Recent high prices for energy and food leave many concerned that we are pushing the limits of the earth's system with too many people and too much consumption. One example of our over-indulgence is meat eating. Estimates vary, but in general, a cow has to eat 12 calories of food for us to get one calorie of edible meat. Surely we would use less land and be better off if we just ate less red meat, right?
Let's look more carefully at this question. Just how much land does our meat eating use? Beef is intensive, and the typical American's annual beef intake is 58 pounds. It takes about 2400 square feet of cropland to produce that beef, or the size of the average house. As a whole, we use about 6% of our cropland to grow our annual beef intake.
Other sources of meat are more efficient than beef. It takes 2 calories of input for a calorie of pork, and 4 calories of input for a calorie of chicken. This translates into 400-600 square feet of land, or an area of land about the size of our living rooms, for us to eat the equivalent number of calories as 58 pounds of beef. If we want to use soybeans, tofu, other kinds of beans, or tree nuts like almonds instead, we would use up more land than if we were to get the same number of calories from pigs and chickens.
Well, if we are not using that much land now, aren't we constantly using more land, and consuming more food? One economic "certainty" from the past is that the wealthier people are, the more meat they eat. In the US, meat consumption grew substantially after World War II as per capita income rose, and the middle class grew. People in other parts of the world are less wealthy than we are, and they eat far less meat right now. As their incomes rise, they will consume more meat.
The food reality here in America, though, is not one of endlessly increasing consumption. Over the past 30 years, our diet has actually become a lot less land consuming. Actually, it's pretty amazing what we have done. Based on our typical diet today, we eat the equivalent of about half an acre each year. Back in 1980 we used two-thirds of an acre, or about 35% more land per person, for our food consumption. How have we managed to economize like this?
First, we seem to have turned the corner on overall food consumption. Between 1980 and 2004 per person food consumption in the US rose by 0.6% per year, but it has fallen ever since. This recent reduction probably results from higher real food prices, but it may also have to do with the influence of our national dialogue on obesity. Second, we've changed our diet by consuming more poultry and tree nuts, and less beef. We have traded off more land consuming foods for less land consuming foods.
Third, we have dramatically increased the productivity of our agriculture. Food production in the US, as measured by cereal yields, has increased by 1.6% per year since 1980. About half of the reduction in land needed for our consumption is due to a change in our diet, and the other half is due to an improvement in land productivity.
We are 38% richer in real terms, and population has grown by 36% since 1980, but today we only need 145 million acres to feed ourselves, down from 147 million in 1980. We nevertheless still use about 335 million acres of productive cropland, and an additional 700 million acres of less productive land. The excess food we produce is exported or turned into ethanol.
Eating less meat will not necessarily cause us to use less farmland – exports and ethanol are just too lucrative. But eating less meat, when combined with productivity improvements, does help us use the land we have more effectively. Given a rising global middle class in Latin America and Asia that will demand more food and meat, this will be a good lesson for other countries to learn.
*Along with J Shogren and 2,000 of their closest friends, Brent was on the IPCC which shared the 2007 Nobel Peace Prize with Al Gore.