[HN Gopher] Low-cost gel film can pluck drinking water from dese...
___________________________________________________________________
Low-cost gel film can pluck drinking water from desert air
Author : NickRandom
Score : 149 points
Date : 2022-05-26 13:01 UTC (9 hours ago)
(HTM) web link (news.utexas.edu)
(TXT) w3m dump (news.utexas.edu)
| paulsmith wrote:
| Gel? What I really need is a droid that understands the binary
| language of moisture vaporators.
| aaron695 wrote:
| fallat wrote:
| Ok so it's a sponge soaked in konjac and then dried? Damn, that
| _is_ simple. Could easily make this yourself. I don 't even see
| how this is patentable...
|
| > renewable cellulose and a common kitchen ingredient, konjac
| gum, as a main hydrophilic (attracted to water) skeleton
|
| (artificial sponges are made of cellulose - I learned this just
| last year when washing my dishes and thinking... wtf is this made
| of?)
|
| ---
|
| Seems then you can:
|
| 0. Go to the dollar store
|
| 1. Buy a thin sponge
|
| 2. Buy konjac gum
|
| 3. Buy a tray
|
| 4. Place the thin sponge in the tray, mix the konjac gum with
| water, and pour it into the tray, and place it into your freezer,
| waiting for the water to evaporate...?
|
| 5. Place it now somewhere in a humid place to pull the water out
| of the air
|
| ---
|
| Industrial version of this is probably a ton of thin wafers side-
| by-side in a cube-like fashion, so they can easily come off an
| assembly line
| bradrn wrote:
| It doesn't look quite that simple. The paper describes the
| procedure as follows:
|
| > In a typical fabrication, LiCl powder (0.32-0.82 g) is added
| into 10 mL HPC solution (0-2.0 wt%) forming solution A. The pH
| of solution A can be tuned by NaOH or HCl solution. 0.44 g KGM
| powder is added into solution A and quickly cast into the petri
| dish after vortex. The gelation takes place within 2 min, and
| sit in room temperature for 15 min. Then, the film is placed in
| the fridge (-4 degC) for 3 h followed by 15 min freeze in
| liquid nitrogen. Last, the gel film is ready to use after 12 h
| freeze-drying.
|
| [https://doi.org/10.1038/s41467-022-30505-2]
| natch wrote:
| Dude you don't have liquid nitrogen in your fridge? Such
| common kitchen ingredients. /s
| spenrose wrote:
| Source paper:https://www.nature.com/articles/s41467-022-30505-2
|
| Extracting ubiquitous atmospheric water is a sustainable strategy
| to enable decentralized access to safely managed water but
| remains challenging due to its limited daily water output at low
| relative humidity (<=30% RH). Here, we report super hygroscopic
| polymer films (SHPFs) composed of renewable biomasses and
| hygroscopic salt, exhibiting high water uptake of 0.64-0.96 g g-1
| at 15-30% RH. Konjac glucomannan facilitates the highly porous
| structures with enlarged air-polymer interfaces for active
| moisture capture and water vapor transport. Thermoresponsive
| hydroxypropyl cellulose enables phase transition at a low
| temperature to assist the release of collected water via
| hydrophobic interactions. With rapid sorption-desorption
| kinetics, SHPFs operate 14-24 cycles per day in arid
| environments, equivalent to a water yield of 5.8-13.3 L kg-1.
| Synthesized via a simple casting method using sustainable raw
| materials, SHPFs highlight the potential for low-cost and
| scalable atmospheric water harvesting technology to mitigate the
| global water crisis.
| numtel wrote:
| Seems even better than MOF-based approaches [0]
|
| The linked self-watering soil article [1] makes me wonder if the
| material could be used to reverse desertification.
|
| [0] https://wahainc.com//smithsonian [1]
| https://news.utexas.edu/2020/11/02/self-watering-soil-could-...
| devit wrote:
| Isn't this revolutionary for agricultural use?
|
| What's the catch?
| qayxc wrote:
| One catch might be that it hasn't been tested at scale. The
| results are extrapolations from lab testing in a controlled
| environment.
|
| There's quite a number of inventions and breakthroughs that
| looked great in the lab but never made it to real world
| applications.
|
| Remains to be seen if this approach can work in practice and
| at scale and what the real-world implications would be.
| UncleEntity wrote:
| > What's the catch?
|
| Wide scale harvesting of water from the air will change the
| local climate in unpredictable ways?
| LNSY wrote:
| TBF, that's basically how our entire economy runs, so
| conductr wrote:
| At scale, this seems awful for desert ecology. Plants and animals
| have evolved to survive on bare minimum water. The tiny morning
| dew may be all they get for days/weeks. Now we want to pluck it
| out before they can get any.
|
| It's certainly an interesting technology and achievement but one
| that could be easily misused with "unintended consequences"; or
| so it seems.
| klvino wrote:
| That was my first thought as well, heavy use within an existing
| desert environment would likely have negative ecological
| impact.
|
| When reading through the article, it has potential application
| in areas where a local water supply may not be clean enough to
| drink or lacks sufficient water treatment & filtration.
| Robotbeat wrote:
| Would it? The water will eventually evaporate again. It's not
| like the water is burned up to nothing in a fusion reactor.
| flockonus wrote:
| Could be easily drained down a pipe, the evaporation then
| is not as relevant even if some of it does, efficiency
| would most likely be acceptable.
| buu700 wrote:
| On the flip side, could it potentially be a cost-efficient
| method of dehumidifying cities/towns/villages for human
| comfort?
| conductr wrote:
| Could even replace desalination since humidity has no salt
| and it is generally occurring in a similar area/climate.
| sandworm101 wrote:
| Humidity theoretically doesn't contain salt, but air
| does. Any technology that is harvesting moisture from air
| will involve large amounts of air. That air contains dust
| and sea salt which can contaminate the process. Setup a
| moisture farm to harvest sea breezes and you will have to
| address a salt problem.
|
| In many industries this airborne salt can cause
| corrosion. Talk to anyone with a classic car in LA/SF,
| both cities with sea breezes. They don't want to leave
| them outside too much. That's why the aircraft
| "boneyards" are all in the interior, across the mountains
| from the sea.
| bushbaba wrote:
| And dryer air can absorb more water from the nearby
| sea...so there might not be a huge impact if placed in
| the right spot
| colechristensen wrote:
| It could also do the opposite, if used correctly.
|
| Strong Dune vibes.
|
| You could use these to water plants and set up a cycle where a
| significant portion of the water lost through evaporation was
| reclaimed and gradually accumulated locally. Dot a landscape
| with solar powered stacks of these things feeding appropriately
| selected plantations and you might make the desert bloom or
| help prevent the spread of deserts.
| conductr wrote:
| That's an interesting concept I had not considered. I also am
| not sure if "we" (collective) would roll it out that way. We
| have a track record of consuming resources in the
| easiest/cheapest way with minor consideration of the
| environment. I don't think we'd even view this as a worthy
| investment if all it did was help prevent the spread of
| deserts. We still can't even agree if climate change is real
| and what we should do about it.
| colechristensen wrote:
| To rekindle your hope, see
| https://en.m.wikipedia.org/wiki/Great_Green_Wall_(Africa)
| conductr wrote:
| That's interesting. Reminds me of when I was a kid and
| thought I had a completely unique idea to fill the Sahara
| with water! It will quickly evaporate and turn to a
| rainforest in no time!!
|
| https://en.wikipedia.org/wiki/Sahara_Sea
| dylan604 wrote:
| I have little trust in the "we" doing anything like this
| correctly, at first. By that, I mean that it will be the
| corps to do this as they are the ones with the money to do
| it. Corps being corps, they will lean into being themselves
| and extract all of the everything they can with little
| respect for anything other than their bottom line.
|
| I don't have faith gov't will do it either. Those opposed
| to climate change will argue it is money spent on fake
| science. It'll die in congress (for US,
| s/congress/localGovUselessBody/ for other places).
|
| Someone might get popular enough to crowd source fund it
| with an NGO type thing, but I'm not holding my breath there
| either.
| yonaguska wrote:
| I hope you'll be more optimistic about government
| outcomes, at least as far as opposition is concerned. I
| think I'd fall under your bucket of people that are
| "opposed to climate change", and I put that in quotes,
| because, it's not that I don't believe in climate change
| or anything like that. I just don't believe that the
| current "green" initiatives are the correct way to go
| about solving climate issues. I do however consider
| myself an environmentalist. I care more about the non C02
| pollution that we are causing than simply trying to
| reduce C02 emissions.
|
| I think you'd be hard pressed to find organic opposition
| to tackling environment issues that aren't related to the
| relatively abstract C02 pollution issues. I say organic
| because the corporations responsible for pollution will
| always find ways to manufacture consent that protects
| their own best interests. But, your stereotypical human-
| caused climate change denier is likely someone that
| hunts, fishes, or resides in a rural area, where
| environmental and conservationist concerns are taken very
| seriously, regardless of political affiliation. Your
| opposition is only going to come from people whose
| livelihood is affected by pollution controls. A broader
| swathe of people will always oppose addressing C02
| related climate concerns because it affects literally
| everyone's bottom line in the form of rising cost of
| goods with energy prices going up, and it has abstract
| consequences, rather than concrete ones like your local
| streams being poisoned, or your well water going bad
| because the aquifer has been contaminated.
| konschubert wrote:
| We could maybe do this with todays technology already - solar
| powered desalination plants.
|
| There are plenty of desert coastlines.
|
| Not sure how much that would cost per square meter of
| forest/agriculture, tbh.
| dawsmik wrote:
| https://wxguys.ssec.wisc.edu/2018/02/05/water-in-
| atmosphere/....
| grishka wrote:
| But the water someone plucked out of desert air and drank
| doesn't poof out of existence. They'll eventually pee and sweat
| it out.
| blacksqr wrote:
| The amount of water vapor in the air is functionally infinite
| with respect to any practical means to extract it.
| rtkwe wrote:
| Only true on the large scale but locally you'll still create
| a depleted zone near the ground down wind of a hypothetical
| extraction plant.
| jhgb wrote:
| > Now we want to pluck it out before they can get any.
|
| I suspect that if you think that this is going to give us the
| ability to suck out all the water out of thousands of cubic
| kilometers of desert air any time soon, you're probably being a
| little too optimistic.
| throwaway894345 wrote:
| Deserts are expanding; it seems fine to offset that expanse as
| long as you're somewhat careful not to wipe out an entire
| ecosystem.
| tomcam wrote:
| Sort of an interesting point. But don't forget, in the Sahara,
| for example, there was less vegetation only 5000 or 6000 years
| ago
| AnimalMuppet wrote:
| _Less_ vegetation 5000 years ago? Are you sure you don 't
| mean _more_?
|
| Wikipedia speaks of an "abrupt desertification" 5400 years
| ago.
| ttul wrote:
| At 20C, the maximum water content in air is 17.3 x 10^-3
| kg/m^3.
|
| At 15% relative humidity, then, you can extract a maximum of
| 0.15 x 17.3g = 2.6g from every 1,000L of air.
|
| If a person needs 5L/day for survival (I am making this up),
| then you'd need to dry out 5000 / 2.6 = 1,923L of air each day
| -- that's just short of two cubic meters...
|
| If the density of people living in an area is 50 per square km,
| drying the air out to extract water would deplete the first
| meter of the atmosphere by 10%.
| function_seven wrote:
| 1,923,000L per day, right? So each person would need just
| short of 2,000 m3 of air.
| TwistedWave wrote:
| 1,923m^3, not 1,923L
| bufferoverflow wrote:
| > If a person needs 5L/day for survival (I am making this
| up), then you'd need to dry out 5000 / 2.6 = 1,923L of air
| each day
|
| You made a unit conversion mistake there. It's 1923 cubic
| meters, not liters.
| npc12345 wrote:
| Aren't they equivalent?
| tomrod wrote:
| liter = 0.001 Cubic meter
|
| I was curious so I looked it up because I also did not
| know, ref: https://www.google.com/search?q=liters+in+cubi
| c+meter&oq=lit...
| martyvis wrote:
| Or to better visualise it, it is a 10x10x10 centimetre
| (cm) cube. (Or just a bit less than a 4x4x4 inch cube for
| the unmetrical )
| ttul wrote:
| Correct. 5,000g / 2.6 g per m^3 = 1,923 m^3
|
| Okay let's say the bottom 10m of atmosphere is available
| for water making. That means there are 10 million cubic
| meters of air per square km, or per 50 people. We will need
| to dry out 1,923 x 50 = 96,150 cubic meters of air. But
| there is 10,000,000 available, meaning we are only drying
| out just under 1% of the air.
| conductr wrote:
| If those people are living there 5L/day is nowhere near
| enough water. They are doing more than just surviving. Using
| Arizona as an example, Google tells me 550L/day/person is
| actual usage. I know you just put an assumption in but this
| is a big gap.
| natch wrote:
| > researchers used renewable cellulose and a common kitchen
| ingredient, konjac gum
|
| "konjac gum" a common kitchen ingredient, eh? Let me just check
| my pantry. Odd, seems I am fresh out.
| TrueDuality wrote:
| It is commonly used in Vietnamese cooking. The Konjac plant is
| kind of like corn. Konjac gum is like corn starch.
| burlesona wrote:
| They say this material is cheap and can pull " 13 liters in areas
| with up to 30% relative humidity" ...
|
| Now I'm wondering if you could use this stuff like crazy in hot,
| humid places and whether (a) it could pull enough water to be
| useful for drinking or irrigation, and (b) whether it's possible
| to "locally" lower the ambient humidity (like the reverse of the
| urban heat island effect).
| qayxc wrote:
| Getting the water out from the spongy material could pose a
| challenge in hot environments.
|
| According to the paper, they use heating (60degC) to extract
| the water. In hot environments, however, ambient temperatures
| get quite close to that already (see India at the moment).
|
| The answer to b) would be a no. The technique doesn't work in
| high humidity environments.
| cookingrobot wrote:
| Are you sure it's the absolute temperature of 60d that
| matters, or is the requirement that the sponge is hotter than
| the surrounding air?
| qayxc wrote:
| According to the paper, it's the absolute temperature that
| matters. The desorption is optimal at about 60degC to
| 70degC, meaning the absorption-desoprition cycle wouldn't
| work anymore if the ambient temperature is too high. The
| absorption phase took place at 25degC ambient - the
| provided data suggests that the desorption would dominate
| over the absorption above about 50degC.
|
| In conclusion, if the environment is 50degC or hotter, the
| sponge cannot absorb much water from the atmosphere,
| because the kinetics imply that the water would evaporate
| too quickly.
| bell-cot wrote:
| With a somewhat different material, optimized for that
| situation, could this be made to work well in hot, humid
| environments?
|
| _If_ so, then I 'm smelling a plausible solar-powered,
| cheap, modular "emergency life support" system for people
| threatened by extreme web bulb temperature conditions.
| russellbeattie wrote:
| California's coast is lined with mountains which capture huge
| amounts of water from the air as it comes in from the Pacific,
| usually as fog. This is why the redwoods are so massive. I have
| no idea if this technology works at the scale of Cali's water
| deficit, but I've wondered why we haven't lined the peaks of the
| mountains with mesh screens already. Seems like free water we're
| just ignoring.
| Animats wrote:
| It's from U. Texas. Texas has the climate in which that
| technology should work, and a need for more water. This ought to
| be fundable and buildable entirely within Texas. When will the
| first plant be built?
| silencedogood3 wrote:
| silencedogood3 wrote:
| ThinkBeat wrote:
| In my experience, just in the US the desert air is really dry.
| The expression "but it is dry heat", is true. I find hot desert
| weather much better than hot weather in humid areas.
|
| I cant see this scaling. There is not much water to collect to
| begin with.
|
| A person using it sure. A platoon sure.
|
| But if a city of 2000 people started using I cant see it working
| well.
|
| Further the moisture extracted from the air in that city would
| mean even drier air in other places?
| mikepurvis wrote:
| Agree, yeah. Despite the lead of "more than a third of the
| world's population lives in drylands", I would see this as
| being much more applicable to transient usage than long term. A
| few litres of lukewarm water per day would be perfect for
| backcountry camping, or topping up the reservoir in an RV, or
| something. But for anywhere even remotely permanent it almost
| certainly makes more sense to dig a well.
| felipemnoa wrote:
| >>Further the moisture extracted from the air in that city
| would mean even drier air in other places?
|
| I imagine moisture from other places would simply travel to his
| low humidity place to replace the one taken out. Should be
| limitless.
| 1minusp wrote:
| any experts who can verify the validity of the claim of being low
| cost?
| jvanderbot wrote:
| "In a typical fabrication, LiCl powder (0.32-0.82 g) is added
| into 10 mL HPC solution (0-2.0 wt%) forming solution A. The pH of
| solution A can be tuned by NaOH or HCl solution. 0.44 g KGM
| powder is added into solution A and quickly cast into the petri
| dish after vortex. The gelation takes place within 2 min, and sit
| in room temperature for 15 min. Then, the film is placed in the
| fridge (-4 degC) for 3 h followed by 15 min freeze in liquid
| nitrogen. Last, the gel film is ready to use after 12 h freeze-
| drying. The final LiCl concentration in SHPFs is characterized by
| TGA."
|
| "Before the water vapor sorption measurement, all samples are
| dried in a vacuum oven at 90 degC for at least 2 h. "
|
| - Fridge cooling
|
| - liquid nitrogen bath
|
| - 12h freeze drying
|
| That doesn't sound low-cost / easy to manufacture.
|
| https://www.nature.com/articles/s41467-022-30505-2
|
| Figure of test rig:
| https://www.nature.com/articles/s41467-022-30505-2/figures/4
|
| That looks like you capture using a very cold, porus material
| (cold, dry sponge that collects dew, essentially), then heat this
| "sponge" so the water then travels up to a condenser which causes
| it to "dew" and run into a collection chamber.
|
| It's not magic water-cloth, and I don't think it's a weekend
| project, but it's pretty low tech.
|
| What did I get wrong? I'm sure there's something.
| robonerd wrote:
| FWIW real "magic water-cloth" actually exists, but only works
| some places some of the time:
| https://en.wikipedia.org/wiki/Fog_collection
|
| > _The mesh netting is where the condensation of water droplets
| appear. It consists of filaments knitted together with small
| openings, coated with a chemical to increase condensation.
| Shade Cloth is used for mesh structure because it can be
| locally sourced in underdeveloped countries. The filaments are
| coated to be hydrophilic and hydrophobic, which attracts and
| repels water to increase the condensation.[1] This can retrieve
| 2% of moisture in the air. Efficiency increases as the size of
| the filaments and the holes decrease. The most optimal mesh
| netting is made from stainless steel filaments the size of
| three to four human hairs and with holes that are twice as big
| as the filament. The netting is coated in a chemical that
| decreases water droplet 's contact angle hysteresis, which
| allows for more small droplets to form. This type of netting
| can capture 10% of the moisture in the air.[2]_
| etskinner wrote:
| How can something be both hydrophilic and hydrophobic?
| GauntletWizard wrote:
| Different filaments. You form a mesh that creates
| "hotspots" of attraction for water.
| WhitneyLand wrote:
| $2/kg of material to get 6 liters of water per day.
|
| But what's the total yield for the $2? In other words single or
| multiple use?
|
| In some areas of the world there's a serious fresh water crises.
| Very poor people are left buying expensive bottled water to avoid
| disease.
| rodolphoarruda wrote:
| "Proudly made in Arrakis"
|
| Fremen Inc.
| seanw444 wrote:
| So is this essentially just a non-mechanical dehumidifier? How is
| there enough water to pluck, when the point of an arid climate is
| that it's... well, arid? The air is usually as dry as the ground
| in those places. Or so I thought.
| UncleEntity wrote:
| > The air is usually as dry as the ground in those places.
|
| The ground isn't all that dry, you can dig a hole, cover it
| with plastic and get enough water through evaporation/
| condensation to hopefully not die of dehydration if you get
| stranded in the desert.
|
| Something like this would be very helpful for troops in the
| desert since water is heavy and resupply is very critical to
| keep up combat readiness. Back when I was a "speed bump in the
| sand" they drove us out into choke points in the Saudi desert
| to take out a few Iraqi tanks before they overran us in case of
| invasion. Assuming we were able to somehow escape contact our
| mission was to then try to make it to the coast and steal a
| boat through we probably wouldn't have had enough water to
| accomplish the second part. Not even exaggerating a little bit,
| such is the life of a paratrooper.
| NickRandom wrote:
| TFA mentions some figures in paragraph 2
|
| "The team developed a low-cost gel film made of abundant
| materials that can pull water from the air in even the driest
| climates. The materials that facilitate this reaction cost a
| mere $2 per kilogram, and a single kilogram can produce more
| than 6 liters of water per day in areas with less than 15%
| relative humidity and 13 liters in areas with up to 30%
| relative humidity."
| onlyrealcuzzo wrote:
| So for about $26 - you could extract enough water to water a
| fruit tree indefinitely.
|
| Doesn't seem like this would be used for agriculture at scale
| - but it sure could beat digging a well to get water for a
| house.
| astroid wrote:
| I'm going to copy this comment I saw on slashdot re: this
| yesterday that seemed to let some of the air out of the
| whole press release:
|
| "The salt mentioned is not table salt, but lithium
| chloride. Lithium chloride - which makes up a half by
| weight of the film, and is also in obvious demand for
| batteries, is $70/kg or so in bulk."
|
| I haven't really dug in deep myself, but this is the
| comment that deflated me when reading about this yesterday,
| so worth looking into at least imo
| pengaru wrote:
| There's never really 0% humidity in the air, I have a cabin
| near Joshua Tree and it rarely goes below 10% there. It tends
| to increase substantially at night too, which maybe something
| like this can harness then retain through the daytime.
| apienx wrote:
| Thermal degradation plus oxidative processes make the claimed
| "scalable" water-capturing application unfeasible IMHO. The
| authors extract the water by heating to 60 degC. I'm surprised
| neither the Nat. Comm. editor nor any of the reviewers asked for
| a thermo-gravimetric analysis of the material.
| lr wrote:
| How about in wet, hot environments (or even cold ones), like on a
| boat? Watermakers are very expensive and use a lot of
| electricity. If one could do this on a boat to generate clean
| drinking water, that would be pretty amazing. Especially if one
| could use a tube solar oven to heat up the substance.
| timerol wrote:
| Third paragraph of TFA:
|
| > The research builds on previous breakthroughs from the team,
| including the ability to pull water out of the atmosphere[1]
| and the application of that technology to create self-watering
| soil[2]. However, these technologies were designed for
| relatively high-humidity environments.
|
| 1: https://news.utexas.edu/2019/03/13/solar-powered-moisture-
| ha...
|
| 2: https://news.utexas.edu/2020/11/02/self-watering-soil-
| could-...
| jmyeet wrote:
| With the very real risks of climate change and rising sea levels
| I'm wondering how long it will take before someone decides to
| flood the Sahara.
|
| It's worth noting that sea level rise is kinda complex.
|
| First, if an iceberg floating on the ocean melts it doesn't raise
| sea levels. That's the buoyancy principle of displacing an
| object's weight in water.
|
| Second, a lot of ice (eg Antarctica, Greenland) is on land so the
| first point doesn't apply to all ice as some deniers have tried
| to claim.
|
| Third, the sea level rise is partially from ice melt but also
| from thermic expansion.
|
| Fourth, even if you flooded all the below sea level parts of the
| world, it would only account for a fraction of the sea level rise
| so it's not a permanent solution.
|
| But several thousand eyars ago the Sahara was arable land. Some
| parts of the Sahara were >400 feet below sea level so this would
| be a significant body of water. Even as seawater this would
| inject a lot of water into the environment through evaporation
| and normal water cycles.
|
| Obviously this would have an impact on the ecosystem and displace
| some people but we've displaced far more people for less (eg the
| Three Gorges Dam).
|
| This seems like something we should do, no?
| jfoutz wrote:
| there's another fun aspect that I think is neat. water is free
| to move around a little more than ice (especially ice on land).
| The earth is spinning, so the inertia of the water will sort of
| fatten the equator and thin the poles. Sea level might go down
| a little bit at the poles and go up around the equator.
| quaintdev wrote:
| That did notmcross my mind. But this depends on whether there
| is enough water to cause this phenomenon or it might simply
| have no effect.
| lainga wrote:
| > But several thousand eyars ago the Sahara was arable land.
|
| I think the desert status of the Sahara has more to do with a
| combination of oceanic gyre patterns and the structure of the
| Hadley circulation. The Sahara and other latitudes around 30N
| are constantly under a high-pressure zone of descending hot dry
| air which is part of the northern Hadley cell. The exception is
| over India where the Eurasian landmass pulls the ITCZ
| (ascending side of the Hadley cell) way far North and causses
| the monsoons.
|
| I don't think flooding the Sahara would change its aridity any
| more than the Arabian peninsula, despite being surrounded by
| water, is still a desert away from the immediate coastline.
| It's a matter of air moisture, not sea or ground moisture. You
| could try irrigation, though. The Libyans abortively tried that
| under Gaddhafi.
| lordofgibbons wrote:
| I'm not an expert in any of this but from what I know,
| portions of the Arabian peninsula sure do get plenty of rain
| for agriculture from the red sea in the western part.
|
| >don't think flooding the Sahara would change its aridity any
| more than the Arabian peninsula
|
| There's something to be said about the lake effect. It
| certainly happens in U.S and Canada where areas just east of
| the Great Lakes get much more precipitation than other parts
| sumtechguy wrote:
| You may want to look into what the permaculture people are
| doing. That is something that can be done today and has worked
| many times. Many are seeing really good results. The issue for
| that area is most of the vegetation was clearcut for firewood.
| Basically with permaculture they try to put the system back to
| the way it was before it was clearcut.
| wklauss wrote:
| > Obviously this would have an impact on the ecosystem
|
| Anticipating the impact is probably a fool's errand, since
| climate is extremely complex and changes on one part of the
| world affect others. It's not just about displacing people in
| the area, you risk altering the patterns that bring rain to
| places as far as Germany or help grow crops in Brazil. Sahara
| sand plumes play a role in replenishing phosphates in the
| Amazon, for example. Even blanketing some parts with solar
| panels will probably alter global weather patterns
| significantly.
| bushbaba wrote:
| We'd need to flood it with salt water. Best example as to why
| this shouldn't be done is the California Salton Sea ecological
| disaster.
| henearkr wrote:
| What if we do not flood it, but instead make circulate a lot
| of salt water in open-roofed canals (but with leak-proof
| floor and walls) crisscrossing the desert?
|
| Then the humidity would trigger rains and help grow a
| vegetation, and the salt residues would remain inside the
| canals.
|
| Then at some point the vegetation would self-maintain the
| necessary humidity level.
| PeterisP wrote:
| > Then the humidity would trigger rains
|
| Not necessarily, given the weather conditions there it's
| quite plausible that all the evaporation would form clouds
| which would only rain _elsewhere_ and not in that desert.
| filoeleven wrote:
| There are lots of ideas around for desert greening; see the
| linked article for a list. Canals are unlikely to work
| well, but seawater farming is kind of close to your
| proposal. It requires greenhouses to be built though, so I
| don't know how well it scales.
|
| Years ago I read about a system that seemed successful.
| Ridges were built up at the desert's edge, and salt-
| tolerant trees and shrubs were planted on hem to keep the
| ground stable. This change in microclimate promoted more
| greening in the valleys between, which increased overall
| moisture levels. Once this is established, more ridges can
| be constructed further out to repeat the process. It's not
| an easy thing to search the web for, and I don't recall how
| long it takes for one ridge to be productive, but I recall
| thinking it was shorter than I expected (still on the order
| of years, of course).
|
| https://en.m.wikipedia.org/wiki/Desert_greening
| 3-cheese-sundae wrote:
| Canals would silt up very fast. Also, I don't know about
| leak-proof water canals when humanity can't seem to make
| leak-proof sealed oil pipelines, and that's with
| significant financial incentive to do so.
| tharkun__ wrote:
| Interesting, I had to read up on that. Could you elaborate
| how that is related to that though and what makes it a bad
| idea in particular?
|
| From what I just read up on, the Salton Sea over the
| millennia would periodically flood, become a small lake or
| dry out to desert levels. The change that occurred was that
| humanity changed the rhythm of this artificially to a 'flood
| it' state for a prolonged period of time.
|
| They are now complaining that when they changed it to the
| 'small lake' state again, well, shrinking lakes create a
| certain situation.
|
| The _problem_ I do see is really the way the 'flood' state
| was created and other usages of the lake. Runoff from
| agriculture with way too much fertilizer, waste dumping etc.
| and now they wonder why the dust is toxic and stinks.
|
| How would that apply to flooding the Sahara w/ sea water
| perpetually?
| lizknope wrote:
| Some people had ideas to flood the Qattara Depression in
| northwest Egypt.
|
| https://en.wikipedia.org/wiki/Qattara_Depression_Project
|
| It would have provided hydroelectric power and as the water
| evaporated and formed clouds it may have increased rainfall.
|
| The United States wanted to use nuclear bombs to excavate the
| channel to the Mediterranean Sea.
|
| Consequently, use of nuclear explosives to excavate the canal
| was another proposal by Bassler. This plan called for the
| detonation in boreholes of 213 nuclear devices, each yielding
| 1.5 megatons (i.e. 100 times that of the atomic bomb used
| against Hiroshima). This fit within the Atoms for Peace program
| proposed by President Dwight Eisenhower in 1953. Evacuation
| plans cited numbers of at least 25,000 evacuees.
|
| Project Plowshare was pretty crazy. Use nuclear bombs for
| excavation. There were ideas to create artificial harbors by
| using a bombs.
|
| https://en.wikipedia.org/wiki/Project_Plowshare
| sandworm101 wrote:
| >> Second, a lot of ice (eg Antarctica, Greenland) is on land
| so the first point doesn't apply to all ice as some deniers
| have tried to claim.
|
| But what about ice that is 'on land' but also below sea level?
| Iirc roughly half of Antarctica's glacier ice is sitting dry
| ground that is below sea level. Whether melting that ice will
| raise or lower sea levels is more complicated, with variables
| for amounts above/below various points.
| tomrod wrote:
| After deglaciation, land will also rebound over the long
| term, further displacing volume the water/ice occupies.
| sandworm101 wrote:
| Earth is a finite volume. So if the land rebounds in one
| area, does it not have to subside elsewhere?
| tomrod wrote:
| It's more decompression, to my understanding
|
| https://en.wikipedia.org/wiki/Post-glacial_rebound
| CapricornNoble wrote:
| How do I use this to make Dune-style stillsuits? Maybe the gel is
| attached to a flagpole on your back (large surface area with
| airflow is what I'm thinking here), like medieval samurai, and
| your body's movement generates the heat that activates the
| thermo-responsive cellulose? The water needs to then collect in a
| built-in hydration bladder (aka Camelbak).
| dwighttk wrote:
| Need something to cool off the human inside the stillsuit
| dubswithus wrote:
| After the water is in the gel, how does one get it out?
|
| Edit:
|
| > Another designed component, thermo-responsive cellulose with
| hydrophobic (resistant to water) interaction when heated, helps
| release the collected water immediately so that overall energy
| input to produce water is minimized.
| robinsoh wrote:
| "The captured water in the SHPF can be released by >70% within
| 10 min through mild heating at 60 degC under a wide range of RH
| (Fig. 3b and Supplementary Fig. 15). This mild heating
| temperature is realized by introducing the hydrophilic
| thermoresponsive HPC with optimized molecular weight,
| concentration, and pH of the initial precursor (Supplementary
| Figs. 9-14 and Supplementary Table 2)42"
| samstave wrote:
| SHPF == Shit Hits the Proverbial FAN.
|
| Would this be viable in a Window Casing/Screen? system where-by
| you have, instead of a "screen" you have this mesh - then with a
| window moulding application that funnels the water to either an
| "ITS ALL PIPES" type of reclaimation.....
|
| https://www.youtube.com/watch?v=s09pfBEJYHc
| mise_en_place wrote:
| I've been hearing about so-called hydropanels too. Maybe they
| work similarly? It looked like junk science when I initially saw
| one producer of these, called Source Global. It seems to be a
| real thing, however.
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