WARNING ON EARTH'S RAPID AND IRREVERSIBLE CHANGES *PIC*

by Miker12, Thursday, August 26, 2004, 13:55

Earth warned on 'tipping points'

Thursday, 26 August, 2004, 01:01 GMT 02:01 UK
By Alex Kirby
BBC News Online environment correspondent

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...

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...

"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...

"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...

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