Is the Amazon Rainforest Drying Out? A river rises in the Andes
and flows east to the Amazon, Ucayali River in Peru. Photo by
Bates Littlehales/National Geographic/Getty Images TARAPOTO,
Peru -- For tropical ecologist Gregory Asner, flying over the
Peruvian Amazon from the town of Tarapoto is like traveling back
in time. Modern houses, rice paddies and oil palm plantations
give way to steep, forested mountains and then to green,
unbroken forest that curves toward the horizon. Suddenly the
tree canopy below the twin-engine plane turns a mottled gray-
brown, a sign of drought damage that he estimates may affect as
many as half the trees. In this remote corner of Peru's Ucayali
region, Asner, a tropical ecologist at the Carnegie Institution
for Science at Stanford University, is afraid he is seeing the
future. In the last few years this patch of forest has been hit
by two "once-in-a-century droughts" -- one in 2005 and another
in 2010. These dry spells may become more frequent as
temperatures in the tropical Nort