Editing IPCC:AR6/WGII/Chapter-8 (section)

==== 8.5.2.2 Natural Capital ====

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It is well established that climate change compounds the impacts of pressures that humans place on the environment ( ''high confidence'' ) and that environmental degradation can undermine options for adaptation and an enabling environment, with poor and natural resource-dependent groups most acutely affected (see e.g., [https://www.ipcc.ch/chapter/cross-chapter-paper-3 Cross-Chapter Paper 3] for insights from deserts and semiarid areas). Sustainable management of natural capital contributes to building resilience and the natural ability of ecosystems to adapt to climate change ( [[#IPCC--2014a|IPCC, 2014a]] ; see also IPCC SROCC, [[IPCC:Wg2:Chapter:Chapter-5#5.3.2|Section 5.3.2]] , [[#Bindoff--2019|Bindoff et al., 2019]] ). Some systems like mangroves (found in 123 countries, many of which are in the Developing World) offer a broad range of vital ecosystem services ( [[#Hamza--2020|Hamza et al., 2020]] ). Mangroves provide regulating services by acting as a natural defence against sea level rise and storm surges; and by sequestering carbon in both the trees and sediments they capture. Provisioning services (e.g., fish, crabs, timber and fuelwood) from mangroves support livelihoods and livelihood adaptation options, especially for those with few other livelihood opportunities, while these systems also provide important habitat (breeding, spawning and nursery grounds for fish) and biodiversity, and offer cultural services in the forms of education, recreation and spiritual benefits ( [[#Quinn--2017|Quinn et al., 2017]] ). As the frequency of events such as hurricanes, storms and typhoons rises with climate change, natural capital assets like mangroves become increasingly important in protecting coastlines and supporting adaptation. While not reducing the hazard itself, the mangroves reduce exposure and, in some cases, also vulnerability. The literature shows with ''high confidence'' that environmental assets support both climate change mitigation (at a large scale) and adaptation (at a smaller scale), particularly for the poorest groups in society, who directly depend upon natural capital for their subsistence (e.g., [[#Angelsen--2014|Angelsen et al., 2014]] ). In turn, the legal and regulatory context and institutional set up determines who has access rights to different aspects of the natural resource base. This shows how different aspects of the enabling environment work in tandem to constitute one another.

In a market economy, human activities tend to exacerbate degradation of natural capital, despite its role in buffering climate change impacts, supporting mitigation and providing adaptation options. Economic agents base their decisions on market prices, even though market prices do not incorporate the costs of deteriorating natural capital because of externalities and other market failures, that is environmental degradation is not internalised ( [[#Bowen--2012|Bowen et al., 2012]] ). At the same time, expanding populations, capitalism and consumption choices affect the condition of natural capital, alongside short-termism stemming from poverty, linked to the need for survival. All these factors therefore interact, with the aggregate effect of worsening the impacts of climate change, while also undermining future adaptation options, particularly for the poor. Adaptation policies should, but do not always, compensate for the prevalent market failures. For example, in Melanesia, sea walls have been built out of coral by local people in an attempt to reduce the impacts of rising sea levels, leading to outright destruction of some of the world’s most productive and biodiverse coral reefs ( [[#Martin--2016|Martin and Watson, 2016]] ). Similarly, in the Congo Basin, farmers are adapting to increasingly variable rainfall by expanding their cropping activities into forested areas, releasing carbon into the atmosphere through forest clearance activities and threatening biodiversity. Agricultural land is also being degraded globally (see [[#IPCC--2019a|IPCC, 2019a]] ), and this too closes down adaptation and livelihood options for the poorest, natural resource-dependent populations, while jeopardising food security, biodiversity and human health at wider scales. An enabling environment for adaptation therefore demands investment in sustaining natural capital at multiple scales, internalising the costs of degradation, as well as establishing the necessary legal and regulatory frameworks (and associated enforcement) to reduce its degradation ( [[#IPBES--2018|IPBES, 2018]] ).

The literature increasingly shows that approaches such as nature-based solutions (NBS) and ecosystem-based adaptation (see Chapters 2; 6) can offer value for money in tackling climate change from both a mitigation and adaptation standpoint ( [[#Seddon--2020|Seddon et al., 2020]] ). According to the Global Commission on Adaptation, a global investment of USD 1.8 trillion between 2020 and 2030 into adaptation measures such as early warning systems, climate-resilient infrastructure, improved dryland agriculture, mangrove protection, and resilient water resources can yield USD 7.1 trillion in total net benefits ( [[#Global%20Commission%20on%20Adaptation--2019|Global Commission on Adaptation, 2019]] ). NBS operate by harnessing natural processes, sometimes in combination with technological or engineered solutions. Examples encompass green public spaces and parks ( [[#Sahakian--2020|Sahakian and Anantharaman, 2020]] ), green infrastructure, such as urban forests and street trees ( [[#Richards--2017|Richards and Edwards, 2017]] ), which create shade and reduce urban heat island effects whereby urban areas are warmer than their surroundings ( [[#Depietri--2013|Depietri et al., 2013]] ), and support human health and well-being by keeping people in cities more closely linked with nature ( [[#Gulsrud--2018|Gulsrud et al., 2018]] ). NBS also encompasses blue infrastructure including constructed wetlands, bioswales, rain gardens and so forth, which can reduce flood risks ( [[#Haase--2015|Haase, 2015]] ). While the literature is generally positive about the ability of NBS to support climate risk reduction and deliver multiple other benefits ( [[#Connop--2016|Connop et al., 2016]] ), such as green job opportunities, improved provision of recreational space, cleaner air, habitat provision and increased property values ( [[#Emmanuel--2015|Emmanuel and Loconsole, 2015]] ), more research is required to specifically assess and evaluate the conditions and contexts in which these kinds of potential benefits are realised and how they can be mainstreamed into policy ( [[#Frantzeskaki--2019|Frantzeskaki et al., 2019]] ). Similarly, there is ''limited evidence'' on unintended consequences (e.g., methane production, creation of habitat for disease vectors, increased human–wildlife conflict) and how these can be avoided ( [[#Wolch--2014|Wolch et al., 2014]] ).

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