Just as we all die, all species eventually go extinct. However, the rate of extinction varies dramatically, and a new estimate suggests we are currently running at 1000 times the normal rate. This rate of extinction is only seen in the fossil record after incredibly dramatic and unusual occurrences, such as huge asteroid strikes or supervolcano eruptions. In order to calculate the effect humans are having we need to know two things – how many species are disappearing each year, and how many vanish as part of the normal background. Professor Stuart Pimm of Duke University has published a paper in Science in which he and his coauthors, “Document what we know, how it likely differs from what we do not, and how these differences affect biodiversity statistics.”
Pimm's new estimate is that the background rate is 0.1 extinction per million species per year. This is a tenth the figure produced in 1995, in what had been considered the definitive paper on the topic. However, there will be no pushback from the authors of the higher estimate – Pimm was one of the authors of the 1995 paper as well. The rate today is between 100 and 1000 extinctions per million species per year. In other words our way of life may be 10,000 times more deadly than all the threats faced by animals at other times. Climate change, hunting and invasive species are all playing a part, but Pimm says habitat loss is the largest factor.
A combination of habitat protection, captive breeding and action on climate change can avoid a sixth mass extinction.
Kemo D. 7