Scientists in the Climate Intervention Biology Working Group, in which Jessica Hellmann of the University of Minnesota Environmental Institute (UM) is researching the impact of solar climate interventions on ecology.
The study was published in Proceedings of the National Academy of Sciences.
The research group, which included ecologists and climate scientists from top research universities globally, found that more studies were needed to understand the environmental effects of solar radiation modification (SRM) technologies that reflect small amounts of sunlight into space.
The researchers focused on a specific proposed SRM approach – called stratospheric aerosol intervention (SAI) – to create a sulfate aerosol cloud in the stratosphere to reduce some of the incoming radiation and sunlight. This cloud could theoretically be regulated by size and location.
SAI is similar to positioning small reflective particles in the air to repel some of the solar radiation back into space so that part of the radiation does not reach and heat the Earth.
Researchers reiterate that the priority should be to reduce greenhouse gas emissions and preserve biodiversity and ecosystem functions.
We are just beginning to consider the risks and benefits of geoengineering and it is crucial to include ecosystems in cost-benefit studies. We should only do geoengineering if its benefits far outweigh its downsides. As our efforts to halt climate change are modest and slow, the reason for considering geoengineering is growing, and this paper presents ecologists engaging in geoengineering conversation.
Jessica Hellmann, Director, Environmental Institute, University of Minnesota
The complicated nature of the cascading relationships present between climate and ecosystems within the SAI — along with the length, quantity, time, and interruption of the SAI scenario — implies that the SAI is not just a thermostat that reduces heat by several degrees.
Other potential impacts of SAIs are changes in rainfall and an increase in surface UV rays. Although SAI can cool overheated Earth, it cannot combat all the effects of increased atmospheric CO2, like stopping the acidification of the ocean.
When approaching complex issues like these, there is a broad theoretical understanding of the inherent patterns of biodiversity on the Earth’s surface, but that understanding is often given to more detailed experiments examining the biological and physical mechanisms underlying these patterns..
Phoebe Zarnetske, co-lead author of the study and associate professor, Department of Integrative Biology and Ecology, Evolution and Behavior Program, Michigan State University
“I hope the paper will be able to convince ecologists that exploring nature’s response to solar geoengineering is not only important but also interesting – touching on basic environmental issues on topics as diverse as photosynthesis and animal migration, ”Said U alumni Shan Kothari, who contributed to the study while he was at the College of Biological Sciences before joining the University of Montreal.
According to Kothari, an example of how other researchers can look at the results of the study is the assessment of specific conditions arising from solar geoengineering scenarios that can help or hinder the potential of ecosystems to store carbon.
Kothari added that such studies could help the international community think about solar geoengineering with more awareness of the possible benefits and threats.
The study is co-led by Jessica Gurevitch, an ecologist at Stony Brook University in New York. This study was financially supported by the National Science Foundation.
Zarnetske, PL, and others. (2021) Potential environmental impacts of climate interventions by reflecting sunlight to cool the Earth. Proceedings of the National Academy of Sciences. doi.org/10.1073/pnas.1921854118.