The Fagile Species

At a national meeting of biologists and biogeographers held in Arizona in August 1983, the history and dynamics of extinction were the topics of discussion. The consensus was that the number and diversity of living species may be on the verge of plummeting to a level of extinction matching the catastrophe that took place 65 million years ago, and that this event will probably occur within the next hundred years and almost certainly before two hundred years. It will be caused, when it occurs, by the world-wide race for agricultural development, principally in the poorer countries, and by the appalling rate of deforestation. Although tropical forests cover only around 6 percent of the earth’s land, they harbor at least 66 percent of the world’s biota, animals, plants, birds and insects. They are currently being destroyed at the rate of about 100,000 square kilometers per year. Elsewhere on the planet, urban development, chemical pollution and the steady increase in atmospheric carbon dioxide are posing new problems for multitude of species. The animal species chiefly at risk for the near term is humankind. If there is to be a mass extinction just ahead, we will be the most conspicuous victims. Despite our vast numbers, we should not be classify ourselves as an immediately endangered species, on grounds of our total dependence on other vulnerable species for our food, and our simultaneous dependence, as a social species, on each other. ~ Page 121

But do not worry about the life of the earth itself. No extinction, no matter how huge the territory involved or how violent the damage, can possibly bring the earth’s life to an end. Even if we were to superimpose on the more or less natural events now calculated to be heading toward a mass extinction the added violence and radioactivity of a full scale, general nuclear war, we could never kill off everything. We might reduce the numbers of species of multicellular animals and higher plants to a mere handful, but the bacteria and their resident viruses would still be there, perhaps in greater abundance than ever because of the expanding ecosystems created for them by so much death. The planet would be back where things stood a billion years go, with no way of predicting the future course of evolution beyond the high probability that, given the random nature of evolution, nothing quite like us would ever turn up again. ~ Page 122