This is the best tl;dr I could make, original reduced by 85%. (I'm a bot)
It took the lead scientist Luciana Gatti and her colleagues almost a decade of flying back and forth over the forest, collecting samples to be analysed for carbon dioxide concentration, at distinct altitudes and over different areas, from highly deforested to well-conserved ones, for scientists to realise that the game had changed: parts of the Amazon forest are now net carbon contributors.
To restore the net carbon emissions of the Amazon forest to its balance and avoid other portions of the region's forest reaching a tipping point where massive mortality further affects resilience, we must reduce forest loss by deforestation and fires, and invest in massive landscape restoration.
For decades, the so-called Amazon tipping point hypothesis has been predicting that once we reach 20% deforestation of the basin, the system would shift from a carbon sink to a carbon source.