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Comment by evgen | Hacker News Reader

You keep using this word "used", I do not think it means what you think it means...

Fresh water is one of those strange things, where consumption is not necessarily destruction. You 'used' a glass of water that you drank this morning, then excreted it over the rest of the day as urine and water vapor where it became an input for another part of the cycle. The water did not go away when you consumed it, and in this case most of the water 'used' in the production of a litre of sugar-enhanced carbonated water was never lost.

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My opinion on this is totally uninformed.

A quick search for 'global aquifer depletion' yields

"Scientists had long suspected that humans were taxing the world’s underground water supply, but... major aquifers [are] indeed struggling to keep pace with demands from agriculture, growing populations, and industries such as mining." ... "The situation is quite critical" (https://www.washingtonpost.com/news/wonk/wp/2015/06/16/new-n...)

This talks about a water source, and more specifically a slow-filling source that has been tapped too much. This is where you should apply your concern and effort, to the protection and wise management of easily accessible fresh water sources that are being depleted too rapidly.

If someone talks about water usage (usually in a generic 'it takes X gallons to make a Y, so you should feel bad about doing/using Y' format) without regard to the specific sources then they are trying to bullshit you. If they talk about a specific source and use then keep reading to see if the rest of their argument holds up to scrutiny.

It is still relevant though; because for things like soft drinks that have an extremely low price-to-weight ratio, the only production model that makes sense is a local one. Coca-Cola doesn't just have 3 or 4 factories in the US that make soda; they have one (if not more) in every major city. Some of those cities make use of vulnerable water supplies, and some don't.

But ultimately it's the same conversation - any manufacturing of perishable / low-cost-to-weight ratio (e.g. cement is almost always produced at a factory within 50 miles of where it is used) at industrial scale is being done in a consistent, distributed way at many different locations around the country/world. If those processes damage vulnerable environments, they need to be looked at and modified.

Nitpick:

Concrete (as well as mortar, stucco, and other such products) is made locally, both dry and wet mix. Cement is made in remote areas, typically near the limestone quarries, because the process involves large, dirty, smelly kilns.

But the vast majority of the water used is in the sugar-growing stage and and creation of the packaging. Neither of these things are done even remotely locally.

We "use" water so poorly for agriculture and cities. I lived in Imperial Valley California. They have an open canal through a very dry desert for 100 miles. The canal is made of porous concrete that leaks along the way. It is then used in the farms to produce what I was told is the majority of America's lettuces and vegetables.

They LOVE farming out here since there is virtually no rain or weather events to complicate things. They have everything down to a science and a tight schedule that rarely if ever changes. We use up 90%+ of the Colorado River for this one purpose. We then ship these all across the nation using more resources. Seems a bit wasteful.

So how much water to produce a head of lettuce?

http://www.treehugger.com/green-food/from-lettuce-to-beef-wh...

Answered my own Lettuce -- 15 gallons

Chocolate (One Pound) -- 2847 gallons!!!!!

Where the lettuce has 70 calories and the chocolate has 2500. So about a 5:1 difference in efficiency.

You're both right ... the water is still in the system but no longer in the aquifers (instead it's in the oceans, air, lakes, streams, etc). Apparently, a small amount of water is lost to space (but that will increase as the sun grows hotter). When another extinction-level comet smashes into the earth, it will replenish the water we've lost.

Ain't I a ray of sunshine this morning?

Lots of comets burn up in the atmosphere. The water from that also ends up on the surface. No need to have one actually impact.

What water is that?

The massive pockets of ice that tend to form on giant space rocks. Comets contain a lot of ice.

But this is an issue which varies a lot by geographic region. So it depends entirely where the soft drinks are being produced. Most places don't pull water from aquifers.

Also I have no idea where they are even getting this number. I think they are counting everything from rainwater that falls on the sugar beets, to the, water used by steam engines to produce electricity. But it's hard to tell because they don't explain the figure at all.

You can't destroy water, but you can most definitely destroy fresh water. Or else you could have the same argument for just about anything ("I didn't really break your cup, all the pieces are still lying on the floor.")

What if I heated the earths atmosphere and then boiled all the earths water. What would you drink then?

I'd drink soda.

This is especially funny as outside of US, this means baking soda (Sodium bicarbonate). In powder form.

I'm from outside the US, it was just a joke :S

Yes, I can confirm, it was a joke. :) Full disclosure: I am from EU.

Our planet is getting hot, so we will have lot of vapor -> rains -> fresh water. Just collect it instead of dumping it into river or ocean.

I'm not so sure about this. Water -> vapor -> water loop only works if there's a temperature gradient - you need heat to vaporize water and coldness to condense vapor into water again. If the whole planet is getting hotter, the atmosphere could simply get more humid, with no more rain/fresh water.

We have such temperature gradient every night. We have lack of rains in some areas because they are too hot at evening, because of deforestation, but this is an another story.

We also can create temperature gradient by adding shade at some areas, e.g. using SO2 at altitude of about 20km.

The problem is absolute quantities mean nothing: water is a resource which depends on production capacity. So long as it is in sustainable excess there are no problems.

This is an interesting issue for young people today. I'm too old, but young people will have "fun" dealing with land west of the Mississippi being in a massive overpopulation bubble, and folks east of the Mississippi having more water than we know what to do with now, and with climate change we're supposed to have even more water leading to some interesting infrastructure problems.

For a bit less than 50 years I've heard continuous and constant boosterism that the burbs will migrate back into the city center. No really, this time we're serious about it, etc. Its a cliche now. However a much more interesting migration, is over the next generation or two, most of the west half of the USA will have to migrate back to the east half, assuming they want to drink water or grow plants. Its going to be interesting to watch, at least for today's younger kids to watch.

Note that the land will support some people. In 2030 the west is not going to be empty, any more than it was empty in 1830. It just won't have as many people as now.

I doubt it. Several factors spring to mind that will prevent that specific mass migration:

1) The use of a (small) part of the west's capital to pipe water in from further away

2) Opportunities for multiple orders of magnitude better conservation.

3) Desalination

None of those are as easy as "just wait for rain" but as long as it's cheaper than the entire state of California ($10 trillion?) then it's not a financial hardship compared to "everyone just leave."

>You can't destroy water

Sure you can: https://en.wikipedia.org/wiki/Water_splitting

It takes time to get the water back where you can drink it. We had this discussion before when we talked about the drought in California.

It takes energy, not time. It takes a long time if you passively wait for random environmental processes to slowly replace the water, and a very short amount of time if you actively apply energy to the problem.

Where does this energy come from and, more importantly, how many does it cost.

All of our problems could be solved with an unlimited amount of energy applied to them. Most of them were created that way too.

That actually highlights the problem perfectly. Energy is the metric that matters.

With current knowledge and level of technology humanity has, we can make almost anything by applying energy to shuffling dirt. Need gasoline? We can synthesize it. Need gold? We can recycle it out of stuff. Need drinking water? We can make it out of almost anything.

All that's needed is energy, which is something we don't have much of. Last time I checked we didn't have the world full of nuclear reactors. Until we hit a sustainable and ridiculous energy abundance, we can't assume we can fix any global problem with energy - there's not enough of it to go around.

EDIT: Wording.

Why not run the world on nuclear power? With breeder reactors, there is enough uranium for more than million years of current world electricity consumption. Nuclear energy is cheap, and modern reactor designs are safe.

Yes, I agree. I might have not worded my comment clearly enough. What I meant is: I don't see the world being full of nuclear powerplants right now, so we don't have a sustainable energy surplus to stupidly waste.

EDIT: Fixed wording in the original comment; I hope it's clearer now.

It's never cheap. It's plagued by construction cost overruns. We're having this problem with Hinkley Point C at the moment: http://www.theguardian.com/business/2016/mar/11/edf-chief-ex...

Even given the cost overruns, insurance, nuclear pools, etc it is quite cheap. The only problem with nuclear power is that it is highly centralized and requires significant upfront capital expenditures. And political consequences of radiophobia are so high that investing in nuclear power is limited.

I think that solar and nuclear are the only sustainable power generation methods these days. The rest are either bad for the environment, or ineffective.

Radiophobe here.

I can't accept the morality of handing stewardship of spent nuclear fuel to my children and their children for a thousand generations. Would you still want to be caring for a monster left to us by the people who wrote on cave walls?

As far as a DGR, I'll believe it when a nation other than Finland has shovels in the ground to actually build one.

1) Breeder reactors are reducing the amount of spent fuel to store about 100x. Existing nuclear waste can also be reprocessed.

https://en.wikipedia.org/wiki/Breeder_reactor#Waste_reductio...

2) What monster could be left by stone-age people to us that modern technology couldn't handle?

Modern spent fuel processing methods are great and quite safe (vitrification / underground disposal). I can't imagine a newsworthy worst case scenario with vitrified containers.

1) Sodium-based breeder reactors are terrifying, and considered by most to be a dangerous failed experiment: https://en.wikipedia.org/wiki/Breeder_reactor#Breeder_reacto...

2) As long as we assume that society continues on its current trajectory forever, then yes, there's nothing to worry about. But if it's true that we're in the twilight years of US dominance or relevance as a world power, then we could be in for a significant period of upcoming political/economic turmoil.

So here's another way to look at it: How would the monks and agrarian fiefdoms of the middle ages been at handling a monster leftover by the Romans?

Nuclear fuel waste is much less dangerouns than many other substances created in industrial chemical processes, and occur in much smaller amounts. Managing that is a non-problem compared to other hazardous waste. That people are afraid of radioactive waste and aren't of what their friendly neighbourhood chemical plant produces is pure FUD.

Not exactly, unfortunately. (I am as pro-nuclear as one could be). However, all chemical waste can be neutralized and reprocessed (though this might be expensive to do so). Some nuclear waste can't be reprocessed and has to be stored safely for hundreds of years. This scares some people.

However, it's not _that_ dangerous. Even if containment is breached, it generally stays in the same place and can be collected and put back (happened a lot of times).

> Even if containment is breached, it generally stays in the same place and can be collected and put back (happened a lot of times).

Asse II springs to my mind: https://en.wikipedia.org/wiki/Asse_II_mine An old salt mine used to store low/medium radioactive waste that's under threat of collapse due to ground water. There are plans for the retrieval, but success is far from guaranteed.

This might be a dumb question, but is there any reason other than costs that we couldn't eventually just blast unrecycleable nuclear waste off into the sun/space? There must be an inflection point where the cost of storing the hazardous material safely on earth is more expensive after a period of time than just sending it out of orbit on a space elevator/ICBM.

Sending things to outer space is crazily expensive in terms of fuel; the same holds if you aim for the Sun - the common idea that it's easy is very wrong. The Earth is moving around the Sun at 30km/sec, you need to burn off most of that velocity to actually hit it. For leaving the Solar System, the Internet provides the value of around 40km/sec. You can get most of those speeds by clever use of slingshot maneuvers though, and this is the way we usually do missions to outer planets.

Also, honestly, I don't see the point. The amount of nuclear waste we produce is minuscule compared to other equally or more dangerous chemical substances. Besides wasting perfectly good rocket fuel, destroying it this way would rob us of opportunity to reuse it in the future - hell, we already know how to reprocess some of the spent nuclear fuel for next-gen fission reactors!

"Caring for" meaning simply not entering the tomb labeled "This is not a place of honor"?

Thousands of years is a really long time, especially when you look at how awful people are at learning the lessons of just a generation or two ago.

Most our energy comes from fossil fuels. Even fertiliser for our food. So we can't just replace it all with solar power.

One key questions for rulers and governments from antiquity is how to allow the population to gather energy to survive. It could be farming, or building oil wells and then hand out the profits or build a service economy around the oil.

I couldn't figure out how to maintain a modern population without oil (more people same amount of land) until I saw this on HN the other day https://medium.com/invironment/an-army-of-ocean-farmers-on-t...

Zero input food. Can be used to generate ethanol. All you need is open ocean.

Food for thought.

> Most our energy comes from fossil fuels. Even fertiliser for our food. So we can't just replace it all with solar power.

But we can with nuclear plants, and I'm thinking garden variety fission plants, not the always-30-years-from-now fusion ones. There are various areas where we use fossil fuels only because its more convenient - e.g. ground transportation. We can go electric with most of it. Fertilizers - I'm not sure if petroleum is a necessary chemical component or just energy delivery vector for the production process. Plastics are I think the only area where we can't easily sidestep fossil fuels. But with enough electricity we can still synthesize the compounds we need for those processes.

I have thought about this problem and came to the same conclusion - we need to move to nuclear. But then if most of our energy needs are from nuclear, now we're going to be back in the same situation in 50 years running out of uranium.

Or we could sit in top of our coal power plants slurping oil, wait for the magical thorium reactor and/or solar power to become another 10 times more economical.

Maybe not in 50 years, because it seems that we have a lot of fissile material available[0] that should last us for a long time - long enough to expand past this planet if we continue the growth curve, or at least to advance and deploy renewable solutions without a hurry. But yeah, with continued growth we would hit an energy ceiling in the future too. That ain't bad if reasonably managed - we could fix all the damage done to this planet and expand to the Solar System. But then again, humanity isn't exactly known for reasonable management.

[0] - http://www.withouthotair.com/c24/page_162.shtml

http://www.withouthotair.com/c24/page_162.shtml:

>> "A once-through one-gigawatt nuclear power station uses 162 tons per year of uranium"

>> "World total (conventional reserves in the ground) 4.7[million tons]"

https://en.wikipedia.org/wiki/World_energy_consumption

>> "The IEA estimates that, in 2013, total world energy consumption was 13,541 Mtoe , or 5.67 × 1020 joules, equal to an average power consumption of 18.0 terawatts.[3]"

One gigawatt nuclear plant uses 162 tons per year.

The world uses 18000 gigawatts per year. (40% oil, 10% coal, 15% natural gas, 35% other).

If all the fossil fuel-based energy were replaced with nuclear power, the nuclear power plants need to provide 18000 gigawatts times 65% = 11700 gigawatts.

11700 gigawatts times 162 tons of uranium is 1.9 million tons of uranium, per year.

The world's conventional reserves of 4.7 million tons will last for three years.

The 22 million tons in Phosphate deposits will last for another 10 years. (if and when methods to mine them economically are discovered)

Perhaps the seawater uranium will come in time, but as yet it is not an economical method of uranium extraction. The cost needs to be reduced by 5 to 10 times.

> Most our energy comes from fossil fuels. Even fertiliser for our food. So we can't just replace it all with solar power.

That doesn't follow at all. Why not?

There's plenty of sunlight in the areas with most of the people, and the areas with most of the farmland. We have storage solutions--they're still a little expensive, but they're certainly getting close.

If our current energy came from hydroelectric or geothermal could we replace it with solar? Your statement seems like a complete non sequitur.

This statement may be wrong but for different reasons - it boils down to just how much electricity vs. petroleum we need to use to make fertilizer. I don't know much about fertilizer manufacturing, but from a quick look at Wikipedia I think that for nitrogen ones we could conceivably replace natural gas with some other hydrogen source and run the whole Haber-Bosch stack off electricity.

No, it's not, that's a bit too simple.

In reality, time is the metric the matters, human time. All that stuff you talk about costs human time to build. That's why it's not being built - it's cheaper to do something else.

Once you have a robotic army capable of mining resources and building everything you want, including rebuilding itself, you can just have them throw up a bunch of solar panels and have enough energy for desalination.

I disagree. Human time is not a problem. Yes, in a moral world it would be the most important metric. But nowadays, labour is cheap and abunant. That's why we don't have robotic armies doing stuff all around us - it's cheaper to make people work. We're energy-bound as a civilization now (or, one could say, still).

Perhaps it would be more illuminating to see how much energy was used to create the soft drink.

Or how much energy is used to perform single google query.

The marginal energy is probably not very much. The average energy might be significant, but it's probably dwarfed by a single can of soda if you include the can.

You keep using this word "used", I do not think it means what you think it means...

Energy is one of those strange things, where consumption is not necessarily destruction. You 'used' a joule of energy when you heated up your coffee this morning, then dumped the waste heat to the rest of your kitchen, where it became an input for another part of the cycle. The energy did not go away when you consumed it, and in this case most of the energy 'used' in the production of a cup of coffee was never lost.

[I kid, I kid, I know you meant negentropy, but I just couldn't help myself.]

Good point!

The trouble is just that many popular sources of energy has lot of negative effects ;-)

Energy is about the only resource where this doesn't hold true.

In theory at least, all non-radioactive elemental resources are recoverable from whatever combinations in which they are found, given sufficient energy and information.

Exactly.

Energy is the only resource I know about where there is a physical law stating that this must be true. (To be fair, you could have less energy offset by more mass. But the point stands.)

Not if the thermodynamic laws hold true.

... That's exactly what I was referring to? You seem to be confused. Your responded to a post stating that energy is never destroyed, with the sentence:

"Energy is about the only resource where this doesn't hold true."

Once you use the energy and it turns into heat, you can no longer use it.

First, heat is energy. Second, you can use heat as heat. Third, you can use heat to boil water to turn a turbine to create electricity, which you can use to do very many things, including create heat.

No, you can't do that. If you could do that, you could build a perpetuum mobile.

Yes, you can: https://en.wikipedia.org/wiki/Waste_heat_recovery_unit

Now, whether we can effectively use the energy is an entirely other question. There's plenty of technical limitations. But in a closed system there's no reason an object cannot have perpetual motion with perfect energy recovery. Of course, closed systems don't help us, because they cannot exert useful work outside of the system.

You can't. You can increase the efficiency that way, but you can't use it to produce limitless energy. We wouldn't be burning fossil fuels if that was an option.

You're not "producing" limitless energy. You're reusing the existing energy, because the energy cannot be destroyed. Again, there's no reason why this can't be done within a closed system, except for our technical limitations. Indeed, tracking and recovering energy is the entire idea behind reversible computing.

https://en.wikipedia.org/wiki/Reversible_computing#Physical_...

Exactly. Thank you. Someone gets it. The only problem is energy. If you have enough energy you can make as much fresh water as you want.

Another way to look at this is that water is a proxy for energy. We can replace any fresh water that is 'used' via some application of energy to the abundant salt water on this planet. Soda may be a poor application of energy, but talking about it in terms of water 'used' is mostly FUD.

Did you use a computer to post your comment?

Add to all the current comments in this subthread the fact that every drop of water you keep in a bottle is a drop of water you are keeping out of the system. It's not just what you drink, it's what you remove from the cycle. And you'd like to keep the balance, right?

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