The Boston University study, using NASA satellite data, concluded Amazon rainforests were remarkably unaffected by a once-in-a-century drought in 2005, neither dying nor thriving.
"We found no big differences in the greenness level of these forests between drought and non-drought years, which suggests that these forests may be more tolerant of droughts than we previously thought," said Arindam Samanta, the Boston University study's lead author.
A 2007 report, published by the journal Science, claimed the rainforests actually thrive in drought because of more sunshine under cloudless skies, the scientists said. The latest report said that study was flawed and not reproducible.
"This new study brings some clarity to our muddled understanding of how these forests, with their rich source of biodiversity, would fare in the future in the face of twin pressures from logging and changing climate," said Professor Ranga Myneni.
The research that included Sangram Ganguly of the Bay Area Environmental Research Institute in Sonoma, Calif., appears in the journal Geophysical Research Letters.