Significance
Understanding the sensitivity of tropical vegetation to changes
in precipitation is of key importance for assessing the fate of
the Amazon rainforest and predicting atmospheric CO2 levels.
Using improved satellite observations, we reconcile observational
and modeling studies by showing that tropical vegetation
is highly sensitive to changes in precipitation and El Niño
events. Our results show that, since the year 2000, the Amazon
forest has declined across an area of 5.4 million km2 as a result
of well-described reductions in rainfall. We conclude that, if
drying continues across Amazonia, which is predicted by several
global climate models, this drying may accelerate global
climate change through associated feedbacks in carbon and
hydrological cycles.