THE
world has just 10 years to reverse surging greenhouse gas emissions or
risk runaway climate change that could make many parts of the planet
uninhabitable.

The stark warning comes from scientists who are working on the
final draft of a new report by the Intergovernmental Panel on Climate
Change (IPCC).

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The
report, due to be published this week, will draw together the work of
thousands of scientists from around the world who have been studying
changes in the world’s climate and predicting how they might
accelerate.

They conclude that unless mankind rapidly stabilises
greenhouse gas emissions and starts reducing them, it will have little
chance of keeping global warming within manageable limits.

The results could include the destruction of the Amazon
rainforest and the Great Barrier Reef, the forced migration of hundreds
of millions of people from equatorial regions, and the loss of vast
tracts of land under rising seas as the ice caps melt.

In Europe the summers could become unbearably hot, especially
in southern countries such as Greece, Spain and Italy, while Britain
and northern Europe would face summer droughts and wet, stormy winters.

“The next 10 years are crucial,” said Richard Betts, leader of
a research team at the Met Office’s Hadley Centre for climate
prediction. “In that decade we have to achieve serious reductions in
carbon emissions. After that time the task becomes very much harder.”

Among the scientists’ biggest fears is that rising
temperatures and levels of greenhouse gases could soon overwhelm the
natural systems that normally keep their levels in check.

About half the 24 billion tons of carbon dioxide generated by
human activities each year are absorbed by forests and oceans — a
process without which the world might already be several degrees
warmer.

But as CO2 levels rise and soils dry, microbes can start
breaking down accumulated organic matter, so forests become net
producers of greenhouse gases. The sea’s power to absorb CO2 also falls
sharply as it warms.

The latest research suggests the threshold for such disastrous
changes will come when CO2 levels reach 550 parts per million (ppm),
roughly double their natural levels. This is predicted to happen around
2040-50.

“At the moment the real impact of our emissions is buffered
because CO2 is absorbed by natural systems. However, if we reach this
threshold they could be magnified instead,” said Betts. “It means we
must start the action needed to reduce greenhouse gas emissions in the
next few years.”

His warnings were backed up by Dr Malte Meinshausen, a
researcher at the Potsdam Institute for Climate Impact Research in
Germany. He has used computer modelling to work out what might happen
if greenhouse gas emissions were cut immediately, in 10 years’ time or
later.

His results showed that immediate action might allow mankind
to hold CO2 levels at 450ppm — well below the 550ppm danger level.
However, Meinshausen and his colleagues recognise that this is
unrealistic because the world’s governments are in such disarray over
global warming. The best hope, they say, is that a global plan will
emerge in the next few years, most likely from the renegotiations of
the Kyoto treaty on reducing emissions.

“We have to make sure carbon emissions peak no later than 2015
and then fall at around 3% a year. If we let them keep rising after
that date it becomes much harder to bring them under control,” said
Meinshausen.