IPCC Expert Meeting on Geoengineering

Annex 3: Keynote Abstracts
be terminated abruptly, rapid warming could ensue (Matthews and Caldeira, 2007; Robock et al., 2008), and thus
deployment of an SRM system might be considered to pose an intergenerational transfer of this risk of sudden warming.
These characteristics of SRM techniques – that they could act quickly, be cheap to deploy and by imperfectly offset
anthropogenic climate change (Keith et al., 2010) – have led to varying perspectives on potential uses for SRM, ranging
from being part of a “portfolio” of climate response options that seek to reduce costs of mitigation of climate change risks
(Nordhaus, 1992; Wigley, 2006), to being a response reserved to address specific climate threats or climate “emergencies”
(Blackstock et al., 2009; Caldeira and Keith, 2010).
Based on these characteristics, the relationship between existing geoengineering proposals and current mitigation and
adaptation frameworks are explored in a preliminary way. As a starting point, the wedges framework of Socolow and
Pacala (2004) and the framework for considering adaptation outlined in <strong>IPCC</strong> AR4 (<strong>IPCC</strong> AR4, Working Group II, Chapter
18; <strong>IPCC</strong>, 2007) are used to consider CDR and SRM, identifying where similar and differentiating characteristics exist. This
approximate comparison demonstrates notable similarities between CDR and mitigation, while also identifying some
unique characteristics of SRM that are dissimilar to both mitigation and adaptation options; specifically, SRM focuses on
reducing exposure of populations and ecosystems to climatic changes, rather than their vulnerability to that change (which
is the focus of adaptation). The potential climatic and societal implications of these overlaps and differences, along with the
emergence of CDR and SRM techniques into mainstream climate policy discussions are explored briefly through the
application of scenarios methods.
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