[dohboi]

Thanks vox.

OS wrote: "So if it's almost impossible to get to 100% humidity, why are we discussing it as though that puts us all at dire peril? "

Look at vox's graph.

I can't speak to your own report of your own anecdote.

As to: "Just like all the poor people who live in extremely hot places like Africa year after year are just fine."

I'll say it one more time: We're talking about conditions that have not existed to date persistently in the ambient environment on the earth yet.

[Tanada]

The problem with such assertions is they are bimodal, they require BOTH 35C temperature AND 100% local humidity.

People routinely live in many places all over the Earth where temperatures frequently exceed 35C. However in those places humidity rarely exceeds 50% on the hottest days because the hotter the air is the more water vapor it takes to increase the humidity. Places like Las Vegas and Riyadh Saudi Arabia have lots of living humans in them desert temperatures notwithstanding. I have personally experienced 40C during the drought of 1988 in Michigan with about 40% humidity. Running was not a good idea, but moving around and getting things done was entirely possible. By the same token Baghdad, Iraq AVERAGES 44C in July daily high temperatures. However in the summer months the relative humidity in Baghdad during the summer months is 22%.

Meanwhile Entebbe, Uganda is right smack on the equator, close enough, and it rains a lot so the humidity is always high. Average high temperature year around 27C, all time record high 33C. Nobody boiling in their skins around there. Why? Because even on those really record setting hot days humidity is well under 100%.

Climate change might kill a bunch of Humans, I don't doubt that for a minute, but the Earth is a very complex system with literally millions of micro-climates. People who are in the right micro-climates after the climate flips will tootle along living their lives. Those who are not, won't. Living where you have access to open bodies of water makes a huge difference because a dip in the water will rapidly drop your core body temperature. As some have pointed out basements can be a real blessing especially if you can not afford A/C. For my childhood getting sent to play in the basement was a reward, not a punishment because I grew up in a balloon frame farmhouse with lousy heating and no air conditioning.

The other thing to keep in mind, for every 3000 feet/1000 meters in altitude you ascend you drop 3C in temperature. Entebbe, Uganda which I mentioned earlier is at just over that altitude, 1153 Meters. Humans have lived there for millions of years for a reason, no matter what gyrations we have experienced the climate there is pretty stable.

[dohboi]

Thanks, for the many clarifications, T. Apparently I have not yet been clear enough.

As to: "Earth is a very complex system with literally millions of micro-climates"

Yes, but a whole bunch of those 'micro-climates' are going to move outside the livability range as global temperatures and therefore also global humidity rates continue to climb.

(Do I need to link to the original article again?)

[ritter]

In short, there are variables and coping mechanisms. However, should you be trying to do productive outdoor work (agriculture and construction, for example) in the red zone for any period of time, you will shut down and/or pass on. The body needs to be able to cool itself. I've done work in very hot 110* weather and it sucks. Luckily, I've always had access to ample fluids and a nice cool room to recover in afterward. I think the point is, most of the world's laborers do not have access to such and are fucked should we reach those temperature/humidity levels. As Vox's photo above shows, the'll get cooled down in the fridge, but only after rigamortis has set in.

[Tanada]

Thanks, for the many clarifications, T. Apparently I have not yet been clear enough.

As to: "Earth is a very complex system with literally millions of micro-climates"

Yes, but a whole bunch of those 'micro-climates' are going to move outside the livability range as global temperatures and therefore also global humidity rates continue to climb.

(Do I need to link to the original article again?)

Geeze D I said right there in my diatribe

People who are in the right micro-climates after the climate flips will tootle along living their lives. Those who are not, won't.

What more do you want?

[dohboi]

Sorry, reading to quickly and rather tired and exasperated. Time for a break.

May we all find our own perfect micro-climates!

[AgentR11]

It feels colder in the shade or with a fan on. Still, it is a genuine concern. No question about it.

err, at the temperature&humidity, no it doesn't. The fan will feel like standing in front of a heater. It won't make you cooler.

The cooling you feel from a fan is a result of the state-change energy taken up by the water vapor that results from the sweat on your skin evaporating.

Now, I would like to note that this problem requires 100% humidity; which at 35C is a huge amount of water. We are considered very humid in East Texas; but when the temperature is 95F; the humidity is much more often in the 40's% than in the 90%s; not because there is less water, but because at 95F the air can hold much more water by mass per unit volume before its starts to condense out.

The 2nd thing is that as long as there is electricity, it is easily possible to cool a room to a safe temperature; and you can achieve huge efficiencies over current practice simply by reducing the volume of the space that the air conditioner is responsible for cooling.

The risk here is that it makes human existence very fragile, and fully dependent upon technology. Technology that is now considered a simple matter of luxury and not rising to the level of reliability that true life support systems require. Add to that, it is technology that will be quite difficult to repair at the typical moment that will intersect between need and failure.

For Americans, this feels pretty distant, we have central A/C's; window A/C's; A/C in our cars; we have freezers that can store ice that can be used for conductive cooling..

Imagine telling a few million Brazilians that they now live in a world where if the grid breaks for a few hours at the wrong time... they all die. Unless they are rich enough to own fuel storage, generator, and an A/C suitable for emergency application. That's gonna make for some unhappy campers. Upside might be that civil disturbance would be impossible; the wet bulb temp would be fatal to anyone doing high energy movements outside pretty quickly.

[GHung]

dohboi: "May we all find our own perfect micro-climates! "

That's pretty much it. Those who make the right call and are fortunate enough to make that play stand the better chance. While a great deal of luck will be involved in making it through the bottleneck facing humanity, any deep concern one may have for one's fellow man is purely academic. Not a damn thing any of us can do at this point except prep and hope, while doing one's best to not contribute to the madness.

Now back to my PV-powered 5000 BTU window unit. Ice-cold adult beverages available for any and all takers, while they last. Damned hot, it is....

[AgentR11]

Humans have lived there for millions of years for a reason, no matter what gyrations we have experienced the climate there is pretty stable.

Small addenda, Humans, as in Homo Sapiens haven't been around for "millions". Its why you see me use the term "hominid" quite often. Hominids all share some physical attributes that allow us to consider their environmental requirements; but they aren't "Human" any more than a chimpanzee (also quite a smart, capable ape) is.

Also wise to note, most hominids managed to enjoy their rather huge advantages in the world without wrecking the biosphere. It took Homo Idioticus to achieve that most exceptional result.

People get a very odd idea about how much history humans have with climate variation. In reality, we have virtually no experience with shifts in the Earth's climate; just a very marginal observation that we've seen Earth with a huge amount of ice on it, and we've seen Earth with a bit less ice on it... but still a huge amount. What we'll get to test our survival against is, indeed, something that no hominid has ever experienced or has evolutionary adaption to... an Earth with no ice other than maybe under polar winter-night.

[AgentR11]

I can tell you that I have a 71 year old friend who 2 years ago lived in his trailer a WEEK during an extreme heatwave during very high humidity, where the thermometer read 99 degrees or more every time it was checked. Oh, and he never exercises, has a terrible diet, smokes, and has some heart issues, like a complete left bundle branch block (electrical signal problem).

Hint: At over 95% relative humidity, this put him well within your "fatal" zone for a good 20+ TIMES the supposed limit of six hours.

I think you're making a mistake in thinking "old" "never exercises" "poor diet" and "heart issues" are things that would make his problem much worse.

Muscle mass, fitness, and activity are your enemies. What you list as indicators of stress, are not in this circumstance. Fat, bone, blood, produce almost no body heat that needs to be dissipated. Heart issues and age would indicate that your friend was likely relatively still and not in direct sunlight. Thus, he probably had a slightly elevated body temperature, dissipated the heat he needed to shed by conduction, and survived more or less fine.

OTOH, if I were to go out in those conditions, run a mile, and not have a way to conduct off the heat; I'd likely die of heat stroke. I get "exercised" about this issue because I have often played close to the edge; but I do so only because I know I have a ton of ice, a cold non-carpeted floor to lay my nekkid butt on, a/c and backup a/c, and a big axx fan at the destination!

Heat stress can kill you. But it may not kill who you think it should, or why...

nb.. also, I don't know many instances where you could have a continuous above 95F and above 90% humidity for a week... Maybe you don't want to disclose the exact location for privacy reasons, but maybe a general pointer to the geographic area?

[dohboi]

Thanks for those excellent clarifications, Agent. Maybe people are starting to come to some understanding of the matter?

[SeaGypsy]

Hi Doboi,
I'm hearing you & get you 100%, however according to Vox' graph I should have died every day of last southern summer in Darwin, not to discredit WBT, just some extrapolations as above.

People do physically aclimatise, & it takes several weeks for fit people, much longer if obese or liver function impaired. People in the tropics have a very low blood lipid count, in polar regions, very high. Either extreme will kill a blow in from the other extreme, much quicker than a local.

In reality WBT is very rare, even in the deep tropics. There is almost always some dryness in the air, even 10% will allow a degree of evaporative cooling. The usual pattern is for extreme humidity to be quickly followed by rain, often extreme rain, with the effect of those few percent of dryness working across a vast wet surface area very quickly drops temperature by several degrees. This is literally why in the trpics you often see people in awe, dripping wet, in extacy at the relief of a summer shower. Watch videos of flood aftermaths in cities like Manila, kids having a blast of a time playing in the relative cool of filthy floodwater. It is easy to forget that for the previous several months it may have been not under 26c at night/ 36 max with humidity steadily creeping.

References to 40+ with 40% humidity are totally irrelavent to WBT. Evaporative cooling works a treat far hotter.

[ROCKMAN]

Apparently everyone draws on their own experiences. But there are millions of folks on the Gulf Coast that regularly work outside when the temps are 95F+ and humidity is 90%...or more. In my part of Texas when we have those rare moments of 100F+ and the humidity drops below 60% we refer to it as a bit of relief. In my youth I've worked a 60# jack breaking up bad spots in parking lots in August with 95F+ and 90% humidity. Yes...lots of breaks, But it was real simple: no work...no pay. And yes: folks did occasionally die...even relative healthy folks.

Such is life.

[DoomInTheUK]

Surely this can't be a tricky one to understand.

Humans primarily use evaporation for cooling - a cold shower or bath work far better, but we don't tend to live in either of these, so evaporation will have to do for the rest of the time.

Evaporation only works above a certain temperature/humidity combination. Below that level, you just stay wet and therefore don't loose heat.

A human body requires to be kept within a very narrow temperature range, stray outside of those ranges for tool long and it starts to shut down and eventually you'll die.

35C is just under the core temperature of the human body, which is 37C. A WBT of 35C can be achieved anywhere between 48C at 10% humidity and 31C at 75%.

Nowhere on earth has yet reached these combinations of heat and humidity, but Pakistan has got dangerously close, hence the number of deaths.

[DoomInTheUK]

Ooops posted too quickly, whilst checking the figures - those temps should be adjusted upwards to account for altitude.

[diemos]

Nowhere on earth has yet reached these combinations of heat and humidity, but Pakistan has got dangerously close, hence the number of deaths.

Also, it's Ramadan and the devout are forbidden to drink water during the day.

[AgentR11]

parking lots in August with 95F+ and 90% humidity. Yes...lots of breaks, But it was real simple: no work...no pay. And yes: folks did occasionally die...even relative healthy folks. Such is life.

I know we think like this.. but.
Little challenge for you. Find me, in East Texas, a date, time, and location, where the temp was over 95, and the humidity at, or above 90%, for more than say, 4 hours straight.

What really happens, is that we go out in the morning, and it is 80'ish, and 100% humidity, and it feels like being hosed by an invisible prankster. Then it heats up in the day to 95+, and it still feels very, very wet. The amount of water in the air, has increased from evaporation off the soil, ***BUT*** it hasn't actually increased the percentage humidity; because the capacity of the air to hold moisture has increased far more.

Thus we end up with 95F.. and an absolutely hideous 70% humidity, but we are able to work, sorta, because we still can dissipate heat by evaporation, and the air temp isn't significantly above our regulated body temperature.

95F + 90%.. it just doesn't happen as often as we think it does; and it never persists outside those brief periods of a thunderstorm pouring rain on 130F, half-melted asphalt.

[dohboi]

"Also, it's Ramadan and the devout are forbidden to drink water during the day."

Good point, but I believe some imam or other lifted those restrictions during the heatwave in Pakistan.

As to the other points, people's personal anecdotes are worth approximately squat. We all remember things a bit differently than they are. If you have documented evidence that some location endured wbt's at or above 35 somewhere and people went about their lives happy and clams, post it. Or rather send it to a major scientific journal, since people would have to change all the text books.

Of course, some people are more susceptible than others, within a not-too-broad range.

But again (and again, and again...), the average, healthy adult, even at rest, even in full shade, and even with the strongest wind blowing on him or her, will die within about 6 hours of being exposed to wetbulb temperatures at or above 35 C (95F).

[vox_mundi]

Xtreme Wet Bulb Temp: 95 Degree Fahrenheit = 35 Celsius http://www.srh.noaa.gov/tsa/?n=wbgt

I can't find a single instance where Texas exceeded 85 F (29 C) Wet Bulb Temp (New Orleans gets up to 82 F WB)

Real-Time Texas Wet Bulb Temperature Map (in C): http://coolwx.com/cgi-bin/getanalysis.c ... field=bulb

Houston, TX Stats (in F): http://www.weatherexplained.com/Vol-6/2 ... s-IAH.html


---------------------------JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC AVG

MEAN DRY BULB -------51.6 55.4 61.7 68.4 75.4 81.0 83.6 83.2 78.6 70.0 60.6 54.1 68.6
MEAN WET BULB ------48.1 51.7 56.4 62.6 70.0 74.5 75.7 75.6 71.4 64.2 56.3 47.1 62.8

and http://www.ctiac.com/houeco.htm

Wet Bulb Stats Plano, TX (in F): http://www.planoweather.com/wxwetbulbdetail.php

Wet Bulb Stats for Houston, TX: http://web.utk.edu/~archinfo/EcoDesign/ ... ton_tx.pdf

Wet Bulb Stats for Beaumont, TX: http://www1.ncdc.noaa.gov/pub/data/Engi ... ont_tx.pdf

Wet Bulb Stats for Midland, TX: http://www1.ncdc.noaa.gov/pub/data/Engi ... and_tx.pdf

Western States Stats: http://www.wrcc.dri.edu/htmlfiles/westcomp.wb.html

Wet Bulb Temp In U.S. & Canada with Isoline maps: http://lib.dr.iastate.edu/cgi/viewconte ... e_eng_pubs

Wet Bulb Temp is not the same as Heat Index