In a new study published in the journal Climatic Change, Steven J. Smith & Philip J. Rasch focused on the interplay of potential deployment of Solar Radiation Management geoengineering options and mitigation of greenhouse gas emissions. Among the study’s take-aways:

1. Solar radiation management geoengineering options are only viable in conjunction with emissions reductions due to ocean acidification impacts, the threat of the “termination effect” if we ceased the use of SRM, and the inevitable domination of carbon dioxide in forcing if emissions are not addressed;
2. Should climate sensitivity prove to be high (4.5C/CO2 doubling), global temperatures are projected in the study to increase by 2.4C by the mid-21^stcentury, with even greater temperature increases the longer the delay in transition to a peak and decline scenario;
   1. Emissions reductions can’t ensure that temperature remains below any given threshold in a high scenario threshold; this might justify the use of SRM techniques over an “interim period;”
3. A constant forcing of -0.90 W/m²from 2040 through 2110 via SRM could reduce global mean temperature below a 2C threshold under a high climate sensitivity scenario, with global average temperatures reduced to near 2C throughout this period;
   1. SRM application could be scaled back with lower climate sensitivity results
4. If SRM approaches are applied at low levels, it may be impossible to assess effectiveness for decades;
5. SRM will create different spatial and spectral characteristics and thus not exactly counter greenhouse gas forcing. This means that it would change the climate and thus necessitate additional assessment before deployment could be considered;
6. Policy measures to establish an express linkage between SRM use and greenhouse gas emissions reductions should be considered.

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1. Solar Radiation Management Geoengineering and Climate Sensitivity
2. Geoengineering and Solar Radiation Management
3. Research Needs for Solar Radiation Management (Climate Geoengineering)
4. New Study on How to Achieve Equity in Long-Term Policymaking on Climate
5. New Article on Solar Radiation Management Geoengineering