Editing IPCC:AR6/WGII/Chapter-18 (section)

===== 18.2.5.3.1 Trade-offs and synergies in adaptation, mitigation and climate resilient development =====

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Since AR5, a growing body of literature has emerged that frames adaptation processes as endogenous socioeconomic dynamics, exogenous driving forces and explicit decisions ( [[#Barnett--2014|Barnett et al., 2014]] ; [[#Maru--2014|Maru et al., 2014]] ; [[#Butler--2016|Butler et al., 2016]] ; [[#Kingsborough--2016|Kingsborough et al., 2016]] ; [[#Werners--2018|Werners et al., 2018]] ). Central to this framing is a shift away from viewing adaptation as discrete sets of options that are selected and implemented to manage risk, to thinking about adaptation as a social process that evolves over time, includes multiple decision points, and requires dynamic adjustments in response to new information about climate risk, socioeconomic conditions and the value of potential adaptation responses ( ''very high confidence'' ) ( [[#Haasnoot--2013|Haasnoot et al., 2013]] ; [[#Wise--2016|Wise et al., 2016]] ). This aligns adaptation with aspects of development thinking, including questions around the capacity and agency of different actors to effect change, the governance of adaptation, and the contingent nature of adaptation needs and effectiveness on the future evolution of society and climate change risk.

While ensuring development and adaptation produce synergies that allow for the achievement of sustainable development is challenging, modelling exercises suggest that there are pathways where synergies among the SDGs are realised ( ''very high confidence'' ) ( [[#Roy--2018|Roy et al., 2018]] ; [[#Van%20Vuuren--2019|Van Vuuren et al., 2019]] ) ( [[#18.5|Section 18.5]] ), particularly if longer time horizons are used. These pathways require progress on multiple social, economic, technological, institutional and governance aspects of development, including building human capacity, managing consumption behaviour, decarbonisation of the global economy, improving food and water security, modernising cities and infrastructure, and innovations in science and technology ( [[#Van%20Vuuren--2019|Van Vuuren et al., 2019]] ) ( [[#18.3|Section 18.3]] ). In addition, Olsson et al, ( [[#Olsson--2014|Olsson et al., 2014]] ) and [[#Roy--2018|Roy et al. (2018)]] emphasise the importance of integrating considerations for social justice and equity in the pursuit of sustainable development ( [[#Gupta--2017|Gupta and Pouw, 2017]] ).

The significant overlaps and linkages between development and adaptation practice and a lack of conceptual clarity about adaptation pose a conundrum for scholars (e.g., [[#Bassett--2013|Bassett and Fogelman, 2013]] ; [[#Webber--2016|Webber, 2016]] ), who raise concerns that this potentially leads to trade-offs or mislabelling ( [[#Few--2017|Few et al., 2017]] ). This framing of adaptation and development can result in competition between attainment of sustainable development and policies to reduce the impacts of climate change ( [[#Ribot--2011|Ribot, 2011]] ). Such trade-offs are illustrated by ( [[#Moyer--2019|Moyer and Bohl, 2019]] ) who use a baseline development trajectory based on current trends to project progress on SDGs by 2030. This work concluded that only marginal gains are likely to be achieved under that pathway over the next decade ( [[#Barnes--2019|Barnes et al., 2019]] ).

Emerging evidence also suggests that many adaptation-labelled strategies may exacerbate existing poverty and vulnerability or introduce new inequalities, for example by affecting certain disadvantaged groups more than others, even to the point of protecting the wealthy elite at the expense of the most vulnerable ( [[#Eriksen--2019|Eriksen et al., 2019]] ). Pelling et al. (2016) find that adaptation has been conceived and implemented in such a manner that most projects preserve rather than challenge the status quo. Specifically, the potential for knowledge and the goals of adaptation to be contested by different actors and stakeholders and the need to sustain progress over extended periods of time can constrain the ability to effectively implement actions that lead to sustainable development outcomes that are protected from the impacts of climate change while also delivering climate mitigation outcomes, that is, for CRD ( [[#Bosomworth--2017|Bosomworth et al., 2017]] ; [[#Bloemen--2019|Bloemen et al., 2019]] ). This creates the possibility for specific adaptation actions to result in outcomes that undermine greenhouse gas mitigation and/or broader development goals ( [[#Fazey--2016|Fazey et al., 2016]] ; [[#Wise--2016|Wise et al., 2016]] ; [[#Magnan--2020|Magnan et al., 2020]] ). For example, a study in Bangladesh revealed how local elites and donors used adaptation projects as a lever to push vulnerable populations away from their agrarian livelihoods and into uncertain urban wage labour ( [[#Paprocki--2018|Paprocki, 2018]] ). These types of outcomes are categorised as maladaptation, interventions that increase rather than decrease vulnerability, and/or undermine or eradicate future opportunities for adaptation and development ( [[#Barnett--2010|Barnett and O’Neill, 2010]] ; [[#Juhola--2015|Juhola et al., 2015]] ; [[#Magnan--2016|Magnan et al., 2016]] ; [[#Antwi-Agyei--2017|Antwi-Agyei et al., 2017]] ; [[#Schipper--2020|Schipper, 2020]] ). This inadvertent impact on equity appears to fundamentally contradict a benevolent understanding of transformative adaptation that also champions social justice ( [[#Patterson--2018|Patterson et al., 2018]] ), thus posing long-term maladaptation in opposition to transformative adaptation ( [[#Magnan--2020|Magnan et al., 2020]] ).

Similarly, mitigation efforts, while reducing emissions, can also increase climate impacts vulnerability and undermine adaptation efforts. The same can be said for some poverty alleviation and sustainable development efforts that increase vulnerability for specific segments of the population. For example, in Central America, an evaluation of 12 rural renewable energy projects (either forthe clean development mechanism, early warning systems or rural electrification goals) found that some mitigation and poverty alleviation projects increased vulnerability to families—by excluding them, not adhering to local safety and quality codes and standards, or significantly altering community power dynamics and contributing to conflict ( [[#Ley--2017|Ley, 2017]] ; [[#Ley--2020|Ley et al., 2020]] ).

Synergies between adaptation, mitigation and sustainable development might be promoted by prioritising those CRD strategies most likely to generate synergies ( ''very high confidence'' ) ( [[#Roy--2018|Roy et al., 2018]] ; [[#Karlsson--2020|Karlsson et al., 2020]] ). This could include focusing on poverty alleviation that improves adaptive capacity (e.g., [[#Kaya--2016|Kaya and Chinsamy, 2016]] ; [[#Kuper--2017|Kuper et al., 2017]] ; [[#Ley--2017|Ley, 2017]] ; [[#Sánchez--2017|Sánchez and Izzo, 2017]] ; [[#Stańczuk-Gałwiaczek--2018|Stańczuk-Gałwiaczek et al., 2018]] ; [[#Ley--2020|Ley et al., 2020]] ); renewable energy systems that improve water management and preservation of river ecological integrity (e.g., [[#Berga--2016|Berga, 2016]] ; [[#Rasul--2016|Rasul and Sharma, 2016]] ); or internalising positive externalities, such as subsidies for mitigation options thought to also improve water use efficiency (e.g., [[#Roy--2018|Roy et al., 2018]] ). Similarly, trade-offs might be managed by prioritising strategies such as disqualifying mitigation options thought to have negative social implications ( [[#18.2.5.3.1|Section 18.2.5.3.1]] ), internalising externalities, such as placing a fee or constraint on a negative externality or related activity (Dubash et al., 2022) ( [[#Bistline--2018|Bistline and Rose, 2018]] ), or using complementary policies, such as transfer payments to offset negative mitigation, adaptation or sustainable development strategy implications ( ''very high confidence'' ) (e.g., [[#McCollum--2018b|McCollum et al., 2018b]] ). [[#Roy--2018|Roy et al. (2018)]] discusses the latter, noting, for instance, the possibility of complementary sustainable development payments to avoid global energy access, food security and clean water trade-offs (Box 4.7).

SR1.5 and AR6 assessments of system transitions also find opportunities for synergies and managing trade-offs ( [[#18.3|Section 18.3]] ; Cross-Chapter Box FEASIB). Within each system, mitigation and adaptation options are assessed for their specific benefits and the impacts they can have on one another, as well as with sustainable development. For example, within energy system transitions, the three adaptation options (power infrastructure resilience, reliability of power systems, efficient water use management) have strong synergies with mitigation. While not all mitigation options have strong synergies, the trade-offs can be managed when adaptation and SDGs are also considered. Under land and other ecosystems system transitions, the main trade-off is the competition for land use between potential alternative uses, for example, sustainable agriculture, afforestation/reforestation, purpose-grown biomass for energy. On the other hand, assessment of urban and infrastructure system transitions finds mainly synergies between mitigation and adaptation options with trade-offs that are considered manageable, and there is growing evidence of rural landscape infrastructure benefits to adaptation.

Overall, this literature is relatively new and still developing. It highlights the importance of societal priorities and policy design for realizing synergies. However, the literature is not well developed in terms of how to optimize mitigation, adaptation and sustainable development interventions to achieve multiple priorities.

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