Today there are three sources of growing demand for food: population growth; rising affluence and the associated jump in meat, milk, and egg consumption; and the use of grain to produce fuel for cars.
Population growth is as old as agriculture itself. But the world is now adding close to 80 million people per year. Even worse, the overwhelming majority of these people are being added in countries where cropland is scarce, soils are eroding, and irrigation wells are going dry.
Even as we are multiplying in number, some 3 billion of us are trying to move up the food chain, consuming more grain-intensive livestock products. As incomes rise, annual grain consumption per person climbs from less than 400 pounds, as in India today, to roughly 1,600 pounds, as among those living high on the food chain in the United States, where diets tend to be heavy with meat and dairy products.