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

=== 3.5.1 Introduction ===

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This section assesses the impacts of climate change on ecosystem services (Table 3.25; Chapter 1) and the outcomes on social–ecological systems, building on previous assessments (Table 3.26). [[#3.5.2|Section 3.5.2]] assesses how changes in biodiversity influence ecosystem services. Then Sections 3.5.3 and 3.5.4 assess provisioning services (food and non-food), [[#3.5.5|Section 3.5.5]] assesses supporting and regulating services, and [[#3.5.6|Section 3.5.6]] , cultural services. Where evidence exists, the section evaluates how the vulnerability and adaptive capacity of social–ecological systems govern the manifestation of impacts on each ecosystem service.

'''Table 3.25 |''' Ocean and coastal ecosystem services a

{| class="wikitable"
|-
! Ecosystem service category

! Components

! Ocean and coastal examples

|-
| Provisioning

| Food and feed

| Status of harvested marine fish, invertebrates, mammals and plants.

|-
|
| Medicinal, biochemical and genetic resources

| Existence of, and access to, biological resources that could offer future prospects for development, including marine fish, invertebrates, mammals, plants, microbes and viruses.

|-
|
| Materials and assistance

| Existence of, and access to, minerals, shells, stones, coral branches and dyes used to create other goods; availability of marine organisms to exhibit in zoos, aquariums and as pets.

|-
|
| Energy

| Existence of, and access to, sources of energy, including oil and gas reserves; solar, tidal and thermal ocean energy; and biofuels from marine plants.

|-
| Supporting and regulating

| Habitat creation and maintenance

| Status of nesting, feeding, nursery and mating sites for birds, mammals and other marine life, and of resting and overwintering places for migratory marine life or insects. Connectivity of ocean habitats.

|-
|
| Dispersal and other propagules

| Ability of marine life to spread gametes and larvae successfully by broadcast spawning reproduction, and ability of adults to disperse widely.

|-
|
| Regulation of climate

| Status of carbon storage and sequestration, methane cycling in wetlands, and dimethyl sulphide creation and destruction.

|-
|
| Regulation of air quality

| Status of aquatic processes that maintain and balance CO 2 , oxygen, nitrogen oxides, sulphur oxides, volatile organic compounds, particulates and aerosols.

|-
|
| Regulation of ocean acidification ( [[#3.2.3|Section 3.2.3.1]] )

| Status of chemical and biological aquatic processes that maintain and balance CO 2 and other acids/bases.

|-
|
| Regulation of freshwater quantity, location and timing

| Status of water storage by coastal systems, including groundwater flow, aquifer recharge and flooding responses of wetlands, coastal water bodies and developed spaces.

|-
|
| Regulation of freshwater and coastal water quality

| Status of chemical and biological aquatic processes that retain and filter coastal waters, capture pollutants and particles, and oxygenate water (e.g., natural filtration by sediments including adsorbent minerals and microbes).

|-
|
| Regulation of organisms detrimental to humans and marine life

| Status of grazing that controls harmful algal blooms and algal overgrowth of key ecosystems. Environmental conditions that suppress marine pathogens.

|-
|
| Formation, protection and decontamination of soils and sediments

| Status of chemical and biological aquatic processes that capture pollutants and particles (e.g., adsorption by minerals, microbial breakdown of pollutants).

|-
|
| Regulation of hazards and extreme events

| Ability of coastal environments to serve as wave-energy dissipators, barriers and wave breaks.

|-
|
| Regulation of key elements

| Status of aquatic processes that maintain and balance stocks of carbon, nitrogen, phosphorus and other elements critical for life.

|-
| Cultural

| Physical and psychological experiences

| Existence of, and access to, recreational opportunities including visiting beaches and coastal environments; and aquatic activities such as fishing, boating, swimming and diving.

|-
|
| Supporting identities

| Existence of, and access to, cultural, heritage and religious activities, and opportunities for intergenerational knowledge transfer; sense of place.

|-
|
| Learning and inspiration

| Existence of educational opportunities and characteristics to be emulated, as in biomimicry.

|-
|
| Maintenance of options

| Existence of opportunities to develop new medicines, materials, foods, and resources, or to adapt to a warmer climate and emergent diseases.

|}

Notes:

(a) Adapted from [[#IPBES--2017|IPBES (2017)]] , with examples made specific to ocean and coastal ecosystems by the authors of Chapter 3

'''Table 3.26 |''' Conclusions from previous IPCC assessments about observed and projected climate impacts on ocean and coastal biodiversity and ecosystem services

{| class="wikitable"
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! Ecosystem service and chapter subsection

! Observed impacts

! Projected impacts

|-
| All ( [[#3.5|Section 3.5]] )

| Climate change has affected marine ‘ecosystem services with regionally diverse outcomes, challenging their governance ( ''high confidence'' ). Both positive and negative impacts result for food security through fisheries ( ''medium confidence'' ), local cultures and livelihoods ( ''medium confidence'' ), and tourism and recreation ( ''medium confidence'' ). The impacts on ecosystem services have negative consequences for health and well-being ( ''medium confidence'' ), and for Indigenous Peoples and local communities dependent on fisheries ( ''high confidence'' ) (1.1, 1.5, 3.2.1, 5.4.1, 5.4.2, Figure SPM.2)’ (SROCC SPM A.8; [[#IPCC--2019c|IPCC, 2019c]] ).

| ‘Long-term loss and degradation of marine ecosystems compromises the ocean’s role in cultural, recreational, and intrinsic values important for human identity and well-being ( ''medium confidence'' ) (3.2.4, 3.4.3, 5.4.1, 5.4.2, 6.4)’ (SROCC SPM B.8; [[#IPCC--2019c|IPCC, 2019c]] ).

|-
| Biodiversity ( [[#3.5.2|Section 3.5.2]] )

| ‘[Climate] Impacts are already observed on [coastal ecosystem] habitat area and biodiversity, as well as ecosystem functioning and services ( ''high confidence'' ) (4.3.2, 4.3.3, 5.3, 5.4.1, 6.4.2, Figure SPM.2)’ (SROCC SPM A.6; [[#IPCC--2019c|IPCC, 2019c]] ).

| ‘Risks of severe impacts on biodiversity, structure and function of coastal ecosystems are projected to be higher for elevated temperatures under high compared to low emissions scenarios in the 21st century and beyond’ (SROCC SPM B.6; [[#IPCC--2019c|IPCC, 2019c]] ).

|-
| Food provision ( [[#3.5.3|Section 3.5.3]] )

| ‘Warming-induced changes in the spatial distribution and abundance of some fish and shellfish stocks have had positive and negative impacts on catches, economic benefits, livelihoods, and local culture ( ''high confidence'' ). There are negative consequences for Indigenous Peoples and local communities that are dependent on fisheries ( ''high confidence'' ). Shifts in species distributions and abundance has challenged international and national ocean and fisheries governance, including in the Arctic, North Atlantic and Pacific, in terms of regulating fishing to secure ecosystem integrity and sharing of resources between fishing entities ( ''high confidence'' ) (3.2.4, 3.5.3, 5.4.2, 5.5.2, Figure SPM.2)’ (SROCC SPM A.8.1; [[#IPCC--2019c|IPCC, 2019c]] ).

| ‘Future shifts in fish distribution and decreases in their abundance and fisheries catch potential due to climate change are projected to affect income, livelihoods, and food security of marine resource-dependent communities ( ''medium confidence'' ). Long-term loss and degradation of marine ecosystems compromises the ocean’s role in cultural, recreational, and intrinsic values important for human identity and well-being ( ''medium confidence'' ) (3.2.4, 3.4.3, 5.4.1, 5.4.2, 6.4)’ (SROCC SPM B.8; [[#IPCC--2019c|IPCC, 2019c]] ).

|-
| Non-food consumable provisioning services ( [[#3.5.4.1|Section 3.5.4.1]] )

| Observed impacts on non-food provisioning services not previously assessed.

| ‘Reductions in marine biodiversity due to climate change and other anthropogenic stressors ( [[#Tittensor--2010|Tittensor et al., 2010]] ), such as ocean acidification ( [[#CBD--2009|CBD, 2009]] ) and pollution, might reduce the discovery of genetic resources from marine species useful in pharmaceutical, aquaculture, agriculture, and other industries ( [[#Arrieta--2010|Arrieta et al., 2010]] ), leading to a loss of option value from marine ecosystems’ (WGII AR5 [[IPCC:Wg2:Chapter:Chapter-6#6.4.1.2|Section 6.4.1.2]] ; [[#Pörtner--2014|Pörtner et al., 2014]] )

|-
| Renewable energy ( [[#3.5.4.2|Section 3.5.4.2]] )

| Observed impacts on ocean renewable energy not previously assessed.

| ‘Ocean renewable energy can support climate change mitigation, and can comprise energy extraction from offshore winds, tides, waves, thermal and salinity gradient and algal biofuels. The emerging demand for alternative energy sources is expected to generate economic opportunities for the ocean renewable energy sector ( ''high confidence'' ), although their potential may also be affected by climate change ( ''low confidence'' ) (5.4.2, 5.5.1, Figure 5.23)’ (SROCC SPM C.2.5; [[#IPCC--2019c|IPCC, 2019c]] ).

|-
| Habitat creation and maintenance

( [[#3.5.5.1|Section 3.5.5.1]] )

| ‘[Climate] Impacts are already observed on [coastal ecosystem] habitat area and biodiversity, as well as ecosystem functioning and services ( ''high confidence'' ) (4.3.2, 4.3.3, 5.3, 5.4.1, 6.4.2, Figure SPM.2)’ (SROCC SPM A.6; [[#IPCC--2019c|IPCC, 2019c]] ).

‘In polar regions, ice associated marine mammals and seabirds have experienced habitat contraction linked to sea ice changes ( ''high confidence'' )’ (SROCC SPM A.5.2; [[#IPCC--2019c|IPCC, 2019c]] ).

| ‘In the Southern Ocean, the habitat of Antarctic krill, a key prey species for penguins, seals and whales, is projected to contract southwards under both RCP2.6 and RCP8.5 ( ''medium confidence'' ) (3.2.2, 3.2.3, 5.2.3)’ (SROCC SPM B5.3; [[#IPCC--2019c|IPCC, 2019c]] ).

‘Ocean warming, oxygen loss, acidification and a decrease in flux of organic carbon from the surface to the deep ocean are projected to harm habitat-forming cold-water corals, which support high biodiversity, partly through decreased calcification, increased dissolution of skeletons, and bioerosion ( ''medium confidence'' )’ (SROCC SPM B5.4; [[#IPCC--2019c|IPCC, 2019c]] ).

|-
| Climate regulation and air quality

( [[#3.5.5.2|Section 3.5.5.2]] )

| ‘Global ocean heat content continued to increase throughout [the 1951 to present] period, indicating continuous warming of the entire climate system ( ''very high confidence'' )’ (WGI AR6 TS1.2.3; [[#Arias--2021|Arias et al., 2021]] ).

| ‘The increase in global ocean heat content (TS2.4) will ''likely'' continue until at least 2300 even for low-emission scenarios’ (WGI AR6 Box TS.9; [[#Arias--2021|Arias et al., 2021]] ).

|-
|
| ‘Land and ocean have taken up a near-constant proportion (globally about 56% yr –1 ) of CO 2 emissions from human activities over the past six decades, with regional differences ( ''high confidence'' )’ (WGI AR6 SPM A1.1; [[#IPCC--2021b|IPCC, 2021b]] ).

| ‘While natural land and ocean carbon sinks are projected to take up, in absolute terms, a progressively larger amount of CO 2 under higher compared to lower CO 2 emissions scenarios, they become less effective, that is, the proportion of emissions taken up by land and ocean decrease with increasing cumulative CO 2 emissions. This is projected to result in a higher proportion of emitted CO 2 remaining in the atmosphere ( ''high confidence'' )’ (WGI AR6 SPM B4.1; [[#IPCC--2021b|IPCC, 2021b]] ).

|-
|
| Observed impacts on marine organisms’ contribution to climate regulation not previously assessed.

| ‘The effect of climate change on marine biota will alter their contribution to climate regulation, that is, the maintenance of the chemical composition and physical processes in the atmosphere and oceans ( ''high confidence'' ) ( [[#Beaumont--2007|Beaumont et al., 2007]] )’

(WGII AR5 [[IPCC:Wg2:Chapter:Chapter-6#6.4.1.3|Section 6.4.1.3]] ; [[#Pörtner--2014|Pörtner et al., 2014]] ).

|-
| Provision of freshwater, maintenance of water quality, regulation of pathogens ( [[#3.5.5.3|Section 3.5.5.3]] )

| Observed climate impacts on salinisation of coastal soil and groundwater not previously assessed.

| ‘In the absence of more ambitious adaptation efforts compared to today, and under current trends of increasing exposure and vulnerability of coastal communities, risks, such as erosion and land loss, flooding, salinisation, and cascading impacts due to mean sea level rise and extreme events are projected to significantly increase throughout this century under all greenhouse gas emissions scenarios ( ''very high confidence'' )’ (SROCC SPM B9.1; [[#IPCC--2019c|IPCC, 2019c]] ).

|-
|
| ‘Global warming compromises seafood safety ( ''medium confidence'' ) through human exposure to elevated bioaccumulation of persistent organic pollutants and mercury in marine plants and animals ( ''medium confidence'' ), increasing prevalence of waterborne ''Vibrio'' sp. pathogens ( ''medium confidence'' ), and heightened likelihood of harmful algal blooms ( ''medium confidence'' )’ (SROCC SPM B.8.3; [[#IPCC--2019c|IPCC, 2019c]] ).

| ‘[Risks from marine-borne pollutants and pathogens] are projected to be particularly large for human communities with high consumption of seafood, including coastal Indigenous communities ( ''medium confidence'' ), and for economic sectors such as fisheries, aquaculture, and tourism ( ''high confidence'' ) (3.4.3, 5.4.2, Box 5.3)’ (SROCC SPM B.8.3; [[#IPCC--2019c|IPCC, 2019c]] ).

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|
| ‘Since the early 1980s, the occurrence of harmful algal blooms (HABs) and pathogenic organisms (e.g., ''Vibrio'' ) has increased in coastal areas in response to warming, deoxygenation and eutrophication, with negative impacts on food provisioning, tourism, the economy and human health ( ''high confidence'' )’ (SROCC [[IPCC:Wg2:Chapter:Chapter-5|Chapter 5]] Executive Summary; [[#Bindoff--2019a|Bindoff et al., 2019a]] ).

| ‘Overall, the occurrence of HABs, their toxicity and risk on natural and human systems are projected to continue to increase with warming and rising CO 2 in the 21st century ( [[#Glibert--2014|Glibert et al., 2014]] ; [[#Martín-García--2014|Martín-García et al., 2014]] ; [[#McCabe--2016|McCabe et al., 2016]] ; [[#Paerl--2016|Paerl et al., 2016]] ; [[#Gobler--2017|Gobler et al., 2017]] ; McKibben et al.; 2017; [[#Rodríguez--2017|Rodríguez et al., 2017]] ; [[#Paerl--2018|Paerl et al., 2018]] ; [[#Riebesell--2018|Riebesell et al., 2018]] ) ( ''high confidence'' )’ (SROCC Box 5.4; [[#Bindoff--2019a|Bindoff et al., 2019a]] ).

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| Regulation of physical hazards

( [[#3.5.5.4|Section 3.5.5.4]] )

| ‘Coastal ecosystems are already impacted by the combination of sea level rise, other climate-related ocean changes, and adverse effects from human activities on ocean and land ( ''high confidence'' )... Coastal and near-shore ecosystems including saltmarshes, mangroves, and vegetated dunes in sandy beaches,...provide important services including coastal protection...( ''high confidence'' )’ (SROCC [[IPCC:Wg2:Chapter:Chapter-4|Chapter 4]] Executive Summary; [[#Oppenheimer--2019|Oppenheimer et al., 2019]] ).

| ‘The decline in warm water coral reefs is projected to greatly compromise the services they provide to society, such as...coastal protection ( ''high confidence'' )...’ (SROCC SPM B.8.2; [[#IPCC--2019c|IPCC, 2019c]] ).

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| Ocean and coastal carbon storage

( [[#3.5.5.5|Section 3.5.5.5]] )

| ‘Recent observations show that ocean carbon processes are starting to change in response to the growing ocean sink, and these changes are expected to contribute significantly to future weakening of the ocean sink under medium- to high-emission scenarios. However, the effect of these changes is not yet reflected in a weakening trend of the contemporary (1960–2019) ocean sink ( ''high confidence'' )’ (WGI AR6 [[IPCC:Wg2:Chapter:Chapter-5|Chapter 5]] Executive Summary; [[#Canadell--2021|Canadell et al., 2021]] ).

| ‘Emission scenarios SSP4-6.0 and SSP5-8.5 lead to warming of the surface ocean and large reductions of the buffering capacity, which will slow the growth of the ocean sink after 2050. Scenario SSP1-2.6 limits further reductions in buffering capacity and warming, and the ocean sink weakens in response to the declining rate of increasing atmospheric CO 2 . There is ''low confidence'' in how changes in the biological pump will influence the magnitude and direction of the ocean carbon feedback’ (WGI AR6 [[IPCC:Wg2:Chapter:Chapter-5|Chapter 5]] Executive Summary; [[#Canadell--2021|Canadell et al., 2021]] ).

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| ‘Mangrove, seagrass, and salt marsh ecosystems offer important carbon storage and sequestration opportunities ( ''limited evidence, medium agreement'' ), in addition to ecosystem goods and services such as protection against coastal erosion and storm damage and maintenance of habitats for fisheries species’ (WGII AR5 Technical Summary).

| ‘…under high emission scenarios, sea level rise and warming are expected to reduce carbon sequestration by vegetated coastal ecosystems ( ''medium confidence'' ); however, under conditions of slow sea level rise, there may be net increase in carbon uptake by some coastal wetlands ( ''medium confidence'' )’ (SROCC Chapter 5; [[#Bindoff--2019a|Bindoff et al., 2019a]] ).

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| Cultural services ( [[#3.5.6|Section 3.5.6]] )

| ‘Climate change impacts on marine ecosystems and their services put key cultural dimensions of lives and livelihoods at risk ( ''medium confidence'' ), including through shifts in the distribution or abundance of harvested species and diminished access to fishing or hunting areas. This includes potentially rapid and irreversible loss of culture and local knowledge and Indigenous knowledge, and negative impacts on traditional diets and food security, aesthetic aspects, and marine recreational activities ( ''medium confidence'' )’ (SROCC SPM B.8.4; [[#IPCC--2019c|IPCC, 2019c]] ).

| ‘Future shifts in fish distribution and decreases in their abundance and fisheries catch potential due to climate change are projected to affect income, livelihoods, and food security of marine resource-dependent communities ( ''medium confidence'' ). Long-term loss and degradation of marine ecosystems compromises the ocean’s role in cultural, recreational, and intrinsic values important for human identity and well-being ( ''medium confidence'' )’ (SROCC SPM B.8; [[#IPCC--2019c|IPCC, 2019c]] ).

|}

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