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.

Human population growth is clearly outstripping the possibilities of increasing the supply of food and other prerequisites for satisfactory existence. Already, with around four thousand million people on Earth, the race appears to have been lost by agriculture. The prospect of doubling this population by shortly after the turn of the century is bleak indeed. It is the belief of many, however, that zero population growth will be reached earlier by a catastrophic increase in the number of deaths—most probably from starvation. This also bodes ill for conservation; for as people get more and more hungry, their behaviour towards wildlife and what remains of the natural environment is going to become more and more reckless. The destruction of both wildlife and its habitat may be expected to extend to quite devastating proportions, which will require understanding action in both over- and under-developed countries to counter with any degree of success.

Man is inexorably changing the face of the Earth and weather patterns in directions which could have all manner of widespread ill-effects, and already have had some catastrophic local ones. Yet more and more of the world's productive lands are being paved with concrete, and the productivity of even wider areas is being permanently lost through erosion and laterization following the clearing of forests and other binding vegetation. Simultaneously, many strains of crop plants are being lost which are essential to humanity because they enable plant breeders to develop new agricultural varieties to help keep abreast of changes in pests and weather, and to raise production levels.

Nuclear fission reactors are widely regarded as the chief energy source of the future. This article holds that the hazards of such reactors, in comparison with other prospective energy sources, are unacceptably high. The biological effects of ionizing radiations, as analyzed in the recent BEIR Report (1972) of a committee of the U.S. National Academy of Sciences, are briefly reviewed; the effects include genetic mutations, induction of cancer, and developmental abnormalities. Hazards are encountered at many stages in the process of nuclear power production: in the mining and processing of uranium, in the design and operation of the reactors, and in the handling, shipping, and storage, of the huge quantities of radioactive wastes produced by the reactors. Grave questions have been raised concerning the safety of the emergency core-cooling systems of present reactors; and the planned breeder reactors, which will contain great quantities of plutonium-239, are likely to be even more hazardous. Storage of radioactive wastes, away from all risks of environmental contamination, in order to be acceptable must be secure for about half-a-million years. No place on Earth has yet been found for which such safety can be guaranteed. Hazards of theft, sabotage, and war, are formidable threats to the future of nuclear fission power.

Use of fission power is not compulsory; present supplies of coal are adequate for two or three centuries, though its mining and use will require drastic steps to protect the environment, thereby raising costs. Alternative, and far less dangerously polluting, sources of large-scale energy production exist or can be developed: notably solar energy and probably nuclear fusion, where intensive research gives high promise of adequate systems for large-scale energy production within 20–30 years. Geothermal energy, though more limited in amount, is also promising. Great savings can also be made by reducing the extravagant use of energy, especially in such countries as the United States; and various conservation measures are indicated.

Besides areas with primeval Nature, it is also necessary to protect man-made ecosystems. Under European conditions it is particularly important to turn into protected areas some near-natural landscapes which have never undergone great changes in land-use. One of these territories in the eastern Baltic region is the area of Matsalu Bay, which since 1957 has been the site of the largest Baltic nature reserve, possessing highly specific and valuable ecosystems. The Matsalu landscape is characterized by pasture lands, moist meadows, vast reed-beds, wooded meadows, and juniper groves, which have all been subjected to extensive human influence in the course of several centuries. Under contemporary conditions of management the preservation of these landscape types is somewhat difficult, but it is necessary to find suitable measures to effect it.

To sum up, the dereliction of industrially damaged land will be overcome by the natural processes of weathering, erosion, and leaching, moderated selectively by the influence of vegetation. Old pit-dumps in the Forest of Dean, ancient quarries as at Barnack in Lincolnshire, and the old peat diggings that now constitute the Norfolk Broads, all bear witness to the healing of man-inflicted destruction, given time. But in such a small country as Britain, with such a crowded population, we cannot leave these damaged areas for a sufficient length of time to heal naturally. Instead, we can, and we must—in the interests of health, good living, and the conservation of our assets in land—minimize the destruction which we leave behind, and ensure the conditions under which natural processes will most effectively and most speedily repair such damage as we cannot repair ourselves. So we must establish a landform appropriate to the use to which the land is to be put. We must ensure the adequacy of mineral nutrients for the soil which we wish to regenerate. And we must establish a vegetation that will contribute to those soil-forming processes whereby toxic elements are leached and nutrients retained.

Visitors to Spurn Nature Reserve, located at the south-east tip of Yorkshire, England, were surveyed during the summer holiday season of 1970. It was estimated that about 3,400 groups of people visited the Reserve in the three months of July, August, and September. Only 17% of the visitors were members of the Yorkshire Naturalists’ Trust, which owns the Reserve, and only 12% of the visitors—mostly bird-watchers—came primarily for purposes of nature study. Pressure from the visitors was found to be concentrated, because of topographical and vegetational features, in areas where it could potentially do great harm to the wildlife and to the physical stability of the habitat itself. Examination was made of methods that might be used to control the total number of visitors and their effect upon the environment.

Economic analysis using the Clawson Demand Schedule, gave a Recreational Value for the Reserve of about £2,000 for the three months of this survey. The example would seem noteworthy for other comparable areas as population pressures and tourism increase.

The Lake Wingra Study is an integrated, interdisciplinary programme which has been developing mathematical models of the hydrological, biological, and nutrient, cycles in a man-modified lake-basin in Madison, Wisconsin, USA. Computer simulations based on these models promise to aid in the prediction of urban impact on the land-water systems within the Lake Wingra basin. Such information should also increase the effectiveness of environmental quality management in Lake Wingra and similar watersheds. So far, the greatest success has been the development of process models which describe individual components of highly complex ecosystems. Examples include models of nutrient cycling and the growth of Algae, aquatic weeds, and fish. Further work on synthesizing individual process models of the Lake, and integrating this information with data from other United States and foreign sites, will receive top priority from the Lake Wingra scientists during 1974.

Travel in the Arctic is nowadays predominantly by aircraft or by specifically designed overland vehicles, as few roads exist. Terrain damage resulting from off-road vehicular movement in arctic areas is potentially serious—particularly in the wetter, ice-rich permafrost terrain. Detailed examinations of vehicle trails made in the 1940s indicate that natural recovery and stabilization of these trails has been relatively slow. Several recent controlled tests using a variety of vehicles suggest that long-term impact of the vehicles on the terrain is a function of time of year, type of substrate, vegetation, soil moisture, ground-contact pressure, type of vehicle propulsion (i.e. tracks, air-cushion, etc.), and operator technique.

The pollution of the marine environment by plastics such as polyethylene, polyvinyl chloride, polystyrene, and polyurethane, is discussed. As plastic materials are relatively resistant to oxidative ageing and are generally not degraded by microorganisms, they will accumulate in coastal and oceanic waters. The origin of plastic pollutants, their distribution in the marine environment, and their persistence and ultimate fate, are largely unknown. The technology is available to manufacture plastic materials with a programmed service life which, if widely adopted, would reduce the accumulation of plastics in the sea. But their random distribution should be discouraged on behalf of the marine environment.