[Mb-civic] Earth warned on 'tipping points'

[ean at sbcglobal.net]

Calamities Ahead and New Hopes
Earth warned on 'tipping points'
By Alex Kirby BBC News Online environment correspondent
http://news.bbc.co.uk/2/hi/science/nature/3597584.stm
26 August, 2004

The world has barely begun to recognise the danger of setting off 
rapid and irreversible changes in some crucial natural systems, a 
scientist says.

Professor John Schellnhuber says the most important environmental 
issues for humans are among the least understood.

He told a briefing in Sweden that the Asian monsoon was one of the 
"tipping points" that could change very quickly.

He said a better understanding of the risks was as important as the 
programme to prevent collisions with asteroids.

Professor Schellnhuber is research director of the UK's Tyndall 
Centre for Climate Change Research.

High stakes

He was speaking at the EuroScience Forum in Stockholm, at a 
briefing by the International Geosphere-Biosphere Programme 
entitled Beyond Global Warming: Where On Earth Are We Going?

Professor Schellnhuber said 12 "hotspots" had been identified so far, 
areas which acted like massive regulators of the Earth's environment.

If these critical regions were subjected to stress, they could trigger 
large-scale, rapid changes across the entire planet. But not enough 
was known about them to be able to predict when the limits of 
tolerance were reached.

"We have so far completely underestimated the importance of these 
locations," he said.

"What we do know is that going beyond critical thresholds in these 
regions could have dramatic consequences for humans and other life 
forms."

One example of a hotspot was the North Atlantic current, the ocean 
circulation pattern responsible for bringing warmer air to northern 
Europe, the collapse of which could lead to a very large regional 
climate shift.

Faltering monsoon

Others were the West Antarctic ice sheet, the Sahara desert, and the 
forests of the Amazon basin. Yet another hotspot, Professor 
Schellnhuber said, was the Asian monsoon system.

He told BBC News Online: "Modelling has shown that if air pollution 
and land use change, this could alter the albedo, the reflectivity, of 
the land.

"This in turn could weaken or even suppress the monsoon, and there 
is evidence that several times in the last few years it has in fact been 
weaker.

"We're investing too much in things like improving the accuracy of 
our weather forecasts, while the really vital elements in the Earth's 
system are the unstable phenomena like the monsoon.

"We should have a much better understanding of these tipping 
points, and we have to do everything we can to stop short of 
triggering these instabilities.

Unforeseen speed

"That means we have to know where they are, and they've been off 
the radar screen for far too long.

"Scientists have begun to realise that change could be sudden, not 
gradual - in some cases it could happen within a few decades."

Professor Schellnhuber urged a coordinated global effort to improve 
understanding and monitoring of Earth's "Achilles' heels".

He said: "Such an effort is every bit as important as Nasa's valuable 
asteroid-spotting programme designed to protect the planet from 
collisions.

"If we can afford to gaze up at the sky looking for asteroids, we 
should be able to watch our own planet with as much care."

http://www.earthrainbownetwork.com/Archives2004/TurningTide16
.htm 



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