Studies of past climates show unequivocally what can happen to our atmospheric environment. From climatic history we can learn several very specific lessons.

The climate can change rapidly. Major climatic changes, such as the change from glacial to non-glacial conditions, can occur in a few centuries, even though the adjustment of biota and the wasting of continental ice-sheets may take longer. Smaller changes may take only decades.

Changed climatic states may persist for centuries or millennia. While the climatic excursion of this century appears to have lasted half-a-century or so, the ‘little ice-age’ was at least three centuries long (roughly 1550–1850 A.D.), a North American drought period lasted two centuries, and there was a monsoon failure of seven centuries. These have all been recorded in the evidence of Nature.

Climatic changes may occur in different senses in different parts of the world. This paper has outlined several cases where cooling in the sub-Arctic was associated with reduced rainfall or increased frequency of failure of the monsoon, and a case in which drought in North America was concomitant with wet weather in western Europe.

The climate we think of as normal is quite abnormal by the standards of the past few centuries, and the magnitude of the change since 1945 is significant by comparison with similar changes in the past.

Combining the nature of the recent climatic change with the present narrow margin of world food-grain reserves, an urgent need to consider and react to the possibility of continued climatic variation is indicated.

Plagues of caterpillars and other plant-feeding insects tend to occur where trees and other plants grow as man-made monocultures. Herbivorous insects rarely cause extensive damage to mature trees in tropical forests; but even in the tropics, outbreaks are frequent wherever trees of the same species are grown together—as for example along roadways and in built-up areas. In Africa, in particular, peasant cultivators growing their own food tend to plant a variety of species in the same plot, and it is suggested that these people have found by trial and error that polycultures are more resistant to insect damage than are monocultures. English flower-gardeners maintain polycultures in their herbaceous borders and are rarely troubled by insects, but vegetables are now grown as pure stands. This probably leads to a build-up of pests and a need to use pesticides, which of course is encouraged by the gardening and pesticide industries.

Although there remains considerable controversy over the precise relationship between species diversity and population stability, there is much circumstantial and some direct evidence that plagues of plant-feeding insects are much more likely in pure stands of vegetation than in diverse communities. What might be called the community ecology of peasant cultivation is little understood, and there is an urgent need for research before more and more land is converted to monocultures.

Although they were widely distributed during Cainozoic times, both the Sierra Redwood (Sequoiadendron giganteum) and the Coast Redwood (Sequoia sempervirens) became restricted to greatly reduced ranges in California (and, in the latter instance, southernmost Oregon) during the late Tertiary and Quaternary periods. Today, the Sierra Redwood occurs in about 70 scattered groves, occupying an aggregate of 144 km2 on the west slope of the Sierra Nevada; about 66% of the areas of these groves remain unlogged, and most of these virgin stands are protected within national parks.

Fire suppression policies of the National Park Service and other government land agencies have created conditions that are both unsuited for Sierra Redwood reproduction and hazardous to existing trees. Successful seed germination requires a mineral seed-bed, such as is usually exposed through fire. Burned sites also enhance seedling survival through increased sunlight penetration, reduced competition, and improved soil-moisture content. Fire suppression has, however, allowed the accumulation of large volumes of combustible fuels, increasing the probability of destructive crown-fires. In order to rectify these problems, the National Park Service has begun a programme of prescribed burning in Sequoia–Kings Canyon National Parks; to date, about 3.4 km2 have been treated. Thus, the environmental issues facing the Sierra Redwood involve perpetuating the tree within parks that are secure from commercial utilization.

Recent research has shown that many industrial projects are not being designed with the environment in mind. The intellectual exercise of thinking ‘what impact does this project have on the environment?’ has not yet been made an integral part of industrial project-planning. More thoughtful and informed planning is needed, for reasons of both sound environmental management and, increasingly, sound project economics. An environmentally-oriented mode of planning, in which inputs and means related to environmental concerns are carefully taken into account during the planning, is discussed. This mode represents a tentative summary statement of an emerging consensus. Its objective is to facilitate informed and socially desirable choice among alternative actions in such a manner that adverse environmental consequences will be avoided or at least minimized.

Environmentally-oriented planning requires that a new methodology, that of impact assessment, be fully integrated into the very fabric of planning. Impact assessment consists of three analytical functions: description, prediction, and evaluation. These functions can be translated into a series of tasks, which in their entirety constitute the full process of impact assessment. The process can be achieved operationally by incorporating environmental considerations into planning via five dimensions: multidisciplinary professional involvement, broad public participation, holistic thinking, systematic analysis, and continuous integration. Adoption and application of the process can be encouraged and/or facilitated by a number of internal organizational adjustments, or by external public-policy adjustments.

The use of current money-lending rates as the basis for economic calculations involving long-term assets such as growing timber, agricultural land, or species of wildlife, is unrealistic and can be very damaging to the interests of the environment. An alternative method, using an assessment of risks together with an assessment of the expected ratio of investment: income, is proposed.

Surveys of visitors to a moorland Nature Reserve in Yorkshire, England, were carried out in 1968 and 1973. The major change during the five-years' period is that visitors have increased their interest in conservationally desirable improvements, such as the construction of hides, and have reduced their demand for such amenities as tea-rooms and toilets. It is concluded that the establishment of a picnic site and the creation of a nature trail have made the area more accessible to the general countryside user while not destroying the wildlife conservation potential of the habitat.

This paper continues an earlier discussion of the hazards of nuclear fission, and of the choice of alternatives (Edsall, 1974), in Environmental Conservation, 1(1), pp. 21–30. Important changes have recently occurred in energy policy in the United States. The Energy Research and Development Administration (ERDA), whose mission is to promote the development of all promising forms of energy production, has replaced the Atomic Energy Commission (AEC). A Nuclear Regulatory Commission, independent of ERDA, has been set up. The proposed ERDA budget, however, is largely dominated by the very heavy costs of research and development for the liquidmetal fast breeder reactor (LMFBR). The AEC, in one of its last acts, produced a voluminous environmental impact statement on the LMFBR. A preliminary version of this statement (spring 1974) was sharply and widely criticized as inadequate, and as highly biased in favour of the breeder. The revised statement is now under critical review (March 1975). The AEC has also produced a comprehensive report (the Rasmussen report) on the safety of the current light-water reactors in use in the U.S.A., with the conclusion that a major accident in a nuclear power-plant is so unlikely as to be almost negligible by comparison with other hazards of daily life. It does not consider the hazards of radioactive waste disposal, or of theft and sabotage. Critics have pointed to what they consider grave flaws in the reasoning of the Rasmussen report, so the matter is still highly controversial.

A major challenge in developing programmes for professional education in environmental management is presented by the need to determine how the vast amount of scientific and professional knowledge required for effective environmental management can be efficiently transmitted to prospective or practising ‘environmental coordinators’ in the private and public sectors of society. This paper describes the work conducted at M.I.T., in collaboration with C.E.I., to provide a conceptual and substantive base for such programmes.

The conceptual framework is based on a simplified model of the decision-making steps in environmental management processes. Such a model can be used for isolating certain types of decisions and roles in different social, cultural, administrative, or political, contexts. When once this has been done, the responsibilities and the educational needs of specific classes of ‘environmental managers’ can be identified through studies and interviews.

The substantive base for new educational programmes requires the development of outlines and the identification of reference material for the major bodies of knowledge that comprise the ‘field’ of environmental management. This paper briefly describes the major subject-areas treated in this study: values and perceptions, ecology, environmental effects, environmental indicators, environmental impact assessment methodology, modelling, monitoring, growth and its implications for the future, economics of externalities, environmental law, and administrative processes.

The approach and materials described in this paper are now being used at C.E.I, in the development of educational programmes for practising professionals, and at M.I.T. for graduate and undergraduate students in a variety of disciplines. Thus far, these efforts have been well received and have provided additional information with which to continue designing additional programmes.

Plants are major factors conditioning an environment, and conservation of particular environments depends fundamentally on the maintenance of existing plant communities. In many parts of the world, the destruction of such communities is occurring so rapidly and so completely that entire natural systems are subject to, or threatened with, total destruction. In such cases artificial methods of conserving plant germplasm for ultimate regeneration, for supplementing natural populations, for study, or for use by Man as an economic resource, may be of great significance as one possible means of averting total loss. Under less extreme pressures, the availability of representative propagules of significant taxa or populations may be of crucial assistance as an aid to research directed towards a better understanding of factors affecting survival or competitive advantage in the wild, or as a means of providing stocks for assessment of the potential economic value of existing reserves of wild species.

This paper discusses methods of recording, maintaining, and evaluating, collections of populations of wild species. Plant resources of this kind are extremely vulnerable when maintained under artificial conditions, and a very high proportion of collections are lost within a few years, remain unavailable for general use, or fail to be used owing to inadequate documentation. Conservation of plant germ-plasm as an international resource, in a usable form, depends on a wide acceptance and practice of greatly improved methods of documentation, and requires the creation of effective organizations for surveying, maintaining, and coordinating, plant resources on an international scale.