Trade in tropical timber, while a minor cause of deforestation in the tropics, can be a substantial factor in promoting forest degradation and deforestation. International organizations and conferences increasingly recognize that adverse environmental effects of international trade can be reduced through regulations and economic incentives. Three international agreements, the GATT, the CITES, and the ITTA, now affect the tropical timber trade and are here reviewed. Adopted at different times, they illustrate different philosophies, pursue different objectives, and develop contradictory trade policy perspectives. Legal conflicts among these agreements reduce their effectiveness, and mitigate a global objective of making international trade in tropical timber more responsive to environmental issues. Harmonization among the GATT, the CITES, and the ITTA, and collaboration among organizations in charge of managing these agreements, should be reinforced in order to establish a coherent and uniform policy for tropical timber trade.

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.

The Soviet Union's Crimean peninsula in the Black Sea has the northernmost occurrence of Mediterranean-type climate and vegetation, particularly in its narrow southern coastal strip which has been almost entirely developed for the tourist and health resort trade. Three inland mountain ranges and their vegetation, both forest and steppe, exert a protective influence over the microclimates of the coast and are thus being extensively studied by scientists at the Ministry of Agriculture's Nikita Botanical Garden and at Simferopol State University. Inland of these ranges lies an expanse of former meadow-steppe that is now under cultivation.

In order to protect and study the high concentrations of remaining native and relict taxa of flora and fauna of the peninsula, three Nature preserves have been established on it–two in the mountain zone and northern coastal islands, and one along the southern coast and adjacent lower slopes. Here human access is restricted while long-term ecological studies are undertaken.

The Nikita Botanical Garden is involved in both conservation and exploitation of natural resources, and in improving health conditions of the resort. These tasks are integrated through a programme of mass seed propagation and ecological studies of wild-growing plants, the results of which are then used in landscaping the resort zone and producing industrial plant materials.

This article examines, through a molecular perspective, the ‘ozone-friendly’ refrigerants R-134a and R-123 vis-à-vis R-12 and R-11, which are targeted to be phased out under the Montreal Protocol on Substances that Deplete the Ozone Layer, Final Act (1987). It appears that the molecular weight, size parameter, and dipole moment, of R-134a and R-123, may induce a pronounced effect on the chemical equilibrium of ice particles in the polar stratospheric clouds and subsequently influence the photochemical reactions therein.

Non-polar, high-molecular-weight perfluoropropane (R-218), could be a better substitute for R-12, while R-134, which is a non-polar HFC of the ethane family, could also be a candidate although its molecular weight is lower than that of R-12. The search for a good substitute for R-11, however, must continue.

Representatives of national academies of science from throughout the world met in New Delhi, India, from 24 to 27 October 1993, in a ‘Science Summit’ on World Population. The conference grew out of two earlier meetings—one of the Royal Society of London and the United States National Academy of Sciences, and the other being an international conference organized by the Royal Swedish Academy of Sciences. Statements published by both groups expressed a sense of urgent concern about the expansion of the world's population and concluded that if current predictions of population growth prove accurate and patterns of human activity on the planet remain unchanged, science and technology may not be able to prevent irreversible degradation of the natural environment and continued poverty for much of the world.