More proof that human beings are party to our own demise, but will we act?
Gwynne Dyer says with a mass extinction now under way, as a study reports, human survival is doubtful if we don't change our profligate ways
There are examples of species all over the world that are "essentially the walking dead", said Stanford University professor Paul Ehrlich. "We are sawing off the limb that we are sitting on."
He was talking about the sixth mass extinction, the huge loss of species that is under way right now. It has been discussed in public before, of course, but what Ehrlich and other scientists have done is to document it statistically.
Animals and plants are always going extinct, usually to be replaced by rival species. But the normal turnover rate is quite slow, according to the fossil record. Ehrlich and his colleagues deliberately raised the bar, assuming that the normal rate is twice as high - and still got an alarming result.
In a study published this month in , they report that vertebrates are going extinct at a rate 114 times faster than normal.
"We are now entering the sixth great mass extinction event," said Gerardo Ceballos of the National Autonomous University of Mexico, lead author of the study. "If it is allowed to continue, life would take many millions of years to recover and our species itself would likely disappear early on." Indeed, biologist E. O. Wilson has estimated that, at the current rate of loss, half of earth's higher life forms will be extinct by 2100.
It's fair to say that we are the victims of our own success, but so is the entire biosphere. There were one billion of us in 1800. We are now 7½ billion, on our way to 10 or 11 billion. We have appropriated the most biologically productive 40 per cent of the planet's land surface for our cities, farms and pastures, and there's not much room left for the other species.
