Editing IPCC:AR6/WGIII/Chapter-3 (section)

=== 3.8.1 Frameworks for the Low-carbon Transition and Scenarios ===

<div id="h2-38-siblings" class="h2-siblings"></div>

Effectively responding to climate change and achieving sustainable development requires overcoming a series of challenges to transition away from fossil-based economies. Feasibility can be defined in many ways (Chapter 1). The political science literature ( [[#Majone--1975a|Majone 1975a]] ,b; [[#Gilabert--2012|Gilabert and Lawford-Smith 2012]] ) distinguishes the feasibility of ‘what’ (i.e., emission reduction strategies), ‘when and where’ (i.e., in the year 2050, globally) and ‘whom’ (i.e., cities). It distinguishes desirability from political feasibility ( [[#von%20Stechow--2015|von Stechow et al. 2015]] ): the former represents a normative assessment of the compatibility with societal goals (i.e., SDGs), while the latter evaluates the plausibility of what can be attained given the prevailing context of transformation ( [[#Nielsen--2020|Nielsen et al. 2020]] ). Feasibility concerns are context and time dependent and malleable: enabling conditions can help overcome them. For example, public support for carbon taxes has been hard to secure but appropriate policy design and household rebates can help dissipate opposition ( [[#Murray--2015|Murray and Rivers 2015]] ; [[#Carattini--2019|Carattini et al. 2019]] ).

Regarding scenarios, the feasibility ‘what’ question is the one most commonly dealt with in the literature, though most of the studies have focused on expanding low-carbon system, and yet political constraints might arise mostly from phasing out fossil fuel-based ones ( [[#Spencer--2018|Spencer et al. 2018]] ; [[#Fattouh--2019|Fattouh et al. 2019]] ). The ‘when and where’ dimension can also be related to the scenario assessment, but only insofar that the models generating them can differentiate time and geographical contextual factors. Distinguishing mitigation potential by regional institutional capacity has a significant influence on the costs of stabilising climate ( [[#Iyer--2015c|Iyer et al. 2015c]] ). The ‘whom’ question is the most difficult to capture by scenarios, given the multitude of actors involved as well as their complex interactions. The focus of socio-technical transition sciences on the co-evolutionary processes can shed light on the dynamics of feasibility ( [[#Nielsen--2020|Nielsen et al. 2020]] ).

The when-where-whom distinction allows depicting a feasibility frontier beyond which implementation challenges prevent mitigation action ( [[#Jewell--2020|Jewell and Cherp 2020]] ). Even if the current feasibility frontier appears restraining in some jurisdictions, it is context-dependent and dynamic as innovation proceeds and institutional capacity builds up ( [[#Nielsen--2020|Nielsen et al. 2020]] ). The question is whether the feasibility frontier can move faster than the pace at which the carbon budget is being exhausted. [[#Jewell--2019|Jewell et al. (2019)]] show that the emission savings from the pledges of premature retirement of coal plants is 150 times less than globally committed emissions from existing coal power plants. The pledges come from countries with high institutional capacity and relatively low shares of coal in electricity. Other factors currently limiting the capacity to steer transitions at the necessary speed include the electoral-market orientation of politicians ( [[#Willis--2017|Willis 2017]] ), the status-quo orientation of senior public officials ( [[#Geden--2016|Geden 2016]] ), path dependencies created by ‘instrument constituencies’ ( [[#Béland--2016|Béland and Howlett 2016]] ), or the impacts of deliberate inconsistencies between talk, decisions and actions in climate policy ( [[#Rickards--2014|Rickards et al. 2014]] ). All in all, a number of different delay mechanisms in both science and policy have been identified to potentially impede climate goal achievement ( [[#Karlsson--2020|Karlsson and Gilek 2020]] ) (Chapter 13).

In addition to its contextual and dynamic nature, feasibility is a multi-dimensional concept. The IPCC SR1.5 distinguishes six dimensions of feasibility: geophysical, environmental-ecological, technological, economic, socio-cultural and institutional. At the individual option level, different mitigation strategies face various barriers as well as enablers (see [[IPCC:Wg3:Chapter:Chapter-6|Chapter 6]] for the option-level assessment). However, a systemic transformation involves interconnections of a wide range of indicators. Model-based assessments are meant to capture the integrative elements of the transition and of associated feasibility challenges. However, the translation of model-generated pathways into feasibility concerns ( [[#Rogelj--2018|Rogelj et al. 2018]] b) has developed only recently. Furthermore, multiple forms of knowledge can be mobilised to support strategic decision-making and complement scenario analysis ( [[#Turnheim--2019|Turnheim and Nykvist 2019]] ). We discuss both approaches next.

<div id="3.8.2" class="h2-container"></div>

<span id="feasibility-appraisal-of-low-carbon-scenarios"></span>