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

=== 9.6.4 Ecosystem-based Adaptation in Africa ===

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Ecosystem-based adaptation (EbA) uses biodiversity and ecosystem services to assist people to adapt to climate change ( [[#Swanepoel--2019|Swanepoel and Sauka, 2019]] ). Africa’s Nationally Determined Contributions (NDCs) show 36% of adaptation actions identified by 52 countries are considered to be EbA (Figure 9.20).

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[[File:67ee19000e11abd3395e09f78acef13b IPCC_AR6_WGII_Figure_9_020.png]]

'''Figure 9.20 |''' '''Over a third (36%) of all adaptation actions identified in the NDCs of 52 African countries as of early 2020 were ecosystem-based adaptations (EbA).''' Of these actions ±83% fall within the agriculture, land use/forestry, environment and water sectors. The EbA actions identified from the NDCs span 12 primary sectors and 29 sub-sectors.

EbA can reduce climate impacts and there is high agreement EbA can be more cost-effective than traditional grey infrastructure when a range of economic, social and environmental benefits are also accounted for (Table 9.6; [[#Baig--2016|Baig et al., 2016]] ; [[#Emerton--2017|Emerton, 2017]] ; [[#Chausson--2020|Chausson et al., 2020]] ). This is particularly relevant in Africa where climate vulnerabilities are strongly linked to natural resource-based livelihood practices and existing grey infrastructure levels are low in many regions ( [[#Dube--2016|Dube et al., 2016]] ; [[#Reid--2019|Reid et al., 2019]] ). However, financial constraints limit EbA project implementation ( [[#Mumba--2016|Mumba et al., 2016]] ; [[#Swanepoel--2019|Swanepoel and Sauka, 2019]] ).

'''Table 9.6 |''' The beneficial outcomes of ecosystem-based adaptation (EbA) actions and assessed confidence in these outcomes. Assessment is provided for EbA options in the four most prevalent EbA sectors identified in the Nationally Determined Contributions of 52 African countries (Figure 9.20). See Chapter 2.6.3 and 3.6.2 of this report for further assessment of EbA approaches in terrestrial, freshwater and marine systems.

{| class="wikitable"
|-
! '''Sector'''

! '''EbA Action(s)'''

! '''Outcome(s)'''

! '''Confidence'''

! '''Source(s)'''

|-
| rowspan="3"| Agriculture

| rowspan="2"| Conservation agriculture

| Improved soil and water conservation

| ''High''

| [[#Thierfelder--2017|Thierfelder et al. (2017)]]

|-
| Improved agricultural productivity and drought resilience

| ''Medium''

| [[#Pittelkow--2015|Pittelkow et al. (2015)]] ; [[#Thierfelder--2017|Thierfelder et al. (2017)]] ; Adenle et al. (2019)

|-
| Diversified crop varieties

| Improved agricultural productivity and drought resilience

| ''High''

| [[#Shiferaw--2014|Shiferaw et al. (2014)]] ; [[#Tesfaye--2016|Tesfaye et al. (2016)]] ; [[#Thierfelder--2017|Thierfelder et al. (2017)]]

|-
| rowspan="4"| Environment

| rowspan="4"| Ecosystem protection and restoration

| Carbon sequestration and storage

| ''High''

| [[#Melillo--2016|Melillo et al. (2016)]] ; [[#Griscom--2017|Griscom et al. (2017)]] ; [[#FAO--2018a|FAO (2018a)]]

|-
| Stepping stones for species migrating due to climate change

| ''Medium''

| [[#Beale--2013|Beale et al. (2013)]] ; Roberts et al. (2020)

|-
| Increased ecosystem resilience to disturbance

| ''High''

| [[#Anthony--2015|Anthony et al. (2015)]] ; Sierra-Correa and Cantera Kintz (2015); [[#Kroon--2016|Kroon et al. (2016)]] ; [[#Roberts--2017|Roberts et al. (2017)]]

|-
| Livelihood diversification opportunities from ecotourism, resource harvesting and rangelands (among others)

| ''Medium''

| [[#Lunga--2016|Lunga and Musarurwa (2016)]] ; Bedelian and Ogutu (2017); [[#Agyeman--2019|Agyeman (2019)]] ; [[#Kupika--2019|Kupika et al. (2019)]] ; [[#Naidoo--2019|Naidoo et al. (2019)]]

|-
| rowspan="2"| Forestry and other land use

| rowspan="2"| Restoration/ reforestation

Sustainable forestry and land management

| Restoration of degraded ecosystems and enhanced carbon sequestration

| ''High''

| [[#Mugwedi--2018|Mugwedi et al. (2018)]]

|-
| Reducing pressure on forests for food and energy needs

| ''Medium''

| [[#Peprah--2017|Peprah (2017)]] ; [[#Zegeye--2018|Zegeye (2018)]]

|-
| rowspan="2"| Water

| rowspan="2"| Integrated catchment management

| Improved flood attenuation capacity

| ''High''

| [[#Bradshaw--2007|Bradshaw et al. (2007)]] ; Mwenge Kahinda et al. (2016); Rawlins et al. (2018)

|-
| Improved resilience of freshwater ecosystems

| ''High''

| [[#Ndebele-Murisa--2014|Ndebele-Murisa (2014)]] ; [[#Natugonza--2015|Natugonza et al. (2015)]] ; (2019); [[#Tamatamah--2020|Tamatamah and Mwedzi (2020)]]

|}

Evidence for EbA in Africa is largely case study based and often anecdotal ( [[#Reid--2018|Reid et al., 2018]] ). There is ''high agreement'' that costs, challenges and negative outcomes of EbA interventions are still poorly understood ( [[#Reid--2016|Reid, 2016]] ; [[#Chaplin-Kramer--2019|Chaplin-Kramer et al., 2019]] ), despite limited evidence for the efficacy of context-specific applications at different scales ( [[#Doswald--2014|Doswald et al., 2014]] ).

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==== 9.6.4.1 Terrestrial Ecosystems ====

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Improved ecosystem care and restoration are cost-effective for carbon sequestration while providing multiple environmental, social and economic co-benefits ( [[#Griscom--2017|Griscom et al., 2017]] ; [[#Shukla--2019|Shukla et al., 2019]] ). Protecting and restoring natural forests and wetlands reduces flood risk across multiple African countries ( [[#Bradshaw--2007|Bradshaw et al., 2007]] ). In Kenya, enclosures for rangeland regeneration diversified income sources, which could increase the adaptive capacity of local people ( [[#Mureithi--2016|Mureithi et al., 2016]] ; [[#Wairore--2016|Wairore et al., 2016]] ). Sustainable agroforestry in semi-arid regions provides income sources from fuelwood, fruit and timber and reduces exposure to drought, floods and erosion ( [[#Quandt--2017|Quandt et al., 2017]] ). Forest protection in Zimbabwe maintains honey production during droughts, providing food supply options if crops fail ( [[#Lunga--2016|Lunga and Musarurwa, 2016]] ). Community-based natural resource management in pastoral communities improved institutional governance outcomes through involving community members in decision making, increasing the capacity of these communities to respond to climate change ( [[#Reid--2014|Reid, 2014]] ).

EbA can also increase ecological resilience. Re-introduction of fire and large mammals can restore ecosystem services, enhance adaptive capacity and benefit people by combatting woody encroachment, restoring grazing and increasing streamflow ( [[#Asner--2016|Asner et al., 2016]] ; [[#Stafford--2017|Stafford et al., 2017]] ; [[#Cromsigt--2018|Cromsigt et al., 2018]] ). Herbivores can also reduce fuel loads in areas facing increased fire risk ( [[#Hempson--2017|Hempson et al., 2017]] ).

Protected areas can be ‘stepping stones’ that facilitate climate-induced species range shifts ( [[#Roberts--2020|Roberts et al., 2020]] ), preserve medicinal plant diversity despite climate change ( [[#Kaky--2017|Kaky and Gilbert, 2017]] ) and provide livelihood diversification opportunities (Table 9.6). Protecting 30% of sub-Saharan Africa’s land area could reduce the proportion of species at risk of extinction by around 60% in both low and high warming scenarios ( [[#Hannah--2020|Hannah et al., 2020]] ). The role of protected areas in EbA can be strengthened by: (a) increasing coverage of diverse environments and high carbon storage ecosystems, (b) restoring habitat, (c) maintaining intact habitat, (d) participatory, equitable conservation and adaptation strategies; (e) cooperating across borders and (f) adequate monitoring ( [[#Gillson--2013|Gillson et al., 2013]] ; [[#Rannow--2014|Rannow et al., 2014]] ; [[#Midgley--2015|Midgley and Bond, 2015]] ; [[#Pecl--2017|Pecl et al., 2017]] ; [[#Dinerstein--2019|Dinerstein et al., 2019]] ; [[#Roberts--2020|Roberts et al., 2020]] ).

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==== 9.6.4.2 Freshwater Ecosystems ====

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EbA can mitigate flooding and increase the resilience of freshwater ecosystems (Table 9.6). Adaptation in African freshwater ecosystems is heavily influenced by non-climate anthropogenic factors, including land use change, water abstraction and diversion, damming and overfishing ( [[#Dodds--2013|Dodds et al., 2013]] ; [[#Kimirei--2020|Kimirei et al., 2020]] ; [[#UNESCO%20and%20UN-Water--2020|UNESCO and UN-Water, 2020]] ). Wetlands and riparian areas support biodiversity, act as natural filtration systems and serve as buffers to changes in the hydrological cycle, thereby increasing the resilience of freshwater ecosystems and the people that rely on them ( [[#Ndebele-Murisa--2014|Ndebele-Murisa, 2014]] ; [[#Musinguzi--2015|Musinguzi et al., 2015]] ; [[#Lowe--2019|Lowe et al., 2019]] ). However, national adaptation programmes of action, NAPs and national communications rarely consider the ecological stability of ecosystems safeguarding the very water resources they seek to preserve ( [[#Kolding--2016|Kolding et al., 2016]] ). Some countries have mandated the protection of riparian zones, but implementation is low ( [[#Musinguzi--2015|Musinguzi et al., 2015]] ; [[#Muchuru--2018|Muchuru and Nhamo, 2018]] ). Protecting terrestrial areas surrounding Lake Tanganyika benefited fish diversity ( [[#Britton--2017|Britton et al., 2017]] ). Afforestation reduces water availability but forest restoration and removing invasive plant species can increase water flows in regions facing water insecurity from climate change ( [[#Chausson--2020|Chausson et al., 2020]] ; [[#Le%20Maitre--2020|Le Maitre et al., 2020]] ). Regular, long-term monitoring of African freshwaters would improve understanding of responses to climate change. General principles for this type of monitoring were developed for Lake Tanganyika ( [[#Plisnier--2018|Plisnier et al., 2018]] ) and could be applied to develop harmonised, regional monitoring of African lakes, rivers and wetlands ( [[#Tamatamah--2020|Tamatamah and Mwedzi, 2020]] )

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==== 9.6.4.3 Marine and Coastal Ecosystems ====

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Marine and coastal ecosystems such as mangroves, seagrass and coral reefs provide storm protection and food security for coastal communities ( ''high confidence'' ) ( [[#IPCC--2019d|IPCC, 2019d]] ). Restoring reef systems reduced wave height in Madagascar ( [[#Narayan--2016|Narayan et al., 2016]] ), but there is limited evidence for the efficacy of coral reef restoration at large scales with increased warming ( [[IPCC:Wg2:Chapter:Chapter-3|Chapter 3]] [[IPCC:Wg2:Chapter:Chapter-3#3.6.3|Section 3.6.3]] ). Populations at risk from storm surge and/or sea level rise coincide with areas of high coastal EbA potential from Mozambique to Somalia, and coastlines of the Gulf of Guinea, Gambia, Guinea-Bissau and Sierra Leone ( [[#Jones--2020|Jones et al., 2020]] ). Understanding hotspots of EbA potential is particularly important for west Africa with some of the highest levels of human dependence on marine ecosystems at high risk from climate change and large populations vulnerable to sea level rise (Sections 9.9.3.1; 9.8.5.2; [[#Selig--2018|Selig et al., 2018]] ; [[#Trisos--2020|Trisos et al., 2020]] ).

Marine protected areas (MPAs) can yield multiple adaptation benefits, such as buffering species from extinction and increasing fish stocks, as well as storing large amounts of carbon ( [[#Edgar--2014|Edgar et al., 2014]] ; [[#Roberts--2017|Roberts et al., 2017]] ; [[#Lovelock--2019|Lovelock and Duarte, 2019]] ). However, this potential of MPAs will reach limits with increased warming ( [[#Roberts--2017|Roberts et al., 2017]] ). For example, MPAs cannot prevent coral bleaching at scale and mass die-offs are well-described from MPAs following climate shocks ( [[#Bates--2019|Bates et al., 2019]] ; [[#Bruno--2019|Bruno et al., 2019]] ). However, prioritising MPA coverage of climate refugia, such as the Northern Mozambique Channel, may offer some increased resilience ( [[#McClanahan--2014|McClanahan et al., 2014]] ).

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'''Box 9.3 | Tree planting in Africa'''
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Due to widespread deforestation and forest degradation ( [[#Malhi--2014|Malhi et al., 2014]] ), future scenarios to limit global warming include large-scale reforestation and afforestation ( [[#Griscom--2017|Griscom et al., 2017]] ; [[#Bastin--2019|Bastin et al., 2019]] ). Africa has been targeted through the AFR100 ( https://afr100.org ) to plant ~1 million km 2 of trees by 2030 (Bond et al 2019). Maintaining existing indigenous forest and indigenous forest restoration is a win–win, maximising benefits to biodiversity, adaptation and mitigation ( [[#Griscom--2017|Griscom et al., 2017]] ; [[#Watson--2018|Watson et al., 2018]] ; [[#Lewis--2019|Lewis et al., 2019]] ) ( ''high confidence)'' .

Yet many areas targeted by AFR100 erroneously mark Africa’s open ecosystems (grasslands, savannas, shrublands) as degraded and suitable for afforestation (Figure Box 9.3.1; ( [[#Veldman--2015|Veldman et al., 2015]] ; [[#Bond--2019|Bond et al., 2019]] ) ''(high confidence)'' . These ecosystems are not ''degraded'' , they are ancient ecosystems that evolved in the presence of disturbances (fire/herbivory) ( [[#Maurin--2014|Maurin et al., 2014]] ; [[#Bond--2016|Bond and Zaloumis, 2016]] ; [[#Charles-Dominique--2016|Charles-Dominique et al., 2016]] ). Afforestation prioritises carbon sequestration at the cost of biodiversity and other ecosystem services ( [[#Veldman--2015|Veldman et al., 2015]] ; [[#Bond--2019|Bond et al., 2019]] ). Furthermore, it remains uncertain how much carbon can be sequestered as, compared to grassy ecosystems, afforestation can reduce belowground carbon stores and increase aboveground carbon loss to fire and drought ( [[#Yang--2019|Yang et al., 2019]] ; [[#Wigley--2020b|Wigley et al., 2020b]] ; [[#Nuñez--2021|Nuñez et al., 2021]] ). Thus, afforested areas may store less carbon than ecosystems they replace ( [[#Dass--2018|Dass et al., 2018]] ; [[#Heilmayr--2020|Heilmayr et al., 2020]] ). Afforestation would reduce livestock forage, ecotourism potential and water availability ( [[#Gray%20Emma--2013|Gray Emma and Bond William, 2013]] ; [[#Anadón--2014|Anadón et al., 2014]] ; [[#Cao--2016|Cao et al., 2016]] ; [[#Stafford--2017|Stafford et al., 2017]] ; [[#Du--2021|Du et al., 2021]] ), and may reduce albedo thereby increasing warming ( [[#Bright--2015|Bright et al., 2015]] ; [[#Baldocchi--2019|Baldocchi and Penuelas, 2019]] ).

Exotic tree species are often selected for planting (e.g., ''Pinus'' spp. or ''Eucalyptus'' spp.), but in parts of Africa, they have become invasive ( [[#Zengeya--2017|Zengeya, 2017]] ; [[#Witt--2018|Witt et al., 2018]] ), increasing fire hazards and decreasing biodiversity and water resources ( [[#Nuñez--2021|Nuñez et al., 2021]] ) ''(high confidence)'' . Negative impacts of afforestation on ecosystems are not restricted to plantations of exotic species; they extend to inappropriate planting of native forest species ( [[#Slingsby--2020|Slingsby et al., 2020]] ).

[[File:ad5db9c8a058e1a7ed6f164858cddc79 IPCC_AR6_WGII_Figure_9_Box_9_3_1.png]]

'''Figure Box 9.3.1 |''' '''Many proposed tree planting plans in Africa present risks to biodiversity and livelihoods, because they are focused on'''

(a) naturally non-forested ecosystems like savannas, grasslands and shrublands which

(b) host uniquely adapted biodiversity and

(c) offer important ecosystem services like grazing which supports subsistence and commercial agriculture. Figure adapted from [[#Veldman--2015|Veldman et al. (2015)]] ; [[#Bond--2019|Bond et al. (2019)]] .

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