What Does Exponential Growth Really Mean?
We have accommodated our increasing human population by using more resources and producing more wastes, counting on our planet to provide whatever we want and absorb whatever we discard. Each of these factors – population, resource use, and pollution – has been growing exponentially, but what does that concept really mean? Exponential growth means doubling and then doubling again and then again. Simple examples can create a vivid picture. Suppose you agree to eat one peanut on the first day of the month, two on the second, four on the third, and keep doubling the number every day. How long will a one-pound can of peanuts last? Well, you’ll have eaten the first half of that pound by the eighth day; the second half will be gone on the ninth day. On the tenth day, you’ll open a new can and eat the whole thing. On the fifteenth day you’ll eat 32 pounds of peanuts. On the seventeenth you’ll eat your own weight in peanuts, on the twenty-first a ton, and on the last day of the month, 500 tons
