Solar geoengineering could cause widespread crop failure
Plans to cool the planet by reflecting sunlight back into space would be just as damaging to crop production as extreme heat caused by climate change, the University of California, Berkley, has found.
The research shows that, while helping crops to grow, any improvements in yield caused by cooler temperatures would be cancelled out by lower productivity due to reduced sunlight.
This has important implications for understanding the effects of solar geoengineering, a method proposed to help humanity manage the impacts of global warming.
“It’s a bit like performing an experimental surgery – the side-effects of treatment appear to be as bad as the illness,” study lead author, Jonathan Proctor, said.
“For agriculture, the unintended impacts of solar geoengineering are equal in magnitude to the benefits.”
It has been argued that purposely injecting sulfate aerosols into the upper atmosphere could reflect sunlight and artificially cool the earth, replicating a phenomenon observed when volcanoes erupt.
A study in the Philippines back in 1991 successfully reduced the average global temperature by around half a degree using this method.
However, after monitoring crop production over 30 years, and observing aerosols in the atmosphere using satellite images, the latest study concluded that the loss of sunlight would cancel out the benefits of reduced heat.
Despite the results, Proctor said: “I don’t think we should necessarily write off solar geoengineering. For agriculture, it might not work that well, but there are other sectors of the economy that could potentially benefit substantially.”
Proctor emphasised the need for more research into the human and ecological consequences of deliberately manipulating the Earth’s climate system, both good and bad.
The latest study did not address other types of geoengineering like carbon capture and storage, or the impact on the protective ozone layer, and who decides how temperatures should be.
“Society needs to be objective about geoengineering technologies and develop a clear understanding of the potential benefits, costs and risks,” Proctor continued.
“At present, uncertainty about these factors dwarfs what we understand.”
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