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

==== 3.5.2.6 Infrastructure ====

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Reducing and avoiding the impacts of climate change on infrastructure will require special attention to engineering, land use planning, maintenance operations, local culture and private and public budgeting (AMAP, 2017a <sup>[[#fn:r2054|2054]]</sup> ; AMAP, 2017b <sup>[[#fn:r2055|2055]]</sup> ; AMAP, 2018 <sup>[[#fn:r2056|2056]]</sup> ). In some cases, relocation of human settlements will be required, necessitating more formal methods of assessing relocation needs and identifying sources of funding to support relocations (Cross-Chapter Box 9) ( ''high confidence'' ).

A discussion of the relocation of Alaska’s coastal villages is found in Cross-Chapter Box 9. Alaskan coastal communities are not the only settlements potentially requiring relocation. Subsidence due to thawing permafrost and river and delta erosion makes other rural communities of Alaska and Russia vulnerable, potentially requiring relocation in the future (Bronen, 2015 <sup>[[#fn:r2057|2057]]</sup> ; Romero Manrique et al., 2018 <sup>[[#fn:r2058|2058]]</sup> ). These situations raise issues of environmental justice and human rights (Bronen, 2017 <sup>[[#fn:r2059|2059]]</sup> ), and illustrate the limits of incremental adaptation when transformation change is needed (Kates et al., 2012 <sup>[[#fn:r2060|2060]]</sup> ). In other cases, cultural resources in the form of historic infrastructure are being threatened and require mitigation (Radosavljevic et al., 2015 <sup>[[#fn:r2061|2061]]</sup> ). Responsibility for funding has been a key issue in the relocation process (Iverson, 2013 <sup>[[#fn:r2062|2062]]</sup> ) as well as the overall role of government and local communities in relocation planning (Marino, 2012 <sup>[[#fn:r2063|2063]]</sup> ; Romero Manrique et al., 2018 <sup>[[#fn:r2064|2064]]</sup> ). The Alaska Denali Commission, an independent federal agency designed to provide critical utilities, infrastructure and economic support throughout Alaska, is now serving as the lead coordinating organisation for Alaska village relocations and managing federal funding allocations. Several efforts have also been undertaken to provide assessment frameworks and protocols for settlement relocation as an adaptive resource (Bronen, 2015 <sup>[[#fn:r2065|2065]]</sup> ; Ristroph, 2017 <sup>[[#fn:r2066|2066]]</sup> ) .

While there has been discussion of future ‘climigration’ in rural Alaska (Bronen and Chapin, 2013 <sup>[[#fn:r2067|2067]]</sup> ; Matthews and Potts, 2018 <sup>[[#fn:r2068|2068]]</sup> ), a study of Alaska rural villages threated by climate change showed no outmigration response (Hamilton et al., 2016 <sup>[[#fn:r2069|2069]]</sup> ). Several factors explain the lack of outmigration, including an unwillingness to move, attachment to place, people’s inability to relocate, the effectiveness of alternative ways of achieving acceptable outcomes and methods of buffering through subsidies (Huntington et al., 2018 <sup>[[#fn:r2070|2070]]</sup> ) ( ''medium confidence'' ).

The current pan-Arctic trend of urbanisation (AHDR, 2014 <sup>[[#fn:r2071|2071]]</sup> ) , suggests that climate change responses related to infrastructure in towns and cities of the North will require significant adaptation in designs and increases in spending (Streletskiy et al., 2012 <sup>[[#fn:r2072|2072]]</sup> ). These costs do not include costs related to flooding and other stressors associated with warming or additional costs of commercial and industrial operations. Engineers in countries with permafrost are actively working to adapt the design of structures to degrading permafrost conditions (Dore et al., 2016 <sup>[[#fn:r2073|2073]]</sup> ) and the effects of a warming climate, for example the Cold Climate Housing Research Center of Alaska.

An analysis of the costs of total damages from climate change to public infrastructure in Alaska show the financial benefits of proactive adaptation (Melvin et al., 2017 <sup>[[#fn:r2074|2074]]</sup> ) (Figure 3.12). In addition to global carbon emission mitigation, hardening and redesigning of infrastructure can reduce costs of future climate-related impacts. For example, retrofitting and redesigning of infrastructure in order to handle increased precipitation and warmer temperatures can reduce climate-related costs by 50%, from USD 5.5 to 2.9 billion under RCP8.5 by 2100. The cost savings of retrofitting and redesigning infrastructure is even higher than the savings from carbon mitigation, where impact costs are estimated at USD 4.2 billion under RCP4.5 by 2100. Engineering adaptation provide proportionally similar cost savings no matter which emission scenario was used.

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