As the planet heats up and climate warnings grow more urgent, scientists are studying ideas that once sounded like science fiction. One of the most controversial involves changing the sky itself. A new study from the University of Exeter suggests that a climate engineering technique called stratospheric aerosol injection, or SAI, could help protect the Amazon rainforest from severe climate damage. Using advanced climate models, researchers found that artificially cooling the planet may allow the rainforest to store more carbon and remain more productive, even under extremely high carbon dioxide levels. The findings, published in the journal Earth System Dynamics, arrive at a moment of growing concern for the Amazon. Scientists increasingly fear that rising temperatures and deforestation could push the rainforest toward large-scale dieback, threatening one of the planet’s most important carbon sinks. “Surprisingly, in these three scenarios, we find that the Amazon rainforest is most productive in the scenario with SAI geoengineering,” said co-author Professor Peter Cox, Director of Exeter’s Global Systems Institute. Maps showing the anomaly in the land carbon flux due …