Nine catastrophes
Scientists investigating how quickly global warming could run out of control have now identified nine ‘tipping points’.
Each of these could tip the planet into an increasingly dangerous state that could last for many centuries.
A major international investigation by dozens of leading climate scientists has found that the “tipping points” for all nine could occur within the next 100 years.
A tipping point is defined as the point where a small increase in temperature or other change in the climate could trigger a disproportionately larger change in the future.
catastrophe theory
The concept of ‘tipping points’ comes from a well-developed mathematical model of sudden large-scale changes. These are often called catastrophes - they are: sudden and relatively unexpected, apparently disproportionate to the cause, and irreversible in practice. The maths is called catastrophe theory.
The study came out of a meeting of 36 leading climate scientists in 2005 who drew on the expertise of a further 52 specialists. It is believed to be the first time that scientists have attempted to assess the risks in this way.
Although there are many potential tipping points that could occur this century, it is still possible to avoid them with cuts in greenhouse gases, said Professor Timothy Lenton of the University of East Anglia, who led the study.
He added: “But we should be prepared to adapt … and to design an early-warning system that alerts us to them in time.”
[see also positive catastrophes]
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 Niño: 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.
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July 14th, 2008 at 6:50 pm
I was a graduate student in the 1970s when Dr. Thom visited our campus. I never pursued the math, but the basic concept of irreversable (or difficult to reverse) sudden changes has stayed with me ever since. I think you can add many economic examples to this idea — the most profound being the events that may unfold as peak oil, the bursting of the housing bubble, and other events unfold. The challenge is not that we cannot understand catastrophies, it’s that we remain linear thinkers even after going over the cusp.