Public Release: 2-Aug-2017
Deadly heat waves projected in the densely populated agricultural regions of South Asia
American Association for the Advancement of Science
Hot and humid temperatures in South Asia, which contains one-fifth of the global population, will exceed the upper limit of human survivability by the late 21st century, scientists project, underscoring an urgent need to adopt alternative strategies on top of those currently proposed to alleviate climate change-induced temperature extremes. In 2015, the fifth deadliest heat wave in recorded history affected large parts of India and Pakistan, claiming around 3,500 lives. Many studies in South Asia have charted the trajectory of heat waves linked to climate change and their impact on human health; however, the forecast of “wet-bulb temperature,” or a measure of temperature, humidity and the human body’s ability to cool down in response, is not yet clear. After running high-resolution simulations under two climate scenarios, Eun-Soon Im and colleagues reveal wet-bulb temperatures are projected to approach the survivability threshold (35 degrees Celsius) over most of South Asia, and exceed it at a few locations, by the end of the century under a business-as-usual (BAU) scenario, while reaching dangerous levels (over 31 Celsius) under a mitigation scenario (roughly comparable to the goals pledged by the 2015 UN Conference on Climate Change). The authors also found that the population exposed to harmful wet-bulb temperatures will increase from zero in the present day to about 30% under BAU versus only 2% under the mitigation timeline – a substantial difference that points to the significant impact of climate change mitigation efforts. The increase in humid heat raises important questions of environmental justice in agricultural areas where the inhabitants – the majority of whom work outdoors and have poor access to air conditioning – are most vulnerable, the authors say.
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good article
“In 2015, the fifth deadliest heat wave in recorded history” – So this was cooler than previous heat waves but somehow indicates it’s getting hotter?
“the densely populated agricultural regions” Um… what is this? I thought agricultural regions had LESS population than urban areas.
The dry bulb was 33C and I’m guessing the wet bulb was 2C or so above it when I was mowing the lawn today. I need to use this article as an excuse to avoid yard work. And I live in fairly moderate central Virginia. it was hotter last week, but I suppose we all died
Wet bulb temperature will always be lower than dry bulb, it can never be higher. You have it backwards. On a humid day at 33C dry bulb temperature, the wet bulb temperature will be 24-27C.
Chris never and always are seldom true.
You are incorrect.
Chris is correct and many here seem to not understand the difference between dry bulb and wet bulb temps.
http://www.engineeringtoolbox.com/dry-wet-bulb-dew-point-air-d_682.html
The Wet Bulb temperature always lies between the dry bulb temp and dew point temp. So a Wet bulb survivability temp means that if you take a thermometer and wrap the mercury bulb with evaporating material then the temp lower until the cooling from evaporation reaches equilibrium with heat of the surrounding air. So in affect it is the temperature where sweating no longer cools the human body.
Most desert like temps of 40-50 deg C have ultra low humidity which means sweat can evaporate freely and the wet bulb temp is much lower than the 35 deg C survivability temp.
Occasionally along the gulf coasts you get a sea fog with temperatures in excess of 30 deg C. This is the closest it gets to this survivability temperature and I am told by a Met colleague that it is unbearable to go outside when they occur.
Here are some real world examples. A random snap shot of Kuwait city today. Note Relative humidity is only 8.3%. This would mean the WetBulb temps would be around 25 deg C cooler than dry bulb which would mean a wetbulb temp of 21 deg C.
Jahra ✖
ID: NIL 40586 Lat: 29.3 Lon: 47.7 Elev: 55m
Latest Graph
Temp Dew Point Relative Humidity
46.0°C 4.3°C 8.3%
Bahrain which is surrounded by sea and therefore more humid is 5 deg cooler on dry bulb but has 34% humidity resulting in a wetbulb temp of roughly 28 deg C. Bahrain would feel much hotter than Kuwait city because the human body would only potentially cool down to 28 deg C from sweating as compared to 21 deg C in Kuwait.
Bahrain International Airport ✖
ID: OBBI 41150 Lat: 26.3 Lon: 50.6 Elev: 2m
Latest Graph Metar / Taf
Temp Dew Point Relative Humidity
41.0°C 22.0°C 34.0%
Feels like 46.5°C
Japanese temperatures this century.
MASSIVE warming trend, as you can see ????
The wet bulb temperature is ALWAYS less than or equal to the dry bulb temperature!
When they are equal, we say it is 100% humidity.
The wet bulb is colder because, as water evaporates it absorbs heat and lowers the temperature.
35C is the same as 95F. A wet bulb temperature of 35C means that a person can not cool their skin below 95F via perspiration, which is too close to normal body temperature.
I guess no one has ever survived a steam bath.
Of course they have. But going into a steam bath and sitting there for 30min is a whole lot different than doing manual labor in it for 8 hours. I can’t believe I need to explain this to you.
There will be no more thunder storms. It’s official.
Yet more claims of never before experienced in the whole of Earth’s 4 billion years history threatening all life with just slightly a little while away total destruction and it’s all because of our evil CO2/beef eating/ travel fixated (take your pick) using habits. Do any of these people seriously think they have any credibility left anymore? Chris evidently does but perhaps he has never visited South Asia or South-East Asia and experienced the conditions there? Human resilience is something to see and admire.
Is a wet bulb temperature of 35C even physically possible? It would require massive evaporation, and so is only possible in very wet areas or over the sea. The result will be intense convection, convective clouds and thunderstorms.
Note that extreme heat in India occurrs in late spring and early summer (May or June is the warmest month), once the summer monsoon starts the temperature drops.
http://www.veterinaryhandbook.com.au/images/handbook/contentImg23.png
35 deg C and 100% humidity would do it or 40 deg C and 70% humidity. Neither of these are likely unless something like sea temps rose locally to +35 deg C and I think think this is the point of this article…sea temps do locally rise to low 30s in the Persian Gulf and Red sea and if they rose further then temps could potentially become unbearable, but once again they miss what a lot of climate scientists miss and that is Meteorology. The time of year when you get air temps warmer than 35 deg C is also the time of year when humidity is low so low risk. Yes it is possible, but highly unlikely.
Map of the current maximum wet bulb temperatures experienced around the world.
The highest numbers are around 30C right now. As in 40C, 50% relative humidity; 32C, 90% relative humidity. When you get to these type of numbers, it is most likely just going to rain and cool everything off.
http://web.science.unsw.edu.au/~stevensherwood/images/twmax_highresmap_sm.png
Mad dogs and Englishmen…………..
Do check out the full report available here:
http://advances.sciencemag.org/content/3/8/e1603322.full
I noted “According to the global historical reanalysis for modern record (1979–2015) (5), the largest TWmax rarely exceeds 31°C in the current climate. ”
Get behind the temp terms they are using and you’ll see that the are not talking plain old £%C
It’s another RCP 8.5 fraud.
100% fraudulent junk science…
Claims that RCP 8.5 is “business as usual” or that something is “projected” to happen under RCP 8.5 should be prosecuted as mail or wire fraud.
Further, the estimated 2100 average global temperatures, derived from models, includes temperatures (poorly sampled) from the Arctic, which is generally acknowledged to be warming at least 2X faster than the global average. While the surface area above the Arctic Circle is only about 4%, it appears that the high latitudes experiencing accelerated warming is probably closer to about 25%. Additionally, it is warming more at night and in the Winter, globally, than in the Summer. The averages hide this and presume that the average is a reasonable indicator of Summer daytime temperatures. More excited hand waving that they can put on their CV and ask for more funding.
The “funny” thing is that more warming at night, winter and in the coldest air masses, is actually consistent with an enhanced greenhouse effect. This is actual evidence that supports some degree of AGW.
The problem is that this evidence contradicts the catastrophic version of AGW, maybe even indicating that AGW is a “good thing.”
Except they are, since they are assuming that we keep using fossil fuels for another 83 years but farmers in Asia don’t get richer and move inside and get air conditioning.
Do you really think that by the end of the century we are simply where we are now in terms of technology and wealth?
Farmers don’t get rich and move inside? How exactly is that going to happen when the average farm size in india is less than 3 acres in size?
Wheeee. They can’t forecast what it’s going to be next month, and they think people will believe them when they forecast for 80 years from now?
Totally idiotic $$$ seeking article. The claim is that South Asia will still be a 3rd world outhouse by 2100ad. What a crock of shyte. That is 83 years away and look at how that area has modernised over the last 20 years, let alone 80+. Who knows what advances in technology will be used in the next 30 years. Just a worthless lot of attention seeking designed to ingratiate themselves with the money launderers of AGW.
regards
And they will definitely have plenty of electricity for air-conditioning, given the number of coal fired power stations they are building.
There’s some sort of causal link there I think you may be missing
(and no, they aren’t going to be building that many coal power plants)
CausAl says so
It will be “a 3rd world outhouse” if they keep making energy expensive and unreliable.
In the western suburbs of Sydney last summer it did reach 48C which was a record, but prior to the high of 48 there was a measured temperature of about 43 degrees with a dew point of near 28C, which as anyone will tell you is very high for a dry bulb reading of 43 and more uncomfortable than 48C when the DP is only about 10C.
I find that hard to believe. The only way Sydney reaches such high temperatures is being on the receiving end of north westerly airflows that have travelled thousands of km’s across the hot inland. The DP on a day of 43C would have been in single digits at best. At my location in coastal North Queensland a DP of 28 is rare even with airmasses originating over a tropical/equatorial ocean. I can’t see that such a DP is possible in Sydney with a continental airmass.
NOAA wet bulb temperature calculator…
https://www.weather.gov/epz/wxcalc_rh
If the NOAA converter is correct this paper should be withdrawn.
The use of RCP 8.5 should be an automatic retraction.
I recall walking to work in Abu Dhabi on over 40C days with near 100% humidity. It was not pleasant and required a change of shirt when I got to the office, but strangely I saw no bodies in that streets. Apparently real people just aren’t aware of what the computer models say they should be doing.
It may have felt like 100% humidity, but it was nowhere near that. Mean max humidity for Abu Dhabi ranges from 73-80% during the months of June through September.
I’ve seen it 40C and foggy in Abu Dhabi.
Funny, in the winter when it would be a very pleasant 20-25C the paperboys on the corner would be in heavy coats and watch caps and actually shivering. It’s all what you are used to.
No it was 100%. The mean does not describe the range of variation. The windows were pouring water due to condensation. The 100% humidity days were sometimes capped off by torrential rain, a welcome but rare event, though not as rare as the snow that fell in the Musandam.
There is not enough solar energy anywhere on earth to create air with 100% humidity at 40°C. Think about it carefully. Moisture would literally condense in your lungs. This is close to 51g of water vapor per cubic meter of air.
Solar energy alone cannot supply the energy it would take to evaporate this much water.
I live in a hot humid climate. Many people complain about the humidity, assuming it is close to 100%. But a 40°C day with a 30°C wetbulb temp (which is very hot and very humid.) still is less than half saturated (25g water vapor/cubic meter) about RH of 49%.
A parcel of air at 40°C at 100% humidity has about 70% more heat than it does at 49% humidity. Suggestions that CO2 can increase the heat content of air this much are quite preposterous.
‘Hot and humid temperatures in South Asia, which contains one-fifth of the global population, will exceed the upper limit of human survivability by the late 21st century’
Can’t they just go inside?
And of course the idea that sustained wet bulb temps could reach 35C is simply fantasy and science fiction (courtesy of climate model computer games), just as the idea is that space aliens could invade earth at any moment expressing a desire to serve mankind (on fine space alien china, of course).
Humidity never stays at 100%, so drinking plenty of water and a simple breeze are all it takes to cool the body to a safe level. I’ve worked at sustained dry bulb temps of 120F with peaks up to 140F when I had to climb a ladder to the interior top of greenhouses. It was brutal, but I survived.
When will these damn morons wake up and smell the future energy technologies. Do these morons really believe that people will be driving fossil fueled vehicles even after 2050? Or not be using advanced nuclear reactors way before 2050? Their predictions are based on impossible scenarios and are therefore pure nonsensical blatherings that attempt to frighten, even if you believe their dire estimates of the power of CO2 to warm the planet.
Why won’t fossil fueled vehicles be driven after 2050?
This is as credible as the projections about Tibetan glaciers melting away or an ice free Arctic by 2015.
During the first Gulf War I was in the USN, cruising around in the gulf on the USS Nimitz. As a Nuclear MM I was down running the reactor and generating a lot of steam to run the ship. It was hot and humid 24/7 with ambient temperature in that space ~110 F (44.4 C), once temperature exceeds 100 F (37.8 C) you are required to go into heat stress monitoring which includes taking wet bulb temperature. Sea water temperature was ~86 F (30 C) using our non calibrated sea water injection temperature gage that was +/- 2 F.
We took some wet bulb temp readings along and it had us at 105 F (40.5C) which meant we were only allowed to spend 2 hours at a time down in the space. We had just enough personnel for 3 people on watch per station (should of been double that but feces happens), which is why we never recorded the information and didn’t log a temperature any higher than 100 degrees on our logs. Being on a 2 hr on 4 hr off watch rotation for months on end is not exactly conducive to officially informing our officers of the real conditions down there and they were smart enough not to look at a thermometer when asking us if it was hotter than 100 F.
No one had to go to medical for dehydration, suffered heat exhaustion/stroke or even died though it was higher than that mythical 35 C WBGT. And no, there wasn’t much cooling down off watch either. There were no cold showers to cool down with best we could manage was a luke warm shower, desal is done by flashing sea water into steam and it usually didn’t have time to cool down a lot with our water use vs. storage tank temps. Supposedly our berthing had AC but yeah, they steal parts off those AC units to keep AC working for spaces with electronics and officer berthing.
Good point.
Elephant in the room alert: All such predictions/projections are made using altered temp data that informs computer model programs. I hastily add that these models are ostensibly about as valuable as a [trimmed] in a bottle. They have routinely projected/predicted wildly inaccurate results that very widely and this is true when trying to recreate past temps. Putting faith in them to get even close to the scenarios years, let alone decades, down the road requires…well…FAITH…because it sure is hell ain’t dispassionate, rational objectivity; they’re a farce!
Additionally, the Sun’s going into a minimum that many solar physicists around the globe are “projecting” will be a long protracted one. So all of this time and energy debating whether comments about understanding wetbulb/drybulb (dullbulb?) is no more than an academic exercise. These predicted dangers are not there now and just at importantly, those making these -idiotic-, err, bold projections/predictions will be gone by the time they don’t happen. BS by an other name…
Excuse the typo: The models vary wildly. Not very. Carry on.
A prediction with numbers 83 years in the future. How can anyone call this science with a straight face? It’s ludicrous. It’s science fiction. It’s nonsense. It’s worse than a wild guess.
But it does provide a scary headline and the opportunity to argue how many angels can dance on the head of a pin for those who like to obfuscate with jargon.
And the straight-face is practiced in the mirror – an exercise which is actually pretty easy if you make sure to take the all-important first step and jettison any sense of shame.
The cost effective way to avoid issues is to install coal plants and then provide homes air conditioners.
I think I will promote this scheme and invest in Big Air and make a huge profit!
I think they are taking the political term “Snowflake” too literally.
We were in northern Scotland in the late 90’s, in late May. Beautiful country. Nice folks, although several chided us for our country not signing Kyoto. They were having a heat wave, and the locals were melting. You could tell the Americans – running around in shorts and T-shirts, staying in the sun, while the locals wore jackets.
The high during our two week stay was 68 F, which explains why we Americans were staying in the sun. With that breeze, a tad more clothing was appropriate. But for God’s sake, if it’s hot, take off your coat!
At 40C, as opposed to the 20C you experienced on your trip, the coats were never on in the first place.