Climate scientists take on the ‘it’s not the heat, its the humidity’ meme

From the THE EARTH INSTITUTE AT COLUMBIA UNIVERSITY and “the edge of wetness” department.

Humidity may prove breaking point for some areas as temperatures rise, says study

From US south to China, heat stress could exceed human endurance

Climate scientists say that killer heat waves will become increasingly prevalent in many regions as climate warms. However, most projections leave out a major factor that could worsen things: humidity, which can greatly magnify the effects of heat alone. Now, a new global study projects that in coming decades the effects of high humidity in many areas will dramatically increase. At times, they may surpass humans’ ability to work or, in some cases, even survive. Health and economies would suffer, especially in regions where people work outside and have little access to air conditioning. Potentially affected regions include large swaths of the already muggy southeastern United States, the Amazon, western and central Africa, southern areas of the Mideast and Arabian peninsula, northern India and eastern China.

“The conditions we’re talking about basically never occur now–people in most places have never experienced them,” said lead author Ethan Coffel, a graduate student at Columbia University’s Lamont-Doherty Earth Observatory. “But they’re projected to occur close to the end of the century.” The study will appears this week in the journal Environmental Research Letters.

Warming climate is projected to make many now-dry areas dryer, in part by changing precipitation patterns. But by the same token, as global temperatures rise, the atmosphere can hold more water vapor. That means chronically humid areas located along coasts or otherwise hooked into humid-weather patterns may only get more so. And, as many people know, muggy heat is more oppressive than the “dry” kind. That is because humans and other mammals cool their bodies by sweating; sweat evaporates off the skin into the air, taking the excess heat with it. It works nicely in the desert. But when the air is already crowded with moisture–think muggiest days of summer in the city–evaporation off the skin slows down, and eventually becomes impossible. When this cooling process halts, one’s core body temperature rises beyond the narrow tolerable range. Absent air conditioning, organs strain and then start to fail. The results are lethargy, sickness and, in the worst conditions, death.

Using global climate models, the researchers in the new study mapped current and projected future “wet bulb” temperatures, which reflect the combined effects of heat and humidity. (The measurement is made by draping a water-saturated cloth over the bulb of a conventional thermometer; it does not correspond directly to air temperature alone.) The study found that by the 2070s, high wet-bulb readings that now occur maybe only once a year could prevail 100 to 250 days of the year in some parts of the tropics. In the southeast United States, wet-bulb temperatures now sometimes reach an already oppressive 29 or 30 degrees Celsius; by the 2070s or 2080s, such weather could occur 25 to 40 days each year, say the researchers.

Large swaths of the tropics and beyond may see crushing combinations of heat and humidity in coming decades, according to a new study. CREDIT Ethan Coffel

Lab experiments have shown wet-bulb readings of 32 degrees Celsius are the threshold beyond which many people would have trouble carrying out normal activities outside. This level is rarely reached anywhere today. But the study projects that by the 2070s or 2080s the mark could be reached one or two days a year in the U.S. southeast, and three to five days in parts of South America, Africa, India and China. Worldwide, hundreds of millions of people would suffer. The hardest-hit area in terms of human impact, the researchers say, will probably be densely populated northeastern India.

“Lots of people would crumble well before you reach wet-bulb temperatures of 32 C, or anything close,” said coauthor Radley Horton, a climate scientist at Lamont-Doherty. “They’d run into terrible problems.” Horton said the results could be “transformative” for all areas of human endeavor–“economy, agriculture, military, recreation.”

The study projects that some parts of the southern Mideast and northern India may even sometimes hit 35 wet-bulb degrees Celsius by late century–equal to the human skin temperature, and the theoretical limit at which people will die within hours without artificial cooling. Using a related combined heat/humidity measure, the so-called heat index, this would be the equivalent of nearly 170 degrees Fahrenheit of “dry” heat. But the heat index, invented in the 1970s to measure the “real feel” of moist summer weather, actually ends at 136; anything above that is literally off the chart. On the bright side, the paper says that if nations can substantially cut greenhouse-gas emissions in the next few decades, the worst effects could be avoided.

Only a few weather events like those projected have ever been recorded. Most recent was in Iran’s Bandar Mahshahr, on July 31, 2015. The city of more than 100,000 sits along the Persian Gulf, where seawater can warm into the 90s Fahrenheit, and offshore winds blow moisture onto land. On that day, the “dry” air temperature alone was 115 degrees Fahrenheit; saturated with moisture, the air’s wet bulb reading neared the 35 C fatal limit, translating to a heat index of 165 Fahrenheit.

Bandar Mahshahr’s infrastructure is good and electricity cheap, so residents reported adapting by staying in air-conditioned buildings and vehicles, and showering after brief ventures outside. But this may not be an option in other vulnerable places, where many people don’t have middle-class luxuries.

“It’s not just about the heat, or the number of people. It’s about how many people are poor, how many are old, who has to go outside to work, who has air conditioning,” said study coauthor Alex deSherbinin of Columbia’s Center for International Earth Science Information Network. De Sherbinin said that even if the weather does not kill people outright or stop all activity, the necessity of working on farms or in other outdoor pursuits in such conditions can bring chronic kidney problems and other damaging health effects. “Obviously, the tropics will suffer the greatest,” he said. Questions of how human infrastructure or natural ecosystems might be affected are almost completely unexplored, he said.

Only a handful of previous studies have looked at the humidity issue in relation to climate change. It was in 2010 that a paper in the Proceedings of the National Academy of Sciences proposed the 35-degree survivability limit. In 2015, researchers published a paper in the journal Nature Climate Change that mapped areas in the southern Mideast and Persian Gulf regions as vulnerable to extreme conditions. There was another this year in the journal Science Advances, zeroing in on the densely populated, low-lying Ganges and Indus river basins. The new study builds on this earlier research, extending the projections globally using a variety of climate models and taking into account future population growth.

Elfatih Eltahir, a professor of hydrology and climate at the Massachusetts Institute of Technology who has studied the issue in the Mideast and Asia, said the new study “is an important paper which emphasizes the need to consider both temperature and humidity in defining heat stress.”

Climate scientist Steven Sherwood of the University of New South Wales, who proposed the 35-degree survivability limit, said he was skeptical that this threshold could be reached as soon as the researchers say. Regardless, he said, “the basic point stands.” Unless greenhouse emissions are cut, “we move toward a world where heat stress is a vastly greater problem than it has been in the rest of human history. The effects will fall hardest on hot and humid regions.”


The paper, “Temperature and humidity based projections of a rapid rise in global heat stress exposure during the 21st century,” is available online here and is open access.


As a result of global increases in both temperature and specific humidity, heat stress is projected to intensify throughout the 21st century. Some of the regions most susceptible to dangerous heat and humidity combinations are also among the most densely populated. Consequently, there is the potential for widespread exposure to wet bulb temperatures that approach and in some cases exceed postulated theoretical limits of human tolerance by mid- to late-century. We project that by 2080 the relative frequency of present-day extreme wet bulb temperature events could rise by a factor of 100–250 (approximately double the frequency change projected for temperature alone) in the tropics and parts of the mid-latitudes, areas which are projected to contain approximately half the world’s population. In addition, population exposure to wet bulb temperatures that exceed recent deadly heat waves may increase by a factor of five to ten, with 150–750 million person-days of exposure to wet bulb temperatures above those seen in today’s most severe heat waves by 2070–2080. Under RCP 8.5, exposure to wet bulb temperatures above 35 °C—the theoretical limit for human tolerance—could exceed a million person-days per year by 2080. Limiting emissions to follow RCP 4.5 entirely eliminates exposure to that extreme threshold. Some of the most affected regions, especially Northeast India and coastal West Africa, currently have scarce cooling infrastructure, relatively low adaptive capacity, and rapidly growing populations. In the coming decades heat stress may prove to be one of the most widely experienced and directly dangerous aspects of climate change, posing a severe threat to human health, energy infrastructure, and outdoor activities ranging from agricultural production to military training.


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What about all the heat that against all the Laws of Thermodynamics, went missing a few years ago. It was presumed to be lurking in he ocean depths ready to pop out at a later unnamed date? It could be causing an increase in contemporary humidity? Sarc off!

Neil Jordan

All the heat plunged into the abyss because of Immaculate Convection. The heat is down there, lurking, lurking along with Bathybius haecklii, Polywater, California’s Latent Sea Level Rise, and Godzilla.

Komrade Kuma

I disagree Neil, all the heat went into the brains of ‘climate scientist;, fried them and created a zombie apocalyse of sorts with outbreaks at certain universities, the Nobel Institute and particularly the UN.


You forgot cold fusion…..

Gunga Din

I imagine the deeps oceans are pretty humid.


That shows the depth of your imagination (:-))

Other than the business of what may or may not happen if GHGs are reduced or not, if the temps get that high, whatever the reason, the obvious result wil be that outside activities will be reduced or curtailed for those days and folks will stay inside an air conditioned space. There will NOT be mass human suffering. That claim is just plain moronic.

F. Leghorn

But all the researchers care about is the poor people! Oh, and “where is my grant check? If I don’t get my check I can’t save any more poor people! “

Carbon BIgfoot

And the third world will disappear into the caves from which they immerged.

So much prognostication with so little basis …

Anything that even mentions an RCP scenario, especially RCP8.5, is demonstrably bogus to begin with.


global warming theory be damned……supposed to have the least effect on the tropics…anything goes now


Can someone just tell the “Climate Scientists” to just shut up and go away???

You know when humidity REALLY counts? Winter!!! Low humidity levels in winter air mean static discharges when you touch doorknobs. Higher humidity levels in winter air mean not getting zapped by the doorknobs. See how simple that is? I haven’t used my vaporizer in such a long time, I’ve forgotten where I stored it.

It appears to me that these guys have to have some way to inspire panic attacks in the general public. Hasn’t happened yet. So can we find a way to just send them packing, maybe to a solar system where the central star is a weird green and the one detectable planet is so hot it has rain in the form of liquid glass. (Yes, it does exist.) That would give them some REAL global warming to think about.


I see that the Amazon jungle has the highest concentration of days above 32 C. Since this jungle is supposed to be the “lungs of the earth” the plants should really thrive with increased humidity.

If this supposed increase in global humidity is really true, it’s not like people can’t move further north into Canadian Territories, Siberia, Antarctic, etc.


People moving into the Canadian territories? Woah, just a minute there. Did you ask for our permission? We can elect our own Donald Trump, build a wall and get the Americans to pay for it, eh?

F. Leghorn

Don’t worry. I’m staying right here in the (future wasteland) Southeastern state of Alabama. Bring that climate change on! (No, really. I’m cold, and I hate cold.)

How long would they last in Canada. Today it is -27C with WC at -38C. Tonight’s WC will be -44C. So come on up folks. Trudeau will welcome you and hand you more money than our seniors get for support; folks who can’t speak English or French are most welcome; diversity and inclusivity you know. No formal education necessary. All are welcome to freeze their butts in less than 15 minutes- we call it cold stroke! Summers, however, will be warmer – mosquitos and blackflies will welcome you when you step outside. There is a lot of room in Canada- especially in winter when millions of our permanent residents travel to Florida, Texas, Arizona and Moonbeamistan.

John M. Ware

In the map I see a little pale rectangle squarely over Illinois, home of the nation’s second crookedest government (after California); could politics have anything at all to do with this issue?


“But they’re projected to occur close to the end of the century.”

Very convenient.

The genus student and professors and most alive now will be dead.

US Tax Monies At Work.


But according to NOAA data, global atmospheric humidity, relative and specific, has gone down at altitude and stayed about the same near the surface since 1948. When will it begin rising?


It will be have been rising very soon. Near future distant past perfect, things that have been done long time ago in near future. We also will have always been in war with East Oceania.

Wet-bulb 1.7°C, 35F. I think snow is not a thing of the past yet. Just wanted some GW so I wouldn’t kill myself by wearing thai made running shoes when absentmindedly stepping on the ordinary killer, ice on driveway.

Alan Watt, Climate Denialist Level 7

I think you just invented a new verb tense for English — the future imperfect passive catastrophic. This tense is used to denote things that aren’t happening now, may never have happened, but may/could happen in the future and will definitely be much worse than we thought.

Past: Yesterday it was humid.
Present: Today it is dry
Future: Tomorrow it will rain.
Future Imperfect Passive Catastrophic: The Global Average Humidity Anomaly is projected to be intolerable about the time I retire from my cushy academic research job.

Tom Halla

Another RCP8.5 horror scenario. Why has this not ever happened in the past, even with GHG levels much higher than RCP8.5?


To be fair, the sun’s been getting slowly but steadily hotter over time (or so I understand).

The real problem here is, as I understand it, by the time we reached the levels of RCP6.0, we would have actually used up nearly all the fossil fuels, and would have presumably switched to some different energy source.


I’ve worked in the north of Western Australia and seen people put on woollen jackets at 85 degrees because it was “getting a bit chilly”. We adapt.


My cut off point is about 80F……


Just checked….we’re 82F right now….I have on thick socks..insulated shoes….thick sweat pants….tshirt…..thick sweat shirt

You are too close to the Conch Republic.


Last week, my son-in-law who has been deployed for a year around the equator near Africa flew to Germany. He texted our daughter that he was having a difficult time adjusting to the cold. Today he arrived home where it is currently 9 degrees Fahrenheit.

Yea for the Conch Republic. May they successfully secede and become independent again.


“Climate scientists say that killer heat waves will become increasingly prevalent in many regions as climate warms.”…………..

“Climate scientists say that killer Ice age will become increasingly prevalent……”

23rd December 2017
ICE AGE EARTH: Global FREEZE lasting 120 YEARS threatens ‘more intense’ winters from 2019

………..I kid you not

Bruce Cobb

In other news, rising temperatures caused by man will cause pigs to fly. This will be very bad for aviation, causing many crashes and many fatalities. The horror! Film at 11.

J Mac

“Today’s in-flight meal will be jet roasted and extremely spiral sliced ham…”

F. Leghorn

Thanks for the laugh. It was worth having to clean spit off my screen.


I believe they call that “Turbinated Pork”.


“Millions of Middle-Eastern refugees flee forecasts of 60% bacon bits.”

J Martin

Climate alarmist graph predictions are based on the assumption that increasing co2 will cause the atmosphere to warm which in turn will cause humidity to increase which is where they get the bulk of their warming from. A circular argument or perpetual motion machine.

Problem is that humidity has decreased for decades. So their paper is based on the same assumption that humidity will increase.


temps would have decreased too….if they had not “adjusted” them up

Ian W

The reduction in humidity will lead to lower enthalpy which itself would lead to higher temperatures no need to invoke “green house”(sic) gases.

J Mac

Dim bulb extreme prognostications:
“….extreme wet bulb temperature events could rise by a factor of 100–250…”

Seems like every sentence they write has a “could” in it.

Bloke down the pub

‘Most recent was in Iran’s Bandar Mahshahr, on July 31, 2015. The city of more than 100,000 sits along the Persian Gulf, where seawater can warm into the 90s Fahrenheit, and offshore winds blow moisture onto land.’

John F. Hultquist

A wind is named based on the direction from which it comes.
EX: a north wind moves south; the Westerlies move air east

“offshore” will be the same as a sea breeze – – – from the sea


““offshore” will be the same as a sea breeze – – – from the sea”

These would appear to say otherwise:

“A sea breeze or onshore breeze is any wind that blows from a large body of water toward or onto a landmass…
By contrast, a land breeze or offshore breeze is the reverse effect”

“Well, if the wind is blowing on-shore (that is from out in the ocean and towards the beach)…
On the other hand, an off-shore wind (blowing from the beach side and out towards the ocean)”


“Offshore”, of course means “off” the shore (to the sea).
Sea breezes are “Onshore” winds blowing onto the shore (from the sea).

Your catch reflects the quality of the rest of the paper.


I heard that only mad dogs and Englishmen go out in the noon day sun. Every one else is resting in the shade. Why does this study leave me cold?

F. Leghorn

That’s not the study. That’s the weather leaving you cold. But cheer up – only a few years to go and you won’t be cold ever again.


The weather leaves me cold and dry. I let some water boil to increase the humidity, and drink gin and tonic to relieve the dryness. Tomorrow I will start with the eggnog.

F. Leghorn

Well Merry Christmas


Another nonsensical study based on RCP 8.5 (AKA all future energy from coal), which can’t and so won’t happen. Add the use of dubious model projections, and you have a hot mess of alarmist drivel. Public defunding of most climate research is the only practical response.


I’ve been in South Louisiana during the summer, when it was 96 degrees F with a relative humidity of 96%. (not that rare down on the bayous) I think that works out to a wet bulb of about 35C. Sure, it’s uncomfortable, but it happens every year and you don’t see boatloads of the dead being floated out to the gulf. Mostly you just have another beer, cook up some alligator, and laissez le bon temps roullez.

F. Leghorn

Actually that comes out to a wet-bulb of 36C or 37C so lay down you silly dead guy.

I’m not that far south and grew up before the widespread use of central HVAC (we had a central floor furnace). The house had high ceilings and we used fans. We even had indoor plumbing! ;p.

You adapt to it. (Think lots of water, shade trees, and the afternoon nap). I greatly dislike cold. I can adapt to that, too, if necessary, but I wouldn’t like it. I prefer the south’s weather, even if I do have to dodge the occasional snowstorm, tornado or hurricane.

Steve R

@wws. I am sorry, but the 96°F dry bulb@ 96% relative humidity is simply not feasible on earth. Perhaps it was 96% RH early in the morning during the coolest part of the day?

I too live in the deep South. Lots of people like to complain how humid it is saying 95F@ 95%RH but its not literally true. Examine a psychrometric chart closely and note how much total heat would be in the air under those conditions.
In fact I am tempted to claim this entire article is BS because air at 32°C wet bulb temperature contains at least 30% more heat than most people have ever experienced.


When all you have is a hammer, every problem looks like a nail. Anybody else wonder why EVERYTHING connected to “climate change” is negative? I mean, if it weren’t simply propaganda, you would think there MUST be some positives to “climate change”. Wouldn’t you?


When you look at it, Joey, almost everything that would happen if it was a few degrees warmer is amazingly positive for humans and the biosphere. Too bad its not going to happen. Honestly, the whole CAGW concept is an obvious surreal fantasy that a few clever people have managed to transform into the dominant paradigm. This is hardly unique to climate change. Hans Christian Anderson published “The Emperor’s New Clothes” in 1837; and indication that we humans have always been pretty easy to manipulate.

Roger Graves

I believe it was General Phil Sheridan of US civil war fame who remarked that if he owned both Texas and Hell, he would rent out Texas and live in Hell. Presumably Texas in the 1860’s was just as hot and humid as it is now – having been in Houston in August I know whereof I speak. However, early in the twentieth century someone conveniently invented air conditioning, and Texas became liveable.

Of course, air conditioning takes energy – lots and lots of it. If all that coal/gas/nuclear power is replaced by wind and solar, then the inhabitants of Houston and similar places are going to have to get used to living without air conditioning when the wind dies and/or the sun sets.

Stevan Reddish

So, the move to renewable energy sources is going to make air conditioning unaffordable. This will reverse the flow of people into the southeast that has occurred due to AC availability during the last 50 years.

Thus CAGW fear mongering driving the move to renewables will be the cause of a northerly migration, not global warming.


F. Leghorn

Thus CAGW fear mongering driving the move to renewables will be the cause of a northerly migration, not global warming.

You say that as if it were a bad thing.

Not as likely as you think, at least for the southeastern USA away from the coasts.


“On the bright side, the paper says that if nations can substantially cut greenhouse-gas emissions in the next few decades, the worst effects could be avoided.”

Known with such certainty because their climate religion tells them so. Those climate fools at Lamont-Doherty are never allowed to question the underlying assumptions (like RCP 8.5 is junk alarmism) that make everything they produce junk, i.e. fruit of a poisoned tree, they just keep producing poisoned fruit to feed to the ignorant masses.

These prognostications are very much like the 2007 Arctic sea ice disappearance by 2015 claims. This all just junk alarmism to fuel more grant money to study.
The politicization of science is the real driver behind this junk science.

F. Leghorn

Their big mistake on the ice disappearing was giving such a short timespan. We are all pretty much still alive. This time they learned their lesson and put it out way in the future so it can’t come back on them.

Another impossible RCP 8.5 junk paper. The business as usual (BAU) scenarios for AR4 are A1b or A2. The equivalent for AR5 is intermediate between RCP4.5 and RCP6, but closer to 4.5 than 6. This paper’s abstract says expressly that there is no wet bulb heat problem anywhere with RCP4.5. So there is likely no wet bulb heat problem under any realistic BAU scenario. As reported elsewhere, RCP8.5 is highly unrealistic even though often inccrrectly referred to by warmunists as BAU. Discussed in essay Hiding the Hiatus.

Separate paper science problem. I just looked up the days (not weeks) survivable temp limit with enough water at 100% humidity. Lots of physiology back up. It is indeed 35C. But 100% humidity almost NEVER happens because tstorms form and rain out the water vapor. The paper omits the humidity percent qualifier. Very hot saunas are survivable because the humidity in them is well below 100%. Singapore (because of location) is one of the highest humidity places on earth. Singapore Relative humidity ranges from 70-80%. Just looked it up. I call fearmongering warmunist BS.


‘ Very hot saunas are survivable because the humidity in them is well below 100%.’

It is up to taste whether the humidity is 80% or 95%, or even supersaturated. But I guess about 40 Finns die yearly since they fell asleep in sauna and nobody wakes them. I like sauna at 50C-60C with totally high humidity.


We used to take saunas along shores of Lake Superior and run into water to finish the bath. Only time waters of the lake were pleasant to jump into.

Steve R

For perspective, over 37°C wet bulb, water vapor would litterally condense within your lungs. Certainly fatal.

Richard M

I believe Willis just showed these same areas won’t be getting any warmer. It seems there’s something called a cloud that just might pop up and prevent additional warming once the temperature starts going up. Too bad these models don’t do clouds.


Yep. Down here on the Gulf Coast in the summer it gets hot in the daytime, then it rains, then it cools down. The Gulf is our thermostat.

John F. Hultquist

Between now and the end of times, oops – – “ close to the end of the century”, is sufficient time to fix many issues, namely lack of electricity and A/C. The people of Earth need to get rid of several things to do this, such as “climate scientists.” Add your own crackpots here ____.

Also, read ristvan @ 11:09 and others.

I live in Arizona, when the humidity increase the temperature declines, To have extreme heat require dry air, a humid air carries more heat, not allowing the temperature to increase as much as dry air. Add in humid air leads to thunderstorms, which in turn cools that atmosphere. That is why out hottest days in the Valley of the Sun are around the end of June the first of July right before the monsoon season. Yes 95 F and foggy is pure hell the unfortunate part of the is I saw that in the Minnesota/ North Dakota Red river valley in 1975 after a eight inch rain in Fargo/Moorhead twelve inches on each side then it turned hot. it was late June. The flat Red river valley had miles of water on it. I survived that, add in back them I did not have air-conditioning either at home on in my vehicle.


I have a relative that drove back and forth between Phoenix and Yuma in an unairconditioned car in August. These “drop dead” numbers make no sense whatsoever to me.

That route is low humidity. The 35C threshold is at 100% humidity, which never happens in the real world. See my comment upthread after doing a quick fact check.


The key word in the article is “projections” enough said.


A projection is a prediction that is made by extending an existing data line. This paper’s predictions contain no basis in any data whatsoever.

Stevan Reddish

” along the Persian Gulf, where seawater can warm into the 90s Fahrenheit, and offshore winds blow moisture onto land.”

The paper recognizes that a particularly unusual situation is required to produce killer heat/humidity that they predict: a hot sea adjacent to a very arid coastal plain. These conditions do not apply to the areas they labeled potential problem areas.


Steve R

“Offshore”? Or Onshore?

Meanwhile people continue to retire from Minnesota o Florida and from Victoria to Queensland despite the Wrmistas’ warnings. Some like it hot!


When conjecture and science collide. Conjectured predictions are the result of explaining history without regard to observed data. Or even because of it when it is inconvenient.

I lived in Abu Dhabi in the early 1970s. That’s on the Persian Gulf, but on our side we called it the Arabian Gulf. Humidity was very high – when you walk out the door, your shirt is stuck to you within a couple of steps. I remember a friend sticking a thermometer in the sea near the beach one day and it was 104F. Abu Dhabi was doing pretty well back then, with its building and infrastructure projects all getting underway, and people moving in from all over the world to work there. And a lot of the work was outside. Back then, it was a great place to be. So the projected future conditions that these people are desperately trying to scare you with aren’t exactly new or debilitating. And even if you believe that they are, just take a look at the map and note the vast land areas that won’t be experiencing those conditions.

BTW Steven Sherwood authored that egregious paper that coloured the non-hot-spot bright red.

Mike McMillan

We’re doomed. Again.

Walter Sobchak

A further demonstration the “climate science” is the product of rich white people from Northern Europe. Homo Sapiens is a tropical species. We can survive the mid day heat by finding shady spots and resting until the cool of the evening. Many people who lived in hot climates before modern times adapted by taking a siesta during the oppressive hours and going back to work in the late afternoon.

I continue to insist that warmunism is the last socially acceptable form of racism.

Keith J

Humidity cools the surface. Water vapor is buoyant. The molecular weight of water is 18. Air is around 29.

True enough, but water vapor isn’t exactly water monomers. Don’t overlook the strength of water’s hydrogen bonding, to itself and other chemicals. Plus, for gases, ‘buoyancy’ isn’t what people think it is. For the US standard atmosphere (which is dry), the typical velocity is on the order of 1 km/sec at standard temperature and pressure. Water monomers will move faster, water dimers wouldn’t (on the order of 1.4 km/sec for monomers, dimers would be a bit under 1 km/sec). Gases are completely miscible, unless physically constrained, and even then, they’ll mix fully within the constraints given sufficient time. Liquids, though, may or may not. Don’t conflate them because both are subject to bulk fluid flows.


“The conditions we’re talking about basically never occur – people have never experienced them… but that doesn’t mean that without super-big funding going forward they aren’t horribly real and terrifying and getting worse than we auggghhh!!!!!!”

No. It’s never been 32 C before. The fact that people all over America are rushing to places with 40C summer temperatures seems to be irrelevant. The fact that people love and operate in such temps with little negative effects and lower mortality than cooler places is irrelevant.

The fact is the study is wrong from every aspect it’s hardly worth even commenting. The temperate change they proclaim is 90% of the change they predicted. In other words we have gotten only 10% of the temperature change they predict. After 70 years only 10%. They expect in the next 70 the other 90%. This is normally called speculative because they have missed every prediction they made before.

Even if we give them their prediction there is no evidence that such temperatures will result in negative consequences. Every degree rise in the past RESULTS IN MORE LIFE. Healthier life and longer lives. But we are to believe among other things that we reached the perfect temperature and every change from here is bad. Normally this would be considered improbable. Oh well. This is climate sciology and normal rules don’t apply.

Another problem. Even if species were to die who is to say that this is unnatural. What is the natural extinction rate and formation rate? Large extinctions were associated with advancement of life. Increased rate of evolution is potentially very good. We dont know. We have no way of judging if it is Good or bad. Nothing will probably happen but if it does we still can’t say it is bad.

In the meantime Man continues to improve our handling of natural disasters to the point that almost nobody dies anymore from any negative thing in the environment.

Michael Jankowski

No regional skill, but let’s ignore that and make regional claims.

Excellent point.


Did I misunderstand something about the “wet-bulb” measurement? Because if they are talking about really humid days in the upper 90s (Fahrenheit) THAT HAPPENS ALL SUMMER IN THE DEEP SOUTH.

Not necessarily. In fact, the HHH here is rarely upper 90s with afternoon humidity in the upper 90s. ‘Average summer highs are 90F (25C = 77F, 30C = 86F, 35C = 95F), with a 1sd of 4F or so. I might see no 98F days at all during the 94 days of summer or I might see 30 of them. I can’t recall the last 100F day here, it has been that long. Afternoon relative humidity rarely gets above 50%. Every night, though, it’ll hit 100%, with condensation occurring, sometimes accompanied by fog. Every morning that condensation evaporates.

People need to remember that not everyone lives in the city. AGW is a city thing related to how swarms alter the local environment. Bee hives and ant mounds do the same thing. Forests, too.


It’s been almost a week since I read such utter garbage.

Using global climate models is a total waste of time.


More end of the Earth fantasies from climate ‘scientists’

Anthony Hills

Surely increased humidity also creates clouds that cool during the day and warms the nights if you look at USA max/min temp data as well as precipitation since 1900. The 1930’s were dry and it turned into a dust bowl. Now there is more rain and specific humidity that has lowered days over 100deg F to one 3rd the level in the 1930’s according to the EPA graph and helped reduce forest fires by 80% since the 1930’s according the the US Forest service, except in the brain of CA Gov Jerry Brown. Warming now is not your grandfathers global warming since it is mostly at nightime with more cloud clover and the heat island effect that helps agriculture locally. We need more temperature data that is split between night and day to do relevant climate science. Hard to find. Some of this is unfortunately reversing with a cooling Pacific and lower solar activity that is cooling the planet rapidly since the El Nino turned into a cool La Nina to join the cool PDO cycle change about 2007.

John Harmsworth

I live in Western Canada. That was some scary stuff until I realized they weren’t saying worse than MINUS 32. So, uh, never mind, eh!

John Harmsworth

I have about a foot of humidity on my driveway. I told it it’s supposed to be up in the atmosphere but it’s not moving.

michael hart

Complete and utter drivel, considering climate models can’t even produce a single cloud and convectional thunderstorm.

Not only do these people simply write down whatever their fevered imagination produces, they are also very repetitive. Can any of them even conjure up a disaster scenario that we haven’t heard before, many times? Somebody needs to tell them just how boring they are.

Dr. S. Jeevananda Reddy

I published a series of articles, in Indian Journal of Meteorology, Hydrology & Geophysics, related to human comfort related issues. They are as follows:

1. Effect of radiation on human comfort – 25:433-440 (1974)

It presents a discomfort index for seasons over India using global solar radiation and net radiation. Also compared the radiation discomfort index with temperature discomfort index, wet bulb temperature and humidity mixing ratio;

2. Effective pollution potential over ten Indian stations – 25:445-448 (1974)

Presents the vertical temperature change versus effective pollution potential index

3. Simple formulae for the estimation of wet bulb temperature and precipitable water – 27:163-166 (1976)

Presented methods to estimate wet bulb temperature and precipitable water in the total vertical column

4. Wet bulb temperature distribution over India – 27:167-171 (1976)

Present the spatial and temporal distribution of wet bulb temperature over India and also discussed the effective temperature diagrams over selected cities. Effective temperature — related to wet &dry bulb temperatures and wind speed.

5. A method of forecasting the weather associated with western disturbances – 29:515-520 (1978)

It presents a schematic presentation of circulation patterns in summer and winter and their associated heat and cold waves over India;

3 rd para of the above article “warming climate — death” — a highly hypothetical.

Dr. S. Jeevananda Reddy


Thank you Dr. Very interesting.

Philip Bradley

They appear to have omitted rain from their model.

Their example of Bandar Mahshahr is a location currently beyond the monsoonal zone, where a sufficient
column of humidity never builds to produce convective monsoonal rain. In simple terms, it isn’t humid long enough to rain. Large areas of the world are in a similar position.

Of course, were it more humid for longer, it would rain and cool substantially.

Kaiser Derden

This is nothing more than more Munchausen syndrome behavior from climate science frauds


Around here, “But it’s a dry cold” is more likely to be said.

Steve R

I would like to see some kind of calculation to justify where the heat is going to come from to bring the wet bulb temperature above 32°C. The heat required is definitely not linear with temperature.


For my entire life I have lived, went to school and worked in the SE USA. Until I went to college I never went to a school with air conditioning. No house I lived in or visited had air conditioning again until I left for college. Two-thirds of my career I worked outside from Spring through Fall in temperatures over 90 F(32 C) and mega humidity from sunrise to sunset. Sure it was hot but it didn’t stop us from working or playing outside and no one we lived or worked with died of heat stroke. I did recommend in a legislative subcommittee meeting one time that we could significantly reduce energy use in our state and cut school budgets by requiring public schools and universities to turn off their air conditioning. Public school and university electric bills are a significant portion of the education budget. Some old timers at the meeting agreed. Like myself they had not grown up with air conditioning,

Matt G

“Humidity may prove breaking point for some areas as temperatures rise, says study”

Only scientific evidence points to satellites observing a decline in humidity over decades. Therefore the fact is that temperatures have only slightly increased while humidity has declined.

A decline in humidity, but a increase in temperature doesn’t imply there has been an increase in energy at all. For there to be an increase heat detected both humidity and temperature increases need to be observed.

Global temperatures warming slightly mean very little while humidity is declining because the lower the water vapor, the less energy is needed to reach the same temperature as before.

Global warming may well just be a change in humidity and nothing to do with an actual change in temperature (energy).


“Only scientific evidence points to satellites observing a decline in humidity over decades. Therefore the fact is that temperatures have only slightly increased while humidity has declined.”

No it doesn’t …..

“We conclude from this that it is doubtful that these
negative long‐term specific humidity trends in the NCEP/NCAR reanalysis are realistic for several reasons. First, the newer reanalyses include improvements specifically designed to increase the fidelity of long‐term trends in their parameters, so the positive trends found there should be more reliable than in the older reanalyses. Second, all of the reanalyses except the NCEP/NCAR assimilate satellite radiances rather than being
solely dependent on radiosonde humidity measurements to constrain upper tropospheric humidity. Third, the NCEP/NCAR reanalysis exhibits a large bias in tropical upper tropospheric specific humidity. And finally, we point out that there exists no
theoretical support for having a positive short‐term water vapor feedback and a negative long‐term one.”

Matt G

That paper refers to because ENSO shows positive trends then long term should also have positive trends. Not true because ENSO only affects the atmosphere with each trend for a limited time. The long term trend involves many years without any ENSO trend and this likely would be the most important factor. The increase in El Nino’s are reasonable for this positive short term trend and are irrelevant to the long term trend when ENSO doesn’t have one.

There is support for having a positive short term water vapour feedback and long negative trend because changing trends in ENSO are only temporary and occur less than they don’t. The background trend is dominating the ENSO one due to declining cloud albedo and increasing sunshine hours.


I survived living in New Orleans without AC during the summerz many years ago. School in September was a treat. Sweat would drip from your face and make the ink on your paper run.

The thing I’ve noticed with the way climate science is reported is that it seems some people were never taught how to screen papers. Studies are always just “That’s interesting but so what” because by their nature they haven’t managed to produce anything tangible. Experimental papers are the best. You can have 100 studies and models and it looks like a lot of “evidence” but all it is, is noise.

When I did my PhD the big gold rush was for interdigital electrodes on capacitors, with exotic materials, leading to massive magnetoresistance or ferroelectric effect or whatever. And when you took the time to read the paper and see the tests you realised it was because the devices were lossy as hell. It wasn’t a real effect. And that’s even with experimental results. The hard road to repeatable results were a thin one as well.

You need to learn to screen out the garbage. And stop believing in this peer review myth. Or in the low uncertainty for data sets.

That said when every hypothetical idea is presented as fact by the media and believed by politicians then I can see why you need to keep up with the madness.

Mike Rossander

Baloney. Their premises are all wrong. I served in Fort Polk during the early 90s. We considered a day with a wet-bulb temperature 90F (32C) a normal summer day. In those conditions, we routinely:
– put on heavy clothing including helmets and bulletproof vests
– sealed ourselves in poorly ventilated metal boxes (self-propelled howitzers, etc)
– engaged in heavy manual labor.
Local farmers did much the same in their tractors and other farm machinery.

Yes, there are some things you need to do to mitigate the effects. The first is to acclimate to the climate. You can’t get off the plane from Minnesota and expect to keep up with that level of activity. But when you live down there? Acclimation happens. Second and probably more important is to stay hydrated. Even at 100% humidity, your body needs fluids. 1-2 quarts an hour depending on your level of activity. 5 gallons per person per day was considered normal. Northerners can’t imagine being able to take in that much fluid a day. And frankly, I couldn’t either when I was first stationed there. It becomes normal.

The bottom line is that even assuming their worst case scenario, it’s no worse than humans regularly face and thrive in today. Their “death threshold” is pure bunk.

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