Editing IPCC:AR6/SROCC/Chapter-6 (section)

=== 6.3.3 Risk Management and Adaptation ===

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The most effective risk management strategy in the last few decades has been the development of early warning systems for cyclones (Hallegatte, 2013 <sup>[[#fn:r286|286]]</sup> ). Generally, however, a lack of familiarity with the changed nature of storms prevails. Powerful storms often generate record storm surges (Needham et al., 2015 <sup>[[#fn:r287|287]]</sup> ), such as in the cases of Cyclone Nargis and Typhoon Haiyan but surge warnings had been less well understood and followed because they had tended to be new or rare to the locality (Lagmay et al., 2015 <sup>[[#fn:r288|288]]</sup> ). A US study on storm surge warnings highlights the issue of the right timing to warn, as well as the difficulty in delivering accurate surge maps (Morrow et al., 2015 <sup>[[#fn:r289|289]]</sup> ). Previous experience with warnings that were not followed by hazard events show the ‘crying wolf’ problem leading many to ignore future warnings (Bostrom et al., 2018 <sup>[[#fn:r290|290]]</sup> ).

There is scant literature on the management of storms that follow less common trajectories. The most recent and relatively well-studied ones are Superstorm Sandy in 2012 in the USA and Typhoon Haiyan in 2013 in the Philippines. These two storms were unexpected and having underestimated the levels of impact, people ignored warnings and evacuation directives. In the case of Typhoon Haiyan, the dissemination of warnings via scripted text messages were ineffective without an explanation of the difference between Haiyan’s accompanying storm surge and that of other ‘normal’ storms to which people were used to (Lejano et al., 2016 <sup>[[#fn:r291|291]]</sup> ). Negative experiences of previous evacuations also lead to the reluctance of authorities to issue mandatory evacuation orders, for example, during Superstorm Sandy (Kulkarni et al., 2017 <sup>[[#fn:r292|292]]</sup> ), and contributes to a preventable high number of casualties (Dalisay and De Guzman, 2016 <sup>[[#fn:r293|293]]</sup> ). These examples also show that saving lives and assets through warning and evacuation is limited. Providing biophysical protection measures as well as improving self-reliance during such events can complement warning and evacuation.

After the storms, retreat or rebuild options exist. Rebuilding options can depend on whether insurance is still affordable after the event. Buyout programs, a form of ‘managed retreat’ whereby government agencies pay people affected by extreme weather events to relocate to safer areas, gained traction in recent years as a potential solution to reduce exposure to changing storm surge and flood risk. The decision to retreat or rebuild ''in situ'' depends, at least partially, on how communities have recovered in the past and therefore on the perceived success of a future recovery (Binder, 2014 <sup>[[#fn:r294|294]]</sup> ). However, political and jurisdictional conflicts between local, regional, and national government over land management responsibilities, lack of coordinated nation-wide adaptation plans, and clashes between individual and community needs have led to some unpopular buyout programs after Hurricane Sandy (Boet-Whitaker, 2017 <sup>[[#fn:r295|295]]</sup> ). Relocation (i.e., managed retreat) is often very controversial, can incur significant political risk even when it is in principle voluntary (Gibbs et al., 2016 <sup>[[#fn:r296|296]]</sup> ), and is rarely implemented with much success at larger scales (Beine and Parsons, 2015 <sup>[[#fn:r297|297]]</sup> ; Hino et al., 2017 <sup>[[#fn:r298|298]]</sup> ). In addition, managed retreats are often fraught with legal, distributional and human rights issues, as seen in the case of resettlements after Typhoon Haiyan (Thomas, 2015 <sup>[[#fn:r299|299]]</sup> ; see also Cross-Chapter Box 5 in Chapter 1), and extend to loss of cultural heritage and indigenous qualities in the case of small island states.

If rebuilding ''in situ'' is pursued after catastrophic events and without decreased exposure, it is often accompanied by actions that aim to reduce vulnerability in order to adapt to the increasing risk (Harman et al., 2013 <sup>[[#fn:r300|300]]</sup> ). In many cases, resilient designs and sustainable urban plans integrating climate change concerns, that are inclusive of vegetation barriers as coastal defences and hybrid designs, are considered (Cheong et al., 2013 <sup>[[#fn:r301|301]]</sup> ; Saleh and Weinstein, 2016 <sup>[[#fn:r302|302]]</sup> ). However, often more physical structures that are known to be less sustainable in the long-term, but potentially more protective in the short-term, are constructed (Knowlton and Rotkin-Ellman, 2014 <sup>[[#fn:r303|303]]</sup> ; Rosenzweig and Solecki, 2014 <sup>[[#fn:r304|304]]</sup> ). Anticipatory planning approaches are under way to warn and enable decision making in time (Bloemen et al., 2018 <sup>[[#fn:r305|305]]</sup> ; Lawrence et al., 2018 <sup>[[#fn:r306|306]]</sup> ).

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