Study: Geoengineering Could Boost Amazon Rainforest Carbon Storage

New research from the University of Exeter has investigated the potential effects of a proposed climate intervention, known as stratospheric aerosol injection (SAI), on global vegetation. The study used advanced climate models to compare different future scenarios.

What is Stratospheric Aerosol Injection (SAI)?

SAI is a form of geoengineering designed to cool the planet by reflecting a portion of incoming solar radiation back into space. The method mimics the cooling effect observed after large volcanic eruptions.

Key Findings

The climate model projections indicate that implementing SAI alongside high CO₂ emissions could lead to an increase in global land carbon storage, compared to scenarios with high or mid-range emissions alone.

In the Amazon rainforest specifically, the models showed a significant increase in land carbon storage under a high CO₂ plus SAI scenario.

"Surprisingly, in these three scenarios, we find that the Amazon rainforest is most productive in the scenario with SAI geoengineering," stated co-author Professor Peter Cox.

The detailed results for Amazonia include:

• A 10.8% increase in land carbon storage under a high CO₂ plus SAI scenario, compared to a high CO₂ scenario without SAI.
• An 8.6% more land carbon in the high CO₂ plus SAI scenario compared to a mid-range CO₂ emissions scenario that resulted in similar levels of global warming.

The study suggests that the primary mechanism is that SAI reduces the warming that would otherwise suppress forest and soil carbon growth in high CO₂ scenarios.

Context and Cautions

The Amazon rainforest is widely considered vulnerable to vegetation loss from the combined pressures of rising temperatures and ongoing deforestation. This research implies that SAI could potentially act as a protective measure against climate change-induced carbon losses in the region.

However, the authors are clear about the limitations and concerns surrounding geoengineering.

"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," explained lead author Isobel Parry.

The research team emphasized that while there are legitimate concerns about the implementation of SAI geoengineering, research into its potential impacts should be part of an open scientific discussion.

Publication

The study, titled "Increased Amazon carbon storage under SAI geoengineering," was published in the peer-reviewed journal Earth System Dynamics.