Editing IPCC:AR6/WGII/Chapter-15 (section)

=== 15.3.2 Trends in Exposure and Vulnerability ===

<div id="h2-4-siblings" class="h2-siblings"></div>

Most of the research that has been conducted on exposure and vulnerability from climate change demonstrates that factors including those that are geopolitical and political, environmental, socioeconomic and cultural together conspire to increase exposure and vulnerability of small islands (Box 15.1; [[#Betzold--2015|Betzold, 2015]] ; [[#McCubbin--2015|McCubbin et al., 2015]] ; [[#Duvat--2017b|Duvat et al., 2017b]] ; [[#Otto--2017|Otto et al., 2017]] ; [[#Weir--2017|Weir et al., 2017]] ; [[#Taupo--2018|Taupo et al., 2018]] ; [[#Barclay--2019|Barclay et al., 2019]] ; [[#Hay--2019a|Hay et al., 2019a]] ; [[#Ratter--2019|Ratter et al., 2019]] ; [[#Salmon--2019|Salmon et al., 2019]] ; [[#Bordner--2020|Bordner et al., 2020]] ; [[#Douglass--2020|Douglass and Cooper, 2020]] ; [[#Duvat--2020a|Duvat et al., 2020a]] ). Additional pressures on coastal and marine environments, including overexploitation of natural resources, may further exacerbate possible impacts in the future ( [[#Bell--2013|Bell et al., 2013]] ; [[#Pinnegar--2019|Pinnegar et al., 2019]] ; [[#Siegel--2019|Siegel et al., 2019]] ).

Furthermore, these factors exacerbate climate change-induced problems such as coastal flooding and erosion faced by small islands. These impacts continue to worsen, putting small islands at increasingly higher risk to the impacts of climate change (Box 15.1). There are multiple stressors that affect the vulnerability of small islands to climate change ( [[#McNamara--2019|McNamara et al., 2019]] ).

The problems of increasing exposure and vulnerability are most clearly seen in atoll islands. For example, in the capital of Tuvalu, economic stressors, food-related stressors and overcrowding make the islands much more vulnerable to climate impacts including changing precipitation patterns, ESLs, intense strong winds, warming sea surface temperature (SST) and ocean acidification ( [[#McCubbin--2015|McCubbin et al., 2015]] ). Small islands, in trying to address the problem of limited land availability, put in place practices that lead to increasing exposure for island people. In Majuro, Marshall Islands ( [[#Ford--2012|Ford, 2012]] ), Tarawa, Kiribati ( [[#Biribo--2013|Biribo and Woodroffe, 2013]] ; [[#Duvat--2013|Duvat, 2013]] ), and the Maldives Islands ( [[#Kench--2012|Kench, 2012]] ; [[#Naylor--2015|Naylor, 2015]] ; [[#Duvat--2019b|Duvat and Magnan, 2019b]] ), population growth has led to land reclamation and the building of coastal protection structures, such as seawalls. Land reclamation and coastal protection structures negatively impact coastal and marine ecosystems, including reefs and mangroves, which compromise the protection services that they deliver to island communities through wave energy attenuation and sediment supply ( [[#Gracia--2018|Gracia et al., 2018]] ; [[#Curnick--2019|Curnick et al., 2019]] ; [[#Duvat--2019a|Duvat and Magnan, 2019a]] ) and may impact the long-term sustainable adaptive planning of islands ( [[#Giardino--2018|Giardino et al., 2018]] ). In addition, these construction activities disrupt natural coastal processes, thereby causing coastal erosion, which in turn increases the risk of flooding ( [[#Yamano--2007|Yamano et al., 2007]] ; [[#Duvat--2017b|Duvat et al., 2017b]] ) (Figure 15.3). This becomes a vicious cycle, with more land reclamation necessary to accommodate growing populations. Land reclamation requires stabilisation by protection structures, which then contributes to environmental degradation that increases the exposure and vulnerability of the communities living in these atolls ( [[#Duvat--2017b|Duvat et al., 2017b]] ).

<div id="_idContainer009" class="Figure"></div>

[[File:7d3aefa6ab28385d7a66ad38dcc02ce9 IPCC_AR6_WGII_Figure_15_003.png]]

'''Figure 15.3 |''' '''Percentage of current population in selected small islands occupying vulnerable land (the number of people on land that may be exposed to coastal inundation—either by permanently falling below MHHW, or temporarily falling below the local annual flood height) in 2100 under an RCP''' '''4.''' '''5 scenario (adapted from [[#Kulp--2019|Kulp and Strauss, 2019]] , using the CoastalDEM_Perm_p50 model).''' Positions on the map are based on the capital city or largest town.

<div id="15.3.3" class="h2-container"></div>

<span id="observed-impacts-and-projected-risks-on-natural-systems"></span>