Forests Could Become Source of Warming: Report
Date: 17-Apr-09
Country: US
Author: Timothy Gardner
Forests Could Become Source of Warming: Report Photo: TNK-BP/Handout
A general view shows the 1-billion-barrel Verkhnechonskoye field located
more than 4,000 km (2,500 miles) and six time zones east of Moscow in this
undated handout file photo.
Photo: TNK-BP/Handout
NEW YORK - The world's forests are at risk of becoming a source of
planet-warming emissions instead of soaking them up like a sponge unless
greenhouse gases are controlled, scientists said.
Deforestation emits 20 percent of the world's carbon dioxide when people cut
and burn trees, but standing forests soak up 25 percent of the emissions.
If the Earth heats up 2.5 degrees Celsius (4.5 degrees F) or more,
evaporation from the additional heat would lead to severe droughts and heat
waves that could kill wide swaths of trees in the tropics of Africa,
southern Asia and South America. And emissions from the rotting trees would
make forests a source of global warming.
"If temperatures are growing at the current pace definitely this would
happen at the end of this century or before," said Risto Seppala, chair of a
report by the International Union of Forest Research Organizations, a
nonprofit network of scientists.
The IUFRO will present the report to the UN's Forum on Forests in New York
next week.
Not all areas of the world would suffer immediately and pine forests in
northern parts of the world could benefit at first.
"In the beginning it would mean some very positive consequences," for boreal
forests such as those found in Northern Europe and Canada, said Seppala by
telephone from his home in Finland north of the Arctic Circle. He said
timber and paper industries in the North could prosper as warmer weather
pushes growth of spruce and other trees.
Even forests found in more temperate parts of the world, such as the United
States and Western Europe, could grow faster at first.
"Those who live in industrialized countries in the Northern Hemisphere won't
suffer too much at first," he said.
People in many developing countries with forests tend to rely more on
forests for food, clean water and other basic needs.
But eventually tree pests and parasites that until now have not appeared
much in forests in colder parts of the world are likely to spread north as
temperatures warm, the report said.
An example of pests already moving to the North is the pine beetle, which
has devastated large parts of forests in British Columbia over the past
decade and has moved into the province of Alberta. The pest can be killed by
periods of extreme cold, but the 2007-2008 winter did not kill off the
insects in Alberta.
Much depends on exactly how much temperatures will warm. A Reuters poll
earlier this month of scientists showed that global warming is like to
overshoot a 2 degrees Celsius (3.6 F) rise above pre-industrial levels seen
by many countries as the maximum to avoid the worst of rising sea levels,
floods, droughts and heat waves. Temperatures have already risen 0.7
Celsius.
Steps can be taken to protect forests and help them adapt to warmer
temperatures, such as sustainable harvesting, the IUFRO report said. Perhaps
even more important is cutting global emissions of greenhouse gases, said
Seppala.
(Editing by Christian Wiessner)
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