An new study suggests that blocking sunlight by injecting particles into the atmosphere will not offset the crop damage caused by global warming. The team behind the study analyzed past effects of Earth-cooling volcanic eruptions and how crops respond to changes in sunlight to come to their conclusion.
“Shading the planet keeps things cooler, which helps crops grow better. But plants also need sunlight to grow, so blocking sunlight can affect growth. For agriculture, the unintended impacts of solar geoengineering are equal in magnitude to the benefits,” said lead author Jonathan Proctor of the University of California, Berkeley. “It’s a bit like performing an experimental surgery; the side-effects of treatment appear to be as bad as the illness.”
“Unknown unknowns make everybody nervous when it comes to global policies, as they should,” said Solomon Hsiang, co-lead author of the study and also from UC Berkeley. “The problem in figuring out the consequences of solar geoengineering is that we can’t do a planetary-scale experiment without actually deploying the technology. The breakthrough here was realizing that we could learn something by studying the effects of giant volcanic eruptions that geoengineering tries to copy.”
The team stresses the more research is needed into the ecological and human consequences of geoengineering.
“The most certain way to reduce damages to crops and, in turn, people’s livelihood and well-being, is reducing carbon emissions,” Proctor said.
“Perhaps what is most important is that we have respect for the potential scale, power and risks of geoengineering technologies,” Hsiang added. “Sunlight powers everything on the planet, so we must understand the possible outcomes if we are going to try to manage it.”
The findings were published in Nature.