IPCC Expert Meeting on Geoengineering

Annex 5: Breakout Group Reports
Breakout Group III.2: Solar Radiation Management in the Working Group
Contributions to the <strong>IPCC</strong> AR5
Chair: Don Wuebbles
Rapporteur: Thomas Leisner
The summary that follows, written by the Chair and Rapporteur, characterizes the main points of the BOG III.2 discussion. It
may not reflect the personal views of the BOG’s Chair and Rapporteur. The summary is intended for consideration by <strong>IPCC</strong>
authors of the Fifth Assessment Report (AR5), but is neither endorsed nor approved by the <strong>IPCC</strong> or its Working Groups.
Participants in the BOG considered a series of questions related to geoengineering research, developed by the meeting’s
Scientific Steering Group.
Questions suggested for discussion:
Where might each of the important Solar Radiation Management approaches and issues be evaluated within the <strong>IPCC</strong>
AR5 (i.e., in which Working Group contribution and in which chapters)?
Where might it be best to cover cross-cutting issues that do not neatly fall within one chapter or one Working Group’s
contribution?
Are there some aspects of Solar Radiation Management that require expertise that is missing from the author teams of
Working Group I, II and III? Are there other things the author teams can do to improve their ability to develop a high
quality assessment?
What geoengineering-related glossary terms might the AR5 include? For those terms, what might the corresponding
entries be?
Introduction
The group felt that it will be important to ensure a coherent coverage of geoengineering throughout the AR5 and that the
crosscutting issues would benefit from consistent treatment in the respective chapters. This includes terminology as well as
specific examples or measures of Solar Radiation Management (SRM) that might be discussed. Therefore, the group
focussed mainly on questions one and two and to a lesser extent on questions three and four.
Where might each of the most important SRM approaches and issues be evaluated within the <strong>IPCC</strong> AR5
(i.e., in which Working Group contribution and in which chapters)?
The AR5 chapters where geoengineering should be mentioned have been considered by authors already, particularly in
Working Group I, and the group highlighted the importance of mentioning SRM in all relevant chapters. The BOG
suggested that a common table template could be used throughout the chapters, with the columns reflecting the various
SRM approaches and the rows corresponding to the issues being addressed (see BOG Report I.2). The columns could be the
same throughout AR5, but the rows could be specific to the relevant <strong>IPCC</strong> Working Group or chapter. Some suggestions for
approaches and issues to be considered were worked out in a previous BOG and are summarized below. For in depth
discussion of specific issues, the AR5 lead authors might want to concentrate some discussion especially on the same
specific SRM approach (e.g., some variant of stratospheric aerosol injection) to achieve consistency throughout the report.
Where might it be best to cover cross-cutting issues that do not neatly fall within one chapter or one
Working Group’s contribution?
Crosscutting issues such as geoengineering benefit from consideration throughout the three Working Groups and in the
synthesis report. The group discussed that a crosscutting committee could be formed to establish continuous
communication among the <strong>IPCC</strong> Working Groups on geoengineering issues.
<strong>IPCC</strong> <strong>Expert</strong> <strong>Meeting</strong> on Geoengineering - 91