Early warning signals of simulated Amazon rainforest dieback

• DOI: 10.1007/s12080-013-0191-7
• Publication Date: 2013-05-28T07:49:59Z
• Authors: Chris A. Boulton; Peter Good; Timothy M. Lenton
• Keywords: HadCM3; Predictability; Tipping point (physics)

We test proposed generic tipping point early warning signals in a complex climate model (HadCM3) which simulates future dieback of the Amazon rainforest. The equation governing tree cover suggests that zero and non-zero stable states co-exist, transcritical bifurcation is approached as productivity declines. Forest non-linear change state, declines, should exhibit critical slowing down. use an ensemble versions HadCM3 to for corresponding signals. However, on approaching simulated dieback, expected down are not seen cover, vegetation carbon or net primary productivity. lack convincing trend autocorrelation appears be result system being forced rapidly non-linearly. There robust rise variance with time, but this can explained by increases inter-annual temperature precipitation variability force forest. This failure indicators led us seek more system-specific, observable changing forest stability model. sensitivity ecosystem anomalies (a negative correlation) generally approaches, attributable respiration temperature. As result, atmospheric CO2 positive approaches. indicator has benefit readily real world.