|Biting the Hand that Feeds Us|
"Were living at a very special point in human history
with respect to population growth," says Imhoff. "Were
adding whole country-sized populations of people in decreasing time
intervals." The human race reached one billion people in 1818.
Since then it has been growing geometrically, reaching two billion by
1932, four billion by 1982 and close to six billion by 2000. Though the
growth rate is slowing down now, the Earth is expected to house 10
billion people by the year 2050.
On the whole, Imhoff explains that the human population now consumes and burns as much as 40 percent of all new plant growth on the Earth every year (Imhoff et al., 2000). Most of the best soils in the world have already been cultivated in one fashion or another to grow everything from asparagus to cotton to pine trees to wheat. As the human population expands, it is likely that we will have to keep all the farmland we have as well as cultivate much of the remaining arable land on Earth.
We may, however, be sabotaging ourselves. Along with staggering
population growth over the last century has come a mass movement towards
the cities. Worldwide, human flight towards large urban areas is
boosting the urban population upward three times faster than the general
population growth. Only a third of the planets population lived in
urban areas ten years ago. Now its up to 50 percent and in ten
more years it will be up to two thirds. This mass movement to the
cities has caused urban areas to expand at an enormous rate. In the
United States alone, 19,000 square miles of otherwise rural cropland and
wilderness were developed between 1982 and 1992 (World Resources
|Global population increased by more than 3 timesfrom 1.65 billion in 1900 to 6.06 billion in 2000in just a century. In contrast, the Earths population never reached more than one billion people before 1800. (Graph by Robert Simmon, based on data from the United Nations)|
The problem with all this urban development has to do with where most major cities around the world are located. "Because we are biological entities, we follow biological resources," Imhoff says. He explains that in the past, people laid down the foundations of our modern day metropolises in areas where the land was flat, the water and soil were good and the climate was temperate. These are the same regions that make for good farmland. Though urban sprawl today normally only covers two to five percent of the total land in any given country, that very land may be our most arable. And once an area of land is urbanized, it is very difficult to bring the soil back to its former state.
Population growth and urbanization go hand in hand. (Photograph copyright Photodisc)