1. The ozone layer

A major factor in maintaining the world's existing ecohabitat is a con­centrated layer of ozone gas approximately fifteen miles above the earth's surface. This acts as a shield preventing a harmful quantity of the sun's ultra-violet rays from reaching the earth. It is only in recent years that appropriate technology has enabled the ozone layer to be measured, but during this time it has become evident that it is decreas­ing steadily and substantially. It is also known that chlorofluorocarbon gases (CFCs) destroy ozone molecules. These are being produced and used especially as refrigerants, in the production of foam plastics, and in aerosols. If the depletion of the ozone layer and the creation of 'ozone holes' were to continue, the increased impact of ultra-violet rays could affect not only the animal food chain, but also human health; and whereas cause and effect cannot be conclusively proved there is suf­ficient reason to justify a total and worldwide ban on CFCs which also have an effect on global warming.

As a result of initiatives in this direction, the Vienna Convention for the protection of the Ozone Layer was signed in 1985, followed by the 1987 Montreal Protocol on Substances that Deplete the Ozone Layer, as amended in June 1990. Incremental costs relating to the phasing out of CFCs can be funded in developing country signatories from the Montreal Fund which was established by the Montreal Protocol. The European Union and oilier major industrialised countries have agreed to forbid the manufacture and use of CFCs.

2. Global warming and the

GREENHOUSE EFFECT

hereas change is the essence of the earth's climate, whether in cycles of decades, centuries or millennia, it remains a fact that the rapidly increasing use of fossil fuels could result in unexpected and dangerous consequences; resulting products such as carbon dioxide, methane and nitrous oxide are known to trap heat and create a 'greenhouse' effect. There is always the possibility that global warming might trigger off unexpected and potentially disastrous changes, but its main impact would be to alter the regional emphasis of the world's climate and conse­quently the agriculture - with unknown social and political consequences - and gradually raise the level of the seas and influence ocean currents and marine life.

The major cause of global warming is judged to be the use of fossil fuels - oil, lignite, coal, and wood - mainly in industry, transport and the generation of electricity, but also for domestic purposes; but reserva­tions in respect of the use of nuclear fuels prevent serious reduction of the output of carbon dioxide. Funds for the reduction in growth of global warming gases are to be made available by donor countries through the Global Environment Facility, a joint organisation of the World Bank, the United Nations Development Programme and the United Nations Environmental Programme.

3. Biodiversity

The relatively recent discovery of DNA has opened up the field of genetic engineering, with its prospects of worldwide benefits especially in medicine. Bio-technology, however, is dependent upon the preserva­tion of biodiversity - the vast number of different forms of life existing on the planet - and the ability to have access to such sources. These two matters - preservation and access - more particularly the financial basis on which access is permitted, were the subject of the Convention on Bio-Diversity signed at the 1992 Earth Summit in Rio de Janeiro.