monitor how they respond. Although I suspect they’d rather believe in their failed models, rather than doing a real experiment which could falsify their result?
This report is cargo cult science at its best!
Some places already reach these wet bulb conditions. I’ve gone jogging in Houston on hot/humid summer days when the ground level ozone was allegedly at “dangerous” levels. Ditto for Dallas, Washington, DC, and New York City. It didn’t hurt me one bit.
Isn’t the web bulb temperature the same as the “real feel” temperature on Accuweather?
This isn’t even junk science it is junk modeling. Simply propaganda based on unreliable models and already falsified hypothesis. I guess if you have super computer time being paid for by someone else you can do about anything. That does not mean it is credible. Perhaps they should use that time to do something useful like create avatars and play sim city.
What utter dross! The fools involved in churning out this alarmism for grant dollars might learn something if they took the case off their super computer, instead of feeding garbage into it. The heat sink would probably include a component called a vapor / condensate heat pipe. Taking the time to learn how this component moves heat could enlighten these fear mongers for hire about the role of water vapor in Earth’s atmosphere. Of course it may be asking too much for a professor of Post Normal Climate Science to take an interest in real world physics.
Comparing these two maps, it could be concluded that the W & NW Europe are heading for a cold summer and onwards.
http://weather.unisys.com/surface/sst_anom.html
http://nsidc.org/arcticmet/images/factors/arc_clm.jpg
Quote: “This is because the hottest areas normally have low humidity, like the ‘dry heat’ referred to in Arizona.”
Errrr… are we sure this isn’t a parody article? Ok, probably not, but that was my first thought upon seeing the above.
The fact is that “it’s a dry heat!” is both a slogan of a Phoenix area tourisim campaign from years ago, and as a result, an instant gag line here in Arizona. Why? Because it’s such a glaring lie. (hrrrm, much akin to AGW…)
The deserts of Arizona (Where I live in AZ we had snow last week, so its not all desert) does indeed have hot, dry summers, for about 20 days. Then it starts to get humid, more and more as the days pass. We call it “Monsoon season”, and by around July 4th, it’s so humid that we have freqent thunderstorms, sometimes daily. The humidity drops the temperatures a bit, so it rarely gets above 115 when very humid (Phoenix’s record day, 122, was a true dry heat. I lived there then, and I don’t care if it was dry, it was HOT)
Anything over 110 when it’s a high humidity day is downright miserable, and Monsoon season often lasts until early September. So, in a nutshell, that’s why “it’s a dry heat” will cause most Arizonans to snicker.
A strong contender for the Alarmist Prat of the Year award…
# kwik says:
# May 4, 2010 at 10:36 pm
# Hey Sherwood!
# No time for any more simulations now! Sell your computer and emigrate north!
Typical NH bias – Sherwood should flee south!
Gosh, why stop at 21 degrees, lest aim for 50. The first to die will be the warmists then we’ll die laughing at them – about 50 years later.
This is Prof Sherwood’s notion of risk management (from an interview with the Australian ABC)
“When you’re planning sensibly for anything you plan for the worst case scenario”.
In the real world we manage risk according to ALARP (As Low As Reasonably Practical), accepting that we can’t eliminate risk entirely, and then there’s the world of academia where risk is managed on the Panic Principal. Give me a break!
What’s known as tightening the screw.
50 million years ago? That was during the Eocene Thermal Maximum right?
But there where two major things different then, the atlantic ocean stood in direct connection with the pacific ocean because the panama landbridge had not yet formed and the drake passage was still closed and thereby preventing the thermal isolation of Antarctica.
What we also see in that period is that life in the sea did suffer, but on land it is a different story, in fact during this time species like horses, primates and even toed mammals wich would result in pigs, hippo’s, camels, deer, giraffes, pronghorn, antelopes, sheep and goats made a rapid appearance on this planet, evolution at a breakneck speed.
The Eocene Thermal Maximum gave the final boost for mammals as the new dominant species during the 10 million years when nature experimented with new and old species after the extinction of the dinosaurs.
I doubt it that where would be around here in this time if it was not for the Eocene Thermal Maximum 55 million years ago. Mammals where already there but evolution could have taken another route eventually never giving rise to humanoids.
And for Independence day, on the science it was bad on huge scale, but damn it was entertaining.
The dream goes on. These folk are completely out of touch with reality. Even the IPCC couldn’t go above 7ºC and for that they had to multiply expectable fossil fuel reserves by 4.
If you’ve ever spent a winter in West Lafayette, you’d know why the esteemed Professor thinks that anything over 75F is hot. To me, anything under 80F means turning the heat on.
It thier ‘worse than we thought’ thinking gets any worse, we’re going to see headlines proclaiming renowned GCM scientists bursting into flames. Spontaneous AGW Alarmist Combustion Syndrome = SPAGWACS.
I knew there would be a “puter” model somewhere in this tripe! WAGTD! What would be more refreshing & even lend more credence to it all IMHO, would be for one or two models to contradict the mantra from time to time, suggesting the balance of evidence points towards doom & gloom. Trouble is, they have all lost the plot & we can only expect doomsday scenarios every time! Come you AGWers, put your thinking caps on, must try harder!
Mike McMillan says:
May 4, 2010 at 11:22 pm
What a bunch of lightweights.
It’s so humid here in Houston, we get dew on the grill when we barbeque brisket
Sorry to be Mr Picky, but it’s spelt, “barbecue”! :-))
I’ve been in these conditions, and I am here to tell the tale. I recall extremely well climbing the strairs to the upper floor in Victoria Station in Bombay (as it was then) in July IIRC. The temperature was in the mid to high 30’s, and the humidity seemed to be over 100%, although I’d say it was 99% (and I know exactly what 99% humidity is – we used to get that every day in North Queensland in the wet season).
I had to stop half-way to get my breath, as it is a 2 storey climb and my rucksack weighed about 30 Kgs, but I definitely did not die. I’d have noticed that.
COULD BE is not hard science. It’s speculative science.
At what point will climate scientists stop being COULD BE scientists and start to be WHAT ACTUALLY IS scientists?
Richard Feynman makes this point. He’s interested in what actually IS rather than the any number of COULD BE’s that will sting you every time.
http://pathstoknowledge.net/2010/02/19/cargo-cult-science-a-lesson-from-richard-feynman-for-scientists-of-today-to-learn/
It’s time to bring some responsible predictions into climate science. Prosecute those that make nightmare gore scenarios for yelling fire in crowded venues. It’s illegal in most jurisdictions to yell fire. Maybe even the threat of a criminal action will get them to clean up their act? Nah… not likely, they are too in love with soothsaying gore.
Net warming between 1945-2010, according to HadCRUT is 0.3 deg C. What is the physical mechanism, which will deliver 12 deg C warming in the future?
I am tempted to use the attached e-mail of the author.
Somebody must have sensed that the sheep are no longer being alarmed by invocation of rising sea levels (relocate), droughts (build reservoirs), hurricanes (build better housing), floods (build better drains) or plagues (just see your doctor).
So “somebody” has come up with a final solution. If they can somehow manufacture a scenario where human existence, the very ability of the human body to function, are stopped working by the immutable laws of physics, then they have invented the doomsday weapon of global warming hysteria.
The fact that the GATA required to make this physics work has never occurred in the history of life on earth seems immaterial to the publishers of this paper. They had the idea anyway, so the next logical step was to see if by pumping the correct models with as much GHG as possible – models built with steroidal levels of positive feedbacks – and run them long enough into the future, they could get it to spit out the sacred number they dreamt of.
So sad. Science is being reduced to no more than what if scenarios.
These guys are straining at the upper limits of credibility; my BS meter is hard against the ‘maximum’ stop and my ribs are beginning to ache with laughter. Why have this group of ‘scientists’ indulged themselves in this silly exercise?
I remember one road trip when we stopped at Gulfport Mississippi in August by the Gulf of Mexico… Got out of the car into 99 F air temps and had instant heavy condensation of dew on me. The A/C had my skin temp about 80 F and 99 F at 99% or so humidity made me a wet condensation surface. (We were all of about 20 yards from the water…)
So of course, we all got out of the car and went swimming. Now that’s 100 % humidity! And the water, especially in the shallows, was not much cooler(!). Not exactly my favorite pastime, but livable.
BTW, in an earlier life I worked in a peach cannery stacking boxes of peaches. At times in my home town it was “110 in the shade and there aint no shade”… so you can imagine it was hot in the warehouse. (NO A/C. In fact, the fork lifts would blow hot air on you from their radiators and the cans from the cookers were in the overheads cooling down from 200 F or so.. ) So, it was “way hot” in their and pretty humid some times. One shift we averaged over 400 cases per hour for our line (one guy stacking…) of about 50 lbs / case. Yeah, you sweat… Don’t remember dying from it…
Oh, one of the other “good jobs” in farm country was working at the prune dryer. You would move around large racks of prunes in the oven as they dried. It was, IIRC, 165 F or so in the oven. It was a “good job” because you only worked every other 20 minutes… It was 20 minutes in the oven, 20 minutes recovering. And as you might guess, a load of fresh prunes is kind of wet…
Wonder what they would say about survival in that environment? …
And IIRC there a lot of deep mining operations with humidity near saturation and temps up in the 100+ F range.
Somehow I think they are just making stuff up.
(Oh, and to the commenter about Florida: Yeah, “existence proof” comes to mind. Soon as it gets too hot, this boat load of rain gets dumped and it cools off. Almost like there was some kind of convective feedback loop in operation… Hot -> Humid -> convection -> downpour -> cooler… )
and then the ice age comes ….
The problem is that ‘the computer models’ that these Purdue University climate ‘scientists’ used do not model the hydrologic cycle correctly and show positive feedback to CO2 increases (without limit). This is actually out of date even by NCAR and others. There is now a team of researchers – the “Climate Process Team on Low-Latitude Cloud Feedbacks on Climate Sensitivity (cloud CPT)” that are actually trying to model the hydrologic cycle rather than use a parameter approach based on assumptions. They have found that cloud feedback is strongly negative and that the atmosphere is NOT as sensitive as the previous models claim. See their paper here .
Perhaps Purdue need to ensure that their researchers carry out a full literature survey and keep up to date with research in their field.? Although that would result in less publicity, Purdue would at least still be seen as a serious research establishment.
UK Sceptic said on May 5, 2010 at 12:22 am:
Here’s another. I found this short Discovery News article while searching for something related. Checked Tips & Notes and found this longer article about the new study.
Okay, for a long time now here on WUWT it’s been pointed out how plants benefit from increased CO2 levels. An interesting effect, with more CO2 the plants not only grow larger but can do so with less water.
The new research: Since they will use less water, they will release less water to the atmosphere, which will increase warming. Oh look, they’ve discovered a positive feedback mechanism showing how dangerous CO2 is, that also counters a popular argument for why more CO2 would be beneficial!
Please, pretty please, let there be a new post here on WUWT about that paper. It deserves its own post where we can tear it apart completely and at length, rather than just slip in a few comments at this post about another act of not-really-scientific idiocy and madness.