- The world has barely begun to recognise the danger of
setting off rapid and irreversible changes in some crucial natural systems,
a scientist says.
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- Professor John Schellnhuber says the most important environmental
issues for humans are among the least understood.
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- He told a briefing in Sweden that the Asian monsoon was
one of the "tipping points" that could change very quickly.
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- He said a better understanding of the risks was as important
as the programme to prevent collisions with asteroids.
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- Professor Schellnhuber is research director of the UK's
Tyndall Centre for Climate Change Research.
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- High stakes
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- 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?
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- Professor Schellnhuber said 12 "hotspots" had
been identified so far, areas which acted like massive regulators of the
Earth's environment.
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- 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.
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- "We have so far completely underestimated the importance
of these locations," he said.
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- "What we do know is that going beyond critical thresholds
in these regions could have dramatic consequences for humans and other
life forms."
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- 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.
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- Faltering monsoon
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- 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.
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- 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.
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- "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.
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- "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.
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- "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.
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- Unforeseen speed
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- "That means we have to know where they are, and
they've been off the radar screen for far too long.
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- "Scientists have begun to realise that change could
be sudden, not gradual - in some cases it could happen within a few decades."
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- Professor Schellnhuber urged a coordinated global effort
to improve understanding and monitoring of Earth's "Achilles' heels".
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- He said: "Such an effort is every bit as important
as Nasa's valuable asteroid-spotting programme designed to protect the
planet from collisions.
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- "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."
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- © BBC MMIV http://news.bbc.co.uk/2/hi/science/nature/3597584.stm
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