Murder to produce sustainably, that is. And here are three stories to prove it. In the arid West of the US, overgrazing has been stripping away the ground cover, and the soil, for decades. Some enterprising ranchers have finally seen the light, however, and are experimenting with how they graze cattle, moving their herds more, giving the vegetation time to bounce back, mimicking the behaviour of the mobile herbivores of the African savannas. But the jury is still out on whether it works, whether “sustainable ranching” is just the oxymoron many environmentalists have always said it is. Meanwhile, in Tibet, climate change is drying up streams. Shepherds have to go twice as far to take their flocks to water. Farmers have to dig twice as far down to strike water in their wells. And finally, all over the world, frogs are being driven to extinction because of our taste for their legs. It’s enough to drive one to vegetarianism.