Tuesday, January 11, 2011

Learn from history

Ancient Mass Extinctions Hint at Possible Ocean Future
In sediment traces and fossil records from one of Earth’s most tumultuous periods, geologists have found a narrative linking mass extinctions with planetary biological and geological change.


After dramatic oceanic extinctions 250 million and 200 million years ago, the global carbon cycle turned chaotic. Earth’s biogeochemistry went boom and bust for millions of years thereafter, as if some regulating mechanism were lost — which is exactly what happened.


“People talk about saving biodiversity, and isn’t it good to have a variety of all these creatures. But the reason it matters is because ecosystem function is itself dependent on diversity in the face of normal environmental changes,” said geologist Jessica Whiteside of Brown University. “Lower diversity too much, and the system will lose its resiliency. It will become a slave to otherwise minor environmental changes.”


Scientists say that another mass extinction is now underway, with extinction rates an order of magnitude higher than normal, both on land and at sea. Studies like Whiteside’s suggest what the extinction’s consequences could be — not just for people, on a scale of decades or centuries, but for how the planet will work, millions of years in the future.
Pole shifts, severe weather, mass bird deaths.... Mother Earth is telling us something.

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