For example, i’ve read somewhere that we need around 3,7Litres of water to produce a single cigarette and 2700Litres of water to produce a single t-shirt. Why do we need so much water to produce stuff?
In: 96
Water is a very important industrial material. A *lot* of chemistry is done between chemicals dissolved in water, you often use water to wash impurities or excess chemical away after using it, and of course water is used in the production of raw materials (in your examples, tobacco or cotton farming). I have no idea if your quoted numbers are actually accurate, but it is certainly true that we use a LOT of water in industrial processes.
In both those examples, those materials are sourced from plants. Cigarettes are filled with the leaves of the tobacco plant, t-shirts are made of the buds of the cotton plant. Growing plants takes a ton of water. Plants need water to grow, but they also lose a lot of water to the air unless they are specially adapted plants like cactus that are good at retaining water. And the plants don’t get every bit of water you put on the soil – a lot of it evaporates into the air from the soil or sinks deeper into the ground.
This is not *necessarily* a huge problem, if you are smart about where you grow your plants so you can take advantage of natural rainfall and/or pull water out of a river or lake that is easily refilled by rainfall and snowmelt. It is a problem in areas like the American southwest however where water is piped in from dams on the Colorado river which simply does not have enough water to meet this demand.
And remember water is cycling ALL THE TIME. It’s not like it gets used up never to be seen again. As they say in Scotland: “Today’s rain is tomorrow’s whiskey”….
That includes water used to grow the crops (tobacco and cotton) used to make those goods. It’s not just counting water used in the factory to make those goods.
It uses a lot of water because those plants aren’t “meant” to make those materials. The nicotine in tobacco plants is a pesticide/pest deterrent, so concentrating enough of it in a small package to smoke and get a decent effect takes a lot of plants. Same for cotton; its use as a cloth fiber is ancillary to its biological purpose (cotton “buds”catching wind to spread the seeds it carries to new places), so it’s not like the plants are super efficient at making those materials, even with selective breeding.
Also some calculations might be due to economies of scale.
For example a factory producing 10000 T shirts a day might consume 10000 L of water.
However even if you reduce the output to 50 percent. It might still use 10000L water. This is due to the fixed costs that come with economies of scale.
The world’s population has increased a great deal in the past 100 years. In the past, ordinary rain was good enough. Now, we need to produce more food which requires more water than what we would normally get from rain. Irrigation has existed from centuries, but we need more of it now.
Water is very useful, very abundant, required for life, and the cheapest thing you can buy. But water isn’t “used up” the way your factoid implies.
Useful: water flows. It can hold enormous amounts of heat, and can carry a wide range of other substances. So if you need to move stuff from point A to point B, whether that’s heat in a power plant or dirt on a floor, putting it in water and moving the water is a great choice.
Abundant: the surface of the Earth is covered in the stuff. Apart from rock, which is inconvenient to move around, water is the most common substance on the planet. There’s hundreds of times more water than air.
Life: Because it’s useful and abundant, when life evolved it selected water as the universal carrier substance for biochemistry. (A lifeform that evolved to use say liquid methane to carry out biochemistry wouldn’t get far on Earth!). This makes it even more useful to humans. Most of the thousands of gallons you mention was used to grow tobacco and cotton.
Cheap: water is literally the cheapest substance you can buy. Water for farming in drought-prone places like California costs a [few cents per ton.](https://aquaoso.com/water-trends/california-agricultural-water-prices/). In those same places, purified drinking water costs a few dollars a ton. Sand and dirt in comparison cost $10-$50 a ton because you can’t carry them in pipes. Even in the desert, water is literally cheaper than dirt.
Finally, I think it’s oversimplifying to the point of being dishonest to talk about water being “used up” the way we use oil or coal. Usually the water is still water when we’re done with it, it’s just slightly modified but still useful. Water that enters a public water supply goes through a human household and ends up contaminated with sewage; after treatment that gets dumped into a river where maybe it gets taken up as cooling water by a power plant, which returns it to the river slightly warmer than it was but otherwise unchanged. Later on it might get used for irrigating crops, where it evaporates and falls again as rain somewhere else.
All of these changes are important and have consequences, but water used for one purpose is still fit for use for other purposes, so it’s really not useful to say “X uses 2000 gallons but Y uses 4000 gallons”. A gallon of sewage is not the same as a gallon of power plant effluent or a gallon of radioactive wastewater.
Water has a lot of perks:
1. It is abundant
2. Is needed for agriculture and cattle
3. It is liquid at room temperature
4. It hits a good spot in density being both decently heavy or light based on many industrial uses
5. Has great heat absorbtion capacity
6. Is a great solvant for many chemical uses
7. It is not toxic
8. It is (mostly) incompressible
9. A bunch of other stuff that simply is not crossing my mind at the moment.
This means that water is a **cheap**, **available**, **easily movable**, **practical** substance that can be used for many industrial use cases.
Sad thing is that while water is a renewable resource, **drinkable/clean water** is not (we consume it faster than it is naturally generated).
Sadly we pollute and waste drinkable water, frequently even when other solutions are technically and financially feasible.
Ask McDonald’s and Burger King ..they use millions of gallons of Uk water going to feed the cows and water the grass …for burgers ..lol
First we need water to grow the plants which can be up to 90% water by weight. Then we need water as a solvent since it’s the most common industrial solvent by far. Then there’s secondary processes like washing which almost inevitably used water and the water drank by the workers.
I wouldn’t worry too much about it. We can reclaim and recycle most of that water with a little effort.
Latest Answers