New research conducted by scientists at the University of Exeter presents a groundbreaking perspective on the potential role of geoengineering in safeguarding the Amazon rainforest amid escalating global climate change. Utilizing advanced climate models, the study explores the impacts of Stratospheric Aerosol Injection (SAI), a geoengineering technique designed to reduce Earth’s surface temperatures by increasing the reflection of solar radiation back into space. The scientists reveal that, contrary to previous concerns, SAI may actually enhance the carbon storage capacity of terrestrial ecosystems, particularly the Amazon, which is pivotal for global climate regulation.
Stratospheric Aerosol Injection is inspired by the natural cooling effects observed after major volcanic eruptions, which release vast quantities of sulfate aerosols into the stratosphere. These aerosols reflect sunlight and contribute to temporary cooling by reducing the solar energy that reaches Earth’s surface. The Exeter study’s simulations involved scenarios where SAI is deployed to offset warming from human-generated greenhouse gases, particularly carbon dioxide (CO2). Their models not only assess temperature impacts but delve deeply into terrestrial carbon dynamics and vegetation productivity under different emission and geoengineering scenarios.
One of the major apprehensions about SAI has been its potential to diminish photosynthesis and rainfall by limiting sunlight. Reduced sunlight could theoretically constrain plant growth and reduce vegetation productivity—especially in sensitive regions like tropical rainforests. However, the new Exeter research challenges this notion by showing increases in global land carbon storage under SAI scenarios. Using state-of-the-art coupled climate-carbon cycle models, the research finds that SAI can temper the adverse heat stress on both forests and soils, thereby fostering more robust carbon sequestration.
The Amazon basin emerges as a particularly compelling case in this study. Under a high-CO2 concentration trajectory combined with stratospheric aerosol injection, the Amazon’s land carbon storage increased by approximately 10.8 percent compared to a high-CO2-only baseline. This result is significant because it runs counter to many predictions suggesting the Amazon could suffer large-scale dieback or reduced carbon uptake under climate warming. The cooling induced by SAI mitigates thermal stress and soil respiration losses, promoting healthier ecosystem function and resilience.
Furthermore, when comparing the high CO2 plus SAI scenario to a middle-range CO2 emission projection—which produces a similar degree of global warming—the Amazon still demonstrates an 8.6 percent higher land carbon storage under geoengineering influence. This underscores the potential for SAI to not only counterbalance warming but also enhance vital carbon sinks beyond what conventional emission reductions might achieve. It emphasizes how carefully modeled geoengineering approaches could serve as an emergency tool in preserving ecosystems of global importance.
Professor Peter Cox, co-author and Director of Exeter’s Global Systems Institute, highlights the unexpected nature of these findings. He notes that across all scenarios investigated, including high and moderate CO2 paths with or without SAI, the Amazon rainforest’s productivity was surprisingly greatest under geoengineering conditions. This challenges existing paradigms about the risks and benefits of stratospheric aerosol deployment, suggesting a reevaluation of its environmental impact is warranted.
The Amazon rainforest is widely regarded as one of the most vulnerable biomes to climate-induced changes due to its sensitivity to temperature fluctuations and precipitation patterns. Deforestation further compounds this vulnerability by fragmenting habitats and disrupting natural cycles. This new study suggests that geoengineering interventions like SAI could, at least temporarily, protect the biome by reducing the thermal and hydrological stresses that contribute to carbon losses. Protecting the forest could be critical not only for preserving biodiversity but also for maintaining the carbon balance that influences global climate.
Published in the journal Earth System Dynamics, this research provides a comprehensive analysis of complex Earth system feedbacks involving climate, vegetation, and soil carbon interactions under geoengineering scenarios. While it acknowledges legitimate concerns regarding unintended side effects and governance challenges of deploying SAI at scale, the paper calls for open scientific discussion to evaluate both benefits and risks thoroughly. It stresses that SAI should not be viewed as a silver bullet but as a potential emergency measure complementing emission mitigation and forest conservation efforts.
In particular, Isobel Parry, lead author and researcher at Exeter’s Department of Mathematics and Statistics, emphasizes that the most effective long-term strategy to preserve the Amazon remains a dual approach: aggressively reducing deforestation and curtailing anthropogenic greenhouse gas emissions. Nevertheless, she suggests that SAI geoengineering might provide critical, albeit temporary, relief if global mitigation goals falter and the Amazon faces imminent degradation. The study invites policymakers and scientists alike to consider the role of geoengineering carefully and responsibly.
This investigation represents one of the most detailed modeling exercises to date elucidating how intervention in solar radiation balance affects large tropical biomes. It utilizes simulation runs across multiple climate and emissions scenarios, incorporating carbon cycle feedbacks and spatially detailed ecosystem responses. The findings signify a new chapter in geoengineering research by linking it directly to terrestrial carbon storage outcomes — a central parameter in future climate stabilization models.
Overall, the Exeter study compels the scientific community to reassess the potential ecological consequences of SAI geoengineering with a balanced lens. It motivates further interdisciplinary research to uncover the ranges of possible outcomes, including risks to hydrological cycles, biodiversity, and atmospheric chemistry. Future investigation will be crucial to develop deployment governance frameworks that prioritize safety, transparency, and environmental integrity.
The paper titled “Stratospheric aerosol injection geoengineering has the potential to increase land carbon storage and to protect the Amazon rainforest” not only advances climate science discourse but also provokes critical reflections about humanity’s toolbox for combating climate change. As global leaders grapple with escalating climate impacts, this research suggests geoengineering could play a controversial yet impactful supplemental role in safeguarding irreplaceable ecosystems like the Amazon rainforest.
Subject of Research: The impact of stratospheric aerosol injection geoengineering on land carbon storage and the protection of the Amazon rainforest under climate change scenarios.
Article Title: Stratospheric aerosol injection geoengineering has the potential to increase land carbon storage and to protect the Amazon rainforest
News Publication Date: 22-Apr-2026
Web References:
https://esd.copernicus.org/articles/17/387/2026/
DOI: 10.5194/esd-17-387-2026
Keywords
Geoengineering, Stratospheric Aerosol Injection, Climate Change, Amazon Rainforest, Carbon Storage, Earth System Dynamics, Global Warming Mitigation, Tropical Ecosystems, Climate Modeling, Anthropogenic Greenhouse Gases, Forest Conservation, Carbon Cycle
