IPCC Expert Meeting on Geoengineering

Annex 5: Breakout Group Reports
Authors may also want to avoid singling out geoengineering by imposing special criteria that are not equally
applied to conventional mitigation. For example, it has been noted that CDR has a rebound effect (decreasing
atmospheric CO 2 would reduce ocean CO 2 uptake), but this also applies to conventional mitigation.
With regard to consideration of CDR techniques in the <strong>IPCC</strong> AR5, the group then considered tightening the definition of
CDR. Elements suggested for consideration by authors in the <strong>IPCC</strong> AR5 were the potential for techniques to:
and/or
1. significantly cool global climate (e.g., by removing greater than 1 GtC/yr of CO 2)
2. lead to significant trans-boundary impacts, other than the intended impacts of lowering global atmospheric CO 2.
A refined CDR definition might exclude some techniques from consideration as geoengineering in the <strong>IPCC</strong> AR5 on the
basis of scale (e.g., ocean pipes), or the relative absence of non-CO 2 trans-boundary effects (e.g., no-tillage agriculture).
The figure proposed by BOG I.3 (Figure A.5.1) was thought to be useful to conceptualize these aspects of CDR approaches.
On the basis of these criteria, CDR techniques that are on the left side of the dotted line could be the priorities for
assessment in the <strong>IPCC</strong> AR5.
Treatment of various aspects of CDR across <strong>IPCC</strong> AR5 Working Groups
The BOG discussed which chapter/section of the <strong>IPCC</strong> AR5 might treat each aspect of CDR, with Table 1 produced as a first
attempt at suggestions. The BOG also suggested that the following chapters may cover CDR in a broad sense: for Working
Group 1, Chapter 6 (carbon and other biogeochemical cycles); for Working Group 2, Chapter 20 (climate-resilient
pathways); for Working Group 3, Chapter 2 (risk, framework), Chapter 13 (international governance), Chapter 14 (national
policy).
As the table shows, the treatment of CDR (and geoengineering in general) could be distributed throughout the
contributions of the three <strong>IPCC</strong> AR5 Working Groups. This implies a challenge to present a coherent analysis of CDR. The
group felt that the <strong>IPCC</strong> could consider the following options to meet this challenge: (a) A Technical Report or Special
Report (but this would entail significant work and could only be undertaken after the <strong>IPCC</strong> AR5 process had been
completed); and (b) a topic or box in the synthesis report that brings together the assessment of CDR from across the three
Working Group reports.
Other suggestions
The group recommended that the expert meeting participants should serve as reviewers of the relevant chapters of the
<strong>IPCC</strong> AR5, to help ensure consistent treatment of geoengineering across the different <strong>IPCC</strong> Working Groups.
<strong>IPCC</strong> <strong>Expert</strong> <strong>Meeting</strong> on Geoengineering - 94