The nature of the present (pseudo) and coming (real) energy crises have been indicated. Recent evidence suggests that pollutive dangers from nuclear fission plants are far greater than had been thought. The resuscitation on a large scale of coal as an energy source would give pollutive dangers, including climatic changes due to excess carbon dioxide.

Solar energy systems, earlier impossibly expensive, are now predicted to have the same capital cost-range as have nuclear reactors. Cheap, high-purity silicon coatings which adsorb at <10–4 cm but do not emit at >10–4 cm, thin-film photovoltaics, thermoelectrics, and photosynthesis, are areas of immediate solar energy research interest.

Roof-top energy collection may be a permanent part of the future, but will not avoid the necessity of large ‘solar farms’ to collect energy for industry and transportation. Storage should be in the form of hydrogen: there are advantages in developing cheap hydrogen as a general and clean fuel, for transportation and other purposes.

Ozone in the stratosphere is vital to life on Earth. Yet it is chemically unstable and is susceptible to catalytic destruction from a long list of chemical substances, including NOX, HOX, CIOX, and metal oxides. In the stratosphere, these catalysts can be very active in ozone destruction, even when present at only one part of catalyst per 10,000 of ozone.

Pollutants can reach the stratosphere in two ways: (1) by direct injection, as from supersonic transports, military aircraft, rockets, or nuclear bombs, and (2) by indirect injection from the troposphere, which may occur for inert, water-insoluble substances that will eventually work their way up into the stratosphere.

The mass of catalysts sufficient to destroy stratospheric ozone at a significant, world-wide rate is less than the mass of the annual waste products from several industrial operations. In particular, the mass of nitrogen oxides from the exhausts of 500 supersonic transports is far above the threshold for significant catalytic destruction of ozone. This could have profound effects on the working and very maintenance of the biosphere.

Forestry and Conservation, although inherently kindred interests, have recently diverged to the point of antagonism. Why is this, and how can they be brought together again?

John Evelyn, a founder of forestry, as a matter of public policy, presented it as of much wider significance than the production of timber alone. During the past century, however, a narrower and more materialist approach has prevailed, ignoring the relationship between land, men, and science, and creating conflicts between foresters and conservationists. It is probably common ground that until very recently much of the training of professional foresters has been inadequate to equip them for appreciating the broader role of forestry and for communicating with fellow interests in land-use.

Conservationists equally suffer from deformations arising from their early struggles. They tend to line up in two groups—the ‘polarizers’ who are heirs of the pioneer missionary and compaigning stage, and the ‘integrators’ who are more concerned to find operators in the area of natural resources who are ready to cooperate in acceptable compromises.

Many current practices in forestry unfortunately tend to repel the ‘integrators’ and to drive conservationists into adopting ‘polarizer’ attitudes. Forest managers are at last becoming aware of this problem, and to the importance of decision-making on the basis of underlying scientific principles and facts, which can enable a joint strategy to be developed between foresters and conservationists for the wise and balanced long-term use of the vast forest resource.

The physics problems remaining to be solved to achieve practical fusion power by magnetic confinement techniques are believed to be well posed and soluble. A programme plan recently developed in the United States calls for progressively larger plasma confinement experiments to address these physics questions in line with a serious programme in fusion power engineering. Implementation of the plan is expected to lead to the first production of power from a deuterium–tritium-fuelled system in 1980. Thereafter, three progressively larger experimental electrical power reactors are planned, leading to fusion power commercialization in the later 1990s.

The environmental characteristics of fusion reactors have been estimated by analyzing conceptual reactor designs. It is projected that the only volatile radioactive material in a fusion power-plant will be the tritium fuel. Analyses indicate that tritium leakage can be held to very low levels and accordingly should not pose a significant environmental hazard.

Careful selection of the materials of construction of a fusion reactor core will minimize radioactivity induced by neutron activation. This activity will be nonvolatile, and it can be isolated from the environment by the use of existing techniques. Because this induced activity is short-lived, it does not represent a long-term storage problem.

Anticipated thermal efficiencies of fusion powerplants range from present-day levels (30–40%) using standard conversion systems to about 50% when more exotic techniques (such as liquid-metal topping cycles) are utilized.

The belts of savanna lying to the south of the Sahara are described. Evidence is then presented which suggests that these have been created from forest by shifting cultivation and the use of fire: they have probably developed contemporaneously with the evolution of Man and increase in human population. The effect of climatic changes in creating desert are discussed, and the conclusion is reached that present conditions in much of the Sahara have been engendered almost entirely by human activities. These include felling of trees for firewood and charcoal, or to make their leaves accessible to stock in times of drought and, even more important, overgrazing—especially by goats. Finally, it is suggested that, in the long term, agriculture may not be the most promising way of developing arid regions. Overstocking the savanna and desert must inevitably lead to disaster.

Environmental and floristic evidence is presented to show that, after removal of the White Spruce (Picea glauca) and willow-alder (Salix spp.–Alnus crispa) canopies from exposed sites within the boreal woodland of the Mackenzie River Delta, Northwest Territories, Canada, environmental degradation is such that secondary succession of low-arctic tundra heath, mosses, and lichens, takes place. The extreme exposure of cleared sites enables a hardy group of tundra plants to compete with the local flora and invade the previously forested location.

Even if, as many of us believe, ‘there is time to avoid the abyss’ of non-survival, there is no time for complacency. Rather is there need for eternal vigilance, scientific monitoring, international legal and other enlightened controls, and often very costly action. For Man is inexorably changing the world, though often insidiously and quite unintentionally. Already he has the knowledge and wherewithal to control his numbers, effects, and very destiny, maintaining the biosphere for himself and to some extent for Nature; but has he the collective wisdom? And what are the limits of his folly? It might be thought that many of our chosen items touched on above are either local or not concerned with the environment as a whole, and hence would not constitute real ecodisasters; but when we look just a little ‘below the surface’, we realize that they could engender in the long run quite disastrous effects on the habitat and life support system of Man which, with his present all-too-heavy impress, could mean the far wider environment of Nature and even the entire biosphere. Meanwhile Man's objective in this age of ecological enlightenment should surely be to maintain optimum diversity in the biosphere—with due emphasis on the ‘optimum’ having regard to the direct needs of Nature as well as of himself.

With Man now the unquestioned superdominant of the world, yet continuing to increase his numbers to the extent of projected doubling in 30–40 years and doubling again thereafter, there are thrust upon us an ever-increasing number and burden of conceivable ecodisasters, many of which we have touched on above. Others can already be foreseen and yet others will doubtless emerge. None seems inevitable in itself, at least in widespread magnitude, and few appear to be at all likely; but still something has got to happen to check the projected mounting demomass, and it seems reasonable to expect it to be one or more of cur listed conceivabilities. Which this may turn out to be, presumably sparking otheis and altogether changing the world even more precipitously than has been the case of late, we can only conjecture.