By Devin Powell February 11th, 2012; Vol.181 #3 (p. 5) GAS
STATIONThe Large Scale Biosphere-Atmosphere Experiment in
Amazonia has erected towers in the Brazilian rain forest up to
65 meters high to measure carbon dioxide absorption and
emissions.Scott Saleska In the struggle against global warming,
the Amazon rain forest may be about to switch sides. Its dense
vegetation has long helped cool the planet by removing carbon
dioxide from the atmosphere. But mass tree deaths brought about
by recent droughts and deforestation may be pushing the region
to a point at which it will give off more of the greenhouse gas
than it absorbs. “The Amazon might still be a sink for carbon,
but if it is it’s definitely moving towards being a source,”
says Eric Davidson, director of the Woods Hole Research Center
in Falmouth, Mass. Reporting in the Jan. 19 Nature, Davidson and
14 other researchers from the United States and Brazil weigh
evidence that the world’s largest rain forest has become
increasingly vulnerable to change. Tha