A solar reflector for the earth? Scientists investigate potential risks and benefits

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Nine of the hottest years in human history have taken place in the past decade. Without a major shift in this climate orbit, the future of life on earth is in doubt. Should people, whose fossil-fueled society drives climate change, use technology to slow down global warming?

Since September 2019, the Climate Intervention Biology Working Group, a team of internationally recognized experts in climate science and ecology, has met every month to satisfy science on the demand and consequences of geo-engineering in a cooler earth through a section of to reflect the sun. radiation from the planet — a climate intervention strategy known as solar radiation modification (SRM).

The group’s core report, “Potential Ecological Consequences of Climate Intervention by Reflecting Sunlight to Cool the Earth”, was published in the most recent publication. Proceedings of the National Academy of Sciences (PNAS).

“Participating in this working group was quite striking to me,” said co-author Peter Groffman, an ecosystem ecologist at the Advanced Science Research Center at The Graduate Center, CUNY and the Cary Institute of Ecosystem Studies. “I was not aware that the modeling of climate intervention was so advanced, and I think that climate modelers were not aware of the complexity of the ecosystems involved. This is a strong reminder of the importance of the need for multidisciplinary analysis of complex problems in Environmental Science. “

The interdisciplinary team is led by Phoebe Zarnetske, a community ecologist and associate professor in Michigan State University’s Department of Integrative Biology and the Ecology, Evolution and Behavior Program, and the ecologist Jessica Gurevitch, a leading professor in the Department of Ecology and Evolution at Stony. . Brook University.

Talks between Gurevitch and climate scientist Alan Robock, a leading professor in the Department of Environmental Sciences at Rutgers University, led to the pioneering group, which is more aware than most that geo-engineering is Earth’s atmosphere more than just a science fiction scenario .

“There is a lack of knowledge about the effects of climate intervention on ecology,” Zarnetske said. “As scientists, we need to understand and predict the positive and negative effects it can have on the natural world, identify important knowledge gaps and start predicting what effects it may have on land, marine and freshwater species and ecosystems in the future. ‘

The cost and technology needed to reflect the sun’s heat back into space is currently more achievable than other ideas on climate intervention, such as carbon dioxide (CO)2) from the air. The working group expects their lively discussions and open access paper will encourage an explosion of scientific research on how a climate intervention strategy, known as solar radiation (SRM), coupled with the reduction of greenhouse gas emissions, would affect the natural world.

The feasibility of planet-wide SRM efforts depends on accurate predictions of its myriad outcomes presented by the established computer simulations of the GeoModel Intercomparison Project (GeoMIP). The PNAS paper lays the groundwork for expanding the scope of GeoMIP to include the incredible variety and diversity of the Earth’s ecosystems.

“Although climate models have become quite advanced in predicting climate outcomes from different geo-engineering scenarios, we know very little about the potential risks to species and natural systems,” Gurevitch explained. “Are the risks of extinction, changing species in the community and the need for migration of organisms to survive under SRM greater than those of climate change, or does SRM reduce the risks posed by climate change?”

“Most of the GeoMIP models only simulate abiotic variables, but what about all the living things that are influenced by the climate and depend on energy from the sun?” Zarnetske added. “We need to understand the possible effects of SRM on everything from microorganisms in the soil to migration of monarch butterflies to marine systems.”

Zarnetske’s Spatial and Community Ecology Lab (SpaCE Lab) specializes in predicting how ecological communities respond to climate change across scales from the microcosm to the global, making it unique to help the working group gather important data for future SRM scenarios such as stratospheric aerosol to relieve. intervention (SAI), the focus of the paper.

SAI would reduce some of the sun’s incoming radiation by reflecting sunlight back into space, similar to what happens after large volcanic eruptions. Theoretically, it would be possible to continuously replenish the cloud and regulate its thickness and location to reach the desired target temperature.

But the article reveals the unexplored complexity of cascading relationships between ecosystem function and climate under different SAI scenarios. In fact, according to them, the mitigation of climate change must continue regardless of whether SRM is adopted, and the question is whether some or any SRM can be beneficial in addition to the carbon dioxide.

“Although SAI can cool the earth’s surface to a global temperature target, the cooling can be unevenly distributed, affecting many ecosystem functions and biodiversity,” Zarnetske said. “Rainfall and ultraviolet radiation on the surface will change, and SAI will increase acid rain and not soften the acidification of the ocean.”

In other words, SRM is not a magic bullet to solve climate change. Until the working group’s efforts inspire new research into the effects of different climate intervention scenarios, SRM is more akin to a shot in the dark.

“We hope that this article will pay much more attention to this issue and increase collaboration between scientists in the field of climate science and ecology,” Gurevitch added.

The Climate Intervention Biology Working Group is funded by the National Science Foundation and will present sessions at two upcoming scientific conferences: “Biosphere Responses to Geoengineering” at this month’s annual meeting of the American Association for the Advancement of Science (AAAS) and at The Ecological Society of America in August 2021.


Geoengineering is only a partial solution to fight climate change


More information:
Phoebe L. Zarnetske et al., “Potential ecological consequences of climate intervention by reflecting sunlight to cool the earth,” PNAS (2021). www.pnas.org/cgi/doi/10.1073/pnas.1921854118

Provided by Graduate Center, CUNY

Quotation: A solar reflector for the earth? Scientists investigate potential risks and benefits (2021, April 5), detected on April 6, 2021 from https://phys.org/news/2021-04-sun-reflector-earth-scientists-explore.html

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