We Can’t Go On Feeding – And Breeding – Like This

In the Road Runner cartoons there is usually a scene where Wile E. Coyote, chasing the Road Runner, runs off a cliff. He continues on a horizontal line for a couple of seconds, looking increasingly puzzled and concerned, until he realizes his predicament, tries vainly to reverse course, and falls to the desert below.

This is symbolic of the situation ecologists call “overshoot.” Overshoot is when a species reproduces to a number that its environment can’t sustain.


In 1944, for example, 29 reindeer were introduced onto St. Matthew Island in the Bering Sea. With few competitors, no predators and plenty to eat, the herd increased to about 6,000 by the summer of 1963, consuming almost all available food. That winter most of them died. The surviving population in 1966 numbered 42.

And now the species with the unique ability to change the environment on a colossal scale appears on the verge of making for itself a St. Matthew Island worldwide. At the end of the 19th century, the human population was 1.6 billion. It is now 6.5 billion.

The food that made this amazing increase possible – there’s also sanitation and modern medicine, but food is the base – came primarily by boosting crop yields with petroleum. With fertilizer from natural gas, with crops bred to capitalize on that fertilizer and with petroleum-powered machinery and irrigation wells, we can produce huge yields – more than 7,000 pounds of corn per acre, for example. Just one lifetime ago, corn yields were one-fifth of that. Wheat yields have almost tripled. Similar comparisons can be made for other grains.

But this can’t last. The aquifers, oil and natural gas that made possible a fourfold population increase are finite. Over the coming decades, petroleum will become harder and harder to find, extract and put to use, until eventually it becomes unavailable for agriculture in any significant amount. Meanwhile, another 2 billion people are predicted worldwide by 2050.

Hartford Courant (Connecticut)