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Stratospheric Ozone and Human Health Project

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The Montreal Protocol on Substances that Deplete the Ozone Layer requires, in Article 6, periodic assessments of available scientific, environmental, technical and economic information. The assessments shall be made at least every four years. In fact, assessments were made in 1989, 1991 and, the present one, in 1994. This 1994-Assessment on Environmental Effects is written so that it can be read without having the earlier reports at hand.

The provisions in the Montreal Protocol and its amendments in London (1990) and Copenhagen (1992) have brought about a marked decrease in production and use of ozone depleting chemicals. However, the ozone layer is still becoming thinner, and this is expected to continue until about 1998. Thereafter, a gradual recovery is predicted, but the layer will be damaged for half a century to come. These predictions were made by the Atmospheric Science Panel on the basis of a fairly optimistic scenario, including the assumptions that there will be full and worldwide compliance with the Copenhagen amendments, that no ozone depleting chemicals were overlooked, and that there will be no new threats to the ozone layer.

The present assessment deals with the consequences during the coming decades: the changes in solar ultraviolet radiation reaching the Earth's surface, and the effects on humans, animals, plants, micro-organisms, air quality and materials. A welcome new element, compared with the earlier assessments, is a special chapter on biogeochemical cycles. The main questions from a policy point of view are now: what will be the most important effects, and what can be done to prevent or mitigate these?

These questions are more difficult to answer than those posed initially when the problem of ozone depletion arose. Then the question was, will there be any effects so detrimental as to necessitate protection of the ozone layer? In principle, this could be answered by giving one or two clear-cut examples. The present questions are much broader, and require quantitative knowledge on all effects of potential importance.

Organized science recently paid special attention to the problems posed by ozone depletion. SCOPE, the Scientific Committee on Problems of the Environment (formed by the International Council of Scientific Unions) produced two reports on Effects of Increased Ultraviolet Radiation, one on Biological Systems (1992) and one on Global Ecosystems (1993). SCOPE urges that these important and complicated problems require full utilization of existing research capacity, and a major expansion.

Reality is far from these goals. Funding for research on effects of increased UV-B radiation is so low that it does not even allow full utilization of the research capacity available. This implies that answers to urgent questions cannot be given as quickly as should be possible. We are glad that in spite of these limitations, scientific understanding of the problem is growing, as will be apparent from all chapters in the assessment.

J.C. van der Leun
X. Tang
M. Tevini

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