Solar geoengineering has the potential to boost plant growth and carbon storage in the Amazon, according to a study.

Global temperatures are consistently breaking records, with the last 11 years being the warmest on record. This has led to increased interest in solar radiation management (SRM), often called geoengineering, aimed at reducing or counteracting global warming by reflecting sunlight away from the Earth.

One SRM method that has received a great deal of scientific attention is stratospheric aerosol injection (SAI). This involves injecting reflective particles into the upper atmosphere to artificially cool the Earth by increasing the reflection of incoming solar radiation.

However, concerns have been raised that SAI could suppress vegetation productivity by reducing sunlight and shifting rainfall patterns. 

Researchers at the University of Exeter used five state-of-the-art climate models to test what would happen if SAI was used to cool the planet. They compared three scenarios: a high CO₂ emissions scenario, a mid-range CO₂ emissions scenario and a high CO₂ emissions world that is cooled using SAI.

They found that the latter SAI scenario has the potential to actually increase land carbon storage, the natural process by which ecosystems absorb and store CO₂ from the atmosphere, compared with a mid-range warming scenario. 

The effects of SAI are especially clear in the Amazon rainforest, where land carbon storage increases by 10.8% compared to a high CO₂ scenario. According to the researchers, this is mainly because SAI reduces the warming that suppresses forest and soil carbon growth in this high CO₂ scenario.

The high CO₂ plus SAI scenario also results in 8.6% more land carbon in the Amazon rainforest compared to the mid-range CO₂ emissions scenario, which has a similar level of global warming.

Professor Peter Cox, director of Exeter’s global systems institute and study co-author, said: “Surprisingly, in these three scenarios, we find that the Amazon rainforest is most productive in the scenario with SAI geoengineering.”

The Amazon rainforest is considered particularly vulnerable to global warming and ongoing deforestation; however, the study suggests that SAI could protect this ecosystem against the risk of climate change-induced carbon losses.

The research team says that while there are many legitimate concerns about the possibility of SAI geoengineering in the real world, research on this matter and its impacts needs to be openly discussed.

Isobel Parry, PhD student in Exeter’s department of mathematics and statistics and study lead author, said: “The best protection for the Amazon rainforest in the long-term is a combination of reduced rates of both deforestation and anthropogenic climate change, but SAI might provide some emergency protection if we fail to get climate change under control.”

The study – Stratospheric aerosol injection geoengineering has the potential to increase land carbon storage and to protect the Amazon rainforest – has been published in the journal Earth System Dynamics. 

In the March-April 2026 issue of E+T we took a deep dive into geoengineering, exploring whether these methods can really save us from the worst effects of climate change.

Last year, the Royal Society published a report warning that geoengineering should “never” be the main policy response to climate change as it could exacerbate climate-induced stress on human populations if used incorrectly.