Reduced Moisture Recycling and Lowered Tipping Thresholds Increase Amazon Rainforest Dieback Risk Under Combined Deforestation and Climate Warming
Abstract
Recent research synthesis indicates that the stability of the Amazon rainforest is increasingly threatened by the interaction of global warming and regional land-use change. Deforestation is reducing evapotranspiration-driven moisture recycling, weakening regional precipitation patterns and extending dry seasons. These changes amplify forest stress, increase fire susceptibility, and reduce ecosystem resilience. Modeling results suggest that while warming alone may not be sufficient to trigger large-scale dieback at lower temperature thresholds, the addition of deforestation substantially lowers the warming level at which critical transitions become possible. Together, these interacting drivers increase the probability of partial or large-scale Amazon forest collapse under scenarios of continued warming and land conversion.
1. Introduction
The Amazon rainforest is a coupled climate–biosphere system that plays a critical role in global carbon cycling and regional hydrological stability. Increasing attention has been directed toward its potential as a climate tipping element, in which gradual external forcing could produce abrupt or large-scale ecosystem transitions.
2. Moisture Recycling and System Feedbacks
A defining feature of the Amazon system is internal moisture recycling, driven by evapotranspiration from forest vegetation. This process sustains regional precipitation by maintaining atmospheric humidity and cloud formation. Deforestation reduces evapotranspiration capacity, weakening this feedback loop and increasing the likelihood of prolonged dry seasons.
3. Interaction Between Deforestation and Warming
Recent modeling studies indicate that the Amazon’s resilience is highly sensitive to the combined effects of land-use change and global temperature increase. In simulations, intact forest systems show higher resistance to warming-induced dieback, while deforested or fragmented landscapes exhibit earlier and more abrupt transitions.
Importantly, deforestation lowers the effective temperature threshold for large-scale ecosystem destabilization by reducing moisture availability and amplifying heat stress.
4. Evidence for Declining Ecosystem Resilience
Independent observational studies support a decline in Amazon resilience over recent decades, including:
- Reduced recovery rates following drought events
- Increasing duration and severity of dry seasons in some regions
- Expansion of fire-prone conditions in degraded forest areas
- Early-warning signals consistent with critical slowing down in vegetation dynamics
5. Implications for Tipping Dynamics
The combined influence of warming and deforestation introduces nonlinear risk behavior. Rather than responding independently, these stressors interact in ways that may accelerate ecosystem degradation once critical thresholds are approached.
This suggests that the probability of crossing a tipping threshold is not fixed, but increases under continued land conversion even at relatively moderate global warming levels.
6. Conclusion
The Amazon rainforest is best understood as a coupled climate–ecological system with emerging nonlinear vulnerability. While large-scale dieback is not inevitable, current evidence indicates that the combination of deforestation and global warming significantly lowers stability margins and increases the risk of abrupt or extensive ecosystem transition.
Source:
https://www.nature.com/articles/d41586-026-01158-8
Robust projections of risks to the Amazon rainforest
Amazonian deforestation is altering atmospheric moisture transport; as a result, even low levels of global warming could trigger dieback of most of the remaining forest.