Hot, dry planet. Rate of extinction: zero. Life: extinct!
Civilization does not seem to alter us. Quite the opposite! Humans have savagely hunted down the animals with which they share the globe since they discovered technical ways of compensating for their puny bodies. In historic times humans have exterminated many varieties of animals and birds, though some of them, like the bison, existed in vast numbers.
Myers highlights the rapidly increasing rate of destruction as technology has improved:
As a primitive hunter, man proved himself capable of eliminating species. From the year AD 1600, however, he became able, through advancing technology, to over-hunt animals to extinction in just a few years.
The rate of extinction of species of mammals and birds (not counting lesser creatures and plants) increased from one every four years from 1600 to 1900 AD to one every year in most of the present century. By 1974 writers in Science magazine considered that 1000 species of all kinds were becoming extinct every year. If the tropical forests are substantially cleared:
By the end of the century we shall have lost one million species, possibly many more. Except for the barest handful, they will have been eliminated by the hand of man. (Myers)
This compares with estimates of one species every 1000 years during the mass extinction of the dinosaurs, though the latter must be a serious underestimation because very many species existed—and died—without leaving any remains. Millions of creepy crawlies must have died without trace—and plants. And, for those we do know about, there must also be some degree of averaging over a long time period of much more sudden extinction events because of the generally poor resolution of time in old rocks. When the time resolution is better because deposition was copious, we find that extinction in the Cretaceous could occur extraordinarily rapidly—for some species at least.
J Smit and J Hertogen found that there were no significant changes in the deposits of foraminifera species for over 600 feet in the KT boundary layer, representing millions of years in time, but they disappeared in a fraction of an inch representing “about 200 years”. Mankind’s ability to kill off marine and aquatic species in bulk has developed since the start of the industrial revolution about 200 years ago.
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