Solar Geoengineering

Ava Otano, Student Live Journalist

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What is Geoengineering?

Geoengineering is a term used to describe several technologies with the capacity to manipulate the environment or lessen the effects of climate change. The effects of this technology would be inferior to emission reduction, and would not “solve” humanity’s ability to cope with a changing climate, but it could aid in these efforts. There are two main categories of geoengineering: carbon geoengineering, and solar geoengineering.

What is Solar Geoengineering?

Solar geoengineering either reflects a small fraction of sunlight back into space or increases the amount of sunlight that escapes into space. This is done with the intent to cool the planet. This technology does not directly address the cause of climate change.

Solar geoengineering, also called Solar Radiation Management (SRM), comes in many forms. These include marine cloud whitening, cirrus cloud thinning, space-based technologies, stratospheric aerosol scattering, and others.

In marine cloud whitening, attempts are made to “brighten marine clouds to reflect more sunlight back into space.” This would lessen the amount of sunlight that reaches the surface of Earth and therefore reduce the heat.

In cirrus cloud thinning, high-altitude clouds are reduced to allow more long-range radiation to enter space. With more heat escaping, temperatures would be reduced. Space-based technologies include positioning sun shields in orbit around Earth to reflect more sunlight back into space. Finally, stratospheric aerosol scattering involves putting substances such as sulfate aerosols or calcium carbonate into the atmosphere in order to reflect and scatter a fraction of the sunlight into space.

These technologies have both benefits and flaws. Together, they have the potential to reduce climate change when partnered with low counts of carbon emissions. This could minimize extreme temperatures, changes in water availability, and intensity of tropical storms. By changing the temperature of the ocean surface, coral bleaching is reduced, maintaining favorable conditions for coral reefs. This could also slow or stop species from shifting polewards, which poses dangers to tropical fisheries. This could also lessen sea ice loss, limiting changes in ocean circulation.

Unfortunately, this technology also has negative factors. The local impact of this technology is variable. There are many uncertainties associated with these technologies. Also, because it does not address the problem of carbon emissions, ocean acidification continues, changing ocean chemistry and harming marine ecosystems. The only way SRM addresses carbon emissions is through feedback loops (i.e. as the temperature rises, so do carbon emissions). Also, there are suspicions that less sunlight could affect the water cycle.

Solar geoengineering is not the solitary solution to climate change, but it could be used to lessen the problems brought by it. It’s necessary for people to cut down on their carbon emissions for any of these technologies to make a sizeable impact.

Sources:

https://geoengineering.environment.harvard.edu/geoengineering

https://www.carbonbrief.org/halving-global-warming-with-solar-geoengineering-could-offset-tropical-storm-risk