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The emergence of heat and humidity too severe for human tolerance (2020)

advances.sciencemag.org

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Re: The emergence of heat and humidity too severe for human tolerance (2020)

#231

Post by hh3k0 »

concordDance wrote: post #170
sershe wrote: post #136

There are 4 broad scenarios according to which (or a combination thereof) the climate emergency will develop: 1) In a giant case of prisoners' dilemma, the humanity will coordinate worldwide and rise to the occasion, massively cut emissions, tax carbon, build out renewables, etc. 2) There will be massive technological breakthru-s in carbon capture and/or energy production and/or geo-engineering (and I am not talking…

My money is on space sunshades. While it would cost tens of trillions to make a sunshade by launching from Earth, making sunshades and launching them from the moon should be viable thanks to the lack of atmosphere and low gravity. Assuming that a few million tons of mass is enough to set up a space sunshade manufacturing station (and railgun launch rails) it should only cost a few trillion dollars, cheaper than reduc…

Stratospheric aerosol injection is cheaper and we've got plenty of data for that, as it mimics how volcanic eruptions cool the earth.

Re: The emergence of heat and humidity too severe for human tolerance (2020)

#232

Post by mrfusion »

Dumblydorr wrote: post #221
mrfusion wrote: post #198

The gloom and doom posts on HN seem to be increasing lately. I can go to CNN if I want this kind of content. That being said I would be ok with posts talking about fixing climate change especially if it preserves human rights and dignity.

In your book, what counts as fixing climate while preserving human rights and dignity?

Good question. I could do some examples.

Good: carbon tax or cap and trade (ideally revenue neutral). Electric car subsidies.

Bad: climate lockdowns. Restricting travel. Travel credits. Social credit score tied to climate behavior. (This stuff keeps me up at night)

So bottom line:

Following this https://www.un.org/en/about-us/universal-declaration-of-huma... and this https://en.m.wikipedia.org/wiki/United_States_Bill_of_Rights and you’re fine in my book.

But that’s not an assumption I make these days.

Re: The emergence of heat and humidity too severe for human tolerance (2020)

#233

Post by perrygeo »

dash2 wrote: post #103

At the start of the article: "Results suggest that, under the business-as-usual RCP8.5 emissions scenario..." Roger Pielke is good about this. He points out that the "business-as-usual" scenario is extremely unlikely: https://rogerpielkejr.substack.com/p/the-unstoppable-momentu... I'm not arguing that the original article is uninformative or unimportant.

The RCP8.5 scenario would require that humanity burned almost every last drop of oil and did nothing to mitigate carbon. That's not likely because the remaining fossil fuel deposits are significantly more costly and energy-intensive to extract. Eventually the energy return on energy invested will drop to economically nonviable levels. It's debatable whether the carbon emitted in 8.5 is even physically possible.

My guess is humans collaborating on a green future will mitigate emissions ever so slightly. But it will be energy/financial crises that force us to.

So can we look forward to fewer impacts under a more moderate pathway (say 4.5 w/m^2)? Probably not. The IPCC has consistently under-estimated the impacts and ignored feedback loops. Even the latest AR6 report says "Additional ecosystem responses to warming not yet fully included in climate models, such as CO2 and CH4 fluxes from wetlands, permafrost thaw and wildfires, would further increase concentrations of these gases in the atmosphere." We're locked into runaway climate impacts for centuries either way, not much of a consolation prize.

Re: The emergence of heat and humidity too severe for human tolerance (2020)

#234

Post by lmilcin »

Aeolun wrote: post #227
lmilcin wrote: post #177

I see a lot of uninformed people on this thread thinking 35C wet bulb temperature isn't such a big deal and proposing various ineffective tips to cool down. Let me explain what the issue is, in simple words: WET BULB TEMPERATURE IS NOT TEMPERATURE YOU SEE ON A THERMOMETER. (please, don't nitpick, I am aware of wet bulb thermometers) Wet bulb temperature is combination of temperature and humidity. The simple layman wa…

> going into cellar. The air will get cooler but the humidity will rise. If we are already counting on a wet bulb temperature of 35C, the humidity is likely already very close to 100%. Reducing the temperature is likely to be a net good.

That's false.

TLDR: The air gets cooler but still can't cool you. Your body produces heat that has nowhere to go and you still die. Then the walls of the cellar heat up immediately, because cooling 100% humid air requires sinking a lot of energy.

If you found yourself in conditions of an actual heat wave as described, you would despair at the fact the air can get cooler in your cellar but it doesn't cool you at all.

Which is counterintuitive but unfortunately that's how physics works.

First, humidity does not have to be very close to 100%.

In fact, in most cases it isn't and the reported waves of 35C WBT are almost all between 42 and 44C in absolute temperature. This means the air has to cool down 7-9 degrees before it even reaches dew point.

7-9 degrees is a huge temperature difference when temperature is over 40C.

Unfortunately the problem isn't the air temperature. The problem is your body's ability to remove heat. And if you take air and cool it down the temperature will drop but humidity will rise. The wet bulb temperature is preserved unless you can somehow remove water from air. And with wet bulb temperature being same 35C your body still doesn't have any way to remove heat and you are still going to die.

Only after the air cools down by 7-9 degrees celsius you can start seeing any effects, but don't be too happy.

Because physics has a nasty trick to play on you.

The effects of water condensing on walls of your cellar is going to be your cellar walls heating up immediately.

Yes, water cools stuff efficiently when it evaporates but just as efficiently it heats it up when it condenses.

Conservation of energy is a bitch. Please, learn some physics, it is really fun. And sometimes terrifying.

So your cellar is very likely to have very limited ability to cool down very hot humid air and condense water out of it.

Re: The emergence of heat and humidity too severe for human tolerance (2020)

#235

Post by Causality1 »

toiletaccount wrote: post #41
Causality1 wrote: post #10

Earlier quoted context omitted.

I wonder how practical it would be to sink 30 foot deep concrete tube shelters with a ladder and a lid. They could serve as emergency daytime shelters and someone could climb out at night to search for a location with working power or cooler weather.

itd make more sense to lay a bunch of pipe underground and cycle air through it. or water in a closed circuit with a heat sink.

If you have power you can just use a heat pump like a window unit. This is about places with unreliable or negligible power grid.

Re: The emergence of heat and humidity too severe for human tolerance (2020)

#236

Post by Stratoscope »

rini17 wrote: post #165
jiggawatts wrote: post #143

Earlier quoted context omitted.

> Combined with power outages, as happens in the book, everyone living under such a heat wave will likely die. That's an exaggeration. Extreme heat (including heat waves that exceed this threshold) happen semi-regularly, and the death rate when they occur is nowhere near 100%. More like 0.1% or less. Electrically-powered air conditioning is not the only way to cool a human body. Simply escaping to an underground or s…

Many apartments don't have a bathtub, only a shower. And if everyone keeps tap water running, the pressure will drop down to trickle. Cold cellars can be in short supply, underground car parks tend to get hot too. And seems you probably never bathed in 35°C water, it's definitely not refreshing. And there are psychological issues that people just don't know what to do till it's too late. I was living an apartment wit…

> underground car parks tend to get hot too

This is something that has puzzled me every time I park in the underground garage under City Hall in Palo Alto. It is always so hot down there compared to the outside air.

I was about to ask if anyone knows why that is, and then realized I could search for the answer:

https://www.google.com/search?q=why+do+underground+garages+g...

Lots of interesting opinions there, including a previous HN thread.

One discussion I liked showed up when I'm signed into Google but was missing from an incognito search:

https://philip.greenspun.com/blog/2013/07/05/stupid-geophysi...

Re: The emergence of heat and humidity too severe for human tolerance (2020)

#237

Post by swiley »

specialist wrote: post #229
tomrod wrote: post #206

I wonder if people confuse wet bulb and dry bulb here. Wet bulb is related to how well your air conditioner or sweating will cool you. Dry bulb is what we usually say when taking a temperature reading, or listening to the local news' meteorologist.

Ya, for messaging, "wet bulb" doesn't work well. We need a more intuitive phrase, like a "wind chill factor" for heat + humidity = danger. Edit: chewing on "wet heat factor". What do you think? Cliches like "but it's a 'dry heat' harhar" are already common. So "wet heat" might click.

IMO wet bulb is much more intuitive. The parameters for heat index are subjective.

Re: The emergence of heat and humidity too severe for human tolerance (2020)

#238

Post by throwaway894345 »

pugworthy wrote: post #84
throwaway894345 wrote: post #50

It’s wild to me that even the Biden administration appears so cavalier on climate. $1.2T on infrastructure and a follow up $3.5T budget bill and in both the environmental provisions are lame. Still no carbon pricing or anything that might make Exxon execs too uncomfortable (yes, I know Exxon supports carbon pricing in public because they don’t think anyone will actually do it).

It's not as much what he would do as what he could do. Not everything is going to fly through the house and senate with ease.

I imagine it would be a lot easier if it weren’t bundled with trillions of dollars for other programs. It kind of feels like climate should be the number one priority and while Republicans are close to worthless it feels like Democratic politicians aren’t much more interested in offending their corporate masters. But in general I agree, it’s hard to get these things passed when so many congresspeople are in the pockets of moneyed interests.

Re: The emergence of heat and humidity too severe for human tolerance (2020)

#239

Post by selimthegrim »

rstuart4133 wrote: post #200
jiggawatts wrote: post #143

Earlier quoted context omitted.

> Combined with power outages, as happens in the book, everyone living under such a heat wave will likely die. That's an exaggeration. Extreme heat (including heat waves that exceed this threshold) happen semi-regularly, and the death rate when they occur is nowhere near 100%. More like 0.1% or less. Electrically-powered air conditioning is not the only way to cool a human body. Simply escaping to an underground or s…

> Extreme heat (including heat waves that exceed this threshold) happen semi-regularly The threshold is wet bulb 35 for 7 hours. That is when fit young humans can't survive. Older people die well before that of course. And no, it doesn't happen regularly. I wasn't aware it had happened at all, although others here say it has. But it has come close. From https://www.telegraph.co.uk/global-health/climate-and-people...…

I’m pretty sure Jacobabad has cars.

Re: The emergence of heat and humidity too severe for human tolerance (2020)

#240

Post by throwaway894345 »

losteric wrote: post #69
throwaway894345 wrote: post #50

It’s wild to me that even the Biden administration appears so cavalier on climate. $1.2T on infrastructure and a follow up $3.5T budget bill and in both the environmental provisions are lame. Still no carbon pricing or anything that might make Exxon execs too uncomfortable (yes, I know Exxon supports carbon pricing in public because they don’t think anyone will actually do it).

Blame Congress for the poor investments in America's future. Biden's direct influence is limited to the executive branch.

Traditionally presidents set the agenda and work to get support, but you’re right that it’s a team sport and Biden needs congressional support. It’s disappointing that there isn’t enough support even among Democrats (Biden is trying to push through a $3.5T budget plan without any Republican support so clearly he thinks he can get things done on just a Democratic basis, but apparently he doesn’t think major climate initiatives will be popular with the Democratic crowd?).
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