An opinion piece in the IHT this morning raises the important point that stepped up biofuel production may tax already strained world fresh water supplies. Peter Brabeck-Letmathe, chairman and former chief executive of Nestlé, suggests that if world biofuel production targets are met, water withdrawals for agriculture can increase by as much as one-third. Brabeck-Letmathe writes,
Seventy percent of all water withdrawal is already used in agriculture, and while all such activity requires water, growing enough soy or corn to create biofuels is especially water-intensive. For example, to produce just one gallon of diesel fuel up to 9,000 gallons of water are required. Up to 4,000 gallons are needed to produce enough corn for the same amount of ethanol. By way of contrast, producing enough food to meet the caloric needs of one person for one day in, for example, Tunisia or Egypt requires about 666 gallons of water, and twice as much in California (caloric needs and intakes vary widely from region to region due to dietary customs).
This is bad news considering that it is projected that by 2035, one third of the world (over three billion people) will be facing severe water stress. Even without the increased water pressure of extensive biofuel production, water usage will need to increase substantially in order to feed the world by the middle of the century.
These are the sort of issues that we need to take seriously before plunging headlong into a world where we grow the fuel that drives American (and, increasingly, Chinese) SUVs.