Approaching the midpoint of the '80s, the fast-arriving year 2000 is looking less daunting. A new study, funded by the conservative Heritage Foundation and undertaken by the late Herman Kahn's Hudson Institute, puts forward a more optimistic view. Called ''The Resourceful Earth,'' the study, to be released July 2, projects less crowding despite continued population growth, less pollution, and fewer living at the economic margin.
There have been two schools of thought about the globe's future - the pessimists who have perceived that an exploding population and industrial change would wear down the earth's capacity for ecological recovery and energy and food production; and the optimists who anticipate a tapering off in the population growth curve, greater affluence, sufficient energy supplies, and a greater expanse of arable land.
The decade of the '70s was marked by the darker vision. In 1972 the Club of Rome issued its report called ''Limits of Growth,'' which warned of dire environmental and energy challenges to civilization. The '70s in the United States and elsewhere in the West saw a surge in environmental-protection legislation, efforts to respond to the oil shocks delivered by the oil-producing nations. Jimmy Carter talked about diminishing expectations; he tried to interest Congress and the public in an ambitious synfuels program - itself a trade-off between energy and environmental interests. Mr. Carter capped the decade with his 1980 study ''The Global 2000 Report,'' which projected a civilization and environment worn down by pollution, higher energy costs, and a widening gap between the haves and have-nots.
Politically, the Heritage study is Reaganesque; it recommends relying more on free-market forces to adjust to emerging global demands, unlike the Carter era outlook, which featured government initiative.
No doubt the public prefers to think things will get better, rather than worse. Present evidence suggests that much of the public's investment in the '70 s in environmental protection has paid off, acid rain notwithstanding. Energy supplies have not run low. Hunger in Africa and elsewhere is seen as political as well as ecological and demographic. Who would have anticipated India's progress in food production, again despite its current political tensions with the Sikhs and other ethnic-religious rivalries?
No one should be naive about the risks of crowding, hunger, and potential ecological disaster. Former World Bank president Robert McNamara warns in the latest issue of Foreign Affairs that progress against overpopu-lation is occurring chiefly in the politically more stable regions, and that population curbs in third-world countries could take a Draconian turn.
There is a risk that views of the future can be distorted by political values rooted in the moment's ideological debate. The World Population Conference, to be held in Mexico this August, with 160 nations represented, is hardly the place to promote the current domestic politics of affluent countries.
Earnest scrutiny of environmental and other demands cannot be abandoned: Why look ahead at all if we would simply prefer to believe that things will somehow work out all right?
By and large, society rallied to the alarms of the '70s, paying the cost. In the United States, real personal income has barely grown during the past decade. Industrial growth in Asian lands has spread environmental risk more broadly. The West European job pool appears frozen. The run-up in energy costs for developing nations has been largely financed by debt - which poses its own set of challenges.
And yet who would return to the '70s? At least now optimists can argue their case as vigorously as did the pessimists.
Idealism impels man to look further forward. Perhaps, reviewing this question a decade and a half hence from the vantage point of the year 2000, we will hear widely argued:
The future standard for the globe should be pure water and air, population stability, a universal sufficiency in the standard of living.
Mankind should be able to enhance, not degrade, the globe with civilization, production, and agriculture.
How bravely the world looks at its future affects how much energy it brings to doing what must be done.