Climate Threatens Third of Forests
11/20/98
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Title: Climate Threatens Third of Forests
Source: WWF
Status: Distribute freely with proper credit to source
Date: 11/20/98
Byline: Alex Kirby, Environment Correspondent
The World Wide Fund for Nature (WWF) says the world's changing climate
poses a grave risk to one third of its forests.
WWF says this has serious implications for many plant and animal
species, three-quarters of which depend on the forests for their
survival.
Most scientists believe climate change is being caused by human
activity, especially the burning of fossil fuels like coal, oil and gas.
Carbon dioxide given off as the fuels burn is trapping more and more of
the sun's heat close to the earth, instead of letting it radiate safely
back into space.
Multiple effects
The inexorable rise in temperature is affecting forests in several ways,
says WWF.
Latitudes nearer the poles are becoming warmer -- in fifty years or
less, southern Britain may have a climate like central France today. Yet
some tree species may not be able to keep up with the advancing heat
front.
The climate is likely to become stormier. That may mean an increased
risk of fire for tropical forests already dried out by drought.
Sea levels will continue to rise. Mangrove swamps, home to a wealth of
species, may be at risk.
And in some places, trees will respond to climate change by
encroaching on new areas, taking over African savannahs and Alpine
meadows.
But forests will not only suffer from climate change. Increasingly, they
will contribute to it.
As a tree grows, it absorbs carbon dioxide from the atmosphere to help
it to maturity.
Once it is full-grown, the tree "locks up" the carbon dioxide it
contains, and prevents it from re-entering the atmosphere.
But when the tree decays, or is burnt, all the carbon dioxide it
contains is released, adding to the greenhouse effect.
Scientists estimate that up to one fifth of all greenhouse gases come
from the burning, not of fossil fuels, but of "biomass" -- trees and
other plants.
Some of the burning is accidental. But an increasing number of fires are
started deliberately, to clear land for farming or other human purposes.
A problem or an opportunity ?
The world's forests are key players in the Buenos Aires climate
conference, running from 2 to 13 November.
Because the forests can lock up such immense quantities of carbon
dioxide, some countries are arguing that it makes more sense to plant
trees than to reduce their own greenhouse emissions.
Trees cannot cope with all our pollution
The argument comes mainly from countries in the superleague of polluters,
like the USA.
There is some evidence to support them. A team of American researchers
says the nation's trees could be sucking up just about all the 1.6
billion tonnes of carbon dioxide that the US emits every year.
But other climatologists say the researchers, the Carbon Modeling
Consortium, had to rely on sparse data, and on models whose assumptions
have not been thoroughly tested.
The members of the Consortium are all respected scientists. But, in the
words of the weekly New Scientist magazine, "much more research is
needed before these findings are nearly strong enough to inform policy".
And there is a warning from WWF to the delegates in Buenos Aires.
"Forests are threatened by climate change, so countries should not rely
on them to soak up carbon dioxide", it says. "There is no substitute for
cutting emissions at source".