Tailored Solar Radiation Management to Counteract Global Warming


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An aerosol in the upper atmosphere would reflect more energy. Photo by Soil-net library.

Creating Climate Change: New Findings

A new study, showing an innovative approach in SRM, was published in October 2012 in Nature Climate Change; this study takes into account the climatic differences of different areas, and the consequent variation in effects.

The research was performed by the School of Engineeringand Applied Science of Harvard University (US), in cooperation with the Californian Institute of Technology (Pasadena, US) and the Carnegie Institute of Global Ecology (Stanford, US).

Professor David Keith , from Harvard, leading scientist of the study, explained the most important and novel aspects of this work to Decoded Science: “In the past SRM was used as a one-size-fits-all methodology; in our study, on the contrary, we focused on managing specific risks – an example is the loss of Arctic sea ice.”

Tailoring and Improving the Modeling

To achieve the management of these specific risks, Professor Keith and his coworkers used an improved and tailored mathematical model. The researchers considered the impact of the climate to be a quadratic function of the deviation of both temperature and precipitation, relative to a pre-industrial baseline.

Moreover, they considered a system with both spatial and temporal degrees of freedom; this means they studied different locations and different times of the year (seasonal variation) – for both temperature and precipitation deviations, they used the average value and the worst-case scenario for each location.

Tailores SRM could counteract the Global Warming effect on the Arctic ice. Phot by Public Domain Images.

Improving Climate Change: Promising Results

Professor Keith told Decoded Science that the results were promising: “The results of our study show how SRM could be much more effective if a tailored non-uniform solar reduction is implemented. Considering the specific case of the Arctic sea ice, with a non-uniform solar reduction of just 0.5 % we could restore the same ice level of the pre-industrial baseline. With 0.5 % of uniform solar reduction, on the contrary, we would never achieve this result.”

Further Work and Optimization Needed

Despite the importance of these encouraging results, Professor Keith thinks that much more work needs to be done to improve the modeling further, and to have a better idea of SRM effects, both short and long-term. He tells us that, “Our study showed us the way to go; now we know that we should move away from the one-size-fits-all or all-or-nothing models which have been always used in the past. This is a very important achievement. Now that we know the direction to go, we should continue improving the modeling and the understanding of the SRM and its consequences.”


MacMartin, D., Keith, D., Kravitz, B., and Caldiera, K. Management of trade-offs in geoengineering through optimal choice of non-uniform radiative forcing. (2012). Nature Climate Change, doi:10.1038/nclimate1722. Accessed October 26, 2012.

Environmental Protection Agency (EPA). Climate Change Basics. (2012). Accessed October 26, 2012.

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