LET’S start with a quiz.

Which consumes the most water?

A) a 10-minute shower.

B) a handful of 10 almonds.

C) a quarterpound hamburger patty.

D) a washing machine load.

The answer? By far, it’s the hamburger patty. The shower might use 25 gallons. The almonds take up almost a gallon each, or close to 10 gallons for the handful. The washing machine uses about 35 gallons per load. And that beef patty, around 450 gallons.

The drought in California hit home when I was backpacking with my daughter there recently on the Pacific Crest Trail, and the first eight creeks or springs we reached were all dry.

The crisis in California is a harbinger of water scarcity in much of the world. And while we associate extravagant water use with swimming pools and verdant lawns, the biggest consumer, by far, is agriculture. In California, 80 percent of water used by humans goes to farming and ranching.

That’s where that hamburger patty comes in.
Nicholas Kristof
Human rights, women’s rights, health, global affairs.

I grew up on a sheep and cherry farm near Yamhill, Ore. I worked for a year for the Future Farmers of America, and I still spend time every year on our family farm. But while I prize America’s rural heritage, let’s be blunt: It’s time for a fundamental rethinking of America’s food factory.

A mandarin orange consumes 14 gallons of water. A head of lettuce, 12 gallons. A bunch of grapes, 24 gallons. One single walnut, 2 gallons.

Animal products use even more water, mostly because of the need to raise grain or hay to feed the animals. Plant material converts quite inefficiently into animal protein.