It certainly seems possible that we might leave a scorched planet of advancing deserts and an ailing environment to future generations. The earth has four chief biological systems—fisheries, forests, grasslands and croplands. These systems not only supply us food but also the raw material for our industry. In many parts of the earth, human intake from these systems is more than the systems can support. These systems have reached a level where their productivity is impaired. When this happens, fisheries collapse, forests disappear, grasslands are converted into barren lands and croplands become less productive. People are eating more and more fish hi search of protein. The poor burning more and more wood as fire. So the fish disappear and the forests deplete.
