Lester R. Brown: Author, Ecologist and Economist

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PLOWBOY: Please go on.

BROWN, Perhaps I can explain it better this way: Ecologists-as part of their analytical tools-have a concept called carrying capacity. A rancher, to give an example, carries a certain number of cattle on his land. He knows what the carrying capacity of his land is ... he knows that if he tries to carry too many cattle, they'll overgraze and destroy the grass, and eventually there'll be nothing left. The rancher-because he owns the land and doesn't want it destroyed?has an interest in the long-term productivity of his land . . . consequently, he'll adjust the number of cattle to the land's carrying capacity.

We have a similar situation in economics, although it's not recognized as such. Let's say we have a philanthropic foundation that has an endowment of $100 million. And let's say that the foundation invests its money so that it'll earn interest at the rate of 6% per year. In this case, the foundation's officers can disburse $6 million a year in grants indefinitely. But if the officers begin to respond to a lot of external pressure and start disbursing funds at the rate of $10 million per year ... well, it's only a matter of time before that foundation runs out of money and has to close its doors.

It's the same with biological systems. You can only take so many fish out of the ocean, or so many trees out of the forest, before you begin to exceed the regenerative capacity of the ocean, forest, or whatever.

PLOWBOY: You can overgraze in the short run, but you can't overgraze in the long run.

BROWN: Exactly.

PLOWBOY: Can you give me a real-life example of a biological system that's being overexploited?

BROWN: Probably one of the most dramatic examples I can name is the anchovy fishery off the coast of Peru. At its peak in the late 1960's, the Peruvian anchovy harvest accounted for nearly a fifth of the world's total fish catch. It peaked in 1970 at about 13 million tons, which made Peru the world's largest fishing nation. But at that point, the catch exceeded the sustainable capacity. The annual off-take of anchovies was more than the natural system could bear. As a result, the Peruvian anchovy fishery has collapsed. The 1977 harvest stood at less than a million tons.

In 1960, fully half the families in this country could hope to own a home. As of early 1978, that figure is down to less than 32%.

And this is not an isolated example, by the way. You can see a similar pattern in the world fish harvest. Between 1950 and 1970, the world fish catch more than tripled. It went from 22 million tons to 70 million tons. But in 1970, the trend was has fluctuated between 65 and 70 million tons a year. World population growth, however, has continued ... so-in per capita terms-the catch has fallen by about 14% since 1970. The result has been a rise in fish prices. If you go to your local seafood market, this will be very obvious. The price of almost every form of seafood is going up.

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