Every intervention of man in the environment around him incurs some risk as to both favorable and unfavorable consequences. Every intervention is taken in the face of partial ignorance as to what its effects will be and involves uncertainty as to the ultimate outcome.
Both group effort and individual testimony flow from conviction as to the role of people on earth. In stewardship of the common heritage, a few simple beliefs recur: that all are indeed members of the same human family, that all share in responsibility for the others, that each is capable of responding directly to divine guidance. To seek to translate these into practical action with regard to soil or petroleum or the fish of the sea is not necessarily to do what is directly effective in changing society.
We can be confident that action which is in accord with a few basic beliefs cannot be wrong and can at least testify to the values we will need to cultivate. These are the beliefs that the human race is a family that has inherited a place on the earth in common, that its members have an obligation to work toward sharing it so that none is deprived of the elementary needs for life, and that all have a responsibility to leave it undegraded for those who follow.
The gap between the rich and poor is growing among and within most nations. The political and social effects of unequal location of energy and other mineral resources are acute. Population numbers continue to climb. The global environment shows signs of widespread deterioration. Both natural and social environments are increasingly vulnerable to catastrophic disturbances... There may, however, be a cheering challenge in the possibility that out of its struggle with these realities the human race may move a bit nearer to behaving as if it were indeed one family.
The good news about fresh water is that, even after accounting for the larger volume of water that is unavailable to people from the hydrologic cycle, there is enough on a global scale to support current and anticipated populations on a sustainable basis... Three essential goals are dependable and safe supplies for people, protection and management of the environmental systems through which water moves, and efficient water use. Meeting these goals will require that fresh water not continue to be treated as a free good or as the principal means for disposing of human and industrial wastes.
One effect of benefit-cost analysis is to give any respectable engineer or economist a means for justifying almost any kind of project the national government wants to justify... Exclusive reliance on benefit-cost analysis has been one of the greatest threats to wise decisions in water development.
It would be rash to conclude that, on balance, the environment of the globe as a whole is either deteriorating or improving, or that the survival of the societies we know depends upon filling a simple set of prescriptions. It is all too complex and dynamic, whether it involves managing greenhouse gases or Nile snails... The future condition of the globe's interlocking natural and social systems depends more on human behavior than on the further investigation of natural processes, however desirable that may be.