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    Remember That '140 Liters Of Water In My Cup Of Coffee' Theory? Here's Why Virtual Water Is Bogus
    By Hank Campbell | March 21st 2008 12:11 PM | 16 comments | Print | E-mail | Track Comments
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    A few days ago the internet was abuzz with shocking headlines because the gentleman behind 'virtual water', professor John Anthony Allan of King’s College London, got an award from a water conservation group, the Stockholm International Water Institute (SIWI) for his work on advocating water conservation. Reading the news clippings about it, you'd have thought it was a Nobel prize for perpetual motion.

    Perpetual motion is a good analogy. Generally, if you see something too ridiculous to be true, it's probably not true. A few weeks ago, for example, a VA Tech grad student got a prize for a 'gravity lamp' that was just the kind of alcohol-and-magic-fueled hocus-pocus that sets the internet on fire. It was green energy and cool tech all rolled into one. Except it didn't exist. Rather than being able to power a household bulb for hours, even an unsuitably-large one could only power a tiny 0.1-watt LED for 45 minutes. It's just physics.

    So a few days ago people were aghast and outraged when they saw a number stating that 34 gallons of 'virtual water' went into a cup of coffee. I understand their panic. That means we only have about 9,588,235,294,117,647 cups of coffee left before all the water is gone.(1)

    Except water doesn't actually disappear. There is the same amount of water on earth now as millions of years ago. That's right, you're drinking water a Neanderthal peed in. Water recycles. I understand that only 2.5% of all water is available 'fresh' water but that is why the outrage over coffee and hamburgers is unjustified.

    Trees, for example, give off 70 gallons of water per day just in evaporation. That's two cups of coffee right there coming back to us. So water evaporating from trees provides enough water to result in 392 cups of coffee for every man, woman and child on the planet. Humans use, on average, 50 gallons per day directly, so we'd have to scale that coffee back to just over 390 cups per day.

    My diatribe here is not about the water conservation industry. I am all for clean water. 2 billion people live without proper clean water and even in civilized areas there are 70,000 known chemicals in use that can contaminate water. I am very much against bad water. I am also against bad math.

    Allan has been writing about the 'virtual water' concept for a while, notably in 1998 in the article "Virtual Water: A Strategic Resource Global Solutions to Regional Deficits"(2) published by Ground Water magazine. It had existed in concept before then, since 1993, and he even used it farther back himself under the term "embedded water" but he came up with "virtual water" because, as he said, the term embedded water "did not capture the attention of the water managing community."(3)

    So at least we understand motivation.

    He used it while doing examinations of the middle east and came up with a basic figure in how much water was contained in something like imported grain.(4) His feeling was that the 'virtual water' contained in grain imported into one region of the mid-east was equal to all the water in the Nile so there was trouble brewing, if you'll pardon the coffee pun. From there it took on a life of its own.

    Since that time, the 'hydropolitics' of virtual water have been brought up on occasion yet the one place where it should be obvious now, the middle east, still has no signs of it. There hasn't been a war over water even though they fight over almost everything else.

    There's a reason for that. Real water is what people care about, not pretend water. 'Virtual water' can be used for shock effect but it's basically an intangible and, as we shall see, the math is fuzzy. Even Allan never intended for it to be anything more than conceptual:

    The recent publication by Hoekstra and Hung (2002), which will be discussed at the Third World Water Forum in Kyoto in March 2003, shows that some water engineers liked the idea so much that they have devoted months to adding quantitative substance
    to the conceptual utility of the idea.

    They basically wanted it to be true so they started matching data to the topology. Yet the concept has spread everywhere, sketchy math or not. As a comparison of how far it had spread, I did a search to find out how much water it takes to grow an egg. The most common result I found was 120 gallons of water. For one egg. Stephen Colbert's 'truthiness' says people are more inclined to believe something outrageous if it is vague and this is a perfect example, because I saw the same figure in dozens of places.

    Dr. Jim Arthur of Hi-Line International, an egg producer in Iowa, doesn't know where that number comes from. He says 100 birds lays 80-90 eggs per day and use 4-5 gallons of water. He told Elizabeth Grossman when asked(5), "The 120-gallon figure would have to include water for something other than what the hen consumes directly" which is about 1 ounce of water per egg.

    So it must include the grain. Well, birds eat like ... birds. They don't eat a lot, about 1/2 cup per day for a hen laying those 8 eggs. A ton of grain is going to feed over 10,660 hens for a day and produce 85,300 eggs(6). That should take 10,236,000 gallons of water at 120 gallons each.

    But the 1,000 cubic meters Allan says makes a ton of grain, even using his aggressive virtual water scenario, is only 1 million liters - 263,936 gallons. Somewhere these egg numbers include not only chickens drinking water, but the grain to feed them, the water the farmer drank, the well the water came from, etc., et al, until we end up with 40X the amount of water calculated using food for the hens.

    In other words, it's just made up. So it goes with the odd '633 gallons of water to make a hamburger' claim. Vegetarians want to believe it, but they also wanted to believe walking to the store causes more global warming than driving your car there if you eat meat. As long as they didn't use a calculator, they were right and in that instance they were handed an easy-to-remember platitude ('a gallon of gas per pound of beef') and ran with it despite it being made up. Much like saying it takes 1,000 cubic meters of water to produce a ton of grain.

    So it goes in this instance but there's more than math that's flawed in that reasoning. There's also ecology.

    Let's suppose for argument's sake it does take 34 gallons of water to grow the beans for my coffee. The bulk of that will be rainwater which, as we we all know, happens in places like Colombia. The water is not trucked in from some distant land where it is hurting the ecosystem by being gone. If the water is not used in coffee plants, it will seep into the ground or flow into rivers.

    If we're going to complain about coffee and hamburgers, the Amazon rainforest is one of the top water consumers in the world. If less coffee and hamburgers actually meant more water for African kids who have none, cutting down the rainforest would easily provide water for the 2 billion people without it. Yet no one thinks that's a good idea.

    Clean water in places where people live that have no water is really the issue. We don't have a water shortage, a resource that needs to be rationed. There is a lot of water because, as I mentioned above, only 2.5% of what we have is fresh water. People who talk about a water crisis or wars over rivers are in the advocacy business. Like anything else, if a lobbyist, even one guised as a scientist, starts giving you numbers, you need to examine the data carefully. We have an energy issue when it comes to water, not a mitigation one, because we just need energy to make undrinkable water potable.

    Renewable, clean energy will solve a lot of the water issues that remain, either by desalinatization where there is ocean water available or shipping where there is no water at all. Putting money toward that is a much better strategy than Bono birthday parties.

    So drink all the coffee you want without guilt. Just make sure you pee once in a while and it will all come back around. Your Neanderthal ancestors did it for you, after all.

    Back to this aggressive 'virtual water' math, we can actually have some fun with it. Just for kicks I intend to take on the FTC and see if they fold once I get out the calculator. If there are 34 gallons of water in my cup of coffee I am certain I can prove there are 'five ounces of milk' in a one ounce slice of Kraft cheese.(7)

    NOTES:

    (1) Lenntech Water Facts And Trivia. http://www.lenntech.com/water-trivia-facts.htm

    (2) J.A. Allan (1998) Virtual Water: A Strategic Resource Global Solutions to Regional Deficits Ground Water 36 (4), 545–546 doi:10.1111/j.1745-6584.1998.tb02825.x

    (3) S. Merrett, J.A. Allan, and C. Lant, Virtual Water - the Water, Food, and Trade Nexus: Useful Concept or Misleading Metaphor?

    (4) 1,000 cubic meters of water to produce a ton of grain.

    (5) High Tech Trash: Digital Devices, Hidden Toxics, and Human Health By Elizabeth Grossman Island Press (2006) p.63 ISBN 1559635541

    (6) Hens don't lay eggs every day of their lives. They start at about 6 months of age and then taper off when they get older plus they rest in winter unless you leave a light on. Even using geriatric chickens laying 1 egg a week, the numbers cannot add up.

    (7) August 10, 1992, Federal Appeals Court upholds FTC Ruling That Kraft Misrepresented Calcium Content Of Individual Cheese Slices, http://www.ftc.gov/opa/predawn/F93/kraft-app5.htm

    Comments

    adaptivecomplexity
    I'm still baffled by the virtual water concept. So how much virtual water does it take to make a human being? Do you have to count all the water (and virtual water) consumed by your parents while they raised you, and you grandparents while they raised your parents...

    Mike

    Mike
    Hank
    That's the beauty of just making things up. At least in the 'meat eaters cause more global warming than cars' swindle there was a metric ('it takes a gallon of gas to end up with a pound of beef') that could be disputed by simply showing the data they used and its flaws, namely in trying to compare the energy in a gallon of gas and the energy in a pound of beef and doing it incorrectly.

    Here they make a sweeping claim that can't be disputed. There is no way that it takes 1,000 cubic meters of water to produce a ton of grain in the US and I doubt it does in Egypt, since in the example he used just the grain they import (50MM tons) is equal to all the water in the Nile.

    So there would have been water shortages and wars long before now if it took that much water to grow simple grain.

    Thus, he must be quite literally making the assumption that everything in the entire chain takes its maximum water capacity and then the water disappears for good. Which we know is not true.

    And a hen somehow using 40X the water needed for the grain it eats every day to produce an egg is just one of the sillier extractions that happen when people make calculations from a flawed premise.

    adaptivecomplexity
    That's the beauty of just making things up.

    I've got to somehow incorporate that phrase into my next talk when I start getting speculative.

    Mike

    Mike
    iramjohn
    It makes a world of difference whether you are talking about irrigated crops versus rainfed agriculture. (In western Oklahoma and the Texas panhandle they are dealing with the reality of exhausted aquifers.) As for the beef thing - if it's feedlot beef raised on corn, you can factor in all the energy it takes to produce the corn (mostly fertiliser, which is, of course, a fossil-fuel product)...and it is awfully wasteful of energy. And billions of dollars in subsidies paid to corn producers. I think the problem isn't so much the calculations, but rather how they are applied. They probably make sense in certain circumstances. But once they're released "into the wild" they no longer make sense.
    I have a poultry farm. we use about 1 gallon of water per dozen eggs produced. This inlcudes growing replacement chicks, all birds in production, washing the eggs, all employees use while at work. Much of that water (a little less than 1/3 of the total) is actually sent on its way as water vapor from chicken breath.

    and I want some of those 8 egg per day chickens!

    I find this article to be an excellent example of critical thinking and essential questioning. I have a degree in science (biology) including a minor in philosophy, and I am happy that I can combine both in my day-to-day life. Looking at this case, it is clear that too many of these dire claims actually create the opposite intended effect. In this coffee-water example, the intended effect is to encourage people to drink fewer cups of coffee to save the water supply. In reality, if this were true, we should give up eating altogether. Instead of encouraging people to become more conservative, these stories serve as the "boy who cried wolf" stories. People will not listen when it counts, because they have been mislead too often before hand.

    Thanks for the insight on this catastrophic coffee claim.

    Your so called science degree must be from the internet. No one trained in the field of natural or life sciences would ever call this article "an excellent example of critical thinking and essential questioning". In fact, it's the exact opposite and represents the kind of thinking that is driving this country into the ground.

    The fundamental baseline argument of this article is true: in the natural water cycle, what comes out eventually goes back in, keeping the volume of water on the Earth relatively constant. What you and the author both failed to recognize is that human activity in the form of agriculture, industry, etc. take that water out of the natural water cycle, often resulting in a dead-end form that will not recycle its virtual water content at the end of its life cycle.

    Hank
    The fundamental baseline argument of this article is true: in the natural water cycle, what comes out eventually goes back in, keeping the volume of water on the Earth relatively constant. What you and the author both failed to recognize is that human activity in the form of agriculture, industry, etc. take that water out of the natural water cycle, often resulting in a dead-end form that will not recycle its virtual water content at the end of its life cycle.
    I never said anything of the kind.  What I said was activists can't invent goofy numbers and have them be washed away by cultural and political sympathizers because they agree that more water would be good for people.  Lying has been shown to be bad 100% of the time and that's what these bogus water claims are - outright lies intended to deceive.

    If an oil company made such ridiculous claims about their technology - each barrel of oil adds $5,000 in wealth to every person in America, for example - would you, who claim to represent "the field of natural or life sciences" let it go unchallenged? If you would not, then you are simply rationalizing your politics and calling it 'science'.
    Agreed on the 8egg/day chicken.

    please fix your typo AND the subsequent math:

    He says 100 birds lays 80-90 eggs per day and use 4-5 gallons of water. He told Elizabeth Grossman when asked(5), "The 120-gallon figure would have to include water for something other than what the hen consumes directly" which is about 1 ounce of water per egg.

    So it must include the grain. Well, birds eat like ... birds. They don't eat a lot, about 1/2 cup per day for a hen laying those 8 eggs

    I posted his article to my class in response to a class project on calculating our daily water usage, and this was the teachers reply to your article. I wanted to post it here so that the students would be able to read both sides of the debate if you decide to reply:

    1. "water doesn't actually disappear. There is the same amount of water on earth now as millions of years ago." (it's a cycle, of course there is the same amount of water!)

    This is simply not true.  While the number of atoms of each element remains constant, the number of molecules of a substance constantly changes.  For instance, when a plant takes in water for photosynthesis, the hydrogen atoms are used to produce glucose and other compounds, while the oxygen atoms for diatomic molecules and exit into the atmosphere.  Also, it is the amount of freshwater available in a region that is of utmost concern.  A regions ability to recharge ground/surface water depends on the total evapotranspiration in the area and the land use (some surfaces are more permeable than others).  If freshwater in a region is depleted or is lost to saltwater, then the negative effects are obvious.

    2. "That's right, you're drinking water a Neanderthal peed in." (Yummy)

    Again, this is silly.  You are not drinking the same water... the hydrogen bonds holding together water molecules from thousands of years ago have been broken and rearranged millions of times.... but they are the same atoms (in a sense). I know this is just a Wikipedia link, but check out the links to some of the references... there is a lot of good information from University research:  

    http://en.wikipedia.org/wiki/Virtual_water

    Hank
    If your teacher can do nothing but dispute a joke and get a basic geological fact wrong, your class is in serious trouble.  The fact remains there is the same amount of water today as there was thousands of years ago.

    Of more concern is that no one arguing about whether or not neanderthals peed in water seems to have bothered to check the absolute rubbish the entire 'virtual water' concept is based on.  It is wrong from start to finish and it has become folklore by people who want to believe it and so refuse to check any data at all.
    I understand the sentiment behind your frustration but find your post to be strikingly un"scient"ific. I believe the ones running around in ignorance are the ones who comfortably recall their elementary school lessons that taught that water is recycled. No, mass on Earth doesn't disappear nor appear (yes, we all know this), but it does change form, as the professor you dismissed pointed out.

    What our climatic changes, over-irrigation, and the other heavy water infrastructure we've imposed over the course of several decades have caused and will continue to cause is a change in the integrity, location, and consistency (rainfall-speaking) of our water supply. And the fact that such a small portion of Earth's water is fresh is nothing to minimize -- you write as if you were overwhelmingly confident that we're about to uncover this enormous wellspring of renewable energy capacity needed to desalinize the oceans and ship water to dry regions. I'm feeling a Julian Simon/cornucopian vibe - do I have that wrong?

    By the way, there are many who say that the lack of water wars right now is not an indicator of abundance but rather of the intrinsic interdependence of countries sharing limited natural water systems.

    You, yourself, begin your article with a complaint that speaking of "vagueities" does little practical good for society. Well, being vague about how much water (or oil, or fill-in-the-blank resource) we use when we consume a good isn't particularly useful either. I don't find it anything shameful that Allan (of whom I've just learned through your article tonight) recognizes that he used the concept "virtual water" to capture attention. He should capture our attention - otherwise, as humans, we tend to ignore "issues" until they become problems that seriously impede our normal way of living. In other words, most of us make the majority of our decisions based on short-term benefits. A virtual water model gives us the "h2o" discount rate for items we use in our daily lives. Seeing the long-term costs of our choices as we're making them today can help inform decisions that protect our greatest long-term benefit. In fact, I think it's brilliant that economists and ecologists now more frequently overlap in creating environmental cost-benefit analysis for things like ecosystem services, for example, where natural benefits might seem to collide with development or extraction interests...

    I'm very grateful to all the people who've crunched the numbers to put the carbon calculators and the global footprints and the water consumption quizzes and energy audits out there for the masses. While we hope for accuracy and integrity in entities serving public education, these types of tools are inherently subjective (any NUMBER of decisions about calculations could be considered subjective) and are rough. If the worst they provide is an inflated estimate, then HOPEFULLY the impact is to actually influence a person's decision to be more conservative in his or her consumptive habits (unless you're inherently opposed to that? I ask in earnest!).

    Furthermore, most "consumer eco-calculators", if I can put it that way, do include transportation, if not packaging as well. I don't think I saw those line items come up in your egg analysis, so I thought I'd mention them.

    All the best to you, and I guess I can say thank you for getting my blood boiling tonight!

    Hank
    I'm very grateful to all the people who've crunched the numbers to put the carbon calculators and the global footprints and the water consumption quizzes and energy audits out there for the masses. 
    If an oil company puts out a carbon calculator which happens to be wrong and understates the impact of cars and equipment, I would point it out - you just happen to want to believe their numbers are accurate even when shown they are not.    Or you think that anything is good enough.  That's fine for politicians and advocates but a science site exists to give people straight answers - and the straight answer is that the 'calculator' used by these virtual water people is invented with little basis in fact.
    Just curious, isn't the water going into coffee production cleat and potable? How about the water coming out, is it still good to drink? I know it can be cleaned and reused and that would sove the issue, but I have a feeling that in most countries that are the coffee growers this would not be the case.

    I really dont have any data, just asking.

    Thanks,

    Hank
    In coffee-growing countries the water is basically rainwater - the reason the virtual water metric breaks down is the presumption that water is coming from somewhere it would not otherwise be.  There have been no wars over water, as I noted, in the places where there should have been decades ago, because virtual water is not real and people in deserts don't need to try and grow coffee, that is what trade is for.

    Colombia, for example, has terrific reuse of its water because just like on any farm it seeps into the soil and is recycled - but virtual water doesn't count reuse, it is a one-off.  In one year of using virtual water, there would be more water owed than exists on the planet, and that just isn't possible.