Arboreal Storage for Carbon Dioxide
Weiss, Rick, Peterson, Ivars, Science News
Arboreal storage for carbon dioxide
As carbon dioxide levels in the atmosphere continue to rise, researchers are taking a closer look at potential methods for limiting the increase in order to avoid adverse changes in global climate. "What is required," says Gregg Marland of the Oak Ridge (Tenn.) National Laboratory, "is some way to collect carbon and some place to put it so that it does not accumulate in the atmosphere as carbon dioxide." One possibility, at least in the short term, would be to stimulate the growth of forests. Recently, Marland evaluated what it would take -- by increasing either forest area or tree growth rates -- to remove an additional 5 billion tons of carbon per year from the atmosphere.
His study shows that increasing the area of land covered by forest does not look promising. Although the amount of forested land in the United States and a few other countries has actually increased slightly in recent years, in many parts of the world, especially the tropics, forests are still being cleared without being replaced. Even if the loss of existing forests were halted, it would still take an area roughly the size of Australia planted with a fast-growing tree species such as American sycamore to meet the target reduction in carbon dioxide. "Where would we put the trees? …