Editing IPCC:AR6/WGII/Chapter-9 (section)

=== 9.3.1 Adaptation Feasibility and Effectiveness ===

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Based on a systematic assessment of observed climate adaptation responses in the scientific literature covering 827 adaptation response types in 553 studies (2013–2021), and expert elicitation process, 24 categories of adaptation responses in Africa were identified ( [[#Williams--2021|Williams et al., 2021]] ; Figure 9.7). This assessment excluded autonomous adaptation in ecosystems, such as migration and evolution of animal and plant species.

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'''Figure 9.7 |''' '''Assessment of the feasibility and effectiveness of observed climate adaptation responses under current climate conditions for 24 categories of adaptation responses across regions of Africa.''' The assessment comprised evaluation of each adaptation category along six dimensions: for feasibility these were economic viability, environmental sustainability, social validity, institutional relevance, and technological availability; and for effectiveness this was potential for risk reduction (considering current climate conditions) ( [[#Williams--2021|Williams et al., 2021]] ). Fifty-six experts on the African region were consulted using a structured, expert-driven elicitation process to increase the coverage and robustness of the continent-wide adaptation feasibility and effectiveness assessment in [[#Williams--2021|Williams et al. (2021)]] . Assessment included both peer-reviewed articles and grey literature.

At the current global warming level, 83% of adaptation response categories assessed showed medium potential for risk reduction (that is, mixed evidence of effectiveness). Bulk water infrastructure (including managed aquifer recharge, dams, pipelines, pump stations, water treatment plants and distribution networks), human migration, financial investment for sustainable agriculture, and social infrastructure (including decentralised management, strong community structures and informal support networks) show high potential for risk reduction (high evidence of option’s effectiveness) (Sections 9.6.4; 9.7.3; Boxes 9.8; 9.9; 9.10; 9.11). However, there was limited evidence to assess the continued effectiveness of these options at higher global warming levels ( [[#Williams--2021|Williams et al., 2021]] ) with some options, such as bulk water infrastructure (particularly large dams), expected to face increasing risk with continued warming with damages cascading to other sectors (see Box 9.5), while others, such as crop irrigation and adjusting planting times, may increasingly reach adaptation limits above 1.5°C and 2°C global warming (Sections 9.8.3; 9.8.4).

The majority of adaptation studies were in west and east Africa (Ethiopia, Ghana, Kenya and Tanzania), followed by southern Africa, with the least coming from central and north Africa (Figure 9.7; [[#Williams--2021|Williams et al., 2021]] ). Most studies were on adaptation actions in the food sector, with the least on health (Figure 9.7). The five adaptation response categories with the highest number of reported actions were sustainable water management (food sector), resilient infrastructure and technologies (health sector), agricultural intensification (food sector), human migration (poverty and livelihoods) and crop management (food sector).

No adaptation response categories were assessed to have high feasibility of implementation. Technological barriers dominate factors limiting implementation (92% of adaptation categories have low technological feasibility) followed by institutional barriers (71% of adaptation categories have low institutional feasibility). This assessment matches review studies finding institutional responses to be least common in Africa and highlight inadequate institutional capacities as key limits to human adaptation ( [[#Berrang-Ford--2021|Berrang-Ford et al., 2021]] ; [[#Thomas--2021|Thomas et al., 2021]] ) (Cross-Chapter Box FEASIB in Chapter 18). Feasibility is higher for the social dimension of adaptation responses (with moderate feasibility for 88% of categories). The largest evidence gap is for environmental feasibility for which 67% could not be assessed due to insufficient evidence (Figure 9.7).

Sustainable Water Management (SWM) includes rainwater harvesting for irrigation, watershed restoration, water conservation practices (e.g., efficient irrigation) and less water-intensive cropping (also see [[#9.8.3|Section 9.8.3]] ), and was the most reported adaptation response in the food sector. SWM was assessed with medium economic and social feasibility and low environmental, institutional and technological feasibility. The feasibility of this adaptation category may depend largely on socioeconomic conditions ( [[#Amamou--2018|Amamou et al., 2018]] ; [[#Harmanny--2019|Harmanny and Malek, 2019]] ; [[#Schilling--2020|Schilling et al., 2020]] ), as many African farmers cannot afford the cost of SWM facilities ( [[#9.8.4|Section 9.8.4]] ).

Resilient Infrastructure and Technologies (RIT) for health include improved housing to limit exposure to climate hazards ( [[#Stringer--2020|Stringer et al., 2020]] ), and improved water quality, sanitation and hygiene infrastructure (e.g., technology across all sectors to prevent contamination and pollution of water, improved water, sanitation and hygiene (WASH) approaches such as promotion of diverse water sources for water supply, improving health infrastructure) ( [[#9.10.3|Section 9.10.3]] ). Overall, RIT had medium social feasibility and low institutional and technological feasibility. Bulk water infrastructure was assessed to have high effectiveness, but low institutional and technological feasibility. Increasing variability in climate and environmental challenges has made sustainable and resilient infrastructure design a key priority ( [[#Minsker--2015|Minsker et al., 2015]] ). RIT is, however, generally new in the African context ( [[#Cumming--2017|Cumming et al., 2017]] ) and that may be why there is limited evidence to assess some of its dimensions (economic and environmental feasibility). Construction of resilient public water infrastructures that include safeguards for sanitation and hygiene are expensive and, across national and local levels, planning for its construction poses multiple challenges ( [[#Choko--2019|Choko et al., 2019]] ).

Sustainable agricultural intensification in smallholder farming systems (especially agroecological approaches, such as mixed cropping, mixed farming, no soil disturbance, and mulching) and agroforestry are key response options to secure food for the growing African population ( [[#Nziguheba--2015|Nziguheba et al., 2015]] ; [[#Ritzema--2017|Ritzema et al., 2017]] ). Yet many of these options currently face low institutional and technological feasibility (Figure 9.7). Social and economic feasibility is higher, but barriers include high cost of farm inputs (land, capital and labour), lack of access to timely weather information and lack of water resources can make this option quite challenging for African smallholder farmers (Sections 9.8.1; 9.11.4; [[#Kihila--2017|Kihila, 2017]] ; [[#Williams--2019b|Williams et al., 2019b]] ).

Crop management includes adjusting crop choices, planting times, or the size, type and location of planted areas ( [[#Altieri--2015|Altieri et al., 2015]] ; [[#Nyagumbo--2017|Nyagumbo et al., 2017]] ; [[#Dayamba--2018|Dayamba et al., 2018]] ). This option faces environmental, institutional and technological barriers to feasibility. Social and economic barriers to implementation are fewer. Factors such as tenure and ownership rights, labour requirements, high investment costs and lack of skills and knowledge on how to use the practices are reported to hinder implementation of crop management options by smallholder farmers ( [[#Muller--2013|Muller and Shackleton, 2013]] ; [[#Nyasimi--2017|Nyasimi et al., 2017]] ). For instance, when improved seed varieties are available, high price limits access for rural households ( [[#Amare--2018|Amare et al., 2018]] ; see Sections 9.8.3; 9.8.4).

Human migration was assessed to have high potential for risk reduction (Cross-Chapter Box MIGRATE in Chapter 7, Box 9.8; [[#Rao--2019|Rao et al., 2019]] ; [[#Sitati--2021|Sitati et al., 2021]] ). However, it had low feasibility for economic, institutional and technological dimensions, with limited evidence on environmental feasibility. Institutional factors such as the implementation of top-down policies have been reported as limiting options for coping locally, resulting in migration ( [[#Brockhaus--2013|Brockhaus et al., 2013]] ). Limited financial and technical support for migration limits the extent to which it can make meaningful contributions to climate resilience ( [[#Djalante--2013|Djalante et al., 2013]] ; [[#Trabacchi--2015|Trabacchi and Mazza, 2015]] ). International and domestic remittances are an important resource that can help aid recovery from climate shocks, but inadequate finance and banking infrastructure can limit cash transfers (Box 9.8). Male migration can increase burdens of household and agricultural work, especially for women ( [[#Poudel--2020|Poudel et al., 2020]] ; [[#Rao--2020|Rao et al., 2020]] ; [[#Zhou--2020|Zhou et al., 2020]] ). The more agency migrants have (that is, degree of voluntarity and freedom of movement), the greater the potential benefits for sending and receiving areas ( ''high agreement, medium evidence'' ) (Cross-Chapter Box MIGRATE in Chapter 7; Box 9.8)

Adaptation options within a number of categories, including sustainable agriculture practices, agricultural intensification, fisheries management, health advisory services and education, social infrastructure, infrastructure and built environment, and livelihood diversification, were observed to reduce socioeconomic inequalities ( [[#Williams--2021|Williams et al., 2021]] ). Whether adaptation options reduce inequality can be a key consideration enhancing acceptability of policies and adaptation implementation (Box 9.1; [[#9.11.4|Section 9.11.4]] ; [[#Islam--2017|Islam and Winkel, 2017]] ).

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