world news - 18.12.2006
Care needed with carbon offsets
Scientists say the benefits that come from trees
reducing atmospheric carbon dioxide can be outweighed by their capacity
to trap heat near the ground.
Computer modelling indicates that trees only really work to cool the planet if they are planted in the tropics.
The research has been discussed at an American Geophysical Union meeting.
"[In] the seasonally snow-covered regions [at even
higher latitudes], planting new trees could be actually
counter-productive," he told BBC News.
Growing issue
Dr Bala and colleague Ken Caldeira, from the Carnegie
Institution of Washington, used a computer model to determine the
impact which forests in different parts of the planet would have on
temperature.
Their analysis indicates that three key factors are involved:
"Our study shows that tropical forests are very
beneficial to the climate because they take up carbon and increase
cloudiness, which in turn helps cool the planet," explained Dr Bala.
"The darkening of the surface by new forest canopies in
the high-latitude boreal regions allows absorption of more sunlight
that helps to warm the surface," Dr Bala said.
"In fact, planting more trees in high latitudes could be counterproductive from a climate perspective."
The study finds little or no climate benefit when trees are planted in temperate regions.
The scientists warn that many schemes designed to offset emissions of carbon by planting trees may not be appropriate.
"When you plant trees to slow down global warming, you
have to be careful where you do it. I think our study shows clearly the
climate benefits are maximised if you plant them in the tropics," Dr
Bala told BBC News.
Planting forests to combat global warming may be a
waste of time, especially if those trees are at high latitudes, new
research suggests.
"What we have found is in the so-called mid-latitude region where the
United States is located and majority of European countries are
located, the climate benefits of planting will be nearly zero," said
ecologist Govindasamy Bala of Lawrence Livermore National Laboratory.
Planting more trees in high latitudes could be counterproductive from a climate perspective
The further you move from the equator, though, these
gains are eroded; and the team's modelling predicts that planting more
trees in mid— and high-latitude locations could lead to a net warming
of a few degrees by the year 2100.
See also:
- — Weather situation sends cold shivers down the spine of the The Swedish sawmill business
- — Finland worried by Russia’s plans to increase export duties on raw timber
- — Asian Timber Cabal Threatens Creation for Your Dinner Table
- — UN: Negotiators draft new agreement to manage world’s forests
- — Western Forest Products to take extended mill downtime over Christmas due to weather-related log shortages
