Tuesday, February 12, 2008

Nine climate change tipping points

Most cats have nine lives so the saying goes. It is somewat ironic that sientists have come up with no less then nine serious tipping points, each one of them serious events that may trigger larger scale collapse.

Here are the earth's 'nine deaths' according to an article on climate change tipping points in The Independent:

* Arctic sea ice: some scientists believe that the tipping point for the total loss of summer sea ice is imminent.
* Greenland ice sheet: total melting could take 300 years or more but the tipping point that could see irreversible change might occur within 50 years.
* West Antarctic ice sheet: scientists believe it could unexpectedly collapse if it slips into the sea at its warming edges.
* Gulf Stream: few scientists believe it could be switched off completely this century but its collapse is a possibility.
* El NiƱo: the southern Pacific current may be affected by warmer seas, resulting in far-reaching climate change.
* Indian monsoon: relies on temperature difference between land and sea, which could be tipped off-balance by pollutants that cause localised cooling.
* West African monsoon: in the past it has changed, causing the greening of the Sahara, but in the future it could cause droughts.
* Amazon rainforest: a warmer world and further deforestation may cause a collapse of the rain supporting this ecosystem.
* Boreal forests: cold-adapted trees of Siberia and Canada are dying as temperatures rise.

Knee-jerk reactions to such natural shocks will only aggrevate the situation. How to make decisions under such complex uncertainties is an area that warrants far more attention.

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