IPCC Expert Meeting on Geoengineering

Annex 5: Breakout Group Reports
Several other possible techniques such as hurricane suppression, modifying storm track position and protecting glaciers
were also discussed. Some participants thought that these ideas were too small scale and may be better considered on the
scale of adaptation, but they could also be assessed by the <strong>IPCC</strong> where literature is available.
Framing
The group felt that it was important to consider frameworks for assessing geoengineering, such as in the wider context of
mitigation and climate change adaptation. Choice of baseline for comparing techniques was repeatedly discussed. The
group acknowledged that publications have different baselines and this could make assessment of the literature difficult.
Activities such as the Geoengineering Model Intercomparison Project (GEOMIP) could be useful as baselines are
comparable (Kravitz u. a. 2011).
BOG participants discussed value judgments in assessing geoengineering techniques. Words such as “good” and “bad” or
even “effectiveness” and “side-effects” can be awkward when there are winners and losers both from geoengineering and
mitigation. Authors should try to be explicit when value judgments and/or assumptions are made.
The BOG discussed the advantages of the radiative forcing metric. It also considered the importance of assessing other
aspects of the physical climate, as not all radiative forcings are created equal: there are regional effects and hydrological
cycle effects, and radiative forcings can have different efficacies for even the globally averaged surface temperature.
Other framing issues considered were the timescale of deployment, the testability of techniques, their scalability, any
termination effects from turning schemes off, and the timescales of such effects. How SRM could influence CO 2 was also
considered, as were the costs that might be included in assessments.
Overall there was a general focus on Working Group I issues. Due to lack of time and the direction of the conversation
several issues particularly surrounding Working Group II and III issues were not covered in detail.
References
Kravitz B., Alan Robock, O. Boucher, H. Schmidt, K.E. Taylor, G. Stenchikov, and M. Schulz, 2011: The Geoengineering
Model Intercomparison Project (GeoMIP). Atmospheric Science Letters 12, 162–167. (DOI: 10.1002/asl.316).
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