Development is about ‘improvement’. However there have been different and often conflicting viewpoints on the improvement of ‘what’ and ‘how’ to improve. The diversity of positions has resulted in a multitude of metrics to track development, some more influential than others on policy. Alternative measures of development, while numerous, generally seek to nuance the connection between economic growth and human well-being. Because they maintain core notions of progress and, in some cases, economic growth seen in more mainstream models of development, they are less vehicles for transformation than continuations of thinking and action fundamentally at odds with the needs of CRD. These include the Measure of Economic Welfare (Nordhaus and Tobin, 1973), the Index of Sustainable Economic Welfare (Cobb and Daly, 1989), the Genuine Progress Indicator (Escobar, 1995), the Adjusted Net Saving Index or the Genuine Savings Index (GSI), The Human Development Index (HDI), the Inequality-Adjusted Human Development Index (UNDP, 2016a), the Gender Development Index, the Gender Inequality Index, the Multidimensional Poverty Index, the Index of Sustainable Economic Welfare (ISEW) (Daly and Cobb, 1989), the Genuine Progress Indicator (GPI) (Kubiszewski et al., 2013), Gross National Happiness (GNH) (Ura and Galay, 2004), Measures of Australia’s Progress (MAP) (Trewin and Hall, 2004), the OECD Better Life Index (OECD, 2019a) and the Happy Planet Index (NEF, 2016).

In terms of their historical trajectory, different perspectives on development can be broadly divided into five categories.

1. Development as economic growth (1950s onwards) : Equating development with economic growth was a natural outcome of the dominance of economics as the major discipline to study problems of newly independent countries in the 1950s (Escobar, 1995), measured through GDP. Environment was not a policy concern in the immediate period after decolonisation. The GDP measure has withstood the test of time, in spite of being an inexact measure of human well-being, and is the widely used metric globally to track development. Recent improvements to GDP have tried to account for environmental factors (Gundimeda et al., 2007; United Nations, 2021 ).
2. Development as distributional improvements (1970s onwards) : That economic growth does not automatically result in decline in poverty and improved distribution of income became apparent in the 1970s. Welfare measures were thus promoted that involved ‘redistribution with growth’ (Chenery, 1974). These distributional concerns have re-emerged in the last two decades with the widening gap between the richer and poorer groups of the population (Chancel and Piketty, 2019) and also the increased attention to ‘ecological distribution conflicts’ (Martinez-Alier, 2021). The political economy perspective, highlighting continued dependencies of countries in the Global South on the Global North, now evolved into political ecology highlighting environmental concerns between and within countries. Environment was not yet a policy priority, despite the links between development and environment becoming clearer.
3. Development as participation (1980s onwards) : Bottom-up responses emphasising sustainable livelihoods and local-level development emerged in the 1980s. The movement, which involved independent and uncoordinated efforts by grassroots activists, social movements and non-governmental organisations (NGOs), became ‘mainstreamed’ into development in the 1990s (Chambers, 2012). The multi-dimensional nature of poverty was acknowledged at the global policy level (World Bank, 2000) and there was wider acceptance of the role of non-economics social sciences as well as critical approaches in research on development and poverty (Thomas, 2008). Participatory development involved decentralisation and local planning, emphasising protection of local natural resources in addition to improving living standards.
4. Development as expansion of human capabilities (1980s onwards) : The human development and capabilities approach was the first formidable response to the GDP-centric view of development (Sen, 2000; Deneulin and Shahani, 2009). Studies showed that improvements in income did not necessarily improve human well-being in other dimensions such as health and education, or more broadly put, ‘freedoms’ (Ruggeri Laderchi et al., 2003). The capabilities idea was influential in global policy making through Human Development Reports and metrics such as Human Development Index (HDI) and Multidimensional Poverty Index (MPI). However, environmental sustainability was not a major component in this approach until much later (Alkire and Jahan, 2018). Recent improvements to HDI such as the planetary pressures-adjusted HDI (United Nations, 2020) is a step in this direction.
5. Development as post-growth (2010 onwards) : The late 1980s saw a big push towards taking the environment to the centre of the global policy agenda (World Commission on Environment and Development, 1987). However, progress in addressing environmental questions has been slow. As compared with Millennium Development Goals (MDGs), SDGs aim to tackle environmental concerns by explicitly tracking progress on multiple indicators. Nevertheless, the approach in these policy propositions sits largely within the economic growth framework itself. The climate change challenge and the financial crisis of 2008 led many scholars, ecological economists and environmental social scientists in particular, to argue for a post-growth world. Post-growth (Jackson, 2021), degrowth (Kallis, 2018; Hickel et al., 2021) and other environmentalist scholarship takes inspiration from critiques of development such as post-development (Escobar, 1995). The argument here is not for better metrics but for imagining and working towards systemic change in the wake of the climate crisis. The challenge however is how to account for historical differences in economic growth and living standards between the Global North and the Global South and to protect the interests of Global South in the spirit of ‘common but differentiated responsibilities’ to climate change adaptation and mitigation. As empirical studies in the Global South have demonstrated (Lele et al., 2018), developing countries face multiple stressors, climate change being just one among them, and there are multiple normative concerns in developing country contexts, such as equity and justice, and not merely resilience (very high confidence).

Achieving CRD requires framings of development that move away from linear paradigms of development as material progress by focusing on diversity and heterogeneity, well-being and equality, not only in contemporary practices, but also pathways of change over time (Gibson-Graham, 2005; Gibson-Graham, 2006). Such approaches, which are fundamentally aligned with ecological and ecosystem-based environmental assessments that identified heterogeneity of approaches and actions as the most effective path to a sustainable world (Millennium Ecosystem Assessment, 2005), emphasise the importance of cultural, linguistic and religious diversity, not merely as alternative sources of information about the world, but as different paradigms of well-being (Kallis, 2018). These include Indigenous and local knowledge that provide alternatives to these framings of the world (Cross-Chapter Box INDIG). This broad reframing of development includes a focus on visions such as ‘buen vivir’ (Cubillo-Guevara et al., 2014; Walsh, 2018; Acosta et al., 2019), ecological Swaraj (Kothari et al., 2014; Demaria and Kothari, 2017; Shiva, 2017) and Ubuntu (Dreyer, 2015; Ewuoso and Hall, 2019), among others. All are linked by relationships with nature radically different from the Western mechanistic vision, presenting not only framings of development and the environment that yield locally appropriate CRDPs, but serve as examples of alternative ways of living in balance with nature that might inform similar thinking in other places.

Differing perspectives on development are in part determined by the multiple diverse priorities held by different actors and nations. Another reason is that development is not a linear process with a single goal, and active development planning requires simultaneously taking multiple processes and factors into account. This is well illustrated by growing attention to climate security. The AR5 delivered conflicting messages regarding climate change and security (Gleditsch and Nordås, 2014), yet the understanding of climate-related security risks has made substantial progress in recent years (von Uexkull and Buhaug, 2021). Although there remains considerable research gaps in certain regions (Adams et al., 2018), a large body of qualitative and quantitative studies from different disciplines provides new insight into the relationship of climate change and security (Buhaug, 2015; De Juan, 2015; Brzoska and Fröhlich, 2016; Abrahams and Carr, 2017; Sakaguchi et al., 2017; Moran et al, 2018; Scheffran, 2020). Though not the only cause (Sakaguchi et al., 2017; Mach et al., 2019), climate change undermines human livelihoods and security, because it increases the populations vulnerabilities, grievances and political tensions through an array of indirect—at times nonlinear—pathways, thereby increasing human insecurity and the risk of violent conflict (van Baalen and Mobjörk, 2018; Koubi, 2019; von Uexkull and Buhaug, 2021). Indeed, context, as well as timing and spatial distribution, matter and need to be accounted for (Abrahams, 2020).

In line with this better understanding, climate change and security have been reframed in the political space, to focus more on human security. The solutions to climate-related security risks cannot be military, but are linked to development and people’s vulnerabilities in complex social and politically fragile settings (Abrahams, 2020). This has resulted in integration of climate-related security risk into institutional and national frameworks (Dellmuth et al., 2018; Scott and Ku, 2018; Aminga and Krampe, 2020), including several Nationally Determined Contributions (NDCs) (Jernnäs and Linnér, 2019; Remling, 2021). One example is the UN Climate Security Mechanism—set up in 2018 between UNDP, UNEP and UN DPPA to help the UN more systematically address climate-related security risks and devise prevention and management strategies. Yet work remains in bridging these concerns with practical responses on the ground (Busby, 2021). Especially since emerging research building on the maladaptation literature shows that this practice cannot just mean adding adaptation and mitigation to the mix of development strategies in a given location, as this may have unintended and unanticipated effects and might even backfire completely (Dabelko et al., 2013; Magnan et al., 2020; Mirumachi et al., 2020; Schipper, 2020; Swatuk et al., 2021). In extremely underdeveloped, fragile contexts such as Afghanistan, the local-level side effects of climate adaptation and mitigation projects might result in different development outcomes and question the potential for sustainable peace (Krampe et al., 2021). Given the clearer understanding of the intertwined nature of climate change, security and development—especially in fragile and conflict affected regions—a rethinking of how to transfer this knowledge into policy solutions is necessary for the formulation of CRD.

Mitigation, including greenhouse gas emissions reductions, avoidance, and removal and sequestration, as well as management of other climate forcing factors (WGIII AR6), is a key element of addressing climate risk and pursuing CRD. There are numerous individual and system mitigation options throughout the economy and within human and natural systems (very high confidence) (Chapter 16; Section 18.5). Limiting global average warming has been found to reduce climate risks (IPCC, 2018a; IPCC, 2019b), and limiting global average warming to any temperature level has also been found to be associated with broad ranges of potential global emissions pathways that represent future uncertainty in the evolution of socioeconomic, technological, market and physical systems (very high confidence) (Rose and Scott, 2018; Rose and Scott, 2020). Pathways consistent with limiting warming to 2°C and below have been found to require significant deployment of mitigation options spanning energy, land use and societal transformation ((Lecocq et al., 2022; Riahi et al., 2022); Section 18.3). and substantial economic, energy, land use, policy and societal transformation (Lecocq et al., 2022; Riahi et al., 2022). Such emissions pathways would represent deviations from current trends that raise issues about their feasibility and therefore plausibility (Rose and Scott, 2018; Rose and Scott, 2020).

The technical and economic challenge of limiting warming has been found to increase nonlinearly with greater ambition, fewer mitigation options, less than global cooperative policy designs and delayed mitigation action ((Riahi et al., 2022); Table 18.2). Table 18.2 provides a high-level summary of pathway characteristic ranges based on the WGIII AR6 assessment. Global pathways find large regional differences in mitigation potential, as well as the degree of regional nonlinearity with greater mitigation ambition. These represent opportunities for mitigation, but how this effort and cost would be facilitated and distributed respectively is a policy question.

Table 18.2 illustrates that greater climate ambition implies more aggressive emissions reductions in each region, and earlier regional peaking of emissions (if they have not peaked to date). Near-term regional emissions increases are possible, even for 1.5°C compatible pathways, but significantly lower emissions than today are shown in all regions by 2050. Increases in total regional energy consumption and fossil energy are observed for many pathways, even in the most ambitious where energy consumption growth is potentially slower compared with less ambitious pathways. By 2050, regional fossil energy declines, but is not eliminated in any region. Regional growth in electricity use is substantial in all pathways, even the most ambitious, with the growth continuing and accelerating with time and regional dependence on electricity (share of total energy consumption) also growing significantly. The broad ranges are an indication of uncertainty and risk for regional transitions, noting that full uncertainty is likely broader than what is captured by emissions scenario databases (Rose and Scott, 2018; Rose and Scott, 2020). Among other things, pathways commonly assume idealised climate policies with immediate implementation, and model infeasibilities (i.e., models unable to solve) increase with climate ambition and pessimism about mitigation technologies (e.g., Clarke et al., 2014; Bauer et al., 2018; Rogelj et al., 2018; Muratori et al., 2020), highlighting the increasing challenge and potential for actual infeasibility with lower global warming targets. Together, Table 18.2 provides insights into the increasingly demanding system and development transitions associated with lower global warming levels, as well as some of the low-carbon transition uncertainties and risks (see also Figure 18.5).

Past assessment has evaluated representative mitigation strategies in terms of economic, technological, institutional, socio-cultural, environmental/ecological and geophysical viability, as well as relationships to SDGs (de Coninck et al., 2018). The strategies assessment analysis has been updated for AR6 (Cross-Chapter Box FEASIB). These assessments identify types of barriers that could affect an option’s feasibility. Among other things, this work finds that, other than public transport and non-motorised transport, every other mitigation option evaluated had at least one feasibility dimension that represented a barrier or obstacle. The barriers also imply that there are trade-offs in these feasibility dimensions to consider. The assessment of mitigation option-sustainable development relationships identifies related literature and derives aggregate characterisations. Concerns about the potential sustainable development implications of some mitigation technologies may be motivation for precluding the use of some mitigation options. For instance, the potential food security and environmental quality implications of bioenergy have received significant attention in the literature (e.g., Smith et al., 2013). However, constraining or precluding the use of bioenergy without or with CCS could have significant implications for the cost of pursuing ambitious climate goals, and potentially the attainability of those goals (e.g., Clarke et al., 2014; Bauer et al., 2018; Rogelj et al., 2018; Muratori et al., 2020). Bioenergy is not unique in this regard. Social, environmental, and sustainability concerns have also been raised about the large-scale deployment of many low-carbon technologies, for example, REDD+, wind, solar, nuclear, fossil with CCS and batteries. See WGIII Chapter 3 (Riahi et al., 2022) for examples of the potential implications of limiting or precluding different low-carbon technologies.

Overall, as with adaptation options, insights from this aggregate feasibility and sustainable development mapping work are high level and difficult to apply to a specific mitigation context. The feasibility, ranking and sustainable development implications of mitigation options, as well as the list of options themselves, for a given location will vary from location to location, with different criteria and weighting of criteria that reflect the relevant social priorities and differences in markets, technology options and policies for managing risks and trade-offs. Integrated evaluation of criteria and options is needed here as well, that accounts for the relevant geographic context and interactions between options, systems and implications.

Analyses of the potential implications of mitigation on sustainable development has various strands of literature—studies exploring general greenhouse gas mitigation feedbacks to society, assessments of mitigation implications on specific societal objectives other than climate and literature evaluating mitigation implications specifically for sustainable development objectives (Denton et al., 2022; Lecocq et al., 2022; Riahi et al., 2022). In general, mitigation alters development opportunities by constraining the emissions future society can produce, which affects markets, resource allocation, economic structure, income distribution, consumers and the environment (besides climate) (very high confidence). Examples of general development feedbacks from mitigation include estimated price changes, macroeconomic costs, and low carbon energy and land system transformations (Fisher et al., 2007; Clarke et al., 2014; Popp et al., 2014; Rose et al., 2014; Weyant and Kriegler, 2014; Bauer et al., 2018; Rogelj et al., 2018). Examples of mitigation implications for other specific variables of societal interest include evaluating potential effects on air pollutant emissions, crop prices, water and land use change (e.g., McCollum et al., 2018b; Roy et al., 2018), while the literature evaluating mitigation implications specifically for sustainable development objectives includes evaluations on energy access, food security and income equality (e.g., Roy et al., 2018; Arneth et al., 2019; Mbow et al., 2019). Proxy indicators are frequently used to represent whether there might be implications for a sustainable development objective. For example, changes in energy prices are used as a proxy for effects on energy security (e.g., Roy et al., 2018). This is common with aggregate modelling studies, such as those associated with global or regional emissions scenarios and energy systems.

Figure 18.5, derived from WGIII scenarios data, illustrates estimated relationships between mitigation and various sustainable development proxy variables for different global regions. Figure 18.5 illustrates synergies and trade-offs with mitigation, as well as regional heterogeneity, that can intensify with the level of climate ambition—synergies in air pollutants, such as black carbon, NOx and SO2; and trade-offs in overall economic development, household consumption, food crop prices and energy prices for electricity and natural gas. For comparison, recent IPCC assessments also observed similar synergies and trade-offs but did not directly make comparisons regarding overall development nor evaluate potential climates above 2°C (Rogelj et al., 2018; Roy et al., 2018; Mbow et al., 2019). Regional nonlinearity in the economic costs of mitigation with greater climate ambition (i.e., costs rising at an increasing rate with lower warming goals) can be significant within individual models (Rose and Scott, 2018; Rose and Scott, 2020). Figure 18.5 also illustrates transition risks in the potential for significant synergistic and trade-off implications with, for instance, potentially large regional commodity price implications and household consumption losses, as well as more significant air pollution benefits. Note that the 1.5°C results in Figure 18.5 (and Table 18.2) are biased by model infeasibilities. Many models are unable to solve, especially with less optimistic assumptions, resulting in small sample sizes and a different representation of models compared to the 2°C and higher results.

Results such as those in Figure 18.5 illustrate that mitigation–development trade-offs are inevitable and need to be considered and addressed. For instance, Roy (2018) found that although limiting warming to 1.5°C would make it markedly easier to achieve most of the UN’s SDGs, none of the 1.5°C pathways assessed achieved all of the SDGs. A similar conclusion follows from the results in Figure 18.5 based on WGIII AR6 scenarios.. A newer literature is developing, evaluating the potential for managing SDG trade-offs. Results like those in Figure 18.5 provide insights regarding some of the types of strategy sets to consider. Roy et al. (2018) discuss the potential for policies that address distributional implications, such as payments, food support and revenue recycling, as well as education, retraining and technology outreach, subsidies or prioritisation. Recent studies have begun to estimate potential payments to offset trade-offs, such as related to food, water and energy access (e.g., McCollum et al., 2018a). These analyses estimate investments to address specific trade-offs; however, with mitigation redirecting resources away from other productive activities, there is a need to also evaluate the aggregate economy-wide, distributional and welfare effects, including the redistribution effects of managing sustainable development trade-offs.

There are a wide range of mitigation options and systems to consider, with assessment suggesting that a diverse portfolio is practical for pursing climate policy ambitions. However, local context will impact mitigation choices, with unique sustainable development priorities, available mitigation options, sustainable development synergies and trade-offs, and policy design and implementation possibilities.

In practice, adaptation, mitigation and sustainable development interventions are likely to be implemented in portfolio packages rather than as individual discrete options in isolation (high agreement , limited evidence). However, there is a dearth of literature estimating optimal portfolios of global adaptation and mitigation strategies. This is not surprising given the geographic-specific nature of climate impacts and adaptation and the information and computational complexity of representing that detail, as well as mitigation options and interactions. There are, however, different literatures relevant to considering potential combinations of adaptation, mitigation and sustainable development.

At the most aggregate level, there is a long-standing literature exploring economically optimal global trade-offs between climate risks and mitigation (e.g., Manne and Richels, 1992; Nordhaus, 2017; Rose, 2017), as well as global stochastic analysis exploring global risk hedging for a small number of uncertainties (e.g., (Lemoine and Traeger, 2014). Recent work has found optimal global emissions and climate pathways to be highly sensitive to uncertainties and plausible alternative assumptions, with uncertainties throughout the causal chain from society to emissions to climate to climate damages shown to imply a wide range of different possible economically optimal pathways (Rose, 2017). Among other things, this work identifies assumptions consistent with limiting warming to different temperature levels. For example, the combination of potential annual climate damages of 15% of global GDP at 4°C of warming and a less sensitive climate system were consistent with an economically efficient global pathway limiting warming to 2°C. In addition, this work highlights the importance of characterising and managing uncertainties. These types of global aggregate analyses inform discussions regarding long-run global pathways and goals but are not designed to inform local planning.

As discussed in Section 18.2.5.3.1, there are synergies and trade-offs in mitigation, adaptation and sustainable development. For instance, the literature on the global cost-effectiveness of mitigation pathways provides insights regarding aggregate synergies and trade-offs between mitigation and sustainable development (e.g., Figure 18.5). Furthermore, linkages between mitigation and adaptation options have been shown, such as expected changes in energy demand due to climate change interacting with energy system development and mitigation options, changes in future agricultural production practices to manage the risks of potential changes in weather patterns affecting land-based emissions and mitigation strategies, or mitigation strategies placing additional demands on resources and markets. This increases pressure on and costs for adaptation, or ecosystem restoration that provides carbon sequestration and natural and managed ecosystem resiliency benefits, but also could constrain mitigation and impact consumer welfare (WGIII AR6).

Nonlinearities are an important consideration in evaluating risk management combinations. Nonlinearities have been estimated in global and regional mitigation costs and potential economic damages from climate change (very high confidence) ((Riahi et al., 2022); (Clarke et al., 2014; Burke et al., 2015; Rose, 2017). Nonlinear mitigation costs mean increasingly higher costs for each additional incremental reduction in emissions (or incremental reduction in global average temperature). Nonlinear increases in estimated economic climate damage means increasingly higher damages for each additional incremental increase in climate change (e.g., global average temperature). However, the evidence on whether damages increase at an increasing or decreasing rate is mixed (Chapter 16 CWGB: ECONOMIC). Nonlinearities are also suggested in estimated changes in key risks and adaptation costs (Chapters 2 to 16). However, to date, they have not been as explicitly characterised. These nonlinearities imply nonlinearities in climate risk management synergies and trade-offs with sustainable development. Not only do trade-offs vary by climate level, as do synergies, but they increase at an increasing rate and their relative importance can shift across climate levels (very high confidence). Some of this is evident in results such as those shown in Figure 18.5 for mitigation (keeping in mind differences in sample sizes across temperature levels). Uncertainty about the degree of nonlinearity in mitigation, climate damages, key risks and adaptation costs creates uncertainties in the strength of the trade-offs and synergies, but also represents opportunities. For instance, additional mitigation options and more economically efficient policy designs have been shown to reduce mitigation costs and the nonlinearities in mitigation costs (very high confidence) (Riahi et al., 2022). The same is true for adaptation options and adaptation costs.

Infeasibilities of mitigation and adaptation options (Sections 18.4.2.2.1, 18.4.2.2.2), as well as global pathways (Riahi et al., 2022) , are also relevant to consideration of combinations of risk management options. Infeasibility of options implies higher costs and greater cost nonlinearity due to fewer and/or more expensive options, while infeasibility of pathways bounds some of the uncertainty about the pathways relevant to decision making and planning.

Recent observed changes in global energy systems include continued growth in energy demand, led by increased demand for electricity by industry and buildings (very high confidence)(Dhakal et al., 2022) . Growth in energy demand has also been driven by increased demand for industrial products, materials, building energy services, floor space and all modes of transportation. This growth in demand, however, has been moderated by improvements in energy efficiency in industry, buildings and transportation sectors (very high confidence) (Dhakal et al., 2022). There is also a trend of moving away from coal towards cleaner fuels, owing to lower natural gas prices and lower cost renewable technologies, and structural changes away from more energy-intensive industry.

Features of sustainable development, such as enhanced energy access, energy security, reductions in air pollution and economic growth, continue to be the dominant influence on the evolution of energy systems and decision making regarding energy investments and portfolios (very high confidence) (Clarke et al., 2022) . To date, climate policy has been comparatively less influential in driving energy transitions globally. Yet there are examples at the local, regional and national level of policy incentivising rapid changes in energy systems (very high confidence) (Clarke et al., 2022) . Many sustainable development priorities have co-benefits in terms of climate mitigation, such as air pollution and conservation policies reducing short-lived climate forcers and sequestering carbon respectively, as well adaptation benefits, such as improved energy access and environmental quality enhancing adaptive capacity (very high confidence) (Clarke et al., 2022) (de Coninck et al., 2018). Alternatively, sustainable development projects can have negative climate implications with, for instance, hydroelectric projects shut down by droughts or floods resulting in greater use of bunker and fuel oil, as well as natural gas.

In addition to sustainable development priorities driving change in energy systems, observed energy system trends have implications for sustainable development (e.g., IEA et al., 2019). Observed changes in energy system size, rate of growth, composition and operations impact energy access, equity, environmental quality and well-being, with both synergies and trade-offs, including recent improvements in global access to affordable, reliable and modern energy services. For instance, in some countries, such as the USA, there has been a significant shift away from coal as a fuel source for electricity generation in favour of natural gas. More recently, however, renewables have emerged as the dominant form of new electricity generation (Gielen et al., 2019). Similarly, for energy access in developing countries, renewable energy or hybrid distributed generation systems are increasingly being prioritised because of challenges associated with access, costs and environmental impacts from traditional fossil fuel-based energy technologies (Mulugetta et al., 2019).

Energy systems have been a historical driver of climate change, but are also adversely affected by climate change impacts, including short-term shocks and stressors from extreme weather as well as long-term shifts in climatic conditions (very high confidence). The potential for such factors is often incorporated into local system designs, operations and response strategies. There have been changes in observed weather and extreme event hazards for the energy system, but to date, many are not attributable solely to anthropogenic climate change (USGCRP, 2017; IPCC, 2021a). Nevertheless, with observed extremes shifting outside of what has been observed historically, existing design criteria and operations may not be optimal for future climate conditions and contingencies (Chapters 2 to 16). Overall, there is limited historical evidence on the efficacy of adaptation responses in reducing vulnerability of energy systems (high agreement , limited evidence). However, sustainable development trends, such as improving incomes, reducing poverty, and improving health and education have reduced vulnerability (Chapter 16), and improvements in system resiliency to extreme weather events and more efficient water management have occurred that have synergies with adaptation and sustainable development in general.

Available literature indicates that greenhouse gas emissions reductions have been achieved in response to climate actions including financial incentives to promote renewable energy, carbon taxes and emissions trading, removal of fossil fuel subsidies, and promotion of energy efficiency standards (very high confidence) (Clarke et al., 2022). Such policies tend to lead to a lower carbon intensity of GDP, due to structural changes in the use of energy and the adoption of new energy technologies. However, other drivers of change are also present and thus ongoing energy transitions and their future evolution are a response to both climatic and non-climatic considerations, with broader sustainable development priorities being a significant driver of change {Clarke, 2022 #4316.}

Urban areas and their associated infrastructure are critical targets for CRD processes. This is a function of urban areas being the dominant settlement pattern, with over 55% of the global population living in cities (World Bank, 2021). As a consequence, urban areas are also the focal point for energy use, land use change and consumption of natural resources, thereby making them responsible for an estimated 70% of global CO2 emissions (Johansson et al., 2012; Ribeiro et al., 2019). The trend towards increasing urbanisation is anticipated to create both challenges and opportunities for sustainable development, as well as climate action (Güneralp et al., 2017; Li et al., 2019a).

The built environment is increasingly exposed to climate stresses and more frequent co-occurrences of climate shocks than in the past. This has the potential to increase rates of building and infrastructure degradation and increase damage from extreme weather events. The existing adaptation gaps and everyday risks within many cities, particularly those of the Global South, combined with escalating risk from climate change, makes rapid progress in enhancing urban resilience a high priority for CRD (Pelling et al., 2018; Davidson et al., 2019; Lenzholzer et al., 2020). Strategic investments in disaster risk reduction, including climate-resilient green infrastructure, updated building codes and land use planning can provide significant long-term cost savings and social benefits. Moreover, evaluating the relative merits of ‘fail safe’ versus ‘safe to fail’ approaches to infrastructure planning can help to identify more design principles that are more robust to the uncertainties of climate change and urbanisation (Kim et al., 2017a; Kim et al., 2019).

Much of the literature on urban resilience and sustainability focuses on addressing discrete challenges for urban infrastructure subsystems. Climate change has the potential to enhance stress on lifeline infrastructure services such as the provision of electricity, water and wastewater, communications and transportation—subsystems which are often underdeveloped in many regions of the world (Arku and Marais, 2021; Sitas et al., 2021). For example, a warming and more variable climate can increase stress on electricity grids by reducing transmission efficiency, increasing cooling demand requirements, and by increasing exposure to climate shocks such as heatwaves, floods and storms (Bartos and Chester, 2015; Auffhammer et al., 2017; Perera et al., 2020). Accordingly, a significant focus on the energy transition is on achieving the dual goals of reducing the carbon footprint of energy while also increasing resilience of energy supply to current and future threats. For example, renewable energy generation and storage technologies that are modular and distributed and provide enhanced resilience to shocks and stresses from climate change (Venema and Temmer, 2017a).

Similarly, building and maintaining urban water systems that are resilient to climate shocks requires significant changes in water demand, infrastructure and management. Enhancing redundancy in water supply and the flexibility to shift between surface and groundwater options aids adaptation. Decentralised water supply and sanitation options are now feasible and can provide greater resilience than most centralised systems (Parry, 2017), provided they have adequate supply (Leigh and Lee, 2019; Rabaey et al., 2020). Water conservation and green infrastructure options for stormwater management are proven approaches for reducing climate risks (Venema and Temmer, 2017b), with adaptation and mitigation co-benefits. Water demand management and rainwater harvesting contribute to climate change mitigation and increase adaptive capacity by increasing resilience to climate change impacts such as drought and flooding (Paton et al., 2014; Berry et al., 2015). In addition, they can contribute to restoring urban ecosystems that offer multiple ecosystem services to citizens (Berry et al., 2015) {Lwasa, 2022 #4317}. The context-appropriate development of green spaces, protecting ecosystem services and developing nature-based solutions, can increase the set of available urban adaptation options (IPCC, 2018b), while creating opportunities for more complex and dynamic approaches to urban water management (Franco-Torres et al., 2020). For example, the Netherlands’ ‘Room for the River’ policy focuses on not only achieving higher flood resilience, but also improving the quality of riverine areas for human and ecological well-being (Busscher et al., 2019).

An overarching focus of urban sustainability is the reversal of long-standing trends of ecosystem fragmentation and degradation that have resulted in growing separation between human and natural systems within urban environments (IPBES, 2019) (Lwasa et al., 2022). Urban ecosystems and the integration of nature-based solutions and green infrastructure into urban areas can yield benefits that facilitate achievement of the SDGs. There has been growing recognition of urban ecosystems as social, cultural and economic assets that can support economic development while also enhancing resilience to extreme weather events and improving air and water quality (Shaneyfelt et al., 2017; Matos et al., 2019). Investing in urban ecosystems and green infrastructure can provide lower-cost solutions to multiple urban development challenges when compared with traditional infrastructure systems (Terton, 2017). Relatedly, agriculture, while largely a rural system, is increasingly expanding within urban areas. Urban agriculture enables citizens to fulfil some of their food needs, improving urban resilience to food shortages, enhancing biodiversity and increasing coping capacity during disasters (Demuzere et al., 2014; Clucas et al., 2018) (Lwasa et al., 2022). Strengthening urban agroecosystems therefore increases resilience to supply shocks from climate change impacts and can contribute to community cohesion (Temmer, 2017a).

Overall, the discourse in the literature regarding the future of cities emphasises the importance of viewing cities as more than just their physical infrastructure that can be made more resilient through engineering solutions (Davidson et al., 2019). Rather, urban areas are increasingly conceptualised as complex socio-ecological or socio-technical systems (very high confidence) (Patorniti et al., 2017; Patorniti et al., 2018; Visvizi et al., 2018; Savaget et al., 2019). Such frameworks integrate physical, cyber, social and ecological elements of cities in pursuit of resilience and sustainability transitions, and they recognise the role of governance and engagement processes as being central to system change (Temmer, 2017b). Nevertheless, some authors have cautioned that urban transitions will be associated with synergies as well as trade-offs with respect to sustainable development (very high confidence) (Maes et al., 2019; Sharifi, 2020).

Land, oceans and terrestrial ecosystems are in transition globally, with anthropogenic factors including climate change being a major driving force (very high confidence) (IPBES, 2019) (Box 6). Seventy-five percent of the land surface has been significantly altered, 66% of the ocean area is experiencing increasing cumulative impacts and over 85% of wetland areas have been lost (IPBES, 2019). Since 1970, only four out of eighteen recognised ecosystem services assessed have improved in their functioning: agricultural production, fish harvest, bioenergy production and material harvests. The other 14 ecosystem services have declined (IPBES, 2019), raising concerns about the capacity of ecosystems and their services to support sustainable and CRD.

Given the pressures on land, oceans and ecosystems, enhancing resilience to climate change and other pressures of human development is a core priority of transition in these systems. Yet there are a few recorded initiatives that provide evidence of successful improvement in ecosystem resilience (high agreement , limited evidence). Similarly, although there is significant evidence that a broad range of adaptation initiatives have been pursued across global regions and sectors, including a rapid expansion of nature- or ecosystem-based solutions (Mainali et al., 2020), there is limited evidence of how these planned climate adaptation efforts have contributed to enhanced ecosystem resilience. Additional research is necessary to evaluate these efforts in terms of their performance and also to identify mechanisms for scaling them up in different contexts. As an example, Paik et al. (Paik et al., 2020) record the increased diffusion of salt tolerant rice varieties in the Mekong River Delta, which is at risk of sea level rise and an associated saline intrusion. This is a low-cost adaption to saline ingress, that increases food productivity and reduces the risk of outmigration for this vulnerable agricultural region.

Evidence of the interactions between ecosystems and resilience come from a range of sources including both regional and sectoral examples (Box 18.2; Tables 18.7–18.8. For example, regional examples suggest that the use of land to produce biofuels could increase the resilience of production systems and address mitigation needs (Box 2.2). Nevertheless, the potential of bioenergy with carbon capture and storage (BECCS) to induce maladaptation needs deeper analysis (Hoegh-Guldberg et al., 2019). Climate Smart Forestry (CSF) in Europe provides an example of the use of sustainable forest management to unlock the EU’s forest sector potential (Nabuurs et al., 2017). This is in response to diverse climate impacts ranging from pressure on spruce stocks in Norway and the Baltics, on regional biodiversity in the Mediterranean region, and the opportunity to use afforestation and reforestation to store carbon in forests (Nabuurs et al., 2019). CSF considers the full value chain from forest to wood products and energy and uses a wide range of measures to provide positive incentives to firmly integrate climate objectives into the forestry sector. CSF has three main objectives; (i) reducing and/or removing greenhouse gas emissions; (ii) adapting and building forest resilience to climate change; and (iii) sustainably increasing forest productivity and incomes (Verkerk et al., 2020).

Other solutions focus on specific subsectors. Mutually supportive climate and land policies have the potential to save resources, amplify social resilience, support ecological restoration, and foster engagement and collaboration between multiple stakeholders (IPCC, 2019 f, C.1). Land-based solutions can combat desertification in specific contexts: water harvesting and micro-irrigation, restoring degraded lands using drought-resilient ecologically appropriate plants, agroforestry and other agroecological and ecosystem-based adaptation practices (IPCC, 2019 f, B.4.1). Reducing dust, sandstorms and sand dune movement can lessen the negative effects of wind erosion and improve air quality and health. Depending on water availability and soil conditions, afforestation, tree planting and ecosystem restoration programmes using native and other climate-resilient tree species with low water needs, can reduce sand storms, avert wind erosion and contribute to carbon sinks, while improving micro-climates, soil nutrients and water retention (IPCC, 2019 f, B.4.2).

Coastal blue carbon ecosystems, such as mangroves, salt marshes and seagrasses, can help reduce the risks and impacts of climate change, with multiple co-benefits. Over 150 countries contain at least one of these coastal blue carbon ecosystems and over 70 contain all three. Successful implementation of measures of carbon storage in coastal ecosystems could assist several countries in achieving a balance between emissions and removal of greenhouse gases. Carbon storage in marine habitats can be up to 1,000 tC ha –1, higher than most terrestrial ecosystems. Conservation of these habitats would also sustain a wide range of ecosystem services, assist with climate adaptation by improving critical habitats for biodiversity, enhance local fishery production and protect coastal communities from sea level rise (SLR) and storm events (IPCC, 2019b). Ecosystem-based adaptation is a cost-effective coastal protection tool that can have many co-benefits, including supporting livelihoods, contributing to carbon sequestration and the provision of a range of other valuable ecosystem services (IPCC, 2019b).

Diversification of food systems is another component of land, ocean and ecosystem transitions that are consistent with CRD. Balanced diets, featuring plant-based foods such as those based on coarse grains, legumes, fruits and vegetables, nuts and seeds, and animal-sourced food produced in a resilient, sustainable and low-greenhouse gas (GHG) emission manner, are major opportunities for adaptation and mitigation and improving human health. By 2050, dietary changes could free several million km 2 of land and provide a mitigation potential of 0.7–8.0 Gt CO2-eq yr -1, relative to Business-As-Usual projections.

For coastal systems, many frameworks for climate resilience and adaptation have been developed since the AR5 (Hoegh-Guldberg et al., 2014; Settele et al., 2014) with substantial variations in approach between and within countries and across development status. Few studies have assessed the success of implementing these frameworks owing to the time-lag between implementation, monitoring, evaluation and reporting (IPCC, 2019g). As an example, the Nature-Based Climate Solutions for Oceans initiative has the potential to restore, protect and manage coastal and marine ecosystems, adapt to climate change, improve coastal resilience, and enhance their ability to sequester and store carbon (Hoegh-Guldberg et al., 2019).

Polar regions will be profoundly different in the future. The degree and nature of that difference will depend strongly on the rate and magnitude of global climate change, which will influence adaptation responses regionally and worldwide. Future climate-induced changes in the polar oceans, sea ice, snow and permafrost will drive habitat and biome shifts, with associated changes in the ranges and abundance of ecologically important species (IPCC, 2019g). Innovative tools and practices in polar resource management and planning show strong potential in improving society’s capacity to respond to climate change. Networks of protected areas, participatory scenario analysis, decision support systems and community-based ecological monitoring that draws on local and Indigenous knowledge and self-assessments of community resilience contribute to strategic plans for sustaining biodiversity and limit risk to human livelihoods and well-being. Experimenting, assessing and continually refining practices while strengthening links with decision making has the potential to ready society for the expected and unexpected impacts of climate change (IPCC, 2019g).

Industrial emissions have been growing faster since 2000 compared with emissions in any other sector, driven by increased extraction and production of basic materials (Crippa et al., 2019; IEA, 2019) (very high confidence). About one-third of the total emissions are contributed by the industry sector, if indirect emissions from energy use are considered (Crippa et al., 2019). The COVID-19 pandemic has caused a significant decrease in demand for fuels, oil, coal, gas and nuclear energy (IEA, 2020). However, there is concern that the rebound in the crisis will reverse this trend (IEA, 2020). Accordingly, the literature suggests a combined set of measures is beneficial for facilitation a transition of industrial systems in support of CRD. This includes (i) dematerialisation and decarbonisation of industrial systems, (ii) establishment of supportive governance, policies and regulations, and (iii) implementation of enabling corporate strategies.

Decarbonisation and dematerialisation strategies have been proposed as key drivers for the transition of industrial systems (Fischedick et al., 2014; Worrell et al., 2016). The former involves limiting carbon emissions from industrial processes (IEA, 2017; Hildingsson et al., 2019), while the latter involves improving material efficiency, developing circular economies, raw material demand management, environmentally friendly product and process innovations, and environmentally friendly supply chain management (Worrell et al., 2016; Petrides et al., 2018).

Recent modelling suggests that stocks of manufactured capital, including buildings, infrastructure, machinery and equipment, stabilise as countries develop and decouple from GDP (high agreement , medium evidence). For instance, Bleischwitz et al. (2018) confirmed the occurrence of a saturation effect for materials in four energy-intensive sectors (steel, cement, aluminum and copper) in five industrialised countries (Germany, Japan, the UK, the USA and China). High growth in the supply of materials may still drive global demand for new products in the coming years for developing countries that are still far from saturation levels. Therefore, accelerating industrial transitions to drive the decoupling of industrial emissions from economic growth and facilitate broader transformation in industrial systems can be one component of CRD.

Continued transitions in the industrial sector will be contingent on technological innovation. Although technologies exist to drive emissions in industrial sectors to very low or zero emissions, they require 5–15 years of innovation, commercialisation and intensive policies to ensure uptake (Åhman et al., 2017) (high agreement , medium evidence). For instance, several options exist to reduce GHG emissions related to steel production process including increasing the share of the secondary route (Pauliuk et al., 2013), hydrogen-based direct reduced iron (Vogl et al., 2018), aqueous electrolysis rout (Cavaliere, 2019) and plasma process (Quader et al., 2016).

Industrial transitions are also contingent upon consumer behaviour in terms of preferences for, and rates of, consumption of industrial products. Sustainable consumption can play an important role in sustainable production (Allwood et al., 2013; Allwood et al., 2019). This suggests feedbacks between industrial production and consumption in driving industrial transitions. For example, sustainable consumption could be triggered and/or enabled through sustainable production processes that provide more sustainable options to consumers as well as public or private promotional campaigns that promote those options. Meanwhile, demand from consumers for more sustainable options could help to drive the expansion of markets and innovation among industrial producers to meet that demand. However, some have argued that such promotional campaigns that target consumers do little to incentivize sustainable development and climate action (Farrell, 2015; Grydehøj and Kelman, 2017).

This chapter contributes a fifth system transition in addition to the four which have already been introduced by SR1.5: the societal systems transition. While society and people also feature in the other systems transitions, the purpose of defining a fifth transition is to explicitly highlight the challenges associated with changes in behaviour, attitudes, values and consciousness required to achieve CRD. One caveat of considering transitions in societal systems is the limit to which the nature of change is known: transitions accomplish reconfigurations towards a relatively known destination. Historical and current differences between and within nations translate to a multitude of equally valid but diverse priorities for development, for example the understanding of development towards progress as linear has been challenged as being a Western concept by scholars of colonialisation (Sultana et al., 2019). Thus, societal transitions are understood as being intrinsically diverse for the purpose of achieving CRD.

The four systems transitions identified in SR1.5 already include a component of societal change—for example, attitude change is part of public acceptance that facilitates shifts in energy including changing electricity to renewables (Chapter 4 SR1.5, Section 4.3.1.1) and developing nuclear power (Section 4.3.1.3), and behavioural change is a part of shifting irrigation practices to drive required land and ecosystems transitions (Section 4.3.2.1). Extracting societal transitions also allows for a detailed examination of other societal dimensions that facilitate systems transitions, for example justice issues relating to water and energy access and distribution, and land use. Societal transition, sometimes known as ‘societal transformation’, is an established concept in different literatures, as described below. Transformation and transition are terms often used as synonyms (Hölscher et al., 2018), although different schools of thought understand them as sub-components of each other, for example transition driving transformation, or transformation driving transition. For a more detailed discussion on the differences between transition and transformation represented in the literature, see Box 18.1.

Societal transitions for the purpose of this report are understood as the collection of shifts in attitudes, values, consciousness and behaviour required to move towards CRD. This builds on the SR1.5 (IPCC, 2018a: 599) definition of societal (social) transformation: ‘A profound and often deliberate shift initiated by communities towards sustainability, facilitated by changes in individual and collective values and behaviours, and a fairer balance of political, cultural, and institutional power in society’. This includes accepting Indigenous knowledge and local knowledge (IKLK) as an equally valid form of knowledge as compared with Western, scientific knowledge (see Cross-Chapter Box INDIG) and recognition of the role of shifting gender norms to achieve climate resilience (see Cross-Chapter Box GENDER). Changes associated with societal transitions are not specific to defined systems (e.g., energy, industry, land/ecosystems or urban/infrastructure). Rather, these sectoral systems are embedded within broader societal systems, including for example political systems, economic systems, knowledge systems and cultural systems (Davelaar, 2021; Turnhout et al., 2021; Visseren-Hamakers et al., 2021). Changes that happen in these broader social systems can therefore prompt changes in all systems embedded within them, meaning that societal transition is key to transforming across a range of sectors and topics (Leventon et al., 2021). Furthermore, societal transition requires changes in individual behaviours, but also in the broader conditions that shape these behaviours. These broader conditions are largely related to questions of power, in enforcing dominant political economies and social-technological mindsets (Stoddard et al., 2021). This section also briefly describes the various trains of research on societal transitions and transformation.

Because of the multiple sectors, interests and scales that are involved in societal transitions, understanding and creating evidence on transitions requires shifting across system boundaries and finding ways to transcend disciplinary silos. Relevant research includes work within the topic of transformation and transitions (Hölscher et al., 2018). Transformations literature can be split into multiple sub-concepts and requires engagement with multiple schools of thought (Feola, 2015; Feola et al., 2021). Much focus within transformations research is currently related to biodiversity conservation (Massarella et al., 2021), and transitions work tends towards a focus in urban areas (Loorbach et al., 2017). Though there is also work in both that is more broadly labelled as sustainability transformations or transitions (Luederitz et al., 2017). Furthermore, there is likely to be much relevant literature that does not explicitly label itself as transformations or transitions (Feola et al., 2021). For example, we could look to political science theories on policy change (Leventon et al., 2021) and historical perspectives on social change. Bridging these divides will require a deeper rethinking in the research community to undo power structures that marginalise diverse knowledge (Caniglia et al., 2021; Lahsen and Turnhout, 2021).

There are a number of concepts proposed as pathways to creating societal transitions; usually centred around the idea of working with individuals and communities to change their mindsets as a way to change the way they manage their local environments or behave. Transformations work explores how values are pathways towards sustainability, for example by changing values, through making values explicit, through negotiation and by eliciting values (Horcea-Milcu et al., 2019). Human nature connections is a further concept that is identified as a way to shift values and behaviours across a range of disciplines (Ives et al., 2017). The role of learning and Indigenous knowledge is also explored (Lam et al., 2020). These three concepts have had particular salience in discussions around transformations for biodiversity conservation and restoration, related to the IPBES assessment on Values (Pascual et al., 2017; Peterson et al., 2018). They largely focus on the need to engage with people’s values, connections and knowledge to better manage the social–ecological system they are in.

Focusing on bottom-up and community-led transformations, there is emphasis on the role of grassroots organisations in transformations. Community actions around specific locations or topics have parallels to the idea of transformative spaces. They are sites of innovative activity (Seyfang and Smith, 2007). Grassroots organisations can bridge the local and the political scales by politicising actors and creating new interactions between individuals and political processes (Novák, 2021). They are a collective approach to pushing for both individual and societal change (Sage et al., 2021).

Despite a current lack of empirical evidence, there are numerous frameworks emerging for exploring societal transitions across levels. There is focus on pathways for sustainability transitions, which tends to look at projected, normative scenarios for the future, and explore or back-cast the institutional and societal changes that are required to get there (Westley et al., 2011; Sharpe et al., 2016). There is also work that looks at scaling up of smaller sustainability initiatives, through processes of scaling up, scaling out and scaling deep (Moore et al., 2015; Lam et al., 2020). In particular, systems thinking provides an organising framework for bringing together multiple disciplines and perspectives, to understand problem framings, and normative and design aspects of social systems and behaviours (Foster-Fishman et al., 2007). Within this, Meadows (1999) framework of leverage points for systems transformation has been operationalised within the sustainability transformations debate (Abson et al., 2017). Here, system properties relating to system paradigms and design are leverage points where interventions can create greatest system change; shallower leverage points relate to materials and processes. This framework is increasingly being used across a range of sustainability problems as boundary objects for cross-disciplinary, critical research (Fischer and Riechers, 2019; Leventon et al., 2021; Riechers et al., 2021).

Analyses of societal transitions have had limited engagement with adaptation questions. The focus of the sub-field of sustainability transitions on a few industrialised nations, mostly in North America and Europe, limited the field’s development to assumptions born from the experiences in those areas. More recent studies have sought to understand sustainability transitions in other countries, especially emerging economies (Wieczorek, 2018; Köhler et al., 2019). In particular, China has received attention from scholars on sustainability transitions (Huang et al., 2018; Lo and Castán Broto, 2019; Castán Broto et al., 2020; Huang and Sun, 2020). As a result, some pressing issues related to societal transitions for adaptation have received limited attention compared with that paid to other system transitions. However, more recently, scholarship has begun examining transitions that have turned to nature and nature-based solutions. Adaptive transitions are an intermediary step towards sustainability transitions, whereby multiple actions at material and institutional levels are combined towards improving adaptation outcomes (Pant et al., 2015; Scarano, 2017).

An overarching enabling condition for achieving system transitions and transformations is the presence of enabling governance systems (very high confidence). Recent literature on the translation of governance into system transitions in practice suggests four key actions are important. The first is the critical reflection on so-called ‘development solutions’, alternatively framed by some as ‘empty promises’, that worsen climate risk, inequity, injustice and ultimately lead to unsustainable development (Mikulewicz, 2018; Mikulewicz and Taylor, 2020). Examples include development aid (Scoville-Simonds et al., 2020), large-scale development projects such as biofuel production in Ethiopia (Tufa et al., 2018) and urban growth management in Vietnam (DiGregorio, 2015). The second is the recognition that while the power of different actors and institutions is often tied to access to resources and the ability to constrain the actions of others, other dimensions of power such as its ability to produce knowledge as well as its contingency on circumstances and relationships are also important in enabling energy transitions (Avelino et al., 2016; Avelino and Wittmayer, 2016; Lockwood et al., 2016; Ahlborg, 2017; Avelino and Grin, 2017; Partzsch, 2017; Smith and Stirling, 2018). Third, governance systems can help to develop productive interactions between formal government institutions, the private sector and civil society including the provision ‘safe arenas’ for social actors to deliberate and pursue transitional and transformational change (Haukkala, 2018; Törnberg, 2018; Strazds; Ferragina et al., 2020; Koch, 2020) (Section 18.3.1, Box 18.1). Fourth, governance can address challenges such as climate change from a systems perspective and pursue interventions that address the interactions among development, climate change, equity and justice, and planetary health (Harvey et al., 2019; Hölscher et al., 2019). This is evidenced by recent experience with the COVID-19 pandemic response as well as ongoing escalation of disaster risk associated with extreme weather events (Walch, 2019; Cohen, 2020; Schipper et al., 2020b; Wells et al., 2020).

One output from systems of governance is formal policy frameworks and policies that influence processes and outcomes of system transitions that support CRD (Section 18.1.3). The Paris Agreement, for example, provides a framework for CRD by defining a mitigation-centric goal of ‘limiting warming to well below 2°C and enabling a transition to 1.5°C’ (UNFCCC, 2015). It also provides for a broadly defined global adaptation goal (UNFCCC, 2015: Art. 7.1). The NDCs are the core mechanism for achieving and enhancing climate ambitions under the Paris Agreement. However, the pursuit of a given NDC within a specific country will likely necessitate a range of other policy interventions that have more immediate impact on technologies and behaviour, implicating transitions in energy, industry, land and infrastructure (very high confidence) (Section 18.3.1). SDG-relevant activities are increasingly incorporated into climate commitments in the NDCs (at last count 94 NDCs also addressed SDGs), contributing to several (154 out of the 169) SDG targets (Brandi and Dzebo; Pauw et al., 2018). This reflects the potential of the NDCs as near-term policy instruments and signposts for progress towards CRD (medium agreement , limited evidence) (McCollum et al., 2018b).

As reflected by the SDGs (and SDG 13 specifically), the mainstreaming of climate change concerns into development policies is one mechanism for pursuing sustainable development and CRD (very high confidence). However, such mainstreaming has also been critiqued for perpetuating ‘development as usual’, reinforcing established development logics, structures and worldviews that are themselves contributing to climate change and vulnerability (O’Brien et al., 2015) and for obscuring and depoliticising adaptation choices into technocratic choices (Murtinho, 2016; Webber and Donner, 2017; Benjaminsen and Kaarhus, 2018; Khatri, 2018; Scoville-Simonds et al., 2020). The coordinated implementation of sustainable development policy and climate action is nonetheless crucial for ensuring that the attainment of one does not come at the expense of others (Stafford-Smith et al., 2017). For example, aggressive pursuit of climate policies that facilitate transitions in energy systems can undermine efforts to secure sustainability transitions in other systems (Sections 18.3.1.1, 18.2.5.3, Table 18.7).

Several non-climate international policy agreements provide context for CRD such as the 1948 UN Universal Declaration of Human Rights, the UN Declaration on the Rights of Indigenous Peoples (Hjerpe et al., 2015) and the Convention on Biological Diversity (CBD; UNFCCC, 1992), the UN Convention to Combat Desertification (UN, 1994), as well as the more recent Sendai Framework for Disaster Risk Reduction (UNDRR, 2015) and the ‘new humanitarianisms’ which seeks to reduce the gap between emergency assistance and longer term development (Marin and Naess, 2017). Collectively they provide a global policy framework that protects people’s rights that are potentially threatened by climate change (Olsson et al., 2014). These policies are relevant to transitions across multiple systems, particularly in societal systems towards more equitable and just development.

Institutional capacity for system transitions refers to the capacity of structures and processes, rules, norms and cultures to shape development expectations and actions aimed at durable improvements in human well-being. The AR5 highlighted the need for strong institutions to create enabling environments for adaptation and GHG mitigation action (Denton et al., 2014). Institutions stand within the social and political practices and broader systems of governance that ultimately drive adaptation and development processes and outcomes. They are thus produced by them and can become tools by which some actors constrain the actions of others (Gebreyes, 2018). As a consequence, they and can become a significant barrier to change, whether incremental or more transformational (very high confidence). The post-AR5 focus on transformational adaptation and resilience present in the literature suggests that institutions that enable system transitions towards CRD are secure enough to facilitate a wide range of voices, and legitimate enough to change goals or processes over time, without reducing confidence in their efficacy.

The limited literature on institutions and pathways relevant to system transitions and CRD suggests that institutions are most effective when taking a development-first approach to adaptation. This is consistent with the principles of CRD which emphasise not simply reducing climate risk, but rather making development processes resilient to the changing climate. There is agreement in this literature that such an approach allows for the effective integration of climate challenges into existing policy and planning processes (very high confidence) (Pervin et al., 2013; Kim et al., 2017b; Mogelgaard et al., 2018). However, this approach generally rests on an incremental framing of institutional change (Mahoney and Thelen, 2009) based on two critical assumptions. The first is that existing processes and institutions are capable of bringing about system transitions that generate desired development outcomes and thus can be considered appropriate vehicles for the achievement of CRD. A large critical literature questions the efficacy of formal state and multilateral institutions. The evidence for the ability of local, informal institutions to achieve development goals remains uneven, with robust evidence of positive impacts on public service delivery, but more ambiguous evidence on behaviour changes associated with strengthened institutions (Berkhout et al., 2018). The second is that the mainstreaming of adaptation will bring about changes to currently unsustainable development practices and pathways, instead of merely strengthening development as usual by subsuming adaptation to existing development pathways and allowing them to endure in the face of growing stresses (Eriksen et al., 2015; Godfrey-Wood and Otto Naess, 2016; Scoville-Simonds et al., 2020). There is evidence that countries with poor governance have limited adaptation planning or action at the national level, even when other determinants of adaptive capacity are present (Berrang-Ford et al., 2014). This suggests that, in these contexts, adaptation efforts are likely to be subsumed to existing government goals and actions, rather than having transformational impact.

Ongoing innovations in technology, finance and policy have enabled more ambitious climate action over the past decade, including significant growth in renewable energy, electrical vehicles and energy efficiency. However, access to, and the benefits of, that innovation have not been evenly distributed among global regions and communities, and continued innovation is needed to facilitate climate action and sustainable development (very high confidence). Policymakers need useful science and information (Cornell et al., 2013; Kirchhoff et al., 2013; Calkins, 2015; IPCC, 2019 f; Guido et al., 2020) to make informed decisions about possible risks, and the benefits, costs and trade-offs of available adaptation, mitigation and sustainable development solutions (i.e., Article 4.1 of the Paris Agreement; UNFCCC, 2015). Moreover, recent literature has emphasised the need for deep technological, as well social, changes to avert the risks of conventional development trajectories (Gerst et al., 2013; IPCC, 2014a).

An effective and innovative technological regime is one that is integrated with local social entities across different modes of life, local governance processes (Pereira, 2018; Nightingale et al., 2020) and local knowledge(s), which increasingly support adaptation to socio-environmental drivers of vulnerability (Schipper et al., 2014; Nalau et al., 2018; IPCC, 2019 f). These actors and their knowledge are often ignored in favour of knowledge held by experts and policymakers, exacerbating uneven power relations (Naess, 2013; Nightingale et al., 2020). For example, achieving sustainability and shifting towards a low carbon energy system (e.g., hydropower dams, wind farms) remains a contested space with divergent interests, values and future prospects (Bradley and Hedrén, 2014; Avila, 2018; Mikulewicz, 2019), and potential impacts on human rights as embodied by the Paris Agreement (UNFCCC, 2015). A number of studies have emphasised the limits of relying upon technology innovation and deployment (e.g., expansion of renewable energy systems and/or carbon capture) as a solution to challenges of climate change and sustainable development (Section 18.3.1.2). This is because such solutions may fail to consider the local historical contexts and barriers to participation of vulnerable communities, restricting their access to land, food, energy and resources for their livelihoods.

Enabling system transitions towards CRD is dependent in part on the ability to monitor and evaluate system transitions and broader development pathways to identify effective interventions and barriers to their implementation (very high confidence). However, the monitoring and evaluation of individual system transitions, much less CRD, remains highly challenging for multiple reasons (Persson, 2019). The highly contextual nature of resilience, adaptation and sustainable development means that, unlike climate mitigation, it is difficult to define universal metrics or targets for adaptation and resilience (Pringle and Leiter, 2018); (Brooks et al., 2014). This is demonstrated by the Paris Agreement’s global goal for adaptation, The mismatch between timescales associated with resilience and adaptation interventions and those over which the results of such interventions are expected to become apparent tends to result in a focus on the measurement of spending, outputs and short-term outcomes, rather than longer-term impacts (Brooks et al., 2014; Pringle and Leiter, 2018). The need to assess resilience and adaptation against a background of evolving climate hazards, and to link resilience and adaptation with development outcomes, present further methodological challenges (very high confidence) (Brooks et al., 2014).

Currently, the ability to monitor different components of CRD are in various stages of maturity (very high confidence). Monitoring of the SDGs, for example, is a routine established practice at global and regional levels, and UNDP publishes annual updates on progress towards the SDGs (United Nations, 2021 ). For resilience, Brooks et al. (2014) identify three broad approaches to its measurement, each of which could offer potential mechanisms for monitoring progress towards CRD. One is a ‘hazards’ approach, in which resilience is described in terms of the magnitude of a particular hazard that can be accommodated by a system, useful in contexts where thresholds in climate and related parameters can be identified and linked with adverse impacts on human populations, infrastructure and other systems (Naylor et al., 2020). An ‘impacts’ approach is one in which resilience is measured in terms of actual or avoided impacts and is suited for tracking adaptation success in delivering CRD over longer timescales, for example at the national level (Brooks et al., 2014). Finally, a ‘systems’ approach is one where resilience is described in terms of the characteristics of a system using quantitative or qualitative indicators which are often associated with different ‘dimensions’ of resilience (Serfilippi and Ramnath, 2018; Saja et al., 2019). This allows measurement of key indicators that are proxies for resilience at regular intervals, even in the absence of significant climate hazards and associated disruptions (very high confidence) (Brooks et al., 2014) (see also Cross-Chapter Box ADAPT in Chapter 1). Similar criteria could be applied to evaluating adaptation options and their implementation as well as various interventions in pursuit of SDGs.

Worldviews are overarching systems of meaning and meaning-making that inform how people interpret, enact and co-create reality (De Witt et al., 2016). Worldviews shape the vision, beliefs, attitudes, values, emotions, actions and even political and institutional arrangements. As such, they can promote holistic, egalitarian approaches to enable, accelerate and deepen climate action and environmental care (Ramkissoon and Smith, 2014; De Witt et al., 2016; Lacroix and Gifford, 2017; Sanganyado et al., 2018; Brink and Wamsler, 2019 ). Alternatively, they can also serve as significant barriers to system transitions and transformation, based on anthropocentric, mechanistic and materialistic worldviews and the utilitarian, individualist or skeptical values and attitudes they often promote (very high confidence) (Beddoe et al., 2009; van Egmond and de Vries, 2011; Stevenson et al., 2014; Zummo et al., 2020).

Traditional, modern and post-modern worldviews have different, and in many ways, complementary potentials for enabling diverse approaches to climate action and sustainable development. They can also shift societal values and societal concern for climate change (Shi et al., 2015), resulting in changes in behaviour and acceptance of climate change policies (van Egmond and de Vries, 2011; Van Opstal and Hugé, 2013; De Witt et al., 2016; Shaw, 2016) which are predictors of concern. Among the challenges of strongly different climate-related worldviews, is that they rarely co-exist. Some worldviews become incompatible or hostile to other worldviews, openly seeking to dominate, eliminate or segregate competing perspectives (medium agreement , medium evidence) (de Witt, 2015; Jackson, 2016; Nightingale, 2016; Xue et al., 2016; Goldman et al., 2018).

To address these difficult contests, worldviews regarding climate and global environmental change are often expressed in scientific language and themes (Parsons et al., 2016; Goldman et al., 2018). This can exclude other worldviews grounded in other forms of knowledge or ways of knowing which ultimately narrows understanding of climate change and the solution space. Hence, the post-AR5 literature on worldviews focuses on the numerous meanings, associations, narratives and frames of climate change and how these shape perceptions, attitudes and values (Morton, 2013; Boulton, 2016; Hulme, 2018; Nightingale Böhler, 2019). The recognition of the diversity of interpretations and meanings has led to multidisciplinary and transdisciplinary research that incorporates the humanities and the arts (Murphy, 2011; Elliott and Cullis, 2017; Steelman et al., 2019; Tauginienė et al., 2020), feminist studies (MacGregor, 2003; Demeritt et al., 2011; Bell, 2013; Brink and Wamsler, 2019 ; Plesa, 2019) and religious studies (Sachdeva, 2016; McPhetres and Zuckerman, 2018) to examine diverse understandings of reality and knowledge possibilities around climate change. In addition, literature on cultural cognition, epistemological plurality and relational ontologies draws on non-Western worldviews and forms of knowledge (Goldman et al., 2018).

On the other hand, the tendency for certain worldviews to dominate the policy discourse has the potential to exacerbate social, economic and political inequities as well as ontological, epistemic and procedural injustices (very high confidence). Research aimed at exploring the existing political ontology and knowledge politics of exclusion that marginalise certain communities and actors originated in academic or scientific perspectives. This includes institutions such as the IPCC and is subsequently replicated in social representations, including the media, public policy and the development agenda, narrowing possibilities for social transformation (Jackson, 2014; Luton, 2015; Escobar, 2016; Burman, 2017; Newman et al., 2018; Sanganyado et al., 2018; Wilson and Inkster, 2018).

CRD is embedded in social systems, in the political economy and its underlying ideologies, interests and institutions (Section 18.4.1). The pursuit of CRD, and shifting development pathways away from prevailing trends, unfolds in an array of political arenas, from the offices of bureaucrats to parliament buildings, sidewalks and streets, to discursive arenas in which governance actors interact—from the village level to global forums (Jørgensen et al., 2017; Montoute et al., 2019; Sørensen and Torfing, 2019; Pasquini, 2020). Paradoxically, the post-AR5 literature suggests that political arenas are often used to shut down efforts to explore the solution space for climate change and sustainable development (medium agreement, robust evidence) (e.g., Kenis and Mathijs, 2012; Kenis and Mathijs, 2014; Beveridge and Koch, 2016; Kenis and Lievens, 2016; Driver et al., 2018; Meriluoto, 2018; Swyngedouw, 2018; Mocca and Osborne, 2019). Power relationships among different actors create opportunities for people to be included or excluded in collective action (Siméant-Germanos, 2019) (Sections 18.3.1.6, 18.4.3.5). Therefore, as evidenced by examples from the UK (MacGregor, 2019) and China (Huang and Sun, 2020), small-scale collective environmental action has transformative potential in part owing to its ability to increase levels of cooperation among different actors (medium agreement , limited evidence) (Green et al., 2020; Blühdorn and Deflorian, 2021).

In addition to the ‘arm’s length’ acts of voting, social mobilisation, protest and dissent can be critical catalysts for transformative change (Porta, 2020). These are competitions for recognition, power and authority (Nightingale, 2017) that take place in settings. This is evidenced by experiences from the energy sector in Bangladesh which became a contested national policy domain and where social movements eventually transformed the nation’s energy politics (Faruque, 2017). Similarly, in Germany, the nation’s energy transition led to marked changes in agency and legal frameworks, and energy markets drove the proliferation of so-called municipalisations of energy systems—a reversal of years of system privatisation (Becker et al., 2016). Meanwhile, experience in Bolivia demonstrate that the transformative potential of political conflict depends on transcending narrow issues to form broad coalitions with a collective identity that challenge prevailing development objectives and trajectories (Andreucci, 2019). Such examples illustrate the power of the communities as a vanguard against environmentally destructive practices (Villamayor-Tomas and García-López, 2018). Social movements have been successful at countering fossil fuel extraction (Piggot, 2018) and open up political opportunities in the face of increasing efforts to capture natural resources (Tramel, 2018) and are bolstered by resistance from within some corporations and/or their shareholders (Fougère and Bond, 2016; Swaffield, 2017; Walton, 2018 a; Walton, 2018 b).

Coincident with these social movements targeting climate change and sustainability has been a rise of political conservatism and populism as well as growth in misinformation (high agreement , medium evidence) (Mahony and Hulme, 2016; Swyngedouw, 2019). This reflects efforts to maintain the status quo by actors in positions of power in the face of rising social inertia for climate action (Brulle and Norgaard, 2019). Political arenas of the future could include a new body politic that integrates non-humans and a new geo-spatial politics (Latour et al., 2018).

As introduced in the discussion of governance as an enabling condition (Section 18.4.2.1), a wide range of actors are involved in successful adaptation, mitigation, and sustainability policy and practice including national, regional and local governments, communities and international agencies (Lwasa, 2015). As of 2018, 197 countries had between them over 1500 laws and policies addressing climate change as compared with 60 countries with such legislation in 1997 when the Kyoto Protocol was agreed upon (Nachmany et al., 2017; Nachmany and Setzer, 2018). In judicial branches, climate change litigation is increasingly becoming an important influence on policy and corporate behaviour among investors, activists and local and state governments (Setzer and Byrnes, 2019). There is enhanced action on climate change at both national and sub-national levels, even in cases where national policies are inimical, as in the USA (Carmin et al., 2012; Hansen et al., 2013).

The strong role of governments in climate action has implications for the nature of democracy, the relationship between the local and the national state, and between citizens and the state (Dodman and Mitlin, 2015). More integration of government policy and interventions across scales, accompanied by capacity building to accelerate adaptation is needed (very high confidence). Key needs include enhanced funding, clear roles and responsibilities, increased institutional capability, strategic approaches, community engagement and judicial integrity (Lawrence et al., 2015). More resources, and more active involvement of the private sector and civil society can help maintain adaptation on the policy agenda. Multi-level adaptation approaches are also relevant in low-income countries where local governments have limited financial resources and human capabilities, often leading to dependency on national governments and donor organisations (Donner et al., 2016; Adenle et al., 2017).

Unlike mitigation, adaptation has traditionally been viewed as a local process, involving local authorities, communities and stakeholders (Preston et al., 2015). The literature on the governance of adaptation continues to emphasise that local governments have demonstrated leadership in implementation by collaborating with the private sector and academia. Local governments can also play a key role (Melica et al., 2018; Romero-Lankao et al., 2018) in converging mitigation and adaptation strategies, coordinating and developing effective local responses, enabling community engagement and more effective policies around exposure and vulnerability reduction (Fudge et al., 2016). Local authorities are well-positioned to involve the wider community in designing and implementing climate policies and adaptation implementation (Slee, 2015; Fudge et al., 2016). Local governments also help deliver basic services and protect their integrity from climate impacts (Austin et al., 2015; Cloutier et al., 2015; Nalau et al., 2015; Araos et al., 2017). However, the resource limitations of local governments as well as their small geographic sphere of influence suggests the need for more funding for this from higher levels of government, particularly national governments, to address adaptation gaps (very high confidence) (Dekker, 2020). Local adaptation implementation gaps can be linked to limited political commitment at higher levels of government and weak cooperation between key stakeholders (Runhaar, 2018). Incongruities and conflicts can exist between adaptation agendas pursued by national governments and the spontaneous adaptation practices of communities. There may be grounds for re-evaluating current consultative processes integral to policy development, if narrow technical approaches emerge as the norm for adaptation (Smucker et al., 2015).

Therefore, the traditional view of adaptation as a local process has now widened to recognise it as a multi-actor process that transcends scales from the local and sub-national to national and even international (very high confidence) (Mimura et al., 2014). Many of the impacts of climate change are both local and transboundary, so that local, bilateral and multilateral cooperation is needed (Nalau et al., 2015; Donner et al., 2016; Magnan and Ribera, 2016; Tilleard and Ford, 2016; Lesnikowski et al., 2017). National policies and transnational governance should be seen as complementary, especially where they favour transnational engagement with sub- and non-state actors (Andonova et al., 2017). National governments typically act as a pivot for adaptation coordination, planning, determining policy priorities, and distributing financial, institutional and sometimes knowledge resources. National governments are also accountable to the international community through international agreements. National governments have helped enhance adaptive capacity through building awareness of climate impacts, encouraging economic growth, providing incentives, establishing legislative frameworks conducive to adaptation and communicating climate change information (Berrang-Ford et al., 2014; Massey et al., 2014; Austin et al., 2015; Huitema et al., 2016).

The performance of local, national and global economies is a priority consideration shaping perceptions of climate risk and the costs and benefits of different policy responses to climate change. The most commonly used indicator of performance is GDP (Hoekstra et al., 2017). Traditionally, national development efforts have sought to maximise the growth of GDP under the assumption that GDP growth equates not only to economic prosperity (including poverty reduction) but also to increased efficiency and reduced environmental externalities (Ota, 2017). Such assumptions often employ models such as the environmental Kuznets curve (EKC) that postulates that economic development initially increases environmental impacts, but these trends eventually reverse with continued economic growth. Wealthy nations of the Global North, including for example the USA, Great Britain, Iceland and Japan, have had success over the past decade in reducing their GHG emissions while growing their economies (very high confidence). However, attempts to empirically test EKC in different national contexts has yielded mixed results. Case studies in Myanmar, China and Singapore, for example, suggest that the impacts of GDP on environmental quality are contingent on the development context and the environmental impact under consideration (Aung et al., 2017; Lee and Thiel, 2017; Xu, 2018; Chen and Taylor, 2020). In addition, an extensive literature now argues that current patterns of development, and the economic systems underpinning that development, are unsustainable (Washington and Twomey, 2016), and thus economic growth may not necessarily continue indefinitely in the absence of more concerted effort to pursue sustainable development, including reducing the impacts of climate change.

Given such criticisms of the link between development and economic growth, a growing number of researchers argue for the need for alternatives to GDP to guide development and evaluate the costs and benefits of different policy interventions (Hilmi et al., 2015). For example, while GDP growth can drive growth in income, it can also drive growth in inequality which can undermine poverty reduction efforts (very high confidence) (Fosu, 2017). Hence, recent years have seen significant interest in the concept of well-being as a more robust measure for linking policy and the economy with sustainable development for a healthy Anthropocene era (Fioramonti et al., 2019).

Another mechanism for evaluating environmental performance is to include environmental data in the System of National Accounts (SNA) through the System of Environmental-Economic Accounting (SEEA) introduced by the UN. As the international statistical standard for environmental–economic accounting (Pirmana et al., 2019), SEEA includes natural capital resources in national accounting. A number of recent studies conclude that failure to account for natural capital in macroeconomic impact assessments results in overly optimistic outcomes (Pirmana et al., 2019; Jendrzejewski, 2020; Naspolini et al., 2020); (Banerjee et al., 2019; Kabir and Salim, 2019; Keith et al., 2019). For example, Jendrzejewski (2020) inserted natural capital into a computable general equilibrium model of the 2017 European windstorm on state-owned forests in Poland. This resulted in more negative assessment of impacts, suggesting excluding natural capital could lead to erroneous investments, strategies or policies. Similarly, other studies rely on Quality of life (QOL) measurements as alternatives for GDP. Estoque et al. (2018) suggested a ‘QOL-Climate’ assessment framework, designed to capture the social-ecological impacts of climate change and variability.

Another alternative to GDP is Green GDP which seeks to incorporate the environmental consequences of economic growth (Boyd, 2007; Stjepanović et al., 2017; Stjepanović et al., 2019). Green GDP is difficult to measure, because it is difficult to evaluate the environmental depletion and ecological damages of growth (Stjepanović et al., 2019). Although there is no consensus in measuring Green GDP, attempts have been made for select countries including the USA (Garcia and You, 2017), Europe (Stjepanović et al., 2019), China (Chi and Rauch, 2010; Yu et al., 2019; Wang et al., 2020), Ukraine and Thailand (Harnphatananusorn et al., 2019), and Malaysia (Vaghefi et al., 2015). Le (2016) illustrated the potential negative impacts of climate change vulnerability on green growth. Some studies have suggested that focusing on green growth as the only strategy to address climate change would be risky. Hickel and Kallis (2020) argue that green growth is likely to be a misguided goal due to the difficulties of separating economic growth from resource use and, therefore, carbon emissions (see also (Antal and van den Bergh, 2014). Therefore, alternative strategies are required (Hickel and Kallis, 2020). In addition, green growth should also be able to justly respond to social movements involving contestation, internal debates and tensions (Mathai et al., 2018).

The emphasis on Green GDP is mirrored by another concept, Blue Growth, that focuses on pursuing sustainable development through the ecosystem services derived from ocean conservation (Mustafa et al., 2019). Synthesis studies suggest that more intensive use of ocean resources, such as scaling up seaweed aquaculture, can be used to enhance CO2-eq sequestration, thereby contributing to GHG mitigation, while also achieving other economic goals (Lillebø et al., 2017; Froehlich et al., 2019). Similarly, Sarker et al. (2018) present a framework for linking Blue Growth and CRD in Bangladesh, with Blue Growth representing an opportunity for adapting to climate change. Bethel et al. (2021) also links Blue Growth to resilience, noting that a Blue economy can help facilitate recovery from the COVID-19 pandemic. Nevertheless, consistent with earlier assessment of enabling conditions for system transitions (Section 18.4.2.1), implementation of Blue Growth initiatives is contingent upon the successful achievement of social innovation as well as creating an inclusive and cooperative governance structure (very high confidence) (Larik et al., 2017; Soma et al., 2018).

A potential critique of the various alternative metrics and models for economic development is that they are all framed in the context of growth. Over the past decade, ecological economists and political scientists have proposed degrowth (e.g., Kallis, 2011; Demaria et al., 2013) and managing without growth (e.g., Jackson, 2009) as a solution for achieving environmental sustainability and socioeconomic progress. Such concepts are a deliberate response to concerns about ecological limits to growth and the compatibility between growth-oriented development and sustainability (Kallis et al., 2009). Sustainable degrowth is not the same as negative GDP growth, which is typically referred to as a recession (Kallis, 2011). Degrowth goes beyond criticising economic growth; it explores the intersection among environmental sustainability, social justice and well-being (Demaria et al., 2013). Under current economic and fiscal policies (see Box 18.7), degrowth has been argued as an unstable development paradigm because declining consumer demand leads to rising unemployment, declining competitiveness and a spiral of recession (Jackson, 2009: 46). More comprehensive modelling of socioeconomic performance understands the segments of sufficient social transformation to guarantee maintenance and rises in well-being coupled with reduced ‘footprints’ (Raworth, 2017; Hickel, 2019; D’Alessandro et al., 2020).

Knowledge–technology arenas comprise the interaction in knowledge spaces connected to technology transitions. The institutional and political architecture through which knowledge and technology interact is described in sustainability transitions literature (Fazey et al., 2018b; Sengers et al., 2019l Kanger, 2020 #3709). A common theme explored in that literature is the ability of actors to access and apply various forms of knowledge as a means of effecting change. Different forms of innovation are recognised as a core enabling condition for achieving system transitions for CRD (Section 18.3.3; Cross-Chapter Box INDIG). However, while scientific and technology knowledge may be useful, in some cases, they remain subordinate to political agendas, or are controlled by actors in positions of power and thus not equitably distributed (very high confidence) (Mormina, 2019). Participatory decision making, for example, assumes that multiple actors, with differing motivations, agency and influence, engage with climate decision making and co-produce actions. Yet some actors may not participate in the process if the proposed actions do not align with their motivations or if they do not have adequate agency (Roelich and Giesekam, 2019). Hence, effectively using knowledge to inform policy is challenging for both scientists, policymakers and civil society alike.

Science, technology and innovation (STI) policies are expected to shape expectations of the potential for a better world based on access to information, clean technologies, higher labour productivity, economic growth and a healthier environment (Brasseur and Gallardo, 2016; Schot and Steinmueller, 2018; Singh et al., 2018; Mormina, 2019; Bamzai-Dodson et al., 2021). STI policies are considered as ‘social goods for development’. Hence, STI policies are often proposed or implemented as means of addressing environmental challenges such as climate change along with SDGs such as the reduction of inequality, poverty and environmental pollution (Mormina, 2019). Realising the benefits of STI, however, may be contingent on building broader STI capacity and bolstering nations’ systems of innovation (very high confidence) (Mormina, 2019). This could include building global research partnerships to address priority STI needs as well as long-standing gaps between the Global North and South. Such an approach shifts the framing of STI as one focused on individual investigators to one comprised of building knowledge networks. It also creates opportunities for integration of disparate forms of knowledge and innovation, including local and Indigenous knowledge, into global knowledge systems (Cross-Chapter Box INDIG).

Furthermore, an extensive literature increasingly incorporates natural and ecological systems as knowledge domains relevant to understanding opportunities for sustainability and CRD. For example, the literature on socio-ecological systems (SES) (Sterk et al., 2017; Holzer et al., 2018; Avriel-Avni and Dick, 2019; Martínez-Fernández et al., 2021) as well as social, ecological and technological systems (SETS) (McPhearson and Wijsman, 2017; Webb et al., 2018; Ahlborg et al., 2019), explicitly integrate ecological knowledge into sustainability, including concepts such as planetary boundaries (Section 18.1.1), adaptation and nature-based solutions, natural resources management, rights and access to nature, and understanding of how humans govern society–nature interactions in the face of climate change (Benjaminsen and Kaarhus, 2018; Mikulewicz, 2019; Nightingale et al., 2020). Some of these interactions are explained in Cross-Chapter Box INDIG, including conflict over which knowledges are recognised as valuable in understanding and responding to climate change and therefore shape the nature of climate actions. Actor engagement in stewardship, solidarity and inclusion of multiple knowledges and nature–society connectedness can highlight the intertwined nature of ecological change and knowledge relations, thereby supporting shifts to sustainability (Pelling, 2010; Hulme, 2018; Ives et al., 2019; Nightingale et al., 2020) (see also Box 18.6).

The expanding definition of what constitutes credible, relevant and legitimate knowledge is leading to the democratisation of knowledge and efforts to address historical inequities in access to knowledge (Ott and Kiteme, 2016; Rowell and Feldman, 2019). This is reflected in the communication of science, which is increasingly focused on reducing the distance between internal scientific and public communication and more engagement in public science governance and knowledge production (Waldherr, 2012; Peters, 2013). One innovative approach in co-production of knowledge is mobilising communities through citizen science (Heigl et al., 2019). This also presents additional opportunities to incorporate local knowledge with scientific research, and better match scientific capability to societal needs.

Societal choices and development trajectories emerge from decisions made in different arenas which intersect and interact across levels and scales, in diverse institutional settings—some formal with their associated instruments and interventions, while others are informal. Since AR5, both formal and informal setting are increasingly arenas of debate and contestation regarding development choices and pathways (very high confidence) (Section 18.4.4, Chapters 1, 6, 8, 10 and 17). Community arenas exist from the local to the global scale and constitute the many interactions between governance actors, often transcending any one scale to reflect the emergent outcomes of interactions in political, economic, socio-cultural, knowledge-technology and ecological arenas of engagement. Actions within and between these five arenas hence come together in the community arena of engagement. While community engagement is often described at the level of villages and cities (Ziervogel et al., 2021) (Chapter 8), communities in terms of people interacting with each other sharing worldviews, values and behaviours, also exist at the regional and global levels. For example, civil society engagement in climate action reached a peak in 2019, notably through the global youth movement which led to large global mobilisation and street demonstrations on all continents and in many large cities (Bandura and Cherry, 2020; Han and Ahn, 2020; Martiskainen et al., 2020). Calling for enhanced climate action by governments and other societal actors, the youth movement was supported by many other societal groups and networks, including arenas of community interaction.

While the SR1.5 (de Coninck et al., 2018) for the first time comprehensively assessed behavioural dimensions of climate change adaptation, most literature still has a greater focus on what triggers mitigation behaviour (Lorenzoni and Whitmarsh, 2014; Clayton et al., 2015). Meanwhile, with CRD still a relatively young concept, there is little literature focused on what motivates action in pursuit of CRD rather than its sub-components of climate action and sustainable development. Nevertheless, a common motivation that is emerging in the literature is clinically significant levels of climate distress among individuals (Bodnar, 2008), which is experienced as a continuing distress over a changed landscape which no longer offers solace, also known as solastalgia (high agreement , medium evidence) (Albrecht et al., 2007). This is accompanied by a shift from blaming natural forces for disasters to attributing it to human negligence, which is known to lead to more acute perceptions of risk as well as more prolonged post-traumatic stress disorder (PTSD) than trauma arising from non-human causes. Improving social connections, acknowledging anxiety, reconnecting to nature and finding creative ways to re-engage are identified as ways of managing this growing anxiety (Lertzman, 2010; Clayton et al., 2017). Climate action in communities at various scales could fulfil many of these needs.

Two important elements of understanding the opportunities and challenges associated with the pursuit of CRD in different regional contexts are a) the geographic variability in climate conditions that shape livelihoods, behaviours and responses of human and natural systems; and b) how those conditions could shift in the future in response to climate change, which determines the additional burden that climate change could create for adaptation and sustainable development.

The climate analyses of WGI provide information on regional differences in temperature, rainfall and sea surface temperatures for different global regions and how they are projected to change in response to different levels of aggregate global warming (Table 18.4). Such data reveal that even when aggregated to broad geographic regions, significant variations exist for all of these parameters, which is a function of the baseline climatology of each region. For example, temperatures in Africa and Australia are, on average, warmer than in Europe or North America. Significant variations are also observed for rainfall variables. Such regional variation in climate conditions is part of the regional context that shapes current patterns of development of the past present and future. They influence biodiversity and natural resource availability as well as exposure to climatic extremes (tropical storms, heatwaves and drought) that contribute to disasters.

The WGI data also indicate that increases in globally averaged temperatures will have different consequences for regional climate change (Table 18.4), including variation in the magnitude and, for precipitation, even the direction of change (very high confidence). For example, although average temperatures, daily minimum temperature and the number of days over a given threshold are projected to increase in all regions except Antarctica, the magnitude of the change varies. Moreover, little change is projected for daily maximum temperatures across different regions. Nevertheless, the number of days over different temperature thresholds such as 35°C increases markedly in most regions, reflecting the disproportionate impact that global warming has on the tails of temperature distributions. Given outcomes in many systems including public health, agriculture, ecosystems and biodiversity, and infrastructure are often associated with biophysical thresholds (e.g., physiological or design thresholds), those regions where such thresholds are increasingly exceeded due to climate change may experience disproportionately higher impacts (very high confidence). Given such temperatures occur more frequently in regions such as Africa and Central and South America, this disproportionate exposure is exacerbated by disproportionate vulnerability, adaptation gaps and development needs (very high confidence; Section 18.2.4; Table 18.4).

The regional response of precipitation to globally averaged temperature increases is less clear than temperature, in part due to high intra-region variability. Average daily precipitation remains fairly stable in all global regions in response to higher magnitudes of global warming (Table 18.4). However, 5-day precipitation totals provide a clearer signal of increasing hydrologic activity in response to higher globally averaged temperatures (Table 18.4). Such data does not necessarily reflect changes in rainfall extremes that could occur with downstream consequences for hazards such as drought or flooding. Similarly, while sea surface temperatures (SSTs) are more uniform across global ocean basins, all basins are anticipated to warm in response to higher globally averaged temperatures (Table 18.5). Unlike temperature, however, SST increases are anticipated to be only a fraction of the globally averaged increase in temperature, due in large part to the heat capacity of the oceans. Nevertheless, such higher SSTs have implications not only for ocean ecosystems and the distribution of marine species, but also for weather patterns, such as formation and intensity of tropical cyclones (very high confidence).

The other aspect of the regional climate responses to global temperature increases that is important for CRD is the marked differences observed between changes in response to 1.5°C versus 4°C of warming. Higher levels of global warming are associated with higher regional changes, including changes in extremes of temperature. This in turn increases climate risk to exposed and vulnerable human and natural systems, thereby increasing demand for adaptation. If that demand is not met, then the adaptation gap will be larger, with greater risk of loss and damage (very high confidence) (Schaeffer et al., 2015; Chen et al., 2016; United Nations Environment Programme, 2021). This is true not only for regions, but also at the sectoral level (Section 18.5.2). Therefore, CRD pathways must balance the demands for emissions reductions to reduce exposure, adaptation to manage residual climate change risks, and sustainable development to address vulnerability and enhance capacity for sustainable development.

Table 18.5 | Projected sea surface temperature change ranges by global warming level and ocean biome (°C). Ranges are 5th and 95th percentiles from SSP5-8.5 WGI CMIP6 ensemble results. There is little variation in the 5th and 95th percentile values by GWL across the SSP1-2.6, SSP2-4.5, SSP3-7.0 and SSP5-8.5 projections. Source: WGI AR6 Interactive Atlas (Gutiérrez et al., 2021).

Table 18.4 | Projected continental level result ranges for select temperature and precipitation climate change variables by global warming level. Ranges are 5th and 95th percentiles from SSP5-8.5 WGI CMIP6 ensemble results. There is little variation in the 5th and 95th percentile values by GWL across the SSP1-2.6, SSP2-4.5, SSP3-7.0 and SSP5-8.5 projections. Source: WGI AR6 Interactive Atlas (Gutiérrez et al., 2021).

The various regional chapters within the AR6 WGII report each provide insights into progress towards CRD as well as the opportunities and challenges associated with future pursuit of different CRD pathways. Common indicators of development reflect the significant diversity that exists across different global regions with respect to their development context (very high confidence). For example, the Human Development Index, recently adjusted to reflect the effect of planetary pressures (PPAHDI), illustrates the overall higher levels of development of North America and European countries of the Global North as well as Australasia compared with Asia, Africa, Central and South America and small islands of the Global South. Generally, this reflects the higher levels of vulnerability and greater need for both sustainable developments to reduce poverty and support sustainable economies as well as climate action to address climate risk (Table 18.6).

However, even within a given region, there is significant variation in PPAHDI among nations. Such differences reflect fundamental differences in historical patterns of development, as well as current development needs and challenges, and they imply differences in what future development pathways would be consistent with CRD. In addition, nations and regions with lower PPAHDI values suggests greater capacity challenges for both GHG mitigation and climate adaptation. However, nations and regions with high PPAHDI values also tend to have higher per capita CO2-e emissions production, indicating that economic development based on fossil fuel use undermines both efforts on climate action as well as the SDGs (very high confidence) (Figure 18.6). Such challenges are also reflected by differential Gini coefficients and metrics of state fragility among regions, which reflect inequities in income distribution and broader vulnerability of nations and regions to shocks and stressors (Figure 18.6). In addition, high variation is observed in CO2 emissions production, even among comparatively wealthy nations, suggesting CO2-e emissions of some nations are tightly coupled to development, while others have pursued more carbon neutral development trajectories. Even within regions such as Africa, Asia, Central and South America, and Europe, large within-region variations are observed in inequality and state fragility, suggesting high variability among nations. Given the emphasis in the sustainable development and CRD literature on equity and vulnerability, addressing such determinants of vulnerability is a core design principle for CRDPs.

In addition to development indicators, the literature assessed in the WGII regional chapters indicates that different regions experience a range of development challenges and opportunities that affect the pursuit of CRD (very high confidence). These represent dimensions of governance, institutions, economic development, capacity, and social and cultural factors that shape decision making, investment and development trajectories. For example, significant challenges exist within regions with respect to managing debt and the ability to fund or finance climate action and sustainable development interventions (very high confidence). On the other hand, a broad range of opportunities exist to pursue CRD including challenges with debt and financing of adaptation competing policy objectives, social protection programmes, economic diversification, investing in education and human capital development, and expanding disaster risk reduction efforts (very high confidence).

There are a wide variety of more focused options for climate action and sustainable development (very high confidence). Such options have potential for synergies and trade-offs including implications for GHG mitigation, land use change and conservation, food and water, or social equity. Despite variation in development context, regional assessments suggest CRD efforts will be associated with some common features. For example, in all regions, existing vulnerability and inequality exacerbate climate risk and therefore pose challenges to CRD (very high confidence). Furthermore, low prioritisation of sustainability and climate action in government decision making, low perceptions of climate risk, and path dependence in governance systems and decision-making processes all pose barriers to system transitions, transformation and CRD (very high confidence).

Table 18.6 | Regional synthesis of dimensions of climate resilient development. For each region, quantitative information is provided on common development indicators including the planetary pressures-adjusted human development index (PPHDI, 2020, n= 169 (Human Development Report Office, 2020), Gini coefficients (GINI, most recent year available; n= 156 (World Bank, 2021), Fragile States Index (FRAGILITY; 2021; n= 173 (Fund for Peace, 2021), and per capita CO2 emissions production (CO2/PC, 2018; n= 169 (Human Development Report Office, 2020). Each indicator is associated with a mean value among nations within a specific region as well as the range (minimum to maximum) value. In addition, the table contains evidence of sustainable development challenges and opportunities as well as adaptation/sustainable development options and potential synergies and trade-offs associated with their implementation. Synergies and trade-offs are categorised as follows: (T) Trade-off among policies and practices; (S+) Synergy among policies and practices that enhances sustainability; (S-) Synergy among policies and practices that undermines sustainability.