Perhaps the most important cause for concern, fuelling most of the prophecies of doom, is the perceived deterioration of the environment. It cannot be denied that the natural world is affected by developments such as ozone depletion, deforestations, species extinction and the greenhouse effect. Since most of these development are side-effects of economic growth, many people tend to think that material progress necessarily goes together with ecological deterioration, so that we can no longer speak about global progress. Although some of these ecological problems are quite serious, we must make several qualifications to this pessimistic evaluation.
First, although industrial pollution negatively affects our health, these effects are much smaller than the positive effects brought about by medical advances and a higher standard of living. The on-going increase in life expectancy is incontrovertible proof of this assertion. The fear for different chemical products released in the environment by human activities is often out of proportion with the objective risks. One reason for this is that people tend to overestimate the dangers of artificial toxins in comparison with natural toxins. The fact that something is natural does not mean that it is safe: the traditional tests for carcinogenicity find a similar proportion of potentially cancer-producing chemicals among natural as among artificial products (Ames & Gold, 1997). The best way to reduce mortality from cancer and other "modern" diseases is to promote a more healthy life-style: regular exercise, no smoking, plenty of fruit and vegetables, and reduced consumption of red meat, saturated fats and refined sugars. These simple measures are likely to add several years to our life-expectancy, much more than any reduction in pollution or pesticide use could (Ames & Gold, 1997).
Second, although pollution on the world scale is still increasing, there is a clear trend towards decrease in the developed countries. Statistics for air and water pollution in major cities and regions in Europe and North America show a consistent improvement over the last decades (Simon, 1995). The London smog, which was a notorious killer in the beginning of the 20th century, has all but disappeared. At the same time, the Thames river is teeming with fish again. As economy and technology advance, more money and better techniques become available for minimizing pollution. As the general quality of life increases, people are less willing to undergo the effects of pollution, and more motivated to enjoy a pleasant, natural environment. This leads to more stringent laws on emission of pollutants, and to more encompassing disposal and recycling schemes. There is no reason why the same development would not take place in the poorer countries once they reach a higher level of development.
Third, the problems of global change, although serious, should be considered in the right perspective. The tackling of ozone depletion is an unexpected success story, where the scientific discovery of the destructive effects of CFCs on ozone was followed shortly by the observation of a growing "ozone hole" in the atmosphere, and by an international treaty for the phasing out of CFC production. The release of CFCs has been significantly reduced since, and is expected to stop completely in the next two decades. The ozone hole is predicted to reach its maximum size a few years from now, and start diminishing from then on.
The tackling of global warming by reducing the emission of greenhouse gases is much less forceful, though. International agreements have as yet hardly managed to slow down the increasing production of carbon dioxide by burning fossil fuels. However, the dangers of global warming need to be put into perspective. Recent scientific developments have made it clear that the temperature of the Earth has undergone many large fluctuations during the past thousands of years, and has at times been both significantly colder (the Ice Ages) and significantly warmer than it is now (Stock, 1993). The hypothesized increase of the average temperature with 1 to 3 degrees Celsius by the end of the 21st century would therefore not be unprecedented. Moreover, there is some reason to believe that life and civilisation were in fact thriving better during the warm periods (Moore, 1998), as higher temperatures and rainfall increased crop yields. Though global warming would create a number of problems, its overall effect may be positive rather than negative. If there are "losers" and "winners", then international solidarity can be organized to help the losers. Moreover, there are still plenty of alternative methods to tackle the increase in carbon dioxide, from "fertilizing" the oceans with minerals to boost the growth of algae, to the management of forests so that they absorb a larger amount of carbon-dioxide (Moffat, 1997). In any case there are still so many uncertainties concerning its intensity, effects, or possible ways to avoid it, that concern, further research, and vigorous precautionary action are in order, but pessimism seems inappropriate.
Perhaps the most serious environmental problem is the fast reduction in tropical rain forests, and the concurring loss of biodiversity. Although such losses seem largely irreversible, some qualifications are needed. First, loss of tropical forests is to some degree compensated by increase in temperate forests (Simon, 1995). As countries in the tropical regions get more economically developed, and curtail their demographic expansion, it is likely that they too will start to invest more in forest management, while reducing their need for farmland by increasing agricultural productivity. Second, the history of life shows that here too the Earth has witnessed very large fluctuations, both in forest cover and in species diversity (Stock, 1993). There have been periods where over 96% of known species have been extinguished, yet life always managed to recover and rediversify. With the growing number of natural reserves, increased protection of wildlife, and development of biotechnological means to maintain or increase biodiversity, it is unlikely that we will ever come near to such drastic levels of extinction. The key novelty is that for the first time mankind not only has the power to destroy the natural environment, but also the means to save it.