Drying out of the Amazon, 1987 to 2016. Map of South America that is colour-coded to show the trend in water vapor pressure deficit (VPD) over the 20 years from 1987 to 2016, with darker brown showing a higher deficit. Over the past twenty years, the atmosphere above the Amazon rainforest (upper right) has been drying out, increasing the demand for water and leaving ecosystems vulnerable to fires and drought. This conclusion was drawn from a NASA study that also showed that this increased dryness is primarily the result of human activities. This image is based on data from the Atmospheric Infrared Sounder (AIRS) sensor on NASA's Aqua satellite.