Editing IPCC:AR6/WGIII/Chapter-12 (section)

=== 12.6.2 Sectoral Policy Interactions (Synergies and Trade-offs) ===

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A taxonomy of policy types and attributes is provided by [[IPCC:Wg3:Chapter:Chapter-13#13.6|Section 13.6]] . In addition, the sectoral chapters provide an in-depth discussion of important mitigation policy issues such as policy overlaps, policy mixes, and policy interaction as well as policy design considerations and governance. The point of departure for the assessment in this chapter is a focus on cross-sectoral perspectives aiming at maximising policy synergies and minimising policy trade-offs.

'''Synergies and trade-offs resulting from mitigation policies are not clearly discernible from either sector-level studies or global and regional top-down studies. Rather, they would require a cross-sectoral integrated policy framework''' ( [[#von%20Stechow--2015|von Stechow et al. 2015]] ; [[#Monier--2018|Monier et al. 2018]] ; [[#Pardoe--2018|Pardoe et al. 2018]] ; [[#Singh--2019|Singh et al. 2019]] ) or multiple-objective-multiple-impact policy assessment framework identifying key co-impacts and avoiding trade-offs ( ''robust evidence, high agreement'' ) ( [[#Ürge-Vorsatz--2014|Ürge-Vorsatz et al. 2014]] ) ''.''

Sectoral studies typically cover differentiated response measures while the IAM literature mostly uses uniform efficient market-based measures. This has important implications for understanding the differences in magnitude and distribution of mitigation costs and potentials of [[#12.2|Section 12.2]] ( [[#Karplus--2013|Karplus et al. 2013]] ; [[#Rausch--2014|Rausch and Karplus 2014]] ). There is a comprehensive literature on the efficiency of uniform carbon pricing compared to sector-specific mitigation approaches, but relatively less literature on the distributional impacts of carbon taxes and measures to mitigate potential adverse distributional impacts ( [[#Rausch--2014|Rausch and Karplus 2014]] ; [[#Rausch--2015|Rausch and Reilly 2015]] ; [[#Wang--2016b|Wang et al. 2016b]] ; [[#Åhman--2017|Åhman et al. 2017]] ; [[#Mu--2018|Mu et al. 2018]] ). For example, in terms of cross-sectoral distributional implications, studies find negative competitiveness impacts for the energy-intensive industries ( ''robust evidence,'' ''medium agreement'' ) ( [[#Rausch--2014|Rausch and Karplus 2014]] ; [[#Wang--2016b|Wang et al. 2016b]] ; [[#Åhman--2017|Åhman et al. 2017]] ).

Strong interdependencies and cross-sectoral linkages create both opportunities for synergies and the need to address trade-offs. This calls for coordinated sectoral approaches to climate change mitigation policies that mainstream these interactions ( [[#Pardoe--2018|Pardoe et al. 2018]] ). Such an approach is also called for in the context of cross-sectoral interactions of adaptation and mitigation measures, examples are in the agriculture, biodiversity, forests, urban, and water sectors ( [[#Arent--2014|Arent et al. 2014]] ; [[#Berry--2015|Berry et al. 2015]] ; [[#Di%20Gregorio--2017|Di Gregorio et al. 2017]] ). Integrated planning and cross-sectoral alignment of climate change policies are particularly evident in developing countries’ NDCs pledged under the Paris Agreement, where key priority sectors such as agriculture and energy are closely aligned between the proposed mitigation and adaptation actions in the context of sustainable development and the SDGs. An example is the integration between climate-smart agriculture and low-carbon energy ( ''robust evidence'' , ''high agreement'' ) ( [[#Antwi-Agyei--2018|Antwi-Agyei et al. 2018]] ; [[#England--2018|England et al. 2018]] ). Yet, there appear to be significant challenges relating to institutional capacity and resources to coordinate and implement such cross-sectoral policy alignment, particularly in developing country contexts ( [[#Antwi-Agyei--2018|Antwi-Agyei et al. 2018]] ) ''.''

Another dimension of climate change policy interactions in the literature is related to trade-offs and synergies between climate change mitigation and other societal objectives. For example, in mitigation policies related to energy, trade-offs and synergies between universal electricity access and climate change mitigation would call for complementary policies such as pro-poor tariffs, fuel subsidies, and broadly integrated policy packages (Dagnachew et al. 2018). In agriculture and forestry, research suggests that integrated policy programmes enhance mitigation potentials across the land-use-agriculture-forestry nexus and lead to synergies and positive spillovers ( [[#Galik--2019|Galik et al. 2019]] ). To maximise synergies and deal with trade-offs in such a cross-sectoral context, evidence-based/informed and holistic policy analysis approaches like nexus approaches and multi-target back-casting approaches that take into account unanticipated outcomes and indirect consequences would be needed ( ''robust evidence, high agreement'' ) ( [[#Klausbruckner--2016|Klausbruckner et al. 2016]] ; Hoff et al. 2019; [[#van%20der%20Voorn--2020|van der Voorn et al. 2020]] ) ( ) ''.''

The consequences of large-scale land-based mitigation for food security, biodiversity ( [[#Dasgupta--2021|Dasgupta 2021]] ), the state of soil, water resources, and so on can be significant, depending on many factors, such as economic development (including distributional aspects), international trade patterns, agronomic development, diets, land-use governance and policy design, and not least climate change itself ( [[#Winchester--2015|Winchester and Reilly 2015]] ; [[#Fujimori--2018|Fujimori et al. 2018]] ; [[#Hasegawa--2018|Hasegawa et al. 2018]] ; [[#Van%20Meijl--2018|Van Meijl et al. 2018]] ). Policies and regulations that address other aspects apart from climate change can indirectly influence the attractiveness of land-based mitigation options. For example, farmers may find it attractive to shift from annual food/feed crops to perennial grasses and short rotation woody crops (suitable for bioenergy) if the previous land uses become increasingly restricted due to impacts on groundwater quality and eutrophication of water bodies ( ''robust evidence'' , ''medium agreement'' ) (Sections 12.4 and 12.5).

Finally, there are knowledge gaps in the literature particularly in relation to policy scalability and the extent and magnitude of policy interactions when scaling the policy to a level consistent with low GHG emissions pathways such as 2°C and 1.5°C.

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