Everyone has heard the term 'carbon footprint'. It emerged because of rising concern for greenhouse gas emissions. A newer term has emerged to address another environmental concern regarding water, humanity's most valuable resource. The current definition of a 'water footprint' is "an inventory of the total amount of water that goes into [the] manufacture [of a product]." In the case of a cup of coffee for example, this measure includes not only the twelve ounces of water that the consumer drinks, but also water that goes into watering the coffee plant and other production needs. There is currently a dispute among environmental scientists and researchers regarding which aspects should be taken account into calculating a particular product's water footprint. Is it enough to just give a value for the volume of water used, or should where the water came from also be included in these calculations?
In the February issue of Global Environmental Change (Australia), Brad Ridoutt published a study in which he thinks to have proven the importance water's initial location in the calculation of water footprints. He provides an example: take a jar of pasta sauce and a bag of M&M's. After considering the raw volume of growing the tomatoes, sugar, and other ingredients against the water used in manufacturing M&M's, the water footprint of the sauce is around 52 gallons while that of the M&M's is around 300. Ridoutt says that this is not the whole picture. Since tomatoes are usually grown in hot, dry climates they require heavy use of irrigation drawn from far away water sources. On the other hand, the cocoa and peanuts are grown in more temperate climates and don't require irrigation because they draw their water from the ground. Most agencies acknowledge the importance of Ridoutt's discovery, but think that it is too soon to consider more criteria when calculating water footprints. For now, they think that it is best just to calculate them based on volume.
This is an example of discovery science because Ridoutt started with a hypothesis regarding the calculation of water footprints and proved it with an experiment (sauce vs. M&M's). These findings are very important to humans because they deal with water, our most important resource. Everyone should calculate their water footprint in order to wisely use this resource.
By: Alison Kenward
How Big is Your Water Footprint?
Discover Magazine
Published online on March 29, 2010
2 comments:
Wow I never thought so much "went into" making things, specifically water. Interesting how you have to consider the manufacturing process (and how much water is put in).I'd never heard of the water footprint before, but it makes sense...
I meant how I never thought so much water went into making things :)
Post a Comment