[google is very unhelpful, it’s broken now. I can’t find any posts explaining the specific thing I want to know]
Was asked this question by a friend.
When we say that producing one item of clothing uses x amount of water. She doesn’t see the harm because the water used to grow cotton doesn’t disappear “it’s part of the cycle”.
Pollution must be a factor right? There is a difference between drinking water, saltwater and contaminated water? (Surely they’re not using clean drinking water for production?)
Exasperated by the fact that production is usually performed in areas with poor regulation/infrastructure.
(Is it inherently damaging, or damaging because of how it’s performed?)
Is the water “used” because it becomes vapor? Is it used because the molecules are taken apart? Either way shouldn’t this technically be reversible?
[I am not very articulate, and I find it very difficult to organize my thoughts to words. This question ended up frustratingly inprecise!]
Edit: thanks for the good responses:)
In: Biology
The issue isn’t that “water is gone” but “**fresh** water is gone”.
Fresh water, water usable for cleaning, drinking, cooking, etc, is harder to come by. It takes money and resources to a.) get fresh water, and b.) send it to whoever needs it.
There’s another way of thinking in that clothing comes from plants. Plants require water. A cotton farm, to produce enough material to make one piece of clothing, will need to grow and harvest Y amount of cotton. And it takes X amount of water to grow that many cotton plants.
freshwater is a very limited resource. it’s why places that grow lots of cotton for clothes have trouble with it. at least in part. regulations could definitely impact that but i don’t know a ton about regulations. there should probably be limits on use, because enviroment and all.
otherwise the concern is contaminating water with chemicals and what not. it’s going in the ground or up in the air, but it’s still got chemicals in it, especially if it’s ground water. acid rain’s a thing but contaminating ground water is *super bad*.
but no, it doesn’t really ‘disappear’, we’re just ruining it by polluting it. we should have more waste water plants and what not probably around infrastructure that handles all that. not a civil engineer either, just assuming.
Only so much water is usable fresh water. If you pump all the water out of a local aquifer to grow cotton, it will take thousands of years to refill, and it will never refill if you keep using all the water. So once the reserves are dry, you’ve effectively used up that supply of fresh water, and only paltry amounts will be refilled by rainwater in our lifetimes.
If you live in the US, we have a major problem in the Western states because we use more water than is replenished into the Colorado River and Lake Mead. Nature doesn’t bring more rain just because we use more water, so the lakes and aquifers just run dry.
Try asking chathpt. It’s not always accurate, but it’s like talking to a smart friend and at least you’ll get something more specific than a google “search.”
Water usage is about the amount of available clean enough fresh water we can use that is no longer available. If you produce clothing most water is used to irrigate the crops. Most of that water will evaporate and fall down somewhere else as rain.
That the water is on earth is not enough information for the impact of some parts of the earth. Deserts are not a result of not enough water on earth, is is a result of not enough water in the desert. Water is extremely heavy and we use a lot, so long-distance transportation is hard. If the water would need to go up in elevation you would use an enormous amount of energy to pump it up. We use hydroelectric power plants that extract energy from water going down for a reason. So water transportation is quite limited.
Humans tend to live in large cities and we use a lot of water, if water is used upstream and not longer reaches the city it will be a huge problem. It do not help that there is lots of water somewhere else.
That might not sound bad but is can be if for example you use all the water from a river for irrigation and nothing then reach the ocean or a lake. The [https://en.wikipedia.org/wiki/Aral_Sea](https://en.wikipedia.org/wiki/Aral_Sea) was the third largest lake until it started to shrink in the 1960s and today is almost gone. The water that flowed to it was used for irrigation to primarily produce cotton.
The water is not gone it still is on earth and falls down as rain, but is is not longer where it was and a huge ecosystem has been destroyed.
In the US the Colorado River has been used for irrigation. Hoover Dam produces electricity but alos water for irrigation, primarily in Califonia. The result is almost no water in the ocean and it has had a huge impact on the delta there. The water evaporates from the artificial lake behind the dam and from the field it irritates. The result is a huge environmental impact. There are alos large city that use water for the population and a fixed total amount available. So if crops that use a lot of water are grown there is less water available for city usage and to reach the lower part of the river.
Water from rivers are fed by rain and snow so new water is get available all the time. We can use more than what on average fall from the sky in a year. There is alos water in underground aquifers that we pump water from. They can contain enormous amounts of water. The problem is that might be the result of water flowing down from the surface during million of years. We can pump up water thousands of times faster than the aquifer is refilled. So water in aquifers are often a limited resource and when we pump it all up it takes millions of years to replenish. The water still remains on earth but that do not help anyone in a location where the aquifer was the only available source.
So water usage is about where the water is, in a location, there is a limited amount per year or practically forever for som aquifers. Humans use water on an enormous scale and it can have a huge environmental effect and a effect on available water for human consumption.
When we talk about water use it is almost always in the context of fresh water – water that plants and animals use to drink. This means relatively salt free and clean.
This water is not evenly distributed around the world so looking at it from a global context is mostly useless for particular localities like a town, district or farming area. So this idea of a “water cycle” is simply not very useful. What is most important is how, in these locations, the available fresh water is consumed and allocated to various uses. Fresh water is almost all derived from rain or snowfall. There are parts of the world where it can be pumped from deep underground but that is typically not the major problem.
Water is quite heavy and given the amount needed for farming and livestock, it is way too expensive to try to transport water long distances or up hills and mountains. It makes artificial redistribution a very difficult task.
Although there is a lot of saltwater in seas and oceans, it has the same problem. It is incredibly expensive to desalinate water in the amounts sufficient to do even a little bit of farming. Farming using desalinated water is impractical simply because the cost of desalination and the amount used would make the crops too expensive for people to buy.
This makes water use a big problem for areas with limited water. Population growth, the need for more food, cities and factories expanding all require more and more water. And once this water is used, it is no longer fresh and much of it flows down increasingly smaller and more polluted rivers into the sea. Of course there are also ecological concerns – using too much water from a river threatens fishes (which are usually a source of food).
Water use isn’t about how MUCH water is available in total, it is about where it is and how much is available in particular periods of time and how it is distributed among the various demands.
It’s not about water use per se, it’s more about water *diversion*.
In the natural hydrologic cycle, water evaporates from the oceans, falls as rain, pools into rivers and lakes, and then drains back into the ocean again. This is basic elementary school science. But most modern farming/ranching techniques require active irrigation to water our crops and animals. We also build massive cities that are distant from the rivers and lakes where we traditionally used to build them, so we dredge canals and dam up reservoirs for drinking water and to produce some the electricity we depend on.
All this activity diverts water from its natural course, and much of it gets discharged into the ground near where it’s used instead of the source it was taken from. It can then take centuries or even millennia to return to the ocean.
In the grand scheme of things, this isn’t a problem. All things being equal, the oceans will continue to evaporate and the rain will continue to fall. But the amount of that water that makes it into lakes and rivers is reduced, and that has effects on the downstream ecosystems that depend on those water cycles that existed naturally before we started diverting it. Additionally, minerals that normally wash into those rivers and lakes upstream are less dilute downstream, which can raise their concentrations to levels that are harmful to flora and fauna that require them to be in a certain balance.
Water can be gone / inaccessible for your region if you export your agricultural products to other regions or even other continents.
By sealing large amounts of land for industrialization we also create a large amount of surface runoff into rivers and ultimately oceans. This water would have been retained in the soil to a large degree, further impacting the water cycle of a region.
In a very, very, VERY technical sense, your friend is right. But the question is kinda wrong. It’s not “Will the used up fresh water end up beeing usable fresh water again?”, the answer to that is “yes”. The correct question is “**How long** will it take for the water to be usable again?” If the used water spends years, maybe centuries, slowly moving back to the groundwater level, as salt water in the ocean or it just rained down somewhere else where it is not accessible to us, we can consider it wasted. If you use up a water supply in a year that takes a decade to fill up, that’s not good ressource management.
Desalination will (unfortunately, imho) be worthwile at some point in the future. If we’ll using up our available fresh water supply and continue screwing up the planet, 1L of desalinated water will eventually be cheaper than 1L of fresh water.
Also, with your friends logic oil is basically renewable. Just wait until algae absorb all of the emissioned CO2, then wait a few million years until the algae die, get moved down into the sediments and turn into a black goo. Voila – oil again! totaly eco, green and sustainable! s
As others have said in many different ways, the applicable resource isn’t water, it’s clean usable water, not at all the same thing.
Polluted runoff from cropland is water, but it’s not going to contribute to healthy river ecosystems. Fish going extinct because water has been diverted from their rivers is a real problem.
There are agricultural techniques that help keep usable water in the soil instead of letting it evaporate, but they aren’t suitable for all crops and in general are more expensive.
Aquifers are like huge sponges a hundred meters down, they can hold vast amounts of water with a natural cycle refilling them, but if we pump out too much water too fast the sponge is crushed flat by the weight of the ground and will never refill — the nice convenient source of water is just permanently gone.
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