Scientist warns of sixth great extinction

Posted: 17 January 2002

"There is little doubt that we are standing on the breaking tip of the sixth great wave of extinction in the history of life on earth" says the eminent scientist, Lord May, former Chief Government Scientist in the United Kingdom.

Lord May, who is President of the Royal Society, calculates that birds and mammals are probably becoming extinct 100 to 1000 times faster than the average over many millions of years.

The reason was that humans are consuming somewhere between a quarter and a half of all plants grown last year, he told at audience at the London Natural History Museum, in London, in November 2001.

"The fact that we have more land under cultivation and do it more intensively enables us to get closer to and closer to the dream of agriculture since its dawn, which is to grow crops that no one eats but us, not shared with weeds or insect pests. That has implications all the way down the food chain for biological diversity," he said.

Looking ahead, he said we do not know with any certainty within a factor of 10 how many plants and animals there are alive. "So anyone who tells you the number of animals going extinct this year is an idiot." But the extinction rate was going to increase over the coming century. "An extinction rate 1000 times above the background rate puts us in the ballpark of the acceleration of extinction rates that characterised the big five extinctions in the fossil record, such as the thing that killed the dinosaurs."

Lord May said he was not so concerned about the potential loss of the raw material for biotechnology, since in 20 years humans would be able to design their own medicines. But there was a broad argument that humans depended on services from nature – the cost of cleaning water and pollinating crops by natural means were worth at least the entire gross domestic product of $30 trillion, he said.

However, he doubted that humans would really make a mess of it. "I think it is possible hat that we are clever enough to live in a hugely simplified world."

The core of the problem, he added, was that we do not have any evolutionary experience to act today on behalf of the distant future. "And there are no easy answers."

  • Some event near end of the Ordovician period, 440m years ago, wiped out almost all corals and fish, and 25 per cent of all families of creatures.

  • Near the end fo the Devonian period 370m years ago, many species of fish and 70 per cent of marine invertebrates perished.

  • At the end of the Permian period 225m years ago, between 80 per cent and 96 per cent of all living marine species were extinguished.

  • The Triassic period ended 210m years ago with another mass extinction of sea creatures, and some land animals as well.

  • The Cretaceous period ended 65m years ago with the obliteration of the dinosaurs. Many physicists suspect the Earth suffered a direct hit from an asteroid or that a comet could be to blame for extinction.
© The Guardian (United Kingdom), November 29, 2001.

Source: The Guardian (United Kingdom), November 29, 2001.