A new computer model that includes a forest's effect on regional climate shows that the Amazon rain forest could disappear much more rapidly than previously expected.
Rain forests depend on large amounts of precipitation to remain lush. Much of the moisture taken in by a trees' roots returns to the atmosphere through the leaves in a process called transpiration. In the rain forest, this process has a significant effect on local and regional climates, says James E. Alcock, an environmental scientist at Pennsylvania State University's Abington College in Abington.
Logging and burning for agriculture currently claim about 1 percent of the Amazon rain forest per year. Alcock says that this large-scale deforestation substantially alters the rate of transpiration.
After farmers and loggers cut and burn broad swaths of rain forest, more precipitation runs out of the area via the rivers. This leaves less moisture to return to the atmosphere–and that means, in turn,