Annex 4: Poster Abstracts Categorizati<strong>on</strong> of policy resp<strong>on</strong>ses to climate change with a focus <strong>on</strong> geoengineering Olivier Boucher 1 * and Piers Forster 2 1 Laboratoire de Météorologie Dynamique, IPSL / CNRS / Université P. et M. Curie, Paris, France 2 University of Leeds, United Kingdom Potential policy resp<strong>on</strong>ses to anthropogenic climate change can be broadly classified into four categories: additi<strong>on</strong>al research into climate sciences and carb<strong>on</strong>-free or carb<strong>on</strong>-neutral sources of energy, mitigati<strong>on</strong> (i.e. reducti<strong>on</strong> in anthropogenic emissi<strong>on</strong>s of greenhouse gases), adaptati<strong>on</strong> (i.e. reducti<strong>on</strong> of the impacts of climate change <strong>on</strong> natural and societal systems), and geoengineering. <strong>Geoengineering</strong> is usually defined as the intenti<strong>on</strong>al large-scale manipulati<strong>on</strong> of some element of the Earth system, in an attempt to counteract the effects of anthropogenic climate change. It is sometimes also referred to as climate interventi<strong>on</strong>, climate engineering or planetary engineering. To qualify as geoengineering, an interventi<strong>on</strong> into the Earth system has to deliberately attempt to tackle climate change by a method that does not seek to reduce anthropogenic emissi<strong>on</strong>s of greenhouse gases or other warming agents. For instance, the emissi<strong>on</strong> of anthropogenic aerosols from burning fossil fuels, although resp<strong>on</strong>sible for a cooling effect, is not c<strong>on</strong>sidered to be geoengineering because it is a by-product of our industrial and transportati<strong>on</strong> systems rather than a deliberate acti<strong>on</strong>. The interventi<strong>on</strong>, although it can be localized, also has to have a large-scale effect <strong>on</strong> the climate system. This clearly distinguishes geoengineering from, e.g., weather modificati<strong>on</strong> or other sorts of envir<strong>on</strong>mental engineering which attempt to modify the atmosphere or the land surface <strong>on</strong> a much smaller scale. A number of geoengineering schemes have been proposed in the scientific literature. Their technological maturity, effectiveness, scalability, residual impacts, unintended c<strong>on</strong>sequences and cost vary a great deal and remain uncertain. The Royal Society report (2009) <strong>on</strong> geoengineering categorized geoengineering schemes into solar radiati<strong>on</strong> management (SRM) and carb<strong>on</strong> dioxide removal (CDR) techniques. SRM schemes seek to artificially modify the solar radiati<strong>on</strong> budget to cool the planet. CDR schemes seek to artificially remove carb<strong>on</strong> dioxide from the atmosphere and store it in some form. While the distincti<strong>on</strong> between SRM and CDR is useful, it does not cover all potential geoengineering schemes <strong>on</strong>e can think of. For instance, it has been suggested that the terrestrial radiati<strong>on</strong> budget could also be artificially modified through changes in cirrus clouds and/or atmospheric water vapor in order to decrease the greenhouse effect. Carb<strong>on</strong> dioxide is not the <strong>on</strong>ly l<strong>on</strong>g-lived greenhouse gas in the atmosphere, and air removal can also be envisaged for methane (Boucher and Folberth, 2009) or other gases. Figure A.4.2 lists a large number of approaches to climate change and attempts to refine their groupings into distinct categories. It appears that there is not always a clear divisi<strong>on</strong> between geoengineering and adaptati<strong>on</strong> or between geoengineering and c<strong>on</strong>venti<strong>on</strong>al mitigati<strong>on</strong>. For instance, it has been suggested that the Earth’s albedo could be artificially increased over land by increasing the reflectivity of human dwellings (Akbari et al., 1999) or cropland (Ridgwell et al., 2009). These modificati<strong>on</strong>s may actually be more relevant to local and regi<strong>on</strong>al adaptati<strong>on</strong> to climate change than geoengineering. Furthermore the fr<strong>on</strong>tier between geoengineering and mitigati<strong>on</strong> is not very clear when it comes to biofuels. The large-scale exploitati<strong>on</strong> of biofuels associated with carb<strong>on</strong> capture and storage (CCS) has the potential to remove CO 2 from the atmosphere and qualifies as a CDR scheme, even though biofuels and CCS <strong>on</strong> their own are usually c<strong>on</strong>sidered as c<strong>on</strong>venti<strong>on</strong>al mitigati<strong>on</strong> tools. In c<strong>on</strong>clusi<strong>on</strong> we argue that it is important to develop a clear terminology <strong>on</strong> policy resp<strong>on</strong>ses to climate change, while recognizing that the fr<strong>on</strong>tier between these resp<strong>on</strong>ses is not always clear-cut. We will provide in this presentati<strong>on</strong> a first attempt at developing such a terminology. This will help to decide how geoengineering should fit (or not) in the portfolio of existing climate change policies. Multiple factors have to be c<strong>on</strong>sidered when comparing these policy resp<strong>on</strong>ses, including their technological maturity, effectiveness, scalability, timescale for implementati<strong>on</strong>, risk, residual climate change, unintended c<strong>on</strong>sequences, degree of interference with the climate system, the policy and governance challenges they pose, and their cost. References Akbari H., S. K<strong>on</strong>opacki, and M. Pomerantz, 1999: Cooling energy savings potential of reflective roofs for residential and commercial buildings in the United States. Energy 24, 391–407. <str<strong>on</strong>g>IPCC</str<strong>on</strong>g> <str<strong>on</strong>g>Expert</str<strong>on</strong>g> <str<strong>on</strong>g>Meeting</str<strong>on</strong>g> <strong>on</strong> <strong>Geoengineering</strong> - 45
Annex 4: Poster Abstracts Boucher O., and G.A. Folberth, 2009: New Directi<strong>on</strong>s: Atmospheric methane removal as a way to mitigate climate change? Atmospheric Envir<strong>on</strong>ment 44, 3343–3345. Ridgwell A., J.S. Singarayer, A.M. Hetheringt<strong>on</strong>, and P.J. Valdes, 2009: Tackling regi<strong>on</strong>al climate change by leaf albedo biogeoengineering. Current Biology 19, 146–150. The Royal Society, 2009: <strong>Geoengineering</strong> the climate: Science, governance and uncertainty. Royal Society, L<strong>on</strong>d<strong>on</strong>, UK. 82 pp., (ISBN: 9780854037735). Figure A.4.2: Categorizati<strong>on</strong> of existing and proposed policy resp<strong>on</strong>ses to climate change with a focus <strong>on</strong> geoengineering techniques. <str<strong>on</strong>g>IPCC</str<strong>on</strong>g> <str<strong>on</strong>g>Expert</str<strong>on</strong>g> <str<strong>on</strong>g>Meeting</str<strong>on</strong>g> <strong>on</strong> <strong>Geoengineering</strong> - 46