“The ability to rebuild a margin of safety through reforestation is very real, he said, and it could help reclaim the role trees play in producing moisture in the forests. “I don’t think you’ll ever make it what it was again, but you can certainly improve it,” he said.

Forests are an important part of the region’s water cycle; It is estimated that moisture released into the air from trees is responsible for up to 35 percent of rainfall in the region.

By managing forests with carbon sequestration, hydrology and biodiversity in mind, he said, “you gain several benefits”. Regarding the changes in the Amazon, he said, “It came much earlier than anyone thought 30 years ago because of the widespread use of fire and climate change. But add some water and it will change. “

Any changes will be a long time coming and will face political opposition. Brazilian President Jair Bolsonaro has overseen the rapid deforestation of the Amazon. The government, under increasing pressure, recently announced plans to counter the trend, but deforestation continues to rise.

In a companion article in Nature, Scott Denning, professor in the Atmospheric Science Department at Colorado State University, wrote that the “atmospheric profiles of the work show that the uncertain future is now.”

In an email response to questions, Dr. Denning the new study as the first real large-scale measurement – from different heights over thousands of kilometers and remote sectors – of the phenomenon, an advance that goes beyond traditional measurement in forest locations. The results show “that warming and deforestation in the eastern Amazon have reversed the carbon sink at the regional level and that the change is actually being reflected in atmospheric CO2,” he wrote.

The research flights could be grueling. Dr. Gatti said she took Dramamine before fights, but a colleague refused to get on the plane, saying his wife was pregnant and “it’s too risky”. She replied, “I have two children!”