Outgrowing the Earth: The Food Security Challenge in an Age of Falling Water Tables and Rising Temperatures


Lester R. Brown

Chapter 5. Protecting Cropland: Converting Cropland to Other Uses


In addition to losing cropland to severe soil erosion and desert expansion, the world is also losing cropland to various nonfarm uses, including residential construction, industrial construction, the paving of roads and parking lots, and airports, as well as to recreational uses, such as tennis courts and golf courses. If for every million people added to the world’s population, 40,000 hectares of land are needed for nonfarm uses, adding more than 70 million people each year claims nearly 3 million hectares, part of which is agricultural land. The cropland share of land converted to nonfarm uses varies widely both within and among countries, but since cities are typically located on the most fertile land, it is often high—sometimes 100 percent. 25

China is currently working to create 100 million jobs in the manufacturing sector. With the average factory in China employing 100 workers, China needs to build 1 million factories—many of which will be sited on former cropland. India, with the annual addition of 18 million people and with accelerating economic growth, is facing similar pressures to convert cropland to other uses. 26

Residential building claims on cropland are also heavy. If we assume each dwelling houses on average five people, then adding 70 million or more people to world population each year means building 14 million houses or apartments annually. 27

While population growth spurs housing demand, rising incomes spur automobile ownership. The world automobile fleet is expanding by roughly 9 million per year. (See Figure 5–1.) Each car requires the paving of some land, with the amount paved ranging from a high of 0.07 hectares per vehicle in sparsely populated countries such as the United States, Canada, or Brazil to a low of 0.02 hectares in densely populated areas such as Europe, Japan, China, and India. 28

As long as a fleet is growing, the country has no choice but to pave more land if it wants to avoid gridlock. In India, a country of only 8 million cars, each new million cars require the paving of roughly 20,000 hectares of land. If it is cropland, and of average productivity, this translates into roughly 50,000 tons of grain, enough to feed 250,000 people at the country’s current meager food consumption level. A country that will need to feed an additional 515 million people by 2050 cannot afford to cover scarce cropland with asphalt for roads and parking lots. 29

As the world’s affluent turn to the automobile, they are competing for land with those who are hungry and malnourished. Governments in developing countries are essentially using their financial resources to underwrite the public infrastructure for the automobile often at the expense of the hungry.

In the United States, where 0.07 hectares of paved land is required for each car, every five cars added to the fleet require paving an area the size of a football field. Thus the 2 million cars added to the U.S. fleet each year require asphalting an area equal to nearly 400,000 football fields. 30

Just parking the 214 million motor vehicles owned by Americans requires a vast area of land. Imagine a parking lot with a fleet of 214 million vehicles. If that is difficult, try visualizing a parking lot for 1,000 cars, and then imagine 214,000 such parking lots. The 16 million hectares (61,000 square miles) of U.S. land devoted to roads, highways, and parking lots compares with 21 million hectares that American farmers planted in wheat in 2004. 31

As the new century gets under way, the competition between cars and crops for land is heating up. Until recently the paving over of cropland has occurred largely in industrial countries, where four fifths of the world’s 539 million automobiles are found. But now more and more farmland is being sacrificed in developing countries with hungry populations, calling into question the future role of the car. 32

There is not enough land in China, India, and other densely populated countries like Indonesia, Bangladesh, Pakistan, Iran, Egypt, and Mexico to both support automobile-centered transportation systems and feed people. The competition between cars and crops for land is thus becoming a struggle between the rich and the poor—between those who can afford automobiles and those who are struggling to get enough food to survive.

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