The Amazon rainforest, spanning millions of square kilometers, represents the planet’s most extensive tropical forest and is a cornerstone of global biodiversity and climate regulation. This vast ecosystem stores immense amounts of carbon in its dense vegetation, acting as a critical buffer against climate change. However, there is increasing alarm within the scientific community regarding the potential for irreversible changes to this biome. Recent research published in Communications Earth & Environment reveals that the Amazon could undergo a catastrophic transformation from a lush rainforest to a savannah-like, degraded landscape, driven by a dangerous combination of climate change and land-use alterations. This transformation, known as dieback, threatens to shatter ecological balances that have persisted for millennia and carries profound implications for the Earth’s climate system.
Scientists employed advanced Earth System Models (ESMs), tools that simulate intricate interactions among the atmosphere, biosphere, oceans, and terrestrial environments, to explore long-term projections for the Amazon extending as far as the year 2300. Utilizing the latest model intercomparison frameworks, CMIP5 and CMIP6, which underpin the authoritative IPCC assessment reports, researchers assessed how long-term climatic trends coupled with ongoing deforestation might push the rainforest towards critical tipping points. These tipping points denote thresholds at which the system swiftly transitions into an altered state, with potentially irreversible consequences. The study’s focus is particularly on high-emission scenarios, which forecast continued heavy use of fossil fuels and substantial land-use change throughout the coming centuries.
Dieback is operationally defined in this study as an extreme decline in photosynthetic activity, quantified as an 80% reduction in gross primary production (GPP) relative to pre-industrial levels in regions that were originally highly productive. The models uniformly project that large swathes of the Amazon will experience such dramatic reductions in vegetative productivity well before the 23rd century concludes, though the exact timing and spatial extent vary between models. Intriguingly, the sequence of dieback initiation often begins as early as the 21st century, influenced by temperature increases surpassing 1.5°C above pre-industrial baselines, diminished rainfall patterns, and expansion of agricultural land. This convergence of stressors underscores the compounding nature of climate change impacts when intersecting with human land-use pathways.
A vital finding of the research is the elucidation of the mechanisms driving Amazon dieback. One key driver is the weakening of the Atlantic Meridional Overturning Circulation (AMOC), an essential oceanic conveyor belt transporting warm waters from tropical regions towards the North Atlantic. The gradual slowdown of AMOC under global warming affects atmospheric circulation patterns, including the southward migration of the Intertropical Convergence Zone (ITCZ), a critical zone for tropical precipitation. This displacement results in comparatively hotter and drier conditions over the northern Amazon basin, aggravating drought stress on vegetation. Another crucial factor is the rising concentration of atmospheric carbon dioxide, which paradoxically reduces tree transpiration rates. While elevated CO2 might be expected to enhance plant growth, its suppression of transpiration diminishes atmospheric moisture recycling, further limiting rainfall and exacerbating dryness.
This research advances prior understanding by documenting projected increases in El Niño-like phenomena under high-emission trajectories, which periodically intensify drought and heat stress across the basin. These climate oscillations introduce episodic but impactful periods of environmental stress, compounding the chronic baseline shifts mediated by circulation changes. Importantly, while earlier studies have separately identified warming trends, circulation shifts, and ecosystem vulnerabilities, this study synthesizes these processes across multiple Earth System Models, providing robust evidence of Amazon dieback’s likely occurrence and clarifying the intertwined feedback loops driving it.
Ecologically, the consequences of such systemic changes are severe. Hotter and drier conditions hinder photosynthetic efficiency and elevate respiration rates in plants, thus tipping the carbon balance of the rainforest from net carbon sink to potential carbon source. Reduced precipitation and soil moisture availability limit water uptake and nutrient transport, weakening tree growth and regeneration capabilities. Over time, these impacts culminate in a loss of forest canopy, reduced biodiversity, and increased susceptibility to disturbance events such as fires and pest outbreaks. The southern and marginal areas of the Amazon are especially vulnerable, with land-use change amplifying these stresses and accelerating the pace of ecosystem degradation.
The projections signal a warning clarion call: without immediate and comprehensive mitigation of greenhouse gas emissions and stringent protection of forest ecosystems, the Amazon’s stability cannot be assured. The loss of this vital ecosystem would not only impoverish biodiversity but also disrupt global carbon cycling and atmospheric regulation, potentially accelerating climate change at planetary scales. The authors emphasize that current models might underestimate these risks due to incomplete representation of important ecological processes, including fire dynamics and drought-induced tree mortality, highlighting the need for ongoing refinement of Earth System Models.
The study underscores the urgency of coordinated international efforts aimed at protecting the Amazon. Climate action plans must integrate emission reductions, sustainable land management practices, and robust conservation frameworks to preserve the forest’s resilience. Continued deforestation, alongside warming temperatures, poses a dual threat that could irreversibly shift the Amazon into an alternate, degraded stable state. The complexity of these ecological-climatic feedbacks demands a transdisciplinary approach involving climatologists, ecologists, policymakers, and local communities to devise adaptive strategies that safeguard this global treasure.
Lead researcher Dr. Irina Melnikova, whose photographic documentation within the study captures the Amazon during the dry season, stresses the critical need for further research emphasizing improved ecological parameterizations in climate models. Enhanced model fidelity regarding tropical forest responses to extreme drought, fire regimes, and species adaptation will be paramount for more accurate forecasting and informed policymaking. According to Dr. Melnikova, bridging knowledge gaps in model ecology is essential to better predict timing, spatial scale, and severity of potential dieback events and thus inform global climate resilience initiatives.
The research builds upon the foundational concept of “tipping elements” in Earth systems—components that, once forced beyond thresholds, undergo rapid and irreversible regime changes with far-reaching impacts. The Amazon is a prime example of such a tipping element, with its fate intricately linked to oceanic patterns, atmospheric circulation, land-use practices, and greenhouse gas trajectories. Recognizing and responding to these thresholds is crucial to prevent cascading climatic and ecological disruptions.
As the planet approaches critical climate junctures, studies like this spotlight the interconnectedness of natural systems and human activity. The Amazon’s health reflects global stewardship or neglect. While uncertainties remain, the preponderance of evidence signals that we stand at the brink of a pivotal transformation that will reverberate for centuries if swift actions are not taken. Beyond scientific inquiry, this research is a clarion call for humanity to reassess its relationship with nature and embrace a sustainable trajectory that honors Earth’s intricate and fragile balance.
Subject of Research: Not applicable
Article Title: Amazon dieback beyond the 21st century under high-emission scenarios by Earth System models
News Publication Date: 20-Aug-2025
Web References: http://dx.doi.org/10.1038/S43247-025-02606-5
Image Credits: Credit: NIES
Keywords: Tropical forests, Anthropogenic climate change, Earth climate, Rainforests
