Water consumption is infinite

[MB]

Carbon balance calculations are becoming more and more common. We also do water balance and we could do for commodities such as oil or metals for example. But there is a big difference between water and others.

To find out how much oil was consumed to produce 1 kg of beef, we add the consumption of the breeder, the consumption of the farmers producing animal feed, transport, refrigeration, etc. The further we go in the calculations, the greater the quantity of oil will be; but the numbers will get smaller and smaller so a more detailed calculation might give a figure 20% higher than a quick calculation and an exhaustive calculation say 10% more.

We are sure that the figure obtained is finite because the sum of consumption for all human activities (agriculture, industry, services, transport, heating, etc.) must be equal to the production of oil.

But this is not the case for water. The same water molecule is counted several times in the calculations, so that the total water consumption may very well be much greater than the fresh water available on Earth (without this telling us anything about it). useful). So there is no certainty that a more detailed calculation (adding more and more indirect consumption) will stop one day (mathematically: we cannot be sure that the series converges). So you can produce as huge total water consumption figures as you want with enough elbow grease. For propaganda it's perfect, for information it's perfectly absurd.

[Christophe]

I do not understand your idea but water regenerates naturally, unlike oil (I speak on a human scale)!

Water consumption can therefore be "infinite" as you say since it is renewable.

Be carefull I do not say that there are no big problem supply in the world! But at the planetary scale there is no problem of fresh water (we can speak of the spring 2013 rotten which recharged the water tables like never since 10 years ...)

[sen-no-sen]

But that's not the case for water. The same water molecule is counted several times in the calculations, so total water consumption may well be much higher than the fresh water available on Earth (without this telling us anything about water). useful).

We do not talk about the water cycle for nothing.
When we insist on the fact that 15000L of water is needed to make 1kg of beef it is not actually related to the consumption, for example, of fuel to make 100km.

The water needed for breeding always ends up returning to its source one way or another.
The question therefore does not lie in consumption in terms of finite resource, but in terms of efficiency, or if you prefer performance.

Because with the same consumption of water necessary for the breeding of an ox it is possible to feed 10 to 30 times more people with other food source (potato or sorghum for example).

As mentioned Christophe there is no lack of water at the global level, but a serious problem of water distribution, very important nuance!
It's the same thing when it comes to jobs or housing!

[elephant]

Quite: how much piss, beef for 1 liter of water drunk?

[MB]

with the same water consumption required for raising an ox, it is possible to feed 10 30 times more people with other food sources (eg potato or sorghum).

And with the water consumed by a bridge, how many people could we feed? (See Thread.)

[chatelot16]

water is rarely really consumed ... just used in passing, and remains usable for the next cycle

it's not like oil that's burned once

the consumption of water in a dry area where there are plants to spread seawater is just equivalent to energy consumption

the consumption of water in a cold country is usually not important: we have as much as we want

what is more serious than the mere consumption of water is the polution of water: for example, the exploitation of shale gas by injecting enormous amounts of pigmeat into the soil: it is a blow to be made not drinking water from an entire region

[Ahmed]

In writing:

And with the water consumed by a bridge, how many people could we feed?

MB, you let yourself be abused by an awkward and fundamentally inappropriate wording ...

[Did67]

Going back to the original question, does the series converge, I think the answer is yes, despite the fact that water is not "consumed" in the destructive sense:

a) it is water "fallen from the sky", which, in a given land, is a limited quantity (rainfall x area)

b) and water "recirculated" as a result of human activity (networks), which is also limited: capacity of pumping stations, networks, limited energy used, etc.

So I think the series is converging!

As for the 15 liters, I never knew how they were calculated. I think this is still one of those "media arguments" made to "hit", as the Amazon rainforest is the "lung of the earth".

[the fact remains that "industrial" red meat is a luxury product, both for wasted calories and for water and energy; but it can also be, among the Maasai, the only way to develop very poor grass in an arid climate. Where without that, man would have difficulty in living, not being able to use this biomass - the ruminant has the remarkable capacity to feed on cellulose thanks to the bacteria in its rumen; a ruminant "works" 7 hours a day doing this "job"! Curious, no, this contradiction ???]

[chatelot16]

it is not only in the masaïe that the breeding is a good way to use the ground ... in France also there is place where the breeding is useful!

the absurdity is when instead of having 20 cow that would feed easily in the fields we have to have 200 cow, and buy food grown at great expense

likewise for pigs ... at the time when there was one in each farm, the pig ate all the waste, and did not pollute because they were not concentrated as the current livestock

the common sense peasants, it was not bad

now we are rather subjected to the technocrats ... in the kind of the history of coluche: we give the sahara to a technocrat: in 2 years it lacks sand

[MB]

I think the series is converging!

I agree from a strictly mathematical point of view. But the figure obtained for the total water consumption can be enormous, while the consumption of oil or metal must be equal to the total of historical production.