The path of 'virtual water' related to coffee imports to the Netherlands. Image via the Water Footprint Network
The concepts of a carbon footprint, and, more recently, a water footprint are meant to evoke the mark we leave on the planet with the products and services we create and consume -- to remind us that, say, the beans in our morning cup of coffee took water to grow and created greenhouse gas emissions when they were transported to the store.
But when done in detail, a water footprint also serves to map our virtual path around the planet, the path from the T-shirt worn in San Francisco to the Aral Sea in Uzbekistan dried up by unsustainable cotton production, or to the bones of an endangered Indus River dolphin, a victim of pesticide runoff from the same industry.
Water 'Hot Spots'
It's not enough, Professor Arjan Hoekstra of the University of Twente says, to know that a kilogram of dry pasta takes 1,560 liters of water to produce, or that the average American's lifestyle requires 660,430 gallons a year. A water footprint that also takes into account when and where this water is coming from can help a business or country identify the "hot spots" most impacted by its actions to better direct policies to reduce or offset water use.
Hoekstra's countrymen in the Netherlands, for example, have an overall water footprint half that of Americans, but one that falls much more heavily outside of the country -- 80 percent of the Netherlands' global water footprint is externalized, four times the figure for the United States.
Blue, Green, And Grey Water
Quantity vs. quality is is another important factor not always considered in calculating water footprints, said Hoekstra's fellow panelists at a Universidad Politécnica de Madrid-sponsored event at the 5th World Water Forum. European Union water policies, for example, are more focused on preserving water quality than reducing the overall quantity of water used, said Teresa Elola Calderón of the University of Liège in Belgium.
Sugarcane production in Brazil, on the other hand, may be water-efficient, but it causes intensive degradation to water supplies. That's why Hoekstra includes in his analyses both the "green" (rainwater) and "blue" (surface or groundwater) water that is used up by agriculture and industry and the "grey" water that such activities pollute, diminishing its value to people and nature.
Economic Value of Water
The economic value of water was another hot topic, with Ramón Llamas of the Real Academia de Ciencias de España suggesting that many countries (though not the very poorest) may need to move from a focus on more "crops and jobs per drop" to one of "more cash and nature per drop." Countries like Jordan and Israel are already following this paradigm, he said, importing many of their staple foods from water-rich countries and using their scarce water resources for more economically productive uses.
It seems logical for nations, and people, to grow the foods most suited to their climate and hydrological resources, but might not the reduced water footprint be canceled out by an increased carbon footprint, as imports and exports grow?
Water And Energy Intertwined
Such conundrums show that water and energy -- and climate change -- are not problems that can be tackled separately. If you focus on biomass as an alternative energy source, for example, you end up contributing to water scarcity -- its water footprint is three times that of hydropower and almost 70 times that of crude oil, according to Hoekstra's calculations.
So too do carbon capture and storage schemes, which may seem to be helping fight global warming, increase water use dramatically -- by 50 to 90 percent -- added Jamie Pittock, a WWF research fellow at Australian National University. And many techniques for addressing water scarcity, including desalination, pumping deeper groundwater, and large inter-basin water transfers, are extremely energy-intensive.
Stepping Away From Untenable Trade-Offs
Trying to solve environmental problems this way is like chopping off just one of the Hydra's heads -- two more immediately grow back.
One small step toward better integration comes from the Pacific Institute in the Bay Area, which, Heather Cooley explained, has developed water-to-air computer models that allow managers of both urban and agricultural water districts compare the energy use and greenhouse gas emissions of various water-management plans. It's a good first step away from untenable trade-offs.
More Coverage Of The 5th World Water Forum
What is this 'Big Water Meeting'? Day 1 at the World Water Forum
Linking Water, Conflict, Gender, and Migration: Day 2 at the World Water Forum
More On Water Footprints
Calculate Your Water Footprint
Measure Your Food's Water Footprint
Water: The Hidden Cost of Your Food and Drink
Should Food Labeling Show Water Footprint?
S.E.E.ing Change on Water Sustainability
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