Saturday, February 9, 2008

Putting it all together

There are people who are looking at the actual results of climate change and the picture they find is not pretty.

Scientists identify 'tipping points' of climate change

Nine ways in which the Earth could be tipped into a potentially dangerous state that could last for many centuries have been identified by scientists investigating how quickly global warming could run out of control.

A major international investigation by dozens of leading climate scientists has found that the "tipping points" for all nine scenarios – such as the melting of the Arctic sea ice or the disappearance of the Amazon rainforest – could occur within the next 100 years.

The scientists warn that climate change is likely to result in sudden and dramatic changes to some of the major geophysical elements of the Earth if global average temperatures continue to rise as a result of the predicted increase in emissions of man-made greenhouse gases.

I think the specifics are worth noting; many of them are outside the perview of scenarios already presented.

Irreversible changes

* 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.

Link

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