Studies question value of planting
trees to slow warming
Patricia Reaney / Reuters 9nov00
LONDON - Global warming may evolve more quickly than scientists have predicted, because forests, rather than mitigating climate change, may speed it up, researchers said yesterday.
As environment ministers prepare for a climate change conference next week in the Hague, scientists at Britain's Hadley Center for Climate Prediction and Research said it may be counterproductive to plant forests to absorb carbon dioxide and to reduce global warming.
Two studies published in the science journal Nature, using computer models of global warming, found that as temperatures rise, forests, or so-called carbon sinks, are likely to emit more carbon dioxide into the atmosphere. This would lead to further warming of the climate.
''Our initial results suggest that vegetation and soils, which currently absorb about a quarter of human-made carbon dioxide emissions, could accelerate future climate change,'' said one of the authors, Dr. Peter Cox.
Carbon sinks is one of the issues that will be debated at the Hague conference.
from around the world will try to seal an international agreement to cut emissions of carbon dioxide by an average of 5 percent of 1990 levels by 2012, in line with a treaty agreed in Kyoto, Japan in 1997.
The Kyoto treaty allows countries to plant forests to offset some of their carbon dioxide emissions.
''All we can say ... is that if you want to plant trees to absorb CO2 in order to offset additional future emissions there are a huge amount of uncertainties,'' Dr. Geoff Jenkins, head of the Hadley climate change program, said in a telephone interview.
Environmental groups Greenpeace and the World Wildlife Fund are calling for carbon sinks to be excluded from the Kyoto treaty. Both groups want industrialized countries to achieve their targets by cutting emissions.
The second study in Nature, by Dr. Richard Betts, also showed that planting new forests in cold regions, like Siberia and Canada, could do more harm than good.
This is because in northern countries, where the ground is covered in snow, forests absorb more of the sun's heat than the terrain. The additional exposure to the sun has a warming influence.
