IPCC Expert Meeting on Geoengineering

Annex 5: Breakout Group Reports
Locally or regionally targeted SRM
It was suggested that localized and/or regionally focused impact remediation with targeted SRM may also be considered;
for example, there is some literature on the use of SRM to cool the Arctic. It was unclear where in the AR5 this type of
focused regional intervention could be covered, that is, would it require a separate category or fall under the definition of
SRM? (N.B. geoengineering is usually defined as having large-scale or global impact).
Overlaps
There was a brief discussion about potential overlap of topics such as economics, between Working Groups II and III. It was
suggested that ethical questions may be discussed in Working Group II as well as III.
Definitions of Mitigation and Adaptation
There was discussion about the <strong>IPCC</strong> definition of 'mitigation', whether it refers to emissions reductions or whether it is a
more general term. The <strong>IPCC</strong> Working Group III AR4 definition is:
“Technological change and substitution that reduce resource inputs and emissions per unit of output. Although several
social, economic and technological policies would produce an emission reduction, with respect to Climate Change,
mitigation means implementing policies to reduce greenhouse gas emissions and enhance sinks.”
Although a dictionary definition of the word mitigation would generally mean reducing the impacts of something, it has
come to be used by the <strong>IPCC</strong> to refer to emissions reductions and sink enhancement. Therefore CDR may fall under this
definition but not SRM, even though ordinary usage of the word mitigation may include SRM. It was suggested that the
<strong>IPCC</strong> definition of mitigation should not be changed to include SRM, not least because SRM does not affect atmospheric
concentrations of greenhouse gases. This then led on to a discussion about whether SRM is a form of adaptation. The <strong>IPCC</strong>
Working Group III AR4 definition of adaptation is:
“Initiatives and measures to reduce the vulnerability of natural and human systems against actual or expected climate
change effects. Various types of adaptation exist, e.g. anticipatory and reactive, private and public and autonomous and
planned. Examples are raising river or coastal dikes, the substitution of more temperature-shock resistant plants for
sensitive ones, etc.“
Although SRM could be considered a type of adaptation (to climate change) it was suggested that SRM should be
distinguished from adaptation in the AR5.
Baselines and reference scenarios
Identifying the baselines or reference cases used in SRM literature is important but can be difficult. For Working Group I,
the GEOMIP modelling experiments are an example where consistent baselines are used. However, much of the modelling
work on SRM uses a variety of baselines and reference scenarios (such as 2xCO 2, 4xCO 2, ramping up or not). For Working
Group II it is likely to be difficult to find a consistent baseline or reference case across the literature. Similarly, for Working
Group III (e.g., governance, economics, risk and ethics) the relevance of baselines may need to be discussed even if the
literature is not entirely explicit or consistent. Across all Working Groups, analysis of SRM may need to compare scenarios,
such as with or without SRM. A suggestion was made to consider the impacts of SRM with reference to different
Representative Concentration Pathways (RCPs), that is, would SRM cause a shift from one set of RCP impacts to another,
and what novel impacts would be caused by SRM? It was concluded that it is very important to be transparent about the
reference cases and baseline assumptions.
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).
<strong>IPCC</strong> <strong>Expert</strong> <strong>Meeting</strong> on Geoengineering - 90