Monday, June 29, 2009

Rainforests More Fragile Than Estimated

Mon Jun 29, 2009
From: Discovery News
News Link:

The Amazon rainforest, one of the planet's most precious and besieged natural resources, is even more fragile than realized.

If the planet warms even a moderate amount, a new study predicts that as much as 40 percent of it could be condemned to vanish by the end of the century.

A crippled Amazon could hasten global warming. If a significant portion of its trees die off, their vast stores of carbon would be emitted back into the atmosphere as greenhouse gases, pushing the climate further into dangerous levels of warming.

Chris Jones of the United Kingdom's Met Office and a group of researchers ran a computer simulation of Earth's climate that focused on how vegetation reacts to warming. They found that warming doesn't immediately kill off tropical trees -- it can take up to a century for the forests to respond fully.

But even modest warming could have devastating effects. If the planet warmed just 2 degrees Centigrade (3.6 degrees Fahrenheit) above pre-industrial levels, they found that between 20 percent and 40 percent of the forest could die off.

"Our model predicts quite a severe drying in the Amazon, making trees more vulnerable to fire," Jones said. "The additional heat causes stress, too, damaging their ability to grow fully."