| Summary: | There can be no clearer illustration of the need for human beings to act globally than the issues raised by the impact of human activity on our atmosphere. That we all share the same planet came to our attention in a particularly pressing way in the 1970s when scientists discovered that the use of chlorofluorocarbons (CFCs) threatens the ozone layer shielding the surface of our planet from the full force of the sun's ultraviolet radiation. Damage to that protective shield would cause cancer rates to rise sharply and could have other effects, for example, on the growth of algae. The threat was especially acute to the world's southernmost cities, since a large hole in the ozone was found to be opening up each year over Antarctica, but in the long term, the entire ozone shield was imperiled. Once the science was accepted, concerted international action followed relatively rapidly with the signing of the Montreal Protocol in 1985. The developed countries phased out virtually all use of CFCs by 1999, and the developing countries, given a 10-year period of grace, are now moving toward the same goal. Getting rid of CFCs has turned out to be just the curtain raiser: the main event is climate change, or global warming. Without belittling the pioneering achievement of those who brought about the Montreal Protocol, the problem was not so difficult, for CFCs can be replaced in all their uses at relatively little cost, and the solution to the problem is simply to stop producing them. Climate change is a very different matter. The scientific evidence that human activities are changing the climate of our planet has been studied by a working group of the Intergovernmental Panel on Climate Change (IPCC), an international scientific body intended to provide policy makers with an authoritative view of climate change and its causes. The group released its Third Assessment Report in 2001, building on earlier reports and incorporating new evidence accumulated over the previous five years. The report is the work of 122 lead authors ...
|
|---|