Amazon rainforest growth during drought was an illusion

New Scientist : In 2003, NASA’s remote sensors showed that the Amazon rainforest was reflecting more near-IR light during periods of drought. Because new leaves in the forest canopy reflect more IR than older leaves, the finding suggested that the forest grew better during droughts. However, a new study by Douglas Morton of NASA’s Goddard Space Flight Center and his colleagues indicates that the apparent growth was likely an illusion. Lidar and more sensitive imaging revealed that the near-IR light was probably reflecting off surfaces below the canopy. A separate study of the carbon dioxide absorption of the forests during wet and dry years confirms the lack of growth and overall loss of plant life during drought periods. Luciana Gatti of the City University of São Paulo, Brazil, compared CO₂ levels above the Amazon basin in 2010, a dry year, and 2011, a wet year. During the wet year, the forest was carbon-neutral, while during the dry year, the basin lost nearly 500 million tons of carbon, primarily as a result of fires in the vegetation.