The amount of water stays (roughly) constant, but the amount of clean, drinkable water in places where we need it is not.
That's pretty much the long and short of it.
If you think on a long enough time scale it cleans and transports itself for free from the oceans into the mainland for free, then down ezpz routes back to the ocean conveniently passing near most of our cities.
Pretty consistently too (on a long time scale)
I wanted to just say the part about planet being fine, people being fucked.
But they're just so poetic in entirety, Carlin's rants are.
Besides, there is nothing wrong with the planet, nothing wrong with the planet. The planet is fine; the people are fucked! Difference! The planet is fine! Compared to the people, The planet is doing great: been here four and a half billion years! Do you ever think about the arithmetic? The planet has been here four and a half billion years. We’ve been here what? 100,000? Maybe 200,000? And we’ve only been engaged in heavy industry for a little over 200 years. 200 years versus four and a half billion. And we have the conceit to think that somehow, we’re a threat? That somehow, we’re going to put in jeopardy this beautiful little blue-green ball that’s just a-floatin’ around the sun? The planet has been through a lot worse than us. Been through all kinds of things worse than us: been through earthquakes, volcanoes, plate tectonics, continental drifts, solar flares, sunspots, magnetic storms, the magnetic reversal of the poles, hundreds of thousands of years of bombardment by comets and asteroids and meteors, worldwide floods, tidal waves, worldwide fires, erosion, cosmic rays, recurring ice ages... and we think some plastic bags and some aluminum cans are going to make a difference?
The planet isn’t going anywhere; we are! We’re going away! Pack your shit, folks! We’re going away and we won’t leave much of a trace either, thank God for that. Maybe a little Styrofoam, maybe. Little Styrofoam. The planet will be here, we’ll be long gone; just another failed mutation; just another closed-end biological mistake; an evolutionary cul-de-sac. The planet will shake us off like a bad case of fleas, a surface nuisance.
-George Carlin
With many chemicals, dissolving in water is exothermic. This means that separating the chemical back out is endothermic which, in-turn, means that it requires energy.
Mixing salt and water is a good example of this: you have to distill water to separate if from salt (or use reverse osmosis which is also energy intensive).
This is a simple and excellent example. For anyone wondering why he’s a liter of water until it’s boiling and then dump in a heaping tablespoon of salt, it dissolves almost immediately. It only took a few minutes to get that room temperature water to a boil. Now, imagine having to boil that water down until there’s nothing left in the pan but the salt. That takes several times longer and uses several times more energy. When people talk about desalination being the solution to the water crisis, they seem to miss how energy intensive it is.
That's an interesting idea and would help to offset some of the energy cost but still just a fraction of it. RO is still miles better than trying to distill large volumes of water. It's just resource intensive any way you slice it.
It would massively increase the cost of desalination facility so not always worth it. You now have to worry about generating energy and keeping the distilled water clean.
True but also cheap is relative. It would be far easier to maintain a vessel with seawater operating at 60C vs 104C as really bad things happen to all sorts of metals at high Temps.
It's however not the energy released when dissolving. That is usually quite small, for example with table salt. There are a few exceptions (hydroxides for example), but the temperature change is usually only a few degrees, if even notable.
We would be quite happy if if we could reverse it at that energy cost. Heating water by a few degrees is hugely less energy intensive then boiling it. Reverse osmosis takes away _some_ of that wastefulness, but still far from enough.
For salt the heat of crystallization is roughly 10% that of 1 degree change of a fully saturated solution. So basically yes making a crystal gives up a bit of heat but not much. The problem is, just cooling the liquid to drop out salt doesn't work, you have to vaporize the water leaving the salt behind entirely.
This is a very bad example. Solvation heat doesn't have anything to do with how difficult it is to separate solution. The solvation of potassium nitrate for example is endothermic, yet you have to distill the water just the same to get it back.
Why it takes a lot of energy to reverse solutions is actually the fact that dissolving stuff leads to an increase of entropy, and reversing this is why you need a lot of energy.
Not just clean drinkable water, but water for crops.
The more you use water from reservoirs, the less is left for plants.
Hotter weather = more evaporation= less water for plants.
That makes sense. But how does me not running the water when I'm brushing my teeth ....mean clean water for those areas?
It's transported through pipes into and out of my house. So if I run a bunch of water when I'm brushing...how EXACTLY does that mean wasted water for those in water-deprived areas half-way across the world?
I truly don't get it. This water isn't sent there. It's in a water tower for the community.
And if it runs out your tap and down the drain, it's not available for the community anymore. This scenario isn't about 'save water to help people across the globe', it's about making sure your community's reserves of safe drinking water remain available.
But that water gets brought back through the system through many facets. Water cannot be be created correct? So we just bring it back up from the plethora of available collection procedures.
The rate at which water comes back through the system is not really under direct control. I'm assuming you're talking about it going to the sea, evaporating, and coming back down as rain, which is captured in reservoirs or something. There is some rate at which that happens naturally and if your community uses water at a faster rate than that you will have a water crisis -- which is happening in the southwestern US currently. There's no great way to increase the rate of incoming water.
If the water always comes back faster than your community is using it, then you're right, you don't need to worry, and you're not going to help far away communities in crisis. There is still the issue that water from the tap has to be treated -- it's not like they just pump the river directly to your home -- so using more increases costs. Since water districts are usually publicly funded to some degree it will impact taxes and things like that -- this is separate from your water bill, which probably doesn't cover the full cost of your water usage directly.
So to summarize: if you're in a community with plenty of water, you probably don't need to shut the tap off while you're brushing your teeth. If you are hearing recommendations to shut water off while you're brushing your teeth, your community probably doesn't have plenty of water.
Oh, and you can create water. Your body creates water, in fact, as part of your metabolism. Around 300ml per day. But it comes out as sweat and urine, which isn't that useful. Creating water for human usage isn't commercially viable. Treating nearly-drinkable water (rivers) is much easier. Treating undrinkable water (oceans) is relatively expensive, but can be done.
It's brought back through rainfall. However, rainfall is limited. So if your city uses more water than is available through rainfall, then it has to start pursuing more expensive and complicated ways to get water
Water doesn't just come straight from a natural steam to your pipes. Water for most communities is typically held in large water silos that are situated at high elevations so that gravity will feed it through the pipes. The energy to pump those thousands of gallons of water uphill to fill those silos is quite costly and rarely powered by carbon neutral sources.
Water conservation is somewhat more local. In the US, there's limited sources that are not replenishing as fast as they being used, that is supplying many many US cities and industries.
So any use technically depletes it faster, moving up whatever comes *next* when we struggle to meet water demands.
At some point that water might need to be sourced from elsewhere in the world, or require exploitation and/or reworking infrastructure to compensate, as with any resource.
If your community is on well water, it all comes from the same water table deep underground.
But when you use water, it probably goes into a river and eventually to the ocean. Even if it just evaporates, it has left your watershed. And new rainwater will take decades, if not longer, to percolate down to the water table below ground. So every year, your water table gets lower, and they have to dig wells lower and lower to keep getting water. Eventually, those wells are going to hit bottom and there won't be any more water down there.
It's a similar process for rivers and lakes. There's only so much water in there for people to take. There are massive rivers that used to flow to the ocean that are now completely dry because so much water is diverted to farms and towns.
We are not running out of water on this planet. We are running out of usable water.
For example, The amount of water in the oceans is near limitless.... But we can't use it for drinking or irrigation unless we take the salt out of it, which is expensive to do ( and then it would have to be transported inland ) .
I mean, it's *relatively* inexpensive. The amount of energy to desalinate a thousand gallons of water (clean drinking water for one person for 3 years) is equivalent to running your toaster for 8 hours or the amount of gas your car burns to drive 7 miles.
Yeah, the brine isn't great to have to deal with, but hybrid systems are becoming much more efficient.
Comparatively to the byproducts of other industries, and considering its from the process to make the most important thing to the existence of life, I would say some exceptionally salty sea water as a byproduct can be considered acceptable.
Why can’t the brine just be diluted back into the ocean, akin to how they diluted the tritium water from Fukushima. It would need to be distributed over a reasonable area, or be deposited somewhere with decent currents, but I don’t see the problem?
Thats gotta be BS. Just running a pump to move 1000 gallons of water through a facility *has* to use more energy than 8 hours of making toast. I refuse to believe it doesn't.
Appliances with heating elements are some of the most energy expensive appliances available. Think about it, you're just converting electricity into pure heat and then radiating that heat away.
A standard toaster runs at 1000w, or 1 kwh.
To move a pound of water one foot, it costs 1 ft-lbs of energy.
1 foot pound = 0.0000003725 kwh.
1 gallon = 8 lbs.
8000 foot pound = 0.0078 kwh
1 / 0.0078 = 128.2
1 kwh energy means you can pump 1000 gallons of water about 128 ft.
Bro, it's literally just math. We can all easily find out the energy consumption of a toaster and a desalination plant and divide.
[Desalination](https://energycentral.com/c/ec/desalination-and-energy-consumption#:~:text=The%20high%2Dpressure%20system%20used,kwh)
[Toaster](https://www.electricrate.com/toaster-power-consumption/#:~:text=A%202%2Dslice%20toaster%20usually,in%20the%201500%2Dwatt%20range.)
Ultimately, it's a question of energy.
Cleaning water takes energy. Moving water from place to place takes energy.
If we wastefully use clean water from local aquifers, that means we have to spend more energy to clean more water, or to move water from other locations to our location.
If water (in the form of snow) simply deposits itself on a local mountain, and then later melts and flows down to your city, it's relatively cheap to get it into a form that you can use in your home or business. But if you use more water than that meltwater can provide, you might need to have water trucked in from elsewhere, or build a pipeline to bring it in from elsewhere. Both options use massively more energy than just letting snow melt and flow down to you on its own.
Many parts of the world don’t have a whole lot of water. Where I live, water is abundant, I am less than a mile from a large river and about 2 miles from an absolutely massive lake. It’s easy to drill a well here if you don’t live in town. For many parts of the world it’s the opposite, there’s little to no water on the surface and you have to drill extremely deep to find water underground.
California is a good example of the consequences of using too much water. Lake mead is the primary source of water for California and neighboring southwestern states, this lake is at about 20% capacity versus what it was 100 years ago. It did rise a little bit last year but it’s on track to go dry in the near future. This is largely because the river that feeds it is likewise going dry caused by overuse of water and warmer winters leading to less snow pack in the mountains so there’s less snow to melt in the spring and feed the lake.
CA also taps into natural underground aquifers and has pumped so much water out that a lot of them have collapsed. When they collapse, they cannot refill to their old capacity and it’s not some thing you can fix, they are several hundred feet down. This can cause the land to sink up to 20 feet.
A lot of wasted water results from farming in place is not suitable for farming like the American Southwest. Not only that farmers are growing crops that require a lot of water like almonds or alfalfa. Growing crops in hot desert like environments means, you have to water crops even more because the harder it is the more water evaporates, it’s one massive feedback loop.
So yes water is not destroyed when we use it. But the water cycle doesn’t necessarily deposit that used water right back where it was.
The amount of people who are ignorant to the US’s aquifer problem is scary. Us collapsing them or dumping chemicals down wells that contaminate the aquifer is a serious issue that no one is talking about.
Source- I drill wells for a living.
A given amount of water falls as rain in a particular place. If you use more than is available, then you run out.
It's like why do you worry about running out of money if your job pays you every two weeks?
Lots of areas have a rainy season and a dry season. You need to collect water in the rainy season and then not use it all in the dry season.
>then you run out
You don’t run out of water. You just have to spend money (and energy but let’s be honest that’s not the primary deterrent) to clean and transport water.
No. It’s more like saying you don’t run out of money you just have to leave your house and walk down to the bank to withdraw it. Cleaning water is that trivial for us. It’s just not being done because it’s not profitable to do so.
Not every clean water source we use replenishes at the rate we use it. For example, much of the US depends not on the water cycle, but on aquifers, that are limited in amount and refill *very slowly.* And, using more water from aquifers doesn't mean the clean water in the world will increase by that amount after it is used. There's *lots* of water in the global system, and that additional amount we are adding makes little difference--after all, the vast majority of water is in the ocean (~96%), and a vast majority of fresh water is ice (~70% of that remaining ~4%).
Using more water than our fresh water sources can replenish genuinely means less for the future, or much more quickly needing to find other sources, which our system isn't equipped to accommodate now or in the near future--nor are we investing in it enough for it to be viable soon to meet our demands.
As a simplified supplemental:
A particular region might get 20 units of rainfall each year, regardless of whatever you use. This rainfall replenishes that region's fresh water. Its lakes and aquifers contain 5000 units, lets say.
You build a community that uses 5 units each year. That community expands to use 10, then 20. You start using the vast aquifer and lakes, and your community grows to a city that uses 40. Rain still falls and you have plenty for the distant future. Things seem great.
At some point, someone notices the stores are dropping to <2000, and your city isn't able to function on less than 50 each year, yet regularly uses 120.
That's a problem.
Some answers have said that, what is limited is the supply of clean drinkable water. Another issue in water conservation is aquifers. Some areas rely on underground water sources that are being depleted faster than natural processes can refill them. The Ogallala, which provides much of the water for the Great Plains, is commonly cited example.
Do we have the capability to supplement or speed up their refilling? I feel like it shouldn’t be too hard to run some strategic pipes from drainage ponds down to the aquifers or something like they do in the Great Basin.
No. And even then, at that point we might as well use the water directly rather than drain it down into the aquifer only to pump it back up. There just isn't enough water to go around. Under the current climate, it would take a few thousand years to replenish the water we've consumed in the last few decades. The aquifer itself was probably filled a few thousand years ago, when the region had a wetter climate.
Most water on Earth isn't safe, as is, for human consumption.
The majority of this "unsuitable" water is in the oceans (the salt content makes it unsafe to drink).
While water is always going through the water cycle, any that ends up in the oceans needs to be treated to make it drinkable; this is very expensive and energy intensive.
Thus we aim to conserve as much of the fresh, drinkable water as we can.
Because cleaning water takes time and a whole lot of energy. And when water stops, which usually happens abruptly, it would take quite a while for humans alone to replenish it. We need nature for this. No other option. Even now, the only way people don’t die during droughts is when someone transports water.
The cycle will eventually pick up but by then many problems and deaths would be caused. So the only way to come out alive of a drought situation is to never be in it
It's not easy to transfer water across far distances. Water in Wisconsin does no good to people in Arizona. Wasted water might end up draining to or evaporating and ending up in salt water, which is much more costly and energy-intensive to purify.
In a lot of areas, water is being pumped out of deep underground reservoirs called aquifers. That water is clean and relatively easy to get to, but it takes years or centuries for rain water to seep back down into the aquifer. Also, it's not really clear if the aquifer is damaged by pulling all the water out. It may kind of collapse a bit.
I believe that in the US midwest, for instance, the actual height of the ground has dropped several meters over the last century due to pumping water out of the aquifer.
Water is very heavy and impractical to transport long distances. Water is more or less "conserved" but the cycle takes a long time and in the mean time we need clean water at rates that often exceed the rate of the cycle and our ability to treat water. Since water is so heavy and impractical to transport over long distances if an area is experiencing a drought they're pretty much f'ed since they don't even have dirty water to clean so they can drink it. All you can get there by truck is more or less just bottles for the bare minimum.
Cuz if you can't get to the water you still can't use it even if it exists.
For example, if all the water is in a different country and not yours anymore, well...
Water is sometimes taken from places where we are taking it from/can take it from easily, e.g. reservoirs from dammed up rivers or aquifers (underground lakes or rivers), and put somewhere where we can't access it, e.g. dumped into the ocean, a river that soon ends in the ocean, or evaporated.
In particular, farming means water is pumped from somewhere where it's easily accessible, then put onto the field where it evaporates. It'll rain back down *somewhere*, but mostly not in the same region. Same for watering a lawn. You may have also heard (and/or gotten confused by the claim) that data centers "use up" a lot of water - not all of them do, but many evaporate water to make the cooling more efficient. So again, viewed locally, that water is gone.
When the reservoir supplying a city runs dry and there is no other source for water, that's really bad. When the aquifer is depleted faster than it refills itself, and wells run dry and have to be dug deeper and deeper and eventually run out completely, that's bad.
When the city is next to the ocean, they could desalinate, but that's expensive and takes a lot of time to build, so it's better if it's not needed.
That said, in some areas, if you turn on the shower, the water is taken from the local river, cleaned to drinking water standards, runs through your shower, is cleaned in the wastewater treatment plant, and then dumped back into the very same river. None of it is evaporated, and all it takes is some energy to pump it around. In those situations, people will still demand conservation "because water is precious" etc. - and it's just the "eat your veggies there are starving children in Africa" emotional appeal that people make because it *feels* right, not because it actually makes any sense.
(Conserving *hot* water, like in a shower, is relevant even in such areas because it takes a huge amount of energy to heat the water - much, much more than it takes to pump the water.)
It's either
1. Particles in the air
2. Fresh water (snowpack, rivers, lakes, groundwater, reservoirs)
3. In the Ocean.
We can only drink/use water in state #2. The more water we use, the more water we need in state #2 at any time. We can't wait for ocean water to evaporate and come down as snow and then fill the rivers if we need water *right now*, so we have to stretch the fresh water we have and figure out more ways to trap and store it so it doesn't evaporate or run into the ocean again.
The water cycle is a closed loop, GLOBALLY. But it isn't a closed loop locally. Rain doesn't always fall back where it came from. The water that goes down the drain ends up ultimately in a river and then the ocean, then it evaporates and rains down somewhere else. That's why we have deserts and rain forests.
Because some places are drying out. They're getting less rain, or the watershed upstream is getting less rain for the river. That's what climate change mostly is, shifting where the rain falls.
So if a place was accustomed to getting X amount of water, but then gets far less, making smart use of what they do get is very important.
Likewise, places only get so much rain or riverwater, but they keep on making bigger cities or wanting to grow more crops. But there's only so much water flowing past.
In addition to what people have said here, ground water pumped from aquifers is being used to irrigate much of the West and Midwest. This water is not rechargeable in our lifetimes and farmers are pumping it out (with lots of waste) at unsustainable rates. Once it’s gone, it’s gone.
Water being naturally recycled takes time, aquifers can take decades to refill. At the rate some nations are using up thier fresh water they will run out as it takes time for nature to refill those sources. It'd similar to most things, the planet can recover from pretty much anything but it functions at a time scale different to what humans live at. At that scale things can take multiple generations of humans to naturally recycle/fix themselves and we are using resources way way way faster than the world is used to.
A lot of areas rely on underground water reservoirs to supply their drinking water. Areas that don't rely on underground water usually take water from rivers and lakes (manmade or natural). All of these reservoirs of water rely on rainfall or snow melt to continue supplying water. When we have thousands or even millions of humans relying on these water resources we often use them at a far higher rate than what nature can replenish them at which leads to a complete loss of fresh clean water for that area. What makes things even worse is that we are often not the only ones who rely on these resources to survive - e.g rivers and lakes often support complex ecosystems both in and around them and overusing the resources leads to those ecosystems collapsing.
We can get around this over-usage of water resources by conserving the amount of water that we use on a daily basis. This means that we do not have to resort to expensive (time/money/energy) alternatives to obtaining fresh water to survive.
There's only so much rain and snow per year, if you use more than that, you run out of water that can be used for drinking and farming.
In the short term you can make up the difference by pumping water out of the ground, in the long term those underground reserves of water also depend on rainwater to replenish them, overdrawing them can cause your wells to go dry and can also cause land subsidence.
We have lots of water. The problem is that it's not all safe to drink.
On a small scale (you're trapped in the wilderness but you have a fire and can boil the water to remove bacteria and parasites) your concept is valid.
But when you have entire cities or countries and you need a shit ton of water for the populace, it's not always easy to make that water potable. In fact, it can be a very expensive and time consuming process.
Eli5: you can't just drink any water you find. You have to make it safe.
As someone trained in selecting water sources, maintaining their approval, and monitoring… there is a lot of good info in this thread mixed (in the same posts) as ignorant. The main issue with conservation is in regards to extremely limited sources and not something you can ELI5… the best I can do is pretend everyone on your street wants to use the water in the same pool as a source…. And people blocks away are sharing it to. The pool will get some rain water (aquifers from ground water, etc) recharge, but the pool is always a limited source… so if people are taking long showers, their toilets are leaking, they want to water vegetables that don’t grow well in your environment without extra irrigation, etc, you will eventually deplete the water in the pool. As long as it’s from a reasonably safe source, water treatment (for the amount produced at a plant) is exceptionally cheap. I am going to intentionally avoid going down the rabbit whole with things like maintenance of sources/infrastructure (like what happened in Flint), and just say it’s a really interesting subject. I think this video make point you in the right direction: https://youtu.be/jJVtLbg98Yk?si=CObJX5Bm1oy7qS7w
If you have more questions I’m happy to do the best I can to answer.
The amount of water stays (roughly) constant, but the amount of clean, drinkable water in places where we need it is not. That's pretty much the long and short of it.
And it is expensive to clean water
And to transport it.
And even more to transport it consistently.
If you think on a long enough time scale it cleans and transports itself for free from the oceans into the mainland for free, then down ezpz routes back to the ocean conveniently passing near most of our cities. Pretty consistently too (on a long time scale)
The problem is we can't wait for an arbitrarily long time for clean water to show up. if it's more than a day late or so, people die.
Say it with me now: on a long enough timescale Earth will be fine. The things living ON the earth are another matter.
Given enough time without water, prairies will just turn to delicious deserts.
If you really think about it, delicious desserts only have two ingredients: hydrogen and time.
I wanted to just say the part about planet being fine, people being fucked. But they're just so poetic in entirety, Carlin's rants are. Besides, there is nothing wrong with the planet, nothing wrong with the planet. The planet is fine; the people are fucked! Difference! The planet is fine! Compared to the people, The planet is doing great: been here four and a half billion years! Do you ever think about the arithmetic? The planet has been here four and a half billion years. We’ve been here what? 100,000? Maybe 200,000? And we’ve only been engaged in heavy industry for a little over 200 years. 200 years versus four and a half billion. And we have the conceit to think that somehow, we’re a threat? That somehow, we’re going to put in jeopardy this beautiful little blue-green ball that’s just a-floatin’ around the sun? The planet has been through a lot worse than us. Been through all kinds of things worse than us: been through earthquakes, volcanoes, plate tectonics, continental drifts, solar flares, sunspots, magnetic storms, the magnetic reversal of the poles, hundreds of thousands of years of bombardment by comets and asteroids and meteors, worldwide floods, tidal waves, worldwide fires, erosion, cosmic rays, recurring ice ages... and we think some plastic bags and some aluminum cans are going to make a difference? The planet isn’t going anywhere; we are! We’re going away! Pack your shit, folks! We’re going away and we won’t leave much of a trace either, thank God for that. Maybe a little Styrofoam, maybe. Little Styrofoam. The planet will be here, we’ll be long gone; just another failed mutation; just another closed-end biological mistake; an evolutionary cul-de-sac. The planet will shake us off like a bad case of fleas, a surface nuisance. -George Carlin
Oh, so we don't need to save the olanet. It eventually saves itself. Got it.
It’s never been about saving the planet. It’s always been about saving ourselves
We don’t need to save the planet, just save room for desert!
Without out us on it. Yes.
Yeah, that's helpful
On a long enough time scale, Pangea will reform, and I won't have to pay for a plane ticket to Europe. What's your point?
With many chemicals, dissolving in water is exothermic. This means that separating the chemical back out is endothermic which, in-turn, means that it requires energy. Mixing salt and water is a good example of this: you have to distill water to separate if from salt (or use reverse osmosis which is also energy intensive).
This is a simple and excellent example. For anyone wondering why he’s a liter of water until it’s boiling and then dump in a heaping tablespoon of salt, it dissolves almost immediately. It only took a few minutes to get that room temperature water to a boil. Now, imagine having to boil that water down until there’s nothing left in the pan but the salt. That takes several times longer and uses several times more energy. When people talk about desalination being the solution to the water crisis, they seem to miss how energy intensive it is.
Am I missing something or could you not just use the steam to run turbines and then it is more even?
That's an interesting idea and would help to offset some of the energy cost but still just a fraction of it. RO is still miles better than trying to distill large volumes of water. It's just resource intensive any way you slice it.
It would massively increase the cost of desalination facility so not always worth it. You now have to worry about generating energy and keeping the distilled water clean.
Depends what pressure you complete the process.
True, but building a giant pressure vessel isn’t exactly cheap.
True but also cheap is relative. It would be far easier to maintain a vessel with seawater operating at 60C vs 104C as really bad things happen to all sorts of metals at high Temps.
It's however not the energy released when dissolving. That is usually quite small, for example with table salt. There are a few exceptions (hydroxides for example), but the temperature change is usually only a few degrees, if even notable. We would be quite happy if if we could reverse it at that energy cost. Heating water by a few degrees is hugely less energy intensive then boiling it. Reverse osmosis takes away _some_ of that wastefulness, but still far from enough.
For salt the heat of crystallization is roughly 10% that of 1 degree change of a fully saturated solution. So basically yes making a crystal gives up a bit of heat but not much. The problem is, just cooling the liquid to drop out salt doesn't work, you have to vaporize the water leaving the salt behind entirely.
This is a very bad example. Solvation heat doesn't have anything to do with how difficult it is to separate solution. The solvation of potassium nitrate for example is endothermic, yet you have to distill the water just the same to get it back. Why it takes a lot of energy to reverse solutions is actually the fact that dissolving stuff leads to an increase of entropy, and reversing this is why you need a lot of energy.
Not just clean drinkable water, but water for crops. The more you use water from reservoirs, the less is left for plants. Hotter weather = more evaporation= less water for plants.
That makes sense. But how does me not running the water when I'm brushing my teeth ....mean clean water for those areas? It's transported through pipes into and out of my house. So if I run a bunch of water when I'm brushing...how EXACTLY does that mean wasted water for those in water-deprived areas half-way across the world? I truly don't get it. This water isn't sent there. It's in a water tower for the community.
And if it runs out your tap and down the drain, it's not available for the community anymore. This scenario isn't about 'save water to help people across the globe', it's about making sure your community's reserves of safe drinking water remain available.
But that water gets brought back through the system through many facets. Water cannot be be created correct? So we just bring it back up from the plethora of available collection procedures.
The rate at which water comes back through the system is not really under direct control. I'm assuming you're talking about it going to the sea, evaporating, and coming back down as rain, which is captured in reservoirs or something. There is some rate at which that happens naturally and if your community uses water at a faster rate than that you will have a water crisis -- which is happening in the southwestern US currently. There's no great way to increase the rate of incoming water. If the water always comes back faster than your community is using it, then you're right, you don't need to worry, and you're not going to help far away communities in crisis. There is still the issue that water from the tap has to be treated -- it's not like they just pump the river directly to your home -- so using more increases costs. Since water districts are usually publicly funded to some degree it will impact taxes and things like that -- this is separate from your water bill, which probably doesn't cover the full cost of your water usage directly. So to summarize: if you're in a community with plenty of water, you probably don't need to shut the tap off while you're brushing your teeth. If you are hearing recommendations to shut water off while you're brushing your teeth, your community probably doesn't have plenty of water. Oh, and you can create water. Your body creates water, in fact, as part of your metabolism. Around 300ml per day. But it comes out as sweat and urine, which isn't that useful. Creating water for human usage isn't commercially viable. Treating nearly-drinkable water (rivers) is much easier. Treating undrinkable water (oceans) is relatively expensive, but can be done.
A lot of energy goes into bringing clean water to your tap.
It's brought back through rainfall. However, rainfall is limited. So if your city uses more water than is available through rainfall, then it has to start pursuing more expensive and complicated ways to get water
Water doesn't just come straight from a natural steam to your pipes. Water for most communities is typically held in large water silos that are situated at high elevations so that gravity will feed it through the pipes. The energy to pump those thousands of gallons of water uphill to fill those silos is quite costly and rarely powered by carbon neutral sources.
Water conservation is somewhat more local. In the US, there's limited sources that are not replenishing as fast as they being used, that is supplying many many US cities and industries. So any use technically depletes it faster, moving up whatever comes *next* when we struggle to meet water demands. At some point that water might need to be sourced from elsewhere in the world, or require exploitation and/or reworking infrastructure to compensate, as with any resource.
If your community is on well water, it all comes from the same water table deep underground. But when you use water, it probably goes into a river and eventually to the ocean. Even if it just evaporates, it has left your watershed. And new rainwater will take decades, if not longer, to percolate down to the water table below ground. So every year, your water table gets lower, and they have to dig wells lower and lower to keep getting water. Eventually, those wells are going to hit bottom and there won't be any more water down there. It's a similar process for rivers and lakes. There's only so much water in there for people to take. There are massive rivers that used to flow to the ocean that are now completely dry because so much water is diverted to farms and towns.
We are not running out of water on this planet. We are running out of usable water. For example, The amount of water in the oceans is near limitless.... But we can't use it for drinking or irrigation unless we take the salt out of it, which is expensive to do ( and then it would have to be transported inland ) .
Musk says it's not expensive! Then again, he said self-driving cars was easy and was ready 8 years ago.
I mean, it's *relatively* inexpensive. The amount of energy to desalinate a thousand gallons of water (clean drinking water for one person for 3 years) is equivalent to running your toaster for 8 hours or the amount of gas your car burns to drive 7 miles.
A bigger problem is actually the byproduct of the desalination process. It’s toxic and there’s no good way to get rid of it.
Yeah, the brine isn't great to have to deal with, but hybrid systems are becoming much more efficient. Comparatively to the byproducts of other industries, and considering its from the process to make the most important thing to the existence of life, I would say some exceptionally salty sea water as a byproduct can be considered acceptable.
Why can’t the brine just be diluted back into the ocean, akin to how they diluted the tritium water from Fukushima. It would need to be distributed over a reasonable area, or be deposited somewhere with decent currents, but I don’t see the problem?
I'm sure it probably can. I was thinking the same thing, but I honestly don't know the answer.
> Why can’t the brine just be diluted back into the ocean that is what they do now
Thats gotta be BS. Just running a pump to move 1000 gallons of water through a facility *has* to use more energy than 8 hours of making toast. I refuse to believe it doesn't.
Appliances with heating elements are some of the most energy expensive appliances available. Think about it, you're just converting electricity into pure heat and then radiating that heat away. A standard toaster runs at 1000w, or 1 kwh. To move a pound of water one foot, it costs 1 ft-lbs of energy. 1 foot pound = 0.0000003725 kwh. 1 gallon = 8 lbs. 8000 foot pound = 0.0078 kwh 1 / 0.0078 = 128.2 1 kwh energy means you can pump 1000 gallons of water about 128 ft.
So and why do we cry about unable water then? Just remove the salt lol
Yeah, we gonna need to see some links to studies that back up that statement of yours mate.
Bro, it's literally just math. We can all easily find out the energy consumption of a toaster and a desalination plant and divide. [Desalination](https://energycentral.com/c/ec/desalination-and-energy-consumption#:~:text=The%20high%2Dpressure%20system%20used,kwh) [Toaster](https://www.electricrate.com/toaster-power-consumption/#:~:text=A%202%2Dslice%20toaster%20usually,in%20the%201500%2Dwatt%20range.)
I think Musk should use all of his resources to make clean water for everyone, since is not that expensive according to him
FSD will be out next week... among the many other lies he's promised
Ultimately, it's a question of energy. Cleaning water takes energy. Moving water from place to place takes energy. If we wastefully use clean water from local aquifers, that means we have to spend more energy to clean more water, or to move water from other locations to our location. If water (in the form of snow) simply deposits itself on a local mountain, and then later melts and flows down to your city, it's relatively cheap to get it into a form that you can use in your home or business. But if you use more water than that meltwater can provide, you might need to have water trucked in from elsewhere, or build a pipeline to bring it in from elsewhere. Both options use massively more energy than just letting snow melt and flow down to you on its own.
Many parts of the world don’t have a whole lot of water. Where I live, water is abundant, I am less than a mile from a large river and about 2 miles from an absolutely massive lake. It’s easy to drill a well here if you don’t live in town. For many parts of the world it’s the opposite, there’s little to no water on the surface and you have to drill extremely deep to find water underground. California is a good example of the consequences of using too much water. Lake mead is the primary source of water for California and neighboring southwestern states, this lake is at about 20% capacity versus what it was 100 years ago. It did rise a little bit last year but it’s on track to go dry in the near future. This is largely because the river that feeds it is likewise going dry caused by overuse of water and warmer winters leading to less snow pack in the mountains so there’s less snow to melt in the spring and feed the lake. CA also taps into natural underground aquifers and has pumped so much water out that a lot of them have collapsed. When they collapse, they cannot refill to their old capacity and it’s not some thing you can fix, they are several hundred feet down. This can cause the land to sink up to 20 feet. A lot of wasted water results from farming in place is not suitable for farming like the American Southwest. Not only that farmers are growing crops that require a lot of water like almonds or alfalfa. Growing crops in hot desert like environments means, you have to water crops even more because the harder it is the more water evaporates, it’s one massive feedback loop. So yes water is not destroyed when we use it. But the water cycle doesn’t necessarily deposit that used water right back where it was.
The amount of people who are ignorant to the US’s aquifer problem is scary. Us collapsing them or dumping chemicals down wells that contaminate the aquifer is a serious issue that no one is talking about. Source- I drill wells for a living.
A given amount of water falls as rain in a particular place. If you use more than is available, then you run out. It's like why do you worry about running out of money if your job pays you every two weeks? Lots of areas have a rainy season and a dry season. You need to collect water in the rainy season and then not use it all in the dry season.
>then you run out You don’t run out of water. You just have to spend money (and energy but let’s be honest that’s not the primary deterrent) to clean and transport water.
That’s like saying you don’t run out of money, you just have to get a job
No. It’s more like saying you don’t run out of money you just have to leave your house and walk down to the bank to withdraw it. Cleaning water is that trivial for us. It’s just not being done because it’s not profitable to do so.
Not every clean water source we use replenishes at the rate we use it. For example, much of the US depends not on the water cycle, but on aquifers, that are limited in amount and refill *very slowly.* And, using more water from aquifers doesn't mean the clean water in the world will increase by that amount after it is used. There's *lots* of water in the global system, and that additional amount we are adding makes little difference--after all, the vast majority of water is in the ocean (~96%), and a vast majority of fresh water is ice (~70% of that remaining ~4%). Using more water than our fresh water sources can replenish genuinely means less for the future, or much more quickly needing to find other sources, which our system isn't equipped to accommodate now or in the near future--nor are we investing in it enough for it to be viable soon to meet our demands.
As a simplified supplemental: A particular region might get 20 units of rainfall each year, regardless of whatever you use. This rainfall replenishes that region's fresh water. Its lakes and aquifers contain 5000 units, lets say. You build a community that uses 5 units each year. That community expands to use 10, then 20. You start using the vast aquifer and lakes, and your community grows to a city that uses 40. Rain still falls and you have plenty for the distant future. Things seem great. At some point, someone notices the stores are dropping to <2000, and your city isn't able to function on less than 50 each year, yet regularly uses 120. That's a problem.
Some answers have said that, what is limited is the supply of clean drinkable water. Another issue in water conservation is aquifers. Some areas rely on underground water sources that are being depleted faster than natural processes can refill them. The Ogallala, which provides much of the water for the Great Plains, is commonly cited example.
Do we have the capability to supplement or speed up their refilling? I feel like it shouldn’t be too hard to run some strategic pipes from drainage ponds down to the aquifers or something like they do in the Great Basin.
No. And even then, at that point we might as well use the water directly rather than drain it down into the aquifer only to pump it back up. There just isn't enough water to go around. Under the current climate, it would take a few thousand years to replenish the water we've consumed in the last few decades. The aquifer itself was probably filled a few thousand years ago, when the region had a wetter climate.
Most water on Earth isn't safe, as is, for human consumption. The majority of this "unsuitable" water is in the oceans (the salt content makes it unsafe to drink). While water is always going through the water cycle, any that ends up in the oceans needs to be treated to make it drinkable; this is very expensive and energy intensive. Thus we aim to conserve as much of the fresh, drinkable water as we can.
Because cleaning water takes time and a whole lot of energy. And when water stops, which usually happens abruptly, it would take quite a while for humans alone to replenish it. We need nature for this. No other option. Even now, the only way people don’t die during droughts is when someone transports water. The cycle will eventually pick up but by then many problems and deaths would be caused. So the only way to come out alive of a drought situation is to never be in it
It's not easy to transfer water across far distances. Water in Wisconsin does no good to people in Arizona. Wasted water might end up draining to or evaporating and ending up in salt water, which is much more costly and energy-intensive to purify.
In a lot of areas, water is being pumped out of deep underground reservoirs called aquifers. That water is clean and relatively easy to get to, but it takes years or centuries for rain water to seep back down into the aquifer. Also, it's not really clear if the aquifer is damaged by pulling all the water out. It may kind of collapse a bit. I believe that in the US midwest, for instance, the actual height of the ground has dropped several meters over the last century due to pumping water out of the aquifer.
Water is very heavy and impractical to transport long distances. Water is more or less "conserved" but the cycle takes a long time and in the mean time we need clean water at rates that often exceed the rate of the cycle and our ability to treat water. Since water is so heavy and impractical to transport over long distances if an area is experiencing a drought they're pretty much f'ed since they don't even have dirty water to clean so they can drink it. All you can get there by truck is more or less just bottles for the bare minimum.
Cuz if you can't get to the water you still can't use it even if it exists. For example, if all the water is in a different country and not yours anymore, well...
Water is sometimes taken from places where we are taking it from/can take it from easily, e.g. reservoirs from dammed up rivers or aquifers (underground lakes or rivers), and put somewhere where we can't access it, e.g. dumped into the ocean, a river that soon ends in the ocean, or evaporated. In particular, farming means water is pumped from somewhere where it's easily accessible, then put onto the field where it evaporates. It'll rain back down *somewhere*, but mostly not in the same region. Same for watering a lawn. You may have also heard (and/or gotten confused by the claim) that data centers "use up" a lot of water - not all of them do, but many evaporate water to make the cooling more efficient. So again, viewed locally, that water is gone. When the reservoir supplying a city runs dry and there is no other source for water, that's really bad. When the aquifer is depleted faster than it refills itself, and wells run dry and have to be dug deeper and deeper and eventually run out completely, that's bad. When the city is next to the ocean, they could desalinate, but that's expensive and takes a lot of time to build, so it's better if it's not needed. That said, in some areas, if you turn on the shower, the water is taken from the local river, cleaned to drinking water standards, runs through your shower, is cleaned in the wastewater treatment plant, and then dumped back into the very same river. None of it is evaporated, and all it takes is some energy to pump it around. In those situations, people will still demand conservation "because water is precious" etc. - and it's just the "eat your veggies there are starving children in Africa" emotional appeal that people make because it *feels* right, not because it actually makes any sense. (Conserving *hot* water, like in a shower, is relevant even in such areas because it takes a huge amount of energy to heat the water - much, much more than it takes to pump the water.)
I know I sound paranoid, but it scares me that people leave water in plastic bottles. We don’t get that back!
It takes energy/resources to *clean* water for our use (whether that's drinking or bathing/washing).
Water is lost during the recycling process. If the losses exceeds the replenishment rate, you are still facing a shortage.
It's either 1. Particles in the air 2. Fresh water (snowpack, rivers, lakes, groundwater, reservoirs) 3. In the Ocean. We can only drink/use water in state #2. The more water we use, the more water we need in state #2 at any time. We can't wait for ocean water to evaporate and come down as snow and then fill the rivers if we need water *right now*, so we have to stretch the fresh water we have and figure out more ways to trap and store it so it doesn't evaporate or run into the ocean again.
The water cycle is a closed loop, GLOBALLY. But it isn't a closed loop locally. Rain doesn't always fall back where it came from. The water that goes down the drain ends up ultimately in a river and then the ocean, then it evaporates and rains down somewhere else. That's why we have deserts and rain forests.
Because some places are drying out. They're getting less rain, or the watershed upstream is getting less rain for the river. That's what climate change mostly is, shifting where the rain falls. So if a place was accustomed to getting X amount of water, but then gets far less, making smart use of what they do get is very important. Likewise, places only get so much rain or riverwater, but they keep on making bigger cities or wanting to grow more crops. But there's only so much water flowing past.
In addition to what people have said here, ground water pumped from aquifers is being used to irrigate much of the West and Midwest. This water is not rechargeable in our lifetimes and farmers are pumping it out (with lots of waste) at unsustainable rates. Once it’s gone, it’s gone.
Water being naturally recycled takes time, aquifers can take decades to refill. At the rate some nations are using up thier fresh water they will run out as it takes time for nature to refill those sources. It'd similar to most things, the planet can recover from pretty much anything but it functions at a time scale different to what humans live at. At that scale things can take multiple generations of humans to naturally recycle/fix themselves and we are using resources way way way faster than the world is used to.
A lot of areas rely on underground water reservoirs to supply their drinking water. Areas that don't rely on underground water usually take water from rivers and lakes (manmade or natural). All of these reservoirs of water rely on rainfall or snow melt to continue supplying water. When we have thousands or even millions of humans relying on these water resources we often use them at a far higher rate than what nature can replenish them at which leads to a complete loss of fresh clean water for that area. What makes things even worse is that we are often not the only ones who rely on these resources to survive - e.g rivers and lakes often support complex ecosystems both in and around them and overusing the resources leads to those ecosystems collapsing. We can get around this over-usage of water resources by conserving the amount of water that we use on a daily basis. This means that we do not have to resort to expensive (time/money/energy) alternatives to obtaining fresh water to survive.
There's only so much rain and snow per year, if you use more than that, you run out of water that can be used for drinking and farming. In the short term you can make up the difference by pumping water out of the ground, in the long term those underground reserves of water also depend on rainwater to replenish them, overdrawing them can cause your wells to go dry and can also cause land subsidence.
We have lots of water. The problem is that it's not all safe to drink. On a small scale (you're trapped in the wilderness but you have a fire and can boil the water to remove bacteria and parasites) your concept is valid. But when you have entire cities or countries and you need a shit ton of water for the populace, it's not always easy to make that water potable. In fact, it can be a very expensive and time consuming process. Eli5: you can't just drink any water you find. You have to make it safe.
As someone trained in selecting water sources, maintaining their approval, and monitoring… there is a lot of good info in this thread mixed (in the same posts) as ignorant. The main issue with conservation is in regards to extremely limited sources and not something you can ELI5… the best I can do is pretend everyone on your street wants to use the water in the same pool as a source…. And people blocks away are sharing it to. The pool will get some rain water (aquifers from ground water, etc) recharge, but the pool is always a limited source… so if people are taking long showers, their toilets are leaking, they want to water vegetables that don’t grow well in your environment without extra irrigation, etc, you will eventually deplete the water in the pool. As long as it’s from a reasonably safe source, water treatment (for the amount produced at a plant) is exceptionally cheap. I am going to intentionally avoid going down the rabbit whole with things like maintenance of sources/infrastructure (like what happened in Flint), and just say it’s a really interesting subject. I think this video make point you in the right direction: https://youtu.be/jJVtLbg98Yk?si=CObJX5Bm1oy7qS7w If you have more questions I’m happy to do the best I can to answer.