Water has been described as a finite resource. I’m talking about all water – not fresh drinkin water.
I understand that there are various things that water goes through to be recirculated through the environment, such as being absorbed by the sun and there is a cycle. But how can this lead to water being a finite resource? Are there other ‘destructive’ processes involving water that means it will be lost forever?
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>Water has been described as a finite resource. I’m talking about all water – not fresh drinkin water.
>I understand that there are various things that water goes through to be recirculated through the environment, such as being absorbed by the sun and there is a cycle. But how can this lead to water being a finite resource? Are there other ‘destructive’ processes involving water that means it will be lost forever?
Having “a limited water supply” is simply another way of stating “wastewater treatment is a very time-, infrastructure and resource-intensive process that cannot be provided everywhere”. The logistics involved are mind-boggling and they are what provides an upper limit to the total amount of fresh water that can be used.
Staying below that upper limit (by using less water) is significantly easier than artificially raising the limit by covering the world in wastewater treatment and desalination plants and the infrastructure required to maintain them.
Water is a recyclable resource. It cycles through the environment. You are drinking the same water the dinosaurs drank.
When people talk about water conservation the concern is usually managing droughts in a given area, or having enough clean drinking water. While Earth has plenty of water most of it is in the oceans and desalination is expensive and often done in a way that pollutes the ocean.
We can even react hydrogen and oxygen to make water but on large scales this is impractical because the process makes an explosion.
There is a finite amount of water on Earth, about 10^18 tons. There is only a finite mass for the Earth itself. While 10^18 tons a lot, it’s not an infinite amount. It’s only .025% of the mass of the crust of the Earth.
There is a finite amount of water on Earth, about 10^18 tons. There is only a finite mass for the Earth itself. While 10^18 tons a lot, it’s not an infinite amount. It’s only .025% of the mass of the crust of the Earth.
Water is functionality infinite for our purposes, *clean* and *drinkable* water can run out.
Or at least be used up faster than more is made.
“Water” is functionally infinite. We just don’t have the technology to destroy very much of what’s available on the planet. “Water that humans can use in a given manner or location” is what’s limited.
For example, the Great Lakes. Lake Superior is the largest body of fresh water on the planet and that’s awesome, but it’s too far away to irrigate lawns in Las Vegas. Sin City still needs to conserve water because there isn’t very much water *right there*.
Another example…. The City of Chicago. Chicago is on the shore of Lake Michigan so there’s a functionally infinite supply of fresh water for drinking, irrigation, whatever. Cool. Now imagine the city’s sewage treatment breaks down, and there are poopies floating around Navy Pier. Not cool. The pollution will disrupt the local ecosystem, cause fish kills and algae blooms, and eventually get to the water intake cribs. If the city’s water processing plants start sucking up tons of rotting fish, poops, and laundry detergent, the plants will break down and stop processing water. Suddenly that functionally infinite water resource becomes functionally zero, and you’ve got ten million very thirsty, very stinky people in the metro area wanting to put heads on spikes. The City of Chicago needs to conserve water to keep from overloading the facilities that treat sewage before putting it back into the lake, and to keep from overloading the facilities that pull water out of the lake.
Final example, City of Los Angeles. The Pacific Ocean is right there, but it’s salty. Los Angeles can put its wastewater into the ocean, but it can’t get drinking water out. Los Angeles needs to conserve water because there isn’t enough not-salty water to go around.
It’s not “Water” that’s the problem, it’s the “Water, water everywhere, but not a drop to drink,” issues that’s cause by salt water, or dirty water, or water that’s locked up in the atmosphere and aquifers so it’s not easily available for what humans want to do with it.
It won’t run out in the same way that e.g. fossil fuels will run out. With fossil fuel, there is a limited amount on Earth, and when we use it, it disappears. The fuel is turned into something else, typically carbon dioxide and water. And that carbon dioxide and water isn’t going to turn back into fuel by itself, or by some process that’s always going on on Earth. Technically, over very long time periods, new fuel could be generated by plants and animals decomposing, but that will take millions of years. So, fossil fuels exist on Earth in a limited supply, and if we ever use them all up, there won’t be any more of it.
Water, on the other hand, exists in a cycle. When you use water, you’re not permanently using it up and turning it into something else. For instance, say you use water to give to your plants. Some of the water evaporates soon after you give it, either from the soil or from the leaves of the plant. That water vapor is returned to the water cycle immediately. E.g. it may rise up in the atmosphere, form into clouds, rain down somewhere, flow into a river, and people can then harness water from that river and use it again. Or maybe the water flows into the ocean, where it becomes salty and not usable, but then the water in the ocean evaporates too and can rain down as fresh water again.
Some of the water you gave to your plants will be “locked up” in the plant for a while, inside the plant’s cells. But then when the plant dies, the cells break and the water can come out again and be returned to the water cycle.
In this way, water will never truly run out, because it can keep going around in the water cycle.
However, what can happen is that too many people are using water at the same time. Because, while somebody is using water, it is temporarily removed from the water cycle. It’s a bit like if you live in a housing community that has a bike share program. Say there are 100 bikes that people can use freely. These bikes will never truly run out, as people will return them after use. However, if 100 people are each using a bike at the same time, then there are no bikes at that moment for anyone else to use. That may be okay if it doesn’t happen too often. But now suppose that there are always at least 150 people wanting to use a bike at the same time. As soon as one is returned, it immediately gets snatched up again. This means there are always at least 50 people who need a bike but don’t have access to one. The same thing can happen with water: if the demand for water is greater than the supply (in some location), then there will continuously be a shortage of water, even though water is still going around the cycle and being continuously reused.
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