Fresh Studies Support New Mass Extinction Theoryby Jeremy Lovell, Reuters
Environmental News Network, March 19, 2004
LONDON -- Fears that Earth is undergoing a mass species wipe-out similar to that which destroyed the dinosaurs 65 million years ago gained new ground Thursday with the publication of two British studies.
They found that the rate of loss of insect and plant species across Britain was running at several times what would be considered normal, and had been doing so for a long time.
"The world is experiencing a new mass extinction," Andrew Sugden of Science International magazine told a news conference in London. "These studies are milestones in global change research."
The studies, funded largely by Britain's Natural Environment Research Council, are published in the latest issue of the journal Science.
Earth has undergone five mass extinctions in the last 600 million years, and scientists have speculated for some time that it is in the throes of a sixth.
The two studies of the losses of British butterflies, birds, and plant species by Jeremy Thomas of the Center for Hydrology and Ecology in southwestern England and Carly Stevens of the Open University give new backing for the theory.
"The current rates of extinction over recent centuries are a couple of hundred times greater than normal," Thomas said. "Most ecologists accept that we are approaching the rates of extinction seen in the past five mass extinctions."
Thomas found that 71 percent of butterfly species and 54 percent of bird species in Britain had experienced dramatic losses or extinctions, while Stevens found numerous plant species had already disappeared or were under severe stress.
And while all previous mass extinctions had been due to extra-terrestrial events, the culprit for the current wipe-out was far closer to home.
"As far as we an tell, this one is caused by one animal organism: man," Thomas said.
Habitat loss and degradation as well as human-made pollution were to blame for the steep declines, both scientists said.
In contrast to its impact on some species of flora and fauna, global warming had actually helped boost butterfly numbers by expanding their territory northwards, Thomas said.
"Yet despite this, most of the species have declined," he said. "If it wasn't for global warming the species loss would have been even greater."
Thomas said that while it was a giant leap to extrapolate from the findings on 58 species of butterflies in Britain to the millions of species across the world, it was justifiable.
While it was true that in the cases of the previous five mass extinctions life had bounced back strongly, it had done so over 5 million to 10 million years. That is the blink of an eye in geological terms but considerably longer when viewed against human life expectancy, said Thomas.
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