How can we predict the amount that will be spent to keep the environment clean in the years to come? Do the costs depend primarily on population or on the gross national product (GNP)? How are the costs affected by the way in which the environmental standards are set? What role does technology play? On the one hand it causes more exotic forms of pollution, and on the other it can deal more effectively with current and future pollution problems. And finally, To what extent do environmental outlays improve the quality of life, and to what extent do they decrease societal welfare by diminishing the resources left over for consumption? How do we strike a balance between spending funds for a clean environment and spending funds for other things that contribute to the welfare of people?