Editing IPCC:AR6/SROCC/Chapter-4 (section)

===== 4.4.4.3.3 Adapting decisions over time =====

Irrespective of whether expected utility or robustness criteria are applied, there is ''high confidence'' that an effective way of dealing with large uncertainties is adaptive decision making (also called iterative decision making, adaptive planning or adaptive management), which maintains that decision and decision analysis should be conducted within an iterative policy cycle. This approach includes monitoring of sea level variables and evaluation of alternatives in this light in order to learn from past decisions and collect information to inform future decisions (Haasnoot et al., 2013 <sup>[[#fn:r2175|2175]]</sup> ; Barnett et al., 2014 <sup>[[#fn:r2176|2176]]</sup> ; Burch et al., 2014 <sup>[[#fn:r2177|2177]]</sup> ; Jones et al., 2014 <sup>[[#fn:r2178|2178]]</sup> ; Wise et al., 2014 <sup>[[#fn:r2179|2179]]</sup> ; Kelly, 2015 <sup>[[#fn:r2180|2180]]</sup> ; Lawrence and Haasnoot, 2017 <sup>[[#fn:r2181|2181]]</sup> ). Such a staged approach is especially suitable for coastal adaptation due to the long lead and lifetimes of many coastal adaptation measures and the deep uncertainties in future sea levels (Hallegatte, 2009 <sup>[[#fn:r2182|2182]]</sup> ; Kelly, 2015 <sup>[[#fn:r2183|2183]]</sup> ). Prominent representatives of methods that entail this idea are Dynamic Adaptive Policy Pathways (Haasnoot et al., 2013 <sup>[[#fn:r2184|2184]]</sup> ) and Dynamic Adaptation Planning (Walker et al., 2001 <sup>[[#fn:r2185|2185]]</sup> ). An important prerequisite for any adaptive decision-making approach is a monitoring system that can detect sea level signals sufficiently early to enable the required responses (Hermans et al., 2017 <sup>[[#fn:r2186|2186]]</sup> ; Haasnoot et al., 2018 <sup>[[#fn:r2187|2187]]</sup> ; Stephens et al., 2018 <sup>[[#fn:r2188|2188]]</sup> ).

In recent years, many different frameworks for adaptive decision making have been put forward, including Adaptive Policy Making (Walker et al., 2001 <sup>[[#fn:r2189|2189]]</sup> ), Dynamic Adaptive Policy Pathways (Haasnoot et al., 2013 <sup>[[#fn:r2190|2190]]</sup> ), Dynamic Adaptive Planning (Walker et al., 2013 <sup>[[#fn:r2191|2191]]</sup> ), Iterative risk management (Jones et al., 2014 <sup>[[#fn:r2192|2192]]</sup> ) and Engineering Options Analysis (de Neufville and Smet, 2019). Each frameworks emphasises particular aspects of adaptive decision making and has merits in specific situations depending on the preferences, goals, uncertainties and information at stake (Marchau et al., 2019 <sup>[[#fn:r2193|2193]]</sup> ). Nevertheless, all of these frameworks share the following generic and iterative steps

# Set the stage: Identify current situation, objectives, options (alternatives) and uncertainties.
# Develop a dynamic plan, which consists of a basic plan plus contingency actions to be carried out based on observed triggers.
# Implement basic plan and monitor system for triggers.
# Monitor and act upon triggers.

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