Ashley Goland ’23
Solar geoengineering is a technology that aims to reflect incoming sunlight away from the Earth to reduce the rise of global temperatures, and one proposed approach is to send aerosols into the atmosphere. Although this method may seem like a quick, relatively cheap way to delay further climate change, the effects it could have upon marine and terrestrial organisms are not yet known. In fact, a group of six scientists, including Stony Brook professor Jessica Gurevitch, worries that the sudden changes brought about by use of this technology could threaten species that are not equipped to adjust quickly.
Historical data and the Geoengineering Model Intercomparison Project (GeoMIP) allowed testing of future climate scenarios in which solar geoengineering was or was not implemented. Using numerous models to minimize errors, researchers studied situations in which aerosols were injected into the atmosphere annually for fifty years and then abruptly stopped for twenty years; and observed the predicted consequences on temperature and precipitation.
Rapid implementation of geoengineering could stall and possibly even reverse effects of global warming for a decade or two, but similar climate-driven movements of species were observed in both the simulations involving geoengineering and those without geoengineering. Precipitation would be reduced in numerous areas, increasing the risk for serious forest fires in the Earth’s tropical regions— leading, in turn, to poorer air quality and a loss of biodiversity. Moreover, climate signals were projected to fluctuate as additional years elapse, putting a strain on the populations of certains species and potentially leading to extinctions.
On the tail end of the project, if the application of geoengineering was to be terminated just as suddenly as it began, the resulting large climate velocities (measurements used to track direction and speed of climate shifts) could cripple species that are unable to adapt to major changes in climate. Temperature velocities on land and sea in a post-geoengineering world are expected to be far higher than in a normal scenario, and as the most extreme projected velocities are expected in well-known hotspots of biodiversity such as tropical oceans and the Amazon Basin, a great number of species would be put at risk.
Climate engineering is a viable route to buying time in a changing global climate. However, the outcomes of this research suggest that further consideration is needed to find the best way forward, bearing ecological preservation in mind. Investigations into other geoengineering procedures may allow researchers to develop a safer application of this technology.
 C.H. Trisos, et al., “Potentially dangerous consequences for biodiversity of solar geoengineering implementation and termination.” Nature Ecology & Evolution 2, 475-482 (2018). Doi: https://doi.org/10.1038/s41559-017-0431-0
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