Death Throes of the Rainforest Will Increase Global Warming
10/3/98
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Title: Death throes of the rainforest will increase global warming
Source: From The Electronic Telegraph, Telegraph Group Limited
Status: Copyright 1999, contact source for permission to reprint
Date: October 3, 1998
Byline: Charles Clover Environment Editor
VAST areas of the Amazon rainforest will begin to die around 2050,
releasing carbon into the atmosphere and causing the world to warm
faster than previously expected, the Meteorological Office's Hadley
Centre predicted yesterday.
The latest computer model of how man-made greenhouse gas emissions
will change the global climate forecast the emergence of what
scientists have long feared, a possible "flip effect" by which global
warming could speed up just as mankind attempts to control it.
The centre's refined computer model of the world's climate also showed
that human-caused greenhouse gas emissions have been changing the
world's climate for the past 50 years. It said that 1998 is likely be
the hottest since records began.
In the most startling difference with previous forecasts, the centre's
improved computer model predicted a drop in rainfall over north-
eastern Brazil around 2050 as a result of global warming. This will
mean that vast areas of forest in Brazil will begin to die, according
to another climate model run by the Institute of Terrestrial Ecology.
Elsewhere, tropical forests will turn to grassland or desert - also
increasing carbon emissions.
Forests will reduce the effects of greenhouse gas emissions for the
first half of the next century, absorbing carbon at between two
billion and three billion tons a year. After this, the process will be
reversed as tropical forests begin to die, releasing carbon and adding
to the greenhouse gases in the atmosphere. Dying forests are expected
to release about two billion tons of carbon a year. Present human
emissions of carbon are about seven billion tons a year. Some of this
will be taken up by conifers expanding northwards into regions which
are currently too cold for them.
Geoff Jenkins, of the centre, said yesterday that the predicted "flip
effect" as the trees began to decay was not yet included in climate
models. These currently predict a 3C rise in global temperature over
the next 100 years. He said warming could be expected to be faster
than previously predicted when the new models are run in about three
years.
The predicted climate changes are based on forecasts of likely
"business as usual" emissions of greenhouse gases over the next 60
years. But Mr Jenkins said that a proportion of the changes were
inevitable because of the build-up of gases already in the atmosphere.
Michael Meacher, the environment minister, said the Hadley predictions
made "sobering, extremely disturbing reading". He said Britain would
use the findings "vigorously" at climate talks in Buenos Aires this
week. He said that sections of American business and Congress were
still resisting the British scientists' message that climate change
was happening. Mr Meacher said other centre predictions showed that
global warming would cause "a huge increase in human misery".
The centre's other main predictions are:
- The Gulf Stream will slow down by as much as 20 per cent by the
2050s, but Europe will not cool down as a result because of the
increased warming from the greenhouse effect.
- Water supplies in many of the poorest countries, already stretched
by population growth, will come under more pressure as a result of
climate change. By 2050, an extra 170 million people will face acute
water shortages.
- Crop yields will increase in Europe and Canada but decrease in the
lower latitudes. The United States will lose up to 10 per cent of its
productivity. There will be a shortfall of 90 million tons of grain a
year.
- Global sea rise by the 2050s is expected to be 21cm, exposing an
extra 20 million people to the risk of flooding.
c Copyright of Telegraph Group Limited 1998.