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Virtual Water

post #1 of 6
Thread Starter 

Check out this blog post  on Virtual Water, i.e. a measure of all the water it takes to produce the products we use.  Allegedly, a cotton t-shirt uses 2700 liters (from water evaporated during irrigation while growing cotton, to water used to dilute chemicals used in the manufacturing process).  The blog also highlights solutions -- i.e. going second-hand, or not buying clothes at all(!) -- to address this Virtual Water problem.  Those just don't seem to be always feasible solutions...there's gotta be another way.  

 

I'll admit, though, that it's pretty compelling to see the tag-line on top of the blog:  1000 liters of water for 1 liter of milk...makes me think twice while eating my morning bowl of cereal....

post #2 of 6

Interesting.  I dunno though - a lot of the water they're counting gets evaporated, in which case it's just going back into the water cycle.  So it's not really "wasted" per say.

post #3 of 6
Thread Starter 

 Good point!  Yes, i'm not always sure whether to buy these enviro calculations....this whole Virtual Water thing seems a little overblown (at least with respect to buying clothing).  On the other hand, I do like the idea of buying second-hand/donating/hand-me-downs with respect to clothing.  Don't do it enough, but it seems to be a simple way to be greener.

post #4 of 6

Yeah it's certainly always good to buy secondhand.

 

Water is certainly going to be a major concern, but it's mostly due to global warming and effects like the atmosphere holding more water vapor, smaller snowpacks, etc.   Because of that we're going to have to become more efficient with our water use, so to a certain extent the virtual water thing is valid.  Because once you've used the water and it evaporates, it takes some time for it to condense and return to the sources where we get it from.

post #5 of 6

Obviously we can't stop eating/wearing clothes because crops need water.  It would be nice if that website ranked things in order of water usage, rather than just stating how much water goes into each product.  In Australia, it's been proposed that products start carrying a water rating on them, like the efficiency ratings you see on appliances.

 

www.treehugger.com/files/2008/04/water-ratings-for-food-labelling.php

 

There's a lot of Australian information about how water intensive various crops are, probably because they've been having a lot of drought problems.  And in Australia, between 2004-2005, agriculture accounted for 65% of all water consumed.

 

There, the most water intensive crops are rice, sugar cane, and cotton, but pasture for grazing is the largest overall consumer of H2O.

 

Pasture for grazing uses only 3.5 megalitres/hectare, but uses the most water in total (2.9 million megalitres) because it has the largest area of land under irrigation (814,000 hectares).


Here's a water intensive crop chart-

 

Total water used (megalitres) / average use per hectare (megalitres)


pasture for grazing: 2,887,837 / 3.5
cotton: 1,734,951 / 6.4
rice: 1,253,227 / 12.3
sugar cane: 1,056,598 / 5
pasture for hay/silage: 799,397 / 3.7
cereal crops for grain/seed: 695,365 / 2.4
grapevines: 633,183 / 3.5
fruit and nut trees, berries: 629,639 / 4.5
vegetables 416,875/3.8
other broadacre crops: 166,673 / 3


I wish they broke that down further- "fruits" and "vegetables" are pretty vague.  Another site I looked at listed the following as water intensive crops:

Rice, cotton, alfalfa, apples, pecans, melons, corn, peppers, potatoes, watermelon, peanuts.

post #6 of 6

wow, thanks for posting this, that is amazing! I never would have guessed it was that drastic, I will definitly have to check into this info, thanks for the heads up!

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