A call for global action to move the Amazon forest system away from tipping points

Abstract

A ‘tipping point’ is the point at which a small change to a stressor or ecosystem state causes the whole ecosystem to shift abruptly to an alternative stable state, accelerated by amplifying (or self-reinforcing) feedback mechanisms. When tipping events become contagious like epidemics or wildfires, they may cause systemic collapse. Understanding these boundaries can help society manage Amazonian resilience and avoid crossing tipping points. The scientific literature identifies five potential tipping points in the Amazon, each one related to a particular stressor: (1) 2oC mean global temperature rise relative to pre-industrial levels; (2) 1,000 mm of local annual rain-fall; (3) - 400 mm of maximum cumulative water deficit; (4) dry season length of 6 months; and (5) accumulated forest loss of 20%. Moreover, in areas where rainfall falls below 1,800 mm per year, forests become unstable, with increased risk of crossing tipping points. These five stressors may intensify in synchrony (e.g., less forest could exacerbate and drive less rainfall and more fires), implying that tipping points could emerge sooner than expected. We recommend society work collaboratively to manage these stressors and avert crossing tipping points.