‘Tipping points’ for the Amazon forest

The stability of the Amazon forest–climate equilibrium is being perturbed by a number of human drivers of change (e.g. deforestation, global warming, forest fires, higher CO2 concentrations, and increased frequency of droughts and floods). Quantitative assessments for the maintenance of the tropical forest indicate that ‘tipping points’ may exist for total deforested area (>40%) and for global warming (ΔT > 3–4°C). The likelihood of exceeding a tipping point can be greatly exacerbated by increases in forest fires and droughts, but quantification of those effects is still lacking. Forest resilience can be significantly increased if CO2 ‘fertilization’ effect is proven to be taking place for tropical forests, but it can be offset by continued increases in temperature, rainfall seasonality, and forest fires.