About The Working Group

Proposed solar radiation modification using a tethered balloon to inject sulfate aerosols into the stratosphere. Credit: Hughhunt, CC BY-SA 3.0 https://creativecommons.org/licenses/by-sa/3.0, via Wikimedia Commons

Geoengineering is a set of proposed activities deliberately designed to counter the impacts of environmental change resulting from global warming. It has received increasing attention in the face of failure to limit the inputs of greenhouse gases to the atmosphere.

These ideas are highly controversial among both scientists and the general public. Nevertheless, many schemes for geoengineering have been proposed and some have been extensively studied using complex climate models: these are usually divided between activities aimed at reducing the amount of carbon dioxide in the atmosphere (Carbon Dioxide Removal, CDR) and activities aimed at partially reducing the amount of incoming solar radiation at the surface by increasing the albedo (reflectivity) of the Earth-atmosphere system in order to temporarily cool the planet (Solar Radiation Modification, SRM). This could be done in various ways, such as injecting sulfate precursors in the stratosphere (like volcanoes do) or increasing the condensation nuclei in the marine boundary layer (like ship tracks do). This geoengineering option presents both known and unknown risks to the natural living world. Yet almost nothing is known about the potential impacts of implementation, continuation or termination on natural systems, their functions, and their biodiversity.

Projected surface temperature changes (upper panels) and precipitation changes (lower panels) in 2080-2100 comparing a world with high emissions (SSP5-8.5, ~1100 ppm CO2) versus one with lower emissions (SSP2-4.5, ~600 ppm CO2) (left panels) and a world with high emissions but temperatures cooled using sulfate aerosols at the same levels as SSP2-4.5. Output from CMPI6 models participating in the Geoengineering Model Intercomparison Project (Visioni et al., in review, 2021).

The goal of this workshop and its working group is to develop a research agenda to understand and predict how the biodiversity and functioning of natural systems would be affected by solar radiation modification. Members will develop information to inform policy and public discussion, provide knowledge to incorporate into teaching and outreach, and engage a diverse audience in discussions on the response of living systems to solar radiation modification geoengineering.

References

Zarnetske, P.L., J. Gurevitch, J. Franklin, P. Groffman, C. Harrison, J. Hellmann, F. Hoffman, S. Kothari, A. Robock, S. Tilmes, J. Wu, D. Visioni, L. Xia, and C.-E. Yang, (Accepted): Potential ecological impacts of climate intervention by reflecting sunlight to cool Earth. Proc. Nat. Acad. Sci.

S. Tilmes, D.E. MacMartin, J.T.M. Lenaerts, L. van Kampenhout, L. Muntjewerf, L. Xia, C.S. Harrison, K.M. Krumhardt , M.J. Mills, B. Kravitz, and A. Robock. (2020). Reaching 1.5oC and 2.0oC global surface temperature targets using stratospheric aerosol geoengineering. Earth Systems Dynamics 11:579–601, https://doi.org/10.5194/esd-11-579-2020

Visioni, D., Slessarev, E., MacMartin, D., Mahowald, N. M., Goodale, C. L., and Xia,L. (2020), “What goes up must come down: impacts of deposition in a sulfate geoengineering scenario”, Environmental Research Letters, 15(9), https://iopscience.iop.org/article/10.1088/1748-9326/ab94eb

Visioni, D., MacMartin, D. G., Kravitz, B., Boucher, O., Jones, A., Lurton, T., Martine, M., Mills, M. J., Nabat, P., Niemeier, U., Séférian, R., and Tilmes, S.: Identifying the sources of uncertainty in climate model simulations of solar radiation modification with the G6sulfur and G6solar Geoengineering Model Intercomparison Project (GeoMIP) simulations, Atmos. Chem. Phys. Discuss. [preprint], https://doi.org/10.5194/acp-2021-133, in review, 2021