Thread by @ClimateTipPoint

A brief note on this: this is not yet the big "#Amazon dieback" #TippingPoint (where dieback becomes self-perpetuating across most of the rainforest) as the net CO2 emissions are still largely being driven by degradation and so can still be limited - but it's still not good. 1/7

https://twitter.com/guardian/status/1415327670997602304

There are several steadily worse Amazon milestones – CO2 emissions from degraded areas surpassing CO2 absorption by intact areas, intact areas becoming C sources too due to drought, & a rain-driven tipping point beyond which a wide-scale shift to savannah becomes inevitable. 2/7

These milestones are often conflated in discussions of climate change and the Amazon rainforest though, leading to people incorrectly thinking an Amazon CO2 sink-to-source transition is the same as the full-scale Amazon dieback tipping point. Thankfully, it's not. 3/7

This paper supports the 1st milestone (C source from degraded areas surpassing C sink in intact areas), with net emissions mostly driven by deforestation & fires in degraded forests in the South & East. A paper in March reached a similar conclusion: climatefeedback.org/evaluation/des… 4/7

There's partial evidence for the 2nd milestone (intact areas becoming C sources too due to drought) in this study too, as remaining intact forests in the SE Amazon were found to now be net C sources as well. However, sinks still dominate elsewhere where deforestation is <20%. 5/7

And although there's signs here of regional dieback in intact SE forests & ~20% less moisture being recycled to the West, there's thankfully not yet evidence for dieback becoming self-perpetuating across Amazonia (milestone 3, i.e. the "Amazon dieback" tipping point). 6/7

So, the bad news is that overall the Amazon is now likely contributing to climate change. But the silver lining is that this is happening in areas of strong degradation and not yet in more intact areas, which means stopping deforestation can still limit further CO2 emissions. 7/7

A clarification (h/t @SimonLLewis): while this study doesn't demonstrate wide-scale dieback the location & mechanism is how it would be expected to start, and so we can't rule this out being the start of wider dieback either. All the more reason to halt deforestation ASAP!