The complete or partial collapse of the forests of Amazonia is consistently named as one of the top ten possible tipping points of Planet Earth in a changing climate. However, apart from a few observational studies that showed increased mortality after the severe droughts of 2005 and 2010, the evidence for such collapse depends primarily on modelling. Such studies are notoriously deficient at predicting the rainfall in the Amazon basin and how the vegetation interacts with the rainfall is poorly represented. Here, we use long-term surface-based observations of the air temperature and rainfall in Amazonia to provide a constraint on the modelled sensitivity of temperature to changes in precipitation. This emergent constraint also allows us to significantly constrain the likelihood of a forest collapse or dieback. We conclude that Amazon dieback under IPCC scenario RCP8.5 (crossing the tipping point) is not likely to occur in the twenty-first century.
Bibliographical noteFunding Information:
We greatly appreciate the help of Gillian Kay in obtaining the data from the HadCM3 ensemble. Further details can be found in references 31 and 32. We are thankful to Peter Cox, for his helpful advice and comments on an earlier version of this paper. AJD was originally funded by a Science without borders grant to CN and acknowledges support from the Netherlands Earth System Science Centre Grant/ Award Number: 024.002.001. YC acknowledges support from the China Scholarship Council. Original funding for this work was also provided by the Amazalert project funded by the European Commission.
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