Now that we’re familiar with the idea of carbon footprints, we can add another even more crucial item to our list, our water footprints. The idea is still new, proposed by a Dutch hydro-engineer, Arjen Hoekstra . At a recent conference in Sweden attended by some 2000 scientists, activists and political representatives, he tried to keep a low profile. Nevertheless his idea of “water footprint” became the center of debate. According to his formula, our water footprint is both the water we actually consume, and even more important our virtual footprint, or the water used to manufacturer the products we use. Using his formula, a cup of coffee requires 140 liters of water, a hamburger 2400 liters and a pair of jeans 10,000. How far the idea will go is not yet known, but the fact that our consumerism has consequences for already scarce resources is becoming even more inescapable.