5 ms·

So help me understand this... I eat far less than 3496 liters of food every day, and only a fraction of it is water. So where are the other 3490-something liter

So help me understand this... I eat far less than 3496 liters of food every day, and only a fraction of it is water. So where are the other 3490-something liters of water? Or to put it differently, the link says "3091000 liters of water for producing 200 kilos of boneless beef". Clearly only a tiny fraction of that water is tied up in the animal at any given point. Where is the rest? My point being: even if we all stopped eating meat because it takes too much water to produce, would this actually make a difference in the amount of water available? Or would it just change the rate at which the water is cycled from environment through plants and animals and back into the environment? And in the larger context of the water cycle, does it make any difference? That infographic doesn't seem to touch on any of this, instead handwaving about the water being "virtual" or "hidden in the food you eat". It's not as though 3091000 liters of water just disappear, never to be seen again when those 200 kilos of beef spring into existence.

Veserv 5y ago
Generally speaking, the rest is in the ocean or air. Before it can be reused it must either be in the natural water cycle and rained back down or it can be artificially reclaimed via desalination and the like. Ignoring artificial reclamation, we can view the natural water cycle as producing some amount of fresh water per unit time and underground water stores as containing some amount of fresh water. When we use fresh water in places faster than the water is replenished in those places we must either draw upon water from another place or upon water stores. What "consuming" some quantity of fresh water means is that quantity of fresh water must be "produced" either naturally or artificially otherwise the net stores of water decrease. If we reach zero stores of water then we can no longer "consume" more than is "produced" and thus have no choice but to reduce production of things that "consume" water. If this is sudden and unexpected then we will have a food crisis as we will not be able to produce as much food as we expected.
- NtochkaNzvanova 5y ago
  Thanks, I appreciate the explanation. So is there good evidence that agriculture is causing these stores to run dry? Or is it more a matter of climate change causing droughts, and we're all supposed to "tighten our belts" to mitigate it? (As an aside, thanks also for the interesting info on desalination you shared in other threads. Do you have any pointers to good resources on this topic that are both up-to-date and freely available? I'm very interested in this topic but have found in the past that a lot of the open academic literature is out of date while the up-to-date industry sources are usually paywalled.)
  - Veserv 5y ago
    Having not done any particularly rigorous research, the evidence I have seen indicates that agriculture is the primary driver of natural freshwater store depletion. Climate change may be an exacerbating force, but it is highly likely that freshwater stores are being consumed significantly faster than they are being naturally replenished even if we assume no changes in the natural water cycle. Here is a graphic illustration of the depletion of the Aral Sea [1] and a link to Google Maps [2] to provide perspective on its size if you are unfamiliar with the geography. In terms of solutions, as I have mentioned desalination is a functional solution that developed countries will likely be able to deploy that should make the worst case scenario of mass starvation or thirst unlikely. In fact, given the costs of desalination it is likely that developed countries will be able to deploy it just because they do not want any lifestyle changes. Other than that, the most likely solution will be a massive reduction in water usage which is, based on my recollection, predominantly agriculture (~70%) followed by industrial (~15%) followed by recreational/aesthetic (~12%) followed by personal (~3%) or something similar to that distribution. Given how small personal usage for things such as drinking, cleaning, bathing is, this reduction would largely need to come from agriculture with maybe some coming from reductions in industrial and aesthetic uses such as lawns. Frankly any calls to reduce personal usage should probably be seen as evidence of a lack of understanding of the problem or possibly even a deliberate act of sabotage since it would have little impact on the problem, but come with a large human cost. In terms of the feasibility of water usage reduction, a large reduction in water usage seems quite doable in the US given that it consumes ~3-4x more per-capita than similarly wealthy European countries. To some extent this is a partial misrepresentation since the US is a major food, and thus water, exporter, but I am fairly certain even without looking at the underlying numbers that the US can significantly reduce consumption without significant lifestyle changes. From what I have heard, but not investigated thoroughly, this is mostly blamed on the relatively large amount of meat consumption/production in the US which is not implausible on its face. Assuming this is the case, a reduction in meat consumption to European levels would be a fairly minor change in lifestyle that would dramatically reduce water consumption. Alternatively, the development of meat substitutes or artificial meat with far lower water needs could solve that problem. I am uncertain if this is a sufficient reduction as I do not know about the raw consumption/replenishment rate of water resources, but if it is not it would at least provide a significantly longer lead time to solve the problem in other ways. In terms of research into desalination or the like I do not have any particular resources. Most of my knowledge is fairly surface level from piecing together random snippets that I find and doing some first-principles analysis. [1] https://earthobservatory.nasa.gov/world-of-change/aral_sea.php https://earthobservatory.nasa.gov/world-of-change/aral_sea.p... [2] https://www.google.com/maps/place/Aral+Sea/@45.9900368,43.8676439,5.31z/data=!4m5!3m4!1s0x41ed23b49bf6100f:0x3cde954279e8d69!8m2!3d45.3963063!4d59.6134113 https://www.google.com/maps/place/Aral+Sea/@45.9900368,43.86...

Veserv 5y ago

Generally speaking, the rest is in the ocean or air. Before it can be reused it must either be in the natural water cycle and rained back down or it can be artificially reclaimed via desalination and the like. Ignoring artificial reclamation, we can view the natural water cycle as producing some amount of fresh water per unit time and underground water stores as containing some amount of fresh water. When we use fresh water in places faster than the water is replenished in those places we must either draw upon water from another place or upon water stores. What "consuming" some quantity of fresh water means is that quantity of fresh water must be "produced" either naturally or artificially otherwise the net stores of water decrease. If we reach zero stores of water then we can no longer "consume" more than is "produced" and thus have no choice but to reduce production of things that "consume" water. If this is sudden and unexpected then we will have a food crisis as we will not be able to produce as much food as we expected.

NtochkaNzvanova 5y ago
Thanks, I appreciate the explanation. So is there good evidence that agriculture is causing these stores to run dry? Or is it more a matter of climate change causing droughts, and we're all supposed to "tighten our belts" to mitigate it? (As an aside, thanks also for the interesting info on desalination you shared in other threads. Do you have any pointers to good resources on this topic that are both up-to-date and freely available? I'm very interested in this topic but have found in the past that a lot of the open academic literature is out of date while the up-to-date industry sources are usually paywalled.)
- Veserv 5y ago
  Having not done any particularly rigorous research, the evidence I have seen indicates that agriculture is the primary driver of natural freshwater store depletion. Climate change may be an exacerbating force, but it is highly likely that freshwater stores are being consumed significantly faster than they are being naturally replenished even if we assume no changes in the natural water cycle. Here is a graphic illustration of the depletion of the Aral Sea [1] and a link to Google Maps [2] to provide perspective on its size if you are unfamiliar with the geography. In terms of solutions, as I have mentioned desalination is a functional solution that developed countries will likely be able to deploy that should make the worst case scenario of mass starvation or thirst unlikely. In fact, given the costs of desalination it is likely that developed countries will be able to deploy it just because they do not want any lifestyle changes. Other than that, the most likely solution will be a massive reduction in water usage which is, based on my recollection, predominantly agriculture (~70%) followed by industrial (~15%) followed by recreational/aesthetic (~12%) followed by personal (~3%) or something similar to that distribution. Given how small personal usage for things such as drinking, cleaning, bathing is, this reduction would largely need to come from agriculture with maybe some coming from reductions in industrial and aesthetic uses such as lawns. Frankly any calls to reduce personal usage should probably be seen as evidence of a lack of understanding of the problem or possibly even a deliberate act of sabotage since it would have little impact on the problem, but come with a large human cost. In terms of the feasibility of water usage reduction, a large reduction in water usage seems quite doable in the US given that it consumes ~3-4x more per-capita than similarly wealthy European countries. To some extent this is a partial misrepresentation since the US is a major food, and thus water, exporter, but I am fairly certain even without looking at the underlying numbers that the US can significantly reduce consumption without significant lifestyle changes. From what I have heard, but not investigated thoroughly, this is mostly blamed on the relatively large amount of meat consumption/production in the US which is not implausible on its face. Assuming this is the case, a reduction in meat consumption to European levels would be a fairly minor change in lifestyle that would dramatically reduce water consumption. Alternatively, the development of meat substitutes or artificial meat with far lower water needs could solve that problem. I am uncertain if this is a sufficient reduction as I do not know about the raw consumption/replenishment rate of water resources, but if it is not it would at least provide a significantly longer lead time to solve the problem in other ways. In terms of research into desalination or the like I do not have any particular resources. Most of my knowledge is fairly surface level from piecing together random snippets that I find and doing some first-principles analysis. [1] https://earthobservatory.nasa.gov/world-of-change/aral_sea.php https://earthobservatory.nasa.gov/world-of-change/aral_sea.p... [2] https://www.google.com/maps/place/Aral+Sea/@45.9900368,43.8676439,5.31z/data=!4m5!3m4!1s0x41ed23b49bf6100f:0x3cde954279e8d69!8m2!3d45.3963063!4d59.6134113 https://www.google.com/maps/place/Aral+Sea/@45.9900368,43.86...