Editing IPCC:AR6/WGII/Chapter-16 (section)

=== 16.3.3 Knowledge Gaps in Observed Responses ===

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'''''Many adaptation responses are not documented''''' , and reporting bias is a key challenge for assessment of observed responses. Evidence of absence (i.e., where no adaptations are occurring) is different from absence of evidence (where responses are occurring but are not documented), with implications for understanding trends in global responses.

'''''Adaptation is being reported differently across different sources of knowledge''''' . The peer-reviewed literature, for example, has been primarily reporting reactive adaptation at the individual, household and community levels, while the grey literature has been more mixed, reporting adaptation across governmental levels and civil society, with less focus on individuals and households ( [[#Ford--2015a|Ford et al., 2015a]] ; [[#Ford--2015|Ford and King, 2015]] ). Synthesis of impacts and responses within the private sector is particularly limited ( [[#Averchenkova--2016|Averchenkova et al., 2016]] ; [[#Minx--2017|Minx et al., 2017]] ), further suggesting that knowledge accumulation on climate responses has been particularly slow, and that more ''robust evidence'' synthesis is required to fill key knowledge gaps.

'''''The potential for under-reporting is most acute in the context of minorities and remote and marginalised groups''''' , who are often also the most affected by the impacts of climate change and least able to respond to, or benefit from, the responses to climate change ( [[#Araos--2021|Araos et al., 2021]] ). Deficits in reporting on impacts and responses are well recognised in the Global South, among vulnerable populations (e.g., women, socioeconomically disadvantaged, Indigenous, people living with disabilities) and within civil society (ibid.).

'''''There is growing support for more comprehensive and systematic approaches to assess adaptation progress''''' ( [[#Berrang-Ford--2015|Berrang-Ford et al., 2015]] ; [[#Ford--2015a|Ford et al., 2015a]] ; [[#Ford--2015|Ford and King, 2015]] ; [[#Ford--2016|Ford and Berrang-Ford, 2016]] ; [[#Biesbroek--2018|Biesbroek et al., 2018]] ). Since the AR5, there is increased recognition of the value of integrating diverse knowledge sources to fill knowledge gaps in observation of impacts and responses (Chapter 17; Cross-Chapter Box PROGRESS in Chapter 17). Van Bavel, for example, found that the involvement of local and diverse knowledge can improve the detection ( ''medium confidence'' ) and attribution ( ''medium confidence'' ) of health impacts, and improve the action ( ''high confidence'' ) ( [[#Van%20Bavel--2020|Van Bavel et al., 2020]] ).

'''''A new development since AR5, there is now growing evidence assessing progress on adaptation''''' across sectors, geographies and spatial scales. Uncertainty persists around what defines adaptation and how to measure it (Cross-Chapter Box FEASIB in Chapter 18, [[#UNEP--2021|UNEP, 2021]] ). As a result, most literature synthesising responses is based on documented or reported adaptations only, and is thus subject to substantial reporting bias.

'''''We document implemented adaptation-related responses that could directly reduce risk.''''' Adaptation ''as a process'' is more broadly covered in [[IPCC:Wg2:Chapter:Chapter-17|Chapter 17]] ( [[IPCC:Wg2:Chapter:Chapter-17#17.4.2|Section 17.4.2]] ), including risk management, decision making, planning, feasibility (see Cross-Chapter Box FEASIB in Chapter 18), legislation and learning. Here, we focus on a subset of adaptation activities: adaptation-related responses of species, ecosystems, and human societies that have been implemented and observed, and could directly reduce risk. We consider all adaptation-related responses to assumed, perceived or expected climate risk, regardless of whether or not impacts or risks have been formally attributed to climate change.

'''''We use the term ‘adaptation-related responses’, recognising that not all responses reduce risk.''''' While ‘adaptation’ implies risk reduction, we use the broader term ‘responses’ to reflect that responses may decrease risk, but in some cases may increase risk.

Given ''limited evidence'' to inform comprehensive global assessment of effectiveness and adequacy, we assess evidence that adaptation responses in human systems indicate transformational change. [[IPCC:Wg2:Chapter:Chapter-17|Chapter 17]] considers adaptation planning and governance, including adaptation solutions, success, and feasibility assessment (Cross-Chapter Box FEASIB in Chapter 18). It is not currently possible to conduct a comprehensive global assessment of effectiveness, adequacy or the contribution of adaptation-related responses to changing risk due to an absence of robust empirical literature (discussed further in Cross-Chapter Box PROGRESS in Chapter 17).

'''''In natural ecosystems or species, detectable changes can be considered as ‘impact’ or ‘response’.''''' The distinction between ‘observed impacts’ ( [[#16.2|Section 16.2]] ) and ‘observed responses’ ( [[#16.3|Section 16.3]] ) is not always clear. For example, autonomous distributional shifts in wild species induced by increasing temperatures (an observed impact) may reduce risk to the species (an autonomous adaptation response), but this process can be enhanced or supported by human intervention such as intentional changes in land use. Observed autonomous changes in natural ecosystems or species unsupported by human intervention are treated as impacts (see [[#16.2|Section 16.2]] ).

Adaptation-related responses are frequently motivated by a combination of climatic and non-climatic drivers, and interact with other transitions to affect risk. For societal responses, it is difficult to say whether they are triggered by observed or anticipated changes in climate, by non-climatic drivers or, as is the case in many societal responses, by a combination of all three. In the case of impacts, assessment typically focuses on detection and attribution ''vis à vis'' a counterfactual of no climate change. While there has been some effort to attribute reduced climate risk to adaptation-related responses ( [[#Toloo--2013a|Toloo et al., 2013a]] ; [[#Toloo--2013b|Toloo et al., 2013b]] ; [[#Hess--2018|Hess et al., 2018]] ; [[#Weinberger--2018|Weinberger et al., 2018]] ), in many cases this has not been feasible given difficulties in defining adaptation and empirically disentangling the contribution of intersecting social transitions and changing risks. Literature on adaptation-related response frequently draws on theories of change to assess the likely contribution of adaptations to changes in risk, including maladaptation and co-benefits.

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'''Cross-Chapter Box INTEREG | Inter-regional Flows of Risks and Responses to Risk'''
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Authors: Birgit Bednar-Friedl (Austria, Chapter 13), Christopher Trisos (South Africa, Chapter 9), Laura Astigarraga (Uruguay, Chapter 12), Magnus Benzie (Sweden/UK), Aditi Mukherji (India, Chapter 4), Maarten Van Aalst (the Netherlands, Chapter 16)

'''Introduction'''
Our world today is characterised by a high degree of interconnectedness and globalisation which establish pathways for the transmission of climate-related risks across sectors and borders ( ''high confidence'' ) ( [[#Challinor--2018|Challinor et al., 2018]] ; [[#Hedlund--2018|Hedlund et al., 2018]] ). While the IPCC 5th Assessment Report (AR5) has pointed to this connection of risks across regions as ‘cross-regional phenomena’ ( [[#Hewitson--2014|Hewitson et al., 2014]] ), only a few countries so far have integrated inter-regional aspects into their climate change risks assessments ( [[#Liverman--2016|Liverman, 2016]] ; [[#Surminski--2016|Surminski et al., 2016]] ; [[#Adams--2020|Adams et al., 2020]] ), and adaptation is still framed as a predominantly national or local issue ( [[#Dzebo--2015|Dzebo and Stripple, 2015]] ; [[#Benzie--2019|Benzie and]] [[#Persson--2019|Persson, 2019]] ).

Inter-regional risks from climate change—also called cross-border, transboundary, transnational or indirect risks—are risks that are transmitted across borders (e.g., transboundary water use) and/or via teleconnections (e.g., supply chains, global food markets) ( [[#Moser--2015|Moser and Hart, 2015]] ). The risks can result from impacts, including compound or concurrent impacts, that cascade across several tiers, in ways that either diminish or escalate risk within international systems ( [[#Carter--2021|Carter et al., 2021]] ). Risk transmission may occur through trade and finance networks, flows of people (Cross-Chapter Box MIGRATE in Chapter 7), biophysical flows (natural resources such as water) and ecosystem connections. However, not only risks are transmitted across borders and systems; the adaptation response may also reduce risks at the origin of the risk, along the transmission channel or at the recipient of the risk ( [[#Carter--2021|Carter et al., 2021]] ). This cross-chapter box discusses four inter-regional risk channels (trade, finance, food and ecosystems) and how adaptation can govern these risks.

'''Trade'''
Most commodities are traded on global markets, and supply chains have become increasingly globalised. For instance, specialised industrial commodities such as semiconductors are geographically concentrated in a few countries ( [[#Challinor--2017|Challinor et al., 2017]] ; [[#Liverman--2016|Liverman, 2016]] ). When climatic events like flooding or heat affect the location of these extraction and production activities, economies are not only disrupted locally but also across borders and in distant countries ( ''high confidence'' ), as exemplified by the Thailand flood 2011 that led to a shortage of key inputs to the automotive and electronics industry not only in Thailand but also in Japan, Europe and the USA (Figure Cross-Chapter Box INTEREG.1). For many industrialised countries like the UK, Japan, the USA and the European Union, there is increasing evidence that the trade impacts of climate change are significant and can have substantial domestic impacts ( ''medium confidence'' ) ( [[#Nakano--2017|Nakano, 2017]] ; [[#Willner--2018|Willner et al., 2018]] , [[IPCC:Wg2:Chapter:Chapter-13#13.9.1|Section 13.9.1]] ; [[#Benzie--2019|Benzie and]] [[#Persson--2019|Persson, 2019]] ; [[#Knittel--2020|Knittel et al., 2020]] ). Enhanced trade can transmit risks across borders and thereby amplify damages ( [[#Wenz--2016|Wenz and Levermann, 2016]] ), but it can also increase resilience ( [[#Lim-Camacho--2017|Lim-Camacho et al., 2017]] ; [[#Willner--2018|Willner et al., 2018]] ).

[[File:47f8ef4f9654551d10cee3c0d177faf6 IPCC_AR6_WGII_Figure_16_Cross-Chapter_Box_INTEREG-1.png]]

'''Figure Cross-Chapter Box INTEREG.1 |''' '''Inter-regional climate risks: the example of the trade transmission channel, illustrated for the Thailand flood 2011 ( [[#Abe--2013|Abe and Ye, 2013]] ; [[#Haraguchi--2015|Haraguchi and Lall, 2015]] ; [[#Carter--2021|Carter et al., 2021]]''' '''.''' ''', 2021).'''

'''Finance'''
Climate risks can also spread through global financial markets ( [[#Mandel--2021|Mandel et al., 2021]] ). For the case of coastal and riverine flooding with low adaptation 2080 (RCP 8.5-SSP5), the financial system is projected to amplify direct losses by a factor of 2 (global average), but reach up to a factor of 10 for countries that are central financial hubs ( [[#Mandel--2021|Mandel et al., 2021]] , Figure 13.28). Indirect impacts may also arise through indirect effects on foreign direct investment, remittance flows and official development assistance ( [[#Hedlund--2018|Hedlund et al., 2018]] ).

'''Food'''
The global supply of agricultural products is concentrated to a few main breadbaskets ( [[#Bren%20d’Amour--2016|Bren d’Amour et al., 2016]] ; [[#Gaupp--2020|Gaupp et al., 2020]] , Chapter 5). For instance, Central and South America is one of the regions with the highest potential to increase food supplies to more densely populated regions in Asia, the Middle East and Europe (Chapter 12). The exports of agricultural commodities (coffee, bananas, sugar, soybean, corn, sugarcane, beef livestock) have gained importance in the past two decades as international trade and globalisation of markets have shaped the global agri-food system (Chapter 5).

The export of major food crops like wheat, maize and soybeans from many of the world’s water-scarce area—the Middle East, North Africa, parts of South Asia, North China Plains, southwest USA, Australia—to relatively water-abundant parts of the world carries a high virtual water content (the net volume of water embedded in trade) ( ''high confidence'' ) ( [[#Hoekstra--2012|Hoekstra and Mekonnen, 2012]] ; [[#Dalin--2017|Dalin et al., 2017]] ; [[#Zhao--2019|Zhao et al., 2019]] , Chapter 4). Both importing and exporting countries are exposed to transboundary risk transmission through climate change impacts on distant water resources ( [[#Sartori--2017|Sartori et al., 2017]] ; [[#Zhao--2019|Zhao et al., 2019]] ; [[#Ercin--2021|Ercin et al., 2021]] ). Climate change is projected to exacerbate risk and add new vulnerabilities for risk transmission ( ''medium confidence'' ). Rising atmospheric CO 2 concentration is projected to decrease water efficiency of growing maize and temperate cereal crops in parts of the USA, East and Mediterranean Europe, South Africa, Argentina, Australia and Southeast Asia, with important implications for future trade in food grains ( [[#Fader--2010|Fader et al., 2010]] ). By 2050 (SRES B2 scenario), virtual water importing countries in Africa and the Middle East may be exposed to imported water stress as they rely on imports of food grains from countries which have unsustainable water use ( [[#Sartori--2017|Sartori et al., 2017]] ). Until 2100, virtual trade in irrigation water is projected to almost triple (for SSP2-RCP6.5 scenarios) and the direction of virtual water flows is projected to reverse, with the currently exporting regions like South Asia becoming importers of virtual water ( [[#Graham--2020|Graham et al., 2020]] ). An additional 10–120% trade flow from water-abundant regions to water-scarce regions will be needed to sustain environmental flow requirements on a global scale by the end of the century ( [[#Pastor--2019|Pastor et al., 2019]] ). Exports of agricultural commodities contribute to deforestation, over-exploitation of natural resources and pollution, affecting the natural capital base and ecosystem services ( [[#Agarwala--2020|Agarwala and Coyle, 2020]] ; [[#Rabin--2020|Rabin et al., 2020]] , [[IPCC:Wg2:Chapter:Chapter-12#12.5.4|Section 12.5.4]] ).

'''Species and ecosystems'''
The spatial distributions of species on land and in the oceans are shifting due to climate change, with these changes projected to accelerate at higher levels of global warming ( [[#Pecl--2017|Pecl et al., 2017]] ). These ‘species on the move’ have large effects on ecosystems and human well-being, and present challenges for governance ( [[#Pecl--2017|Pecl et al., 2017]] ). For example, the number of transboundary fish stocks is projected to increase as key fisheries species are displaced by ocean warming ( [[#Pinsky--2018|Pinsky et al., 2018]] ). Conflict over shifting mackerel fisheries has already occurred between European countries ( [[#Spijkers--2017|Spijkers and Boonstra, 2017]] ), because few regulatory bodies have clear policies on shifting stocks; this leaves species open to unsustainable exploitation in new waters in the absence of regularly updated catch allocations to reflect changing stock distributions ( [[#Caddell--2018|Caddell, 2018]] ).

Human health will also be affected as vector-borne diseases such as malaria and dengue shift geographic distributions ( [[#Caminade--2014|Caminade et al., 2014]] ). There is also evidence that many warm-adapted invasive species, such as invasive freshwater cyanobacterium, have spread to higher latitudes because of climate change (Chapter 2).

'''Adaptation to inter-regional climate risks'''
Adaptation responses to reduce inter-regional risks can be implemented at a range of scales: at the point of the initial climate change impact (e.g., assistance for recovery after an extreme event, development of resilient infrastructure, climate-smart technologies for agriculture); at or along the pathway via which impacts are transmitted to the eventual recipient (e.g., trade diversification, re-routing of transport); in the recipient country (e.g., increasing storage to buffer supply disruptions), or by third parties (e.g., adaptation finance, technology transfer) ( [[#Bren%20d’Amour--2016|Bren d’Amour et al., 2016]] ; [[#Carter--2021|Carter et al., 2021]] ; [[#Talebian--2021|Talebian et al., 2021]] ). A knowledge gap exits on the need for, effectiveness of, and limits to adaptation under different socioeconomic and land use futures.

Due to regional and global interdependencies, climate resilience has a global, multi-level public good character ( [[#Banda--2018|Banda, 2018]] ). The benefits of adaptation are therefore shared beyond the places where adaptation is initially implemented. Conversely, adaptation may be successful at a local level while redistributing vulnerability elsewhere or even driving or exacerbating risks in other places ( [[#Atteridge--2018|Atteridge and Remling, 2018]] ). International cooperation is therefore needed to ensure that inter-regional effects are considered in adaptation and that adaptation efforts are coordinated to avoid maladaptation. However, regional- and global-scale governance of adaptation is only just beginning to emerge ( [[#Persson--2019|Persson, 2019]] ).

The United Nations Framework Convention on Climate Change (UNFCCC) Paris Agreement frames adaptation as a ‘global challenge’ (Article 7.2) and establishes the global goal on adaptation (Article 7.1), which provides space for dialogue between parties on the global-scale challenge of adaptation and the need for renewed political and financial investment in adaptation, including to address inter-regional effects ( [[#Benzie--2018|Benzie et al., 2018]] ).

National Adaptation Plans (NAPs) can evolve to consider inter-regional effects as well as domestic ones ( [[#Liverman--2016|Liverman, 2016]] ; [[#Surminski--2016|Surminski et al., 2016]] ; [[#European%20Environment--2020|European Environment, 2020]] ). Regional and international coordination of NAPs, coupled with building capacities and addressing existing knowledge gaps at the country level, can help to ensure that resources are oriented towards reducing inter-regional risks and building systemic resilience to climate change globally ( [[#Booth--2020|Booth et al., 2020]] ; [[#Wijenayake--2020|Wijenayake et al., 2020]] ).

Given the important role of private actors in managing inter-regional climate risks ( [[#Goldstein--2019|Goldstein et al., 2019]] ; [[#Tenggren--2019|Tenggren et al., 2019]] ), efforts will be needed to align public and private strategies for managing inter-regional climate risks to avoid maladaptation and ensure just and equitable adaptation at different scales ( [[#Talebian--2021|Talebian et al., 2021]] ).

Cross-Chapter Box INTEREG

Cross-Chapter Box INTEREG

Cross-Chapter Box INTEREG

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