Scientists in the Climate Intervention Biology Working Group, which includes Jessica Hellmann from the University of Minnesota (U of M) Institute on the Environment, examined the impact of solar climate interventions on ecology.
The study was published in the Proceedings of the National Academy of Sciences.
The research group, which included ecologists and climate scientists from top-class research universities on a global scale, discovered that more studies are required to comprehend the ecological effects of solar radiation modification (SRM) technologies that reflect small amounts of sunlight again into space.
The researchers concentrated on a particular proposed SRM approach—called stratospheric aerosol intervention (SAI)—to make a sulfate aerosol cloud in the stratosphere to decrease a part of incoming radiation and sunlight. This cloud could be theoretically regulated in size and location.
SAI is similar to positioning small reflective particles in the air to reflect a part of the solar radiation again to space, so that a portion of the radiation does not reach and warm Earth.
The researchers reiterate that the priority should be to achieve a decrease in greenhouse gas emissions and the conservation of biodiversity and ecosystem functions.
We are just starting to consider the risks and benefits of geoengineering, and it’s critical that we include ecosystems in cost-benefit studies We should only pursue geoengineering if its benefits strongly outweigh its downsides. Because our efforts to stem climate change are modest and slow, the case for considering geoengineering is growing, and this paper represents the ecologists chiming in to the geoengineering conversation.
Jessica Hellmann, Director, Institute on the Environment, University of Minnesota
The complicated nature of cascading relationships present between climate and ecosystems under SAI—jointly with the length, amount, timing and termination of SAI scenarios—implies that SAI is not merely a thermostat that reduces the heat by a couple of degrees.
SAI’s other prospective impacts are changes in rainfall and increases in surface UV rays. Although SAI may cool the Earth that is overheated, it cannot combat all of the impacts of increasing atmospheric CO2, like stopping ocean acidification.
When we approach complex questions like these, there is a broad scale, theoretical understanding of the inherent patterns of biodiversity across the surface of Earth, but this understanding is often informed by finer-scale experiments that test the biological and physical mechanisms underlying those patterns.
Phoebe Zarnetske, Study Co-Lead Author and Associate Professor, Department of Integrative Biology and Ecology, Evolution, and Behavior Program, Michigan State University
“I hope the paper can convince ecologists that research about nature's responses to solar geoengineering is not just important, but also interesting—touching on core ecological questions about topics as varied as photosynthesis and animal migration,” stated U of M alumni Shan Kothari, who contributed to the study during his time at the College of Biological Sciences before joining the University of Montreal.
According to Kothari, an example of how other researchers can view the results of the study is to assess the special conditions arising from solar geoengineering scenarios that might help or hinder the potential for ecosystems to store carbon.
Kothari added that such studies could help the international community to think about solar geoengineering with more awareness of the possible advantages and threats involved.
The co-lead author of the study is Jessica Gurevitch, an ecologist at Stony Brook University in New York. This study was financially supported by the National Science Foundation.
Zarnetske, P. L., et al. (2021) Potential ecological impacts of climate intervention by reflecting sunlight to cool Earth. Proceedings of the National Academy of Sciences. doi.org/10.1073/pnas.1921854118.