Several controversial statements on climatic change have been issued in recent years by various bodies and individuals, and some governments have expressed concern about the grave implications, for global food and population policies, of possible climatic changes. It was accordingly decided by the Seventh World Meteorological Congress (Geneva, April–May 1975) that WMO should take the lead in promoting studies of climatic changes, and should issue authoritative statements on the subject. The first such statement has been approved by the WMO Executive Committee which recently concluded its annual session in Geneva. This statement, and the technical report on which it is based, are now published below. The technical report was prepared by the Executive Committee Panel of Experts on Climatic Change.

The failure of conventional waste-treatment methods to solve problems associated with complex industrial wastes, suggests that we must re-examine our approach to this problem. Two distinct types of biodegradation, homogeneous and heterogeneous, have been recognized to occur in the environment and are distinguished according to the solubility or insolubility, respectively, of the compound involved. Unfortunately, many of the most persistent toxic compounds fall into the second or insoluble category, and conventional treatment processes are inefficient in dealing with them.

Our studies have shown that the primary site of the biodegradation of these persistent compounds is at the substance–water interface and that the rate of such biodegradation can be greatly increased if the tested compound can be suspended in an aqueous phase as a fine stable emulsion. Our recent work on PCB biodegradation exemplifies the benefit of a multidisciplinary approach in solving environmental problems, and supports the need to continue fundamental research in such areas of applied environmental science.

The development of methods for evaluation of industrial development by investigation of its ecological and health, as well as its social and economic, effects was the aim of UNEP/UNIDO Project EP/INT/73-002. Following six weeks' study of the cotton textile industry in Thailand, recommendations were made regarding criteria, team composition, and methods of utilizing existing information and conducting interviews. Interviews with village people and farmers were found to be a feasible method for qualitative assessment of environmental effects, and for providing information on which losses could be estimated. In all cases the costs of prevention or mitigation of damage were small in comparison with estimated costs of the damage caused.

The paper suggest that developing countries have the opportunity to industrialize without the trauma of extensive damage to health or environment, and that such development is not intrinsically more costly than other types in financial terms. It does, however, demand better understanding of the social, economic, and environmental, characters of a locality before planning begins. In many countries, including Thailand, existing university and other resources, assisted by interviews with the communities concerned, can provide the information required for this understanding, and therefore the delay need not be great.

The quantities and kinds of sediment that have accumulated in Frains and Murray Lakes, Michigan, over known intervals of time, provide a measure of erosion from the watersheds. This study has focused on the ash-weight of sediment and has derived estimates of ‘sediment yield’ from the landscape, though estimates of sediment yield from watersheds have seldom been made from the quantity of sediment accumulating in natural lakes. An exception is Mirror Lake, New Hampshire, where estimates from a core could be compared directly with sediment yields monitored in the last few years in experimental watersheds in the surrounding Hubbard Brook Forest (Likens & Davis, 1975). Detailed study of sediment cores can yield much more information than has been presented here. The chemical constituents of the sediments yield information about the chemistry of lake water and runoff from the watershed, while the remains of phytoplankton that are preserved in the sediment show the progress of eutrophication. A recent study of pre- and post-settlement sediment at Linsley Pond, Connecticut, is an example of a multidisciplinary approach to the determination of human influences on lake history (Brugam, 1975).

The data from Frains Lake permit a reconstruction of erosional events since Man arrived on the scene. The result is similar to Wolman's (1967) history of erosion in the vicinity of Baltimore, Maryland; his reconstruction, however, was based entirely on analogy with modern watersheds that were experiencing different kinds of land-use at the current time. Thus his estimate of pre-settlement erosion, for example, is tentative because there are no undisturbed watersheds today to measure for comparison.