Levers and leverage points for pathways to sustainability

Kai M. A. Chan1 | David R. Boyd1 | Rachelle K. Gould2 | Jens Jetzkowitz3 | Jianguo Liu4 | Barbara Muraca5 | Robin Naidoo1,6 | Paige Olmsted1 | Terre Satterfield1 | Odirilwe Selomane7 | Gerald G. Singh8 | Rashid Sumaila9 | Hien T. Ngo10 | Agni Klintuni Boedhihartono11 | John Agard12 | Ana Paula D. de Aguiar13,14 | Dolors Armenteras15 | Lenke Balint16 | Christopher Barrington-Leigh17 | William W. L. Cheung8 | Sandra Díaz18 | John Driscoll1 | Karen Esler19 | Harold Eyster1 | Edward J. Gregr1 | Shizuka Hashimoto20 | Gladys Cecilia Hernández Pedraza21 | Thomas Hickler22,23 | Marcel Kok24 | Tanya Lazarova24 | Assem A. A. Mohamed25 | Mike Murray-Hudson26 | Patrick O'Farrell27 | Ignacio Palomo28,29 | Ali Kerem Saysel30 | Ralf Seppelt31,32 | Josef Settele33,34 | Bernardo Strassburg35 | Dayuan Xue36 | Eduardo S. Brondízio37


| INTRODUC TI ON
It is now evident that achieving key societal goals associated with sustainability and the environment (Table 1) will require transformative change-'fundamental, system-wide reorganization across technological, economic and social factors, including paradigms, goals and values' (Butchart et al., 2019;Chan et al., 2019;IPBES, 2019b, p. 14; IPCC, 2018; Mace et al., 2018, Razzaque et al., 2019Sachs et al., 2019). Without transformative change, humanity is at risk of losing up to a million species in the near term (Purvis et al., 2019), degrading many of nature's crucial contributions to people (Brauman et al., 2019;Shin et al., 2019), increasing the risk of future zoonoses (UNEP, 2016) and triggering catastrophic climate change (IPCC, 2018). The societal imperative could scarcely be greater.
It is also clear that interventions in pursuit of just a few goals risk having negative effects on others and missing opportunities to realize synergies and manage trade-offs (Palomo et al., 2019;Singh et al., 2018;Tallis et al., 2018). Examples abound: mitigating climate change via geoengineering could threaten other sustainability targets via unequal distribution of costs and international conflict (Gregory, Satterfield, & Hasell, 2016;Keith, 2000). Similarly, intensive food production poses risks to biodiversity (Beckmann et al., 2019), fuels nutrient run-off that can trigger marine hypoxic zones and associated fisheries losses (Donner & Kucharik, 2008) and demands so much water that hydrological cycles and freshwater ecosystems can be undermined . Given such interacting effects, how might interventions address a broader suite of sustainability goals?
To address these complex social-ecological problems, our focus must expand beyond the direct drivers of change (i.e. processes directly affecting nature, land/sea-use change, direct exploitation, climate change, pollution, invasive species, etc., Brondízio et al., 2019;Díaz et al., 2015). In particular, our focus must include indirect drivers (including formal and informal institutions, such as norms, values, rules and governance systems, demographic and sociocultural factors, and economic and technological factors, Brondízio et al., 2019;Cumming et al., 2020;Díaz et al., 2015), which structure economic activities and propel direct drivers. It is well known-for instance-that a safe climate and a healthy biosphere require profound changes to direct drivers, such as phasing out fossil fuels or halting deforestation. However, direct drivers resist intervention because they underpin our current economies and governance institutions (Ehrlich & Pringle, 2008).
Thus, interventions often spark considerable opposition from vested interests who benefit from the status quo, including its prevalent externalization of costs. Conversely, indirect drivers have yet to receive comprehensive directed attention in the context of their impacts on nature and its contributions to people, despite recognition of their importance in some literature oriented towards sustainability transitions or transformations (Broman & Robèrt, 2017;Geels, 2011;Griffiths, 2009;Rotmans, Kemp, & van Asselt, 2001;Shove & Walker, 2007;Westley et al., 2011). Given that the fate of nature and humanity depends on transformative change of the human enterprise (IPBES, 2019a(IPBES, , 2019b, indirect drivers clearly play a central role.
Two linked concepts are relevant to prioritizing indirect drivers: leverage points (where to intervene to change social-ecological systems) and levers (the means of realizing these changes, such as governance approaches and interventions). Both concepts are intended to identify which changes, for which social variables, are likely to have disproportionately large positive effects on social-ecological systems (Meadows, 2009). Although these and related concepts have received attention in sustainability circles (Abson et al., 2017;Fischer & Riechers, 2019), thus far they have been applied only to specific contexts (Scullion et al., 2016) or specific combinations of global goals (West et al., 2014). Related concepts include positive tipping points, sensitive intervention points and social tipping interventions (Farmer et al., 2019;Otto et al., 2020;Tàbara et al., 2018). Levers and leverage points for a broad suite of sustainability objectives might share much in common with those identified for climate and other contexts, but they are also likely to differ.
Many intergovernmental calls for transformative change seem to suggest it can be accomplished by simply scaling-up existing sustainability initiatives (UN Environment, 2019b). The IPBES Global Assessment represented a stark departure from that position, identifying what might be considered a set of elements for sustainable futures-levers and leverage points IPBES, 2019b). In this paper, we build upon that effort by detailing the methodology for identifying these levers and leverage points, and their basis and tensions in the academic literature and in practice. Clearly, policy action to address emerging threats is not a straightforward function of the quality of the evidence (Michaels, 2008;Oreskes, 2004). Thus, a key consideration is how this knowledge resonates with decision makers, and its feasibility for application (Cash et al., 2003). Our intended audience includes diverse scholars and agents of change in civil society, government, business and elsewhere. In particular, these levers and leverage points emerged from consideration of six linked focal issues, including producing food, protecting biodiversity (both on land and in the water), maintaining freshwater supplies and mitigating climate change, all while providing for our growing cities (Aguiar et al., in review;Chan et al., 2019). It thus draws upon a comprehensive 'nexus' analysis (Liu et al., 2018) of scenarios and pathways (Aguiar et al., in review), as well as literature reviews on various indirect drivers and dimensions of social and institutional change . We conclude by discussing current gaps and ways forward, including obstacles and opportunities for transformative changes.

| ME THODS
Levers and leverage points were identified using an iterative expert deliberation process (inspired by Burgman et al., 2011;Singh et al., 2019;Wiklund, 2005), tailored for this purpose and supplemented with review of published literature, peer review and four meetings ( Figure 1). First, we relied on chosen experts to identify a preliminary set of levers and leverage points based on their expertise.
After determining the initial set of levers and leverage points, two parallel but interactive processes contributed to their refinement. One was a nexus analysis (Liu et al., 2018) of intervention scenarios (Ferrier et al., 2016) at multiple scales to derive information about pathways, an analysis which was based on systematic literature reviews as described in Chan et al. (2019) and Aguiar et al. (in review). The second process focused on the levers (e.g. incentives) and leverage points (e.g. consumption), and was based on expert-led literature reviews on factors affecting social and institutional change in the context of sustainability.

| Nexus analysis of scenarios and pathways
While the nexus analysis was designed to offer insights about concrete actions in support of particular sets of goals, it also contributed to identifying those levers and leverage points that are key to achieving transformative changes leading to more sustainable pathways of development (see iterative process, below). Accordingly, we present these methods briefly. To reflect the global transformative change required, our analysis considered how to depart from existing development pathways, vested interests and entrenched structures, to make space for new and more sustainable pathways (Leach, Scoones, & Stirling, 2010;Loorbach, Frantzeskaki, & Avelino, 2017;Sharpe, Hodgson, Leicester, Lyon, & Fazey, 2016). While such transformative change may involve novel processes, it can also involve deepening and accelerating existing processes of change.
In particular, pathways examined here addressed a nexus with six foci of analysis, which were chosen to represent important nature-related challenges to sustainable development and to reflect the underlying bodies of literature (e.g. food production is split between the land and the oceans). These six were considered separately while attending to interdependencies: • Feeding humanity without deteriorating nature on land; • Meeting climate goals while maintaining nature and nature's contributions to people; F I G U R E 1 Workflow for identification of levers and leverage points (LPs Revision, review, refinement • Conserving and restoring nature on land while contributing positively to human well-being; • Maintaining freshwater for nature and humanity; • Balancing food provision from oceans and coasts with nature protection; and • Resourcing growing cities while maintaining the nature that underpins them. For each focus, we conducted systematic literature reviews to identify relevant optimistic scenarios and pathway analyses . We compiled these studies into a database and analysed each with respect to its spatial and temporal scope and scale, goal or vision, scenario type, sectors and pathway elements (including measures, policies and other changes). The six foci are similar to the clusters of Global Environment Outlook 6 (UN Environment, 2019b), which orient around the SDGs, with differences to more strongly integrate biodiversity. These foci are the primary inputs to the cross-cutting insights in the Results.

| Expert-led literature reviews on factors affecting change
The reviews of factors affecting social and institutional change towards sustainability-that is, the identification of levers and leverage points-complemented the nexus analysis of scenarios and pathways (above). When the nexus analysis suggested that a given concept was important to the sustainability outcomes of pathways (e.g. consumption as a driver of environmental impact), the literature reviews sought to elaborate on those concepts and their underlying causes. Our approach was intentionally varied in order to appropriately represent the diversity of levers and leverage points (Meadows, 2009) and the diversity of scholarship underpinning each. We decided, for example, that a quantitative systematic review methodology in this section could bias findings towards particular perspectives and away from others (e.g. qualitative social sciences and humanities). Accordingly, we used a flexible approach. In each case, and each iteration, multiple authors from different perspectives contributed insights regarding how levers could affect the identified sustainable pathways. The experts wrote reviews of the levers and leverage points, backed by relevant literature, through an iterative peer review process. The reviews focused on how levers acting on leverage points contribute to sustainability goals, and sought to fill gaps in understanding that persisted after the initial set of levers and leverage points were determined.

| Iterative process of revision and review
Three rounds of peer review refined the levers and leverage points Clearly, limitations remain, and such processes are constrained by the underlying knowledge being assessed (Martin et al., 2012).
Workshops were attended by the core author team (the aforementioned 22 experts); electronic discussions also included 12 additional 'contributing' authors who helped write text for one or more lever/ leverage point section. Three coordinating lead authors (K. Chan, J.
Agard, J. Liu) all worked to ensure a balanced representation of diverse views, with the assistance of three Co-Chairs (E. Brondizio, S. Díaz, J. Settele) and our review editor (K. Esler).
Because we are interested in global sustainability challenges, we sought levers and leverage points that were independently important, both regionally and globally. Towards this end, we refined levers and leverage points by lumping, splitting and adding key levers and leverage points. When the scenario analysis or the literature suggested that points were substitutable, or that they were parts of a broader meta-concept where some components were more relevant in some contexts, we lumped (e.g. population, per capita consumption and waste were integrated together in the leverage point 2, reduce total material consumption and waste). When a single point comprised several components that appeared to be implementable separately but independently important, we split [e.g. the concept of ecosystem-based management was split into three levers (B-D): Coordination across sectors and jurisdictions, Pre-emptive action and

| Cross-cutting insights
We synthesized the following six cross-cutting insights from the nexus analysis, which were used to structure the levers and leverage points (for more detail on scenarios and pathways, see Aguiar et al., in review;Chan et al., 2019; the latter also expands on all levers, leverage points and case studies/boxes).
No single strategy is likely to yield sufficient transformation to sustainable development and achieve the full suite of international goals for sustainability and nature. Rather, strategies entail largescale change to society and its institutions, with both trade-offs and synergies. Identified pathways involved substantial expansion of protected areas and ecological restoration while integrating biodiversity considerations and safeguards in resource industries and rapidly moving away from fossil fuels, but they also entailed structural economic and legal changes to enable these steps. All foci suggested that pathways realizing multiple targets entailed various measures and instruments applied in concert at local, national, regional and global scales. All six foci involved trade-offs between sectors and social groups, such that compromises are inevitable as conflicting objectives are reconciled. However, the six foci also identified potential synergies where some actions offer benefits across multiple objectives and for many groups.
Consumption patterns are a fundamental driver of material extraction, production and flows, but they are in turn driven by worldviews and notions of good quality of life. Addressing aggregate consumption is a central constituent of pathways for all foci, and is especially useful for addressing trade-offs across foci (e.g. climate mitigation measures might rely more strongly on reducing energy demand than land-based carbon sequestration, to lessen conflicts with food production). The drivers of aggregate consumption were often implicit, for example, although many studies mentioned preferences, value systems and (less often) collective notions of a good quality of life as drivers of consumption, these aspects were generally not represented explicitly in scenarios and pathways.

Collective and organizational action-including behaviour
change-pervade representations of transformative change, including supply chains, conservation and restoration. Consumption changes are intimately tied to habits and behavioural norms, but so too are changes in production practices (e.g. agroecological practices in farming), conservation and restoration. All six foci identified such behavioural and organizational change as central, but scenarios and pathways varied greatly in the detail with which they enabled this change. Many studies appealed to a combination of incentives and awareness raising, even though the latter is generally regarded to have only a weak influence on behaviour (Jacquet & Pauly, 2007;Schultz, 2011), an influence much less than infrastructure and regulations.
Equality and inclusiveness are key constituents of sustainable pathways and were addressed partly via participatory planning, but power disparities remain a challenge. Across the six foci, many studies highlighted the crucial importance of addressing inequalities and involving people in participatory planning, including the urban poor and Indigenous Peoples and local communities (IPLCs). But only a few scenarios and pathways addressed the barriers to transformative change that arise from substantial inequities in power, for example, in the food system, where studies highlighted the difficulties posed by corporate control of seeds, land, agricultural inputs and food distribution. Although the same issues are important in other foci-for example, industrial fishers and seafood distributors exert strong corporate control-they were generally not discussed explicitly in the studies we found. Governance instruments and approaches such as incentives, adaptive management and law and its enforcement are widely recognized as fundamental components of sustainable pathways.

Telecouplings, technology, innovation, investment
There was near universal acknowledgement in the scenarios and pathways of the importance of several governance instruments and approaches, but more attention was paid to some aspects than others. For example, many studies across all foci appealed to the importance of economic incentives, but generally from a behaviourist perspective that treats behaviour as an individual decision. This approach lacks explicit recognition of how incentive programmes also effect change by articulating values at a societal level (see leverage point 3 and lever A below). Studies commonly discussed management and governance approaches as managing several sectors together (integrated management), but much less frequently discussed early action to address emerging threats (precaution) or managing for resilience and adaptation (these considerations were most explicit in the freshwater realm). Many studies across all foci identified particular environmental regulations, but fewer considered the role of consistent monitoring and enforcement and the broader rule of law, although this is often crucial and implicit in scenarios and pathways.
These six insights led us to eight leverage points and five levers that are broadly important and apparently each necessary for transformations to sustainable futures. Thus, a ranking of importance is not possible nor necessary. Although each leverage point provides an opportunity for change towards or away from sustainable pathways, we focus below on changes that are conducive to sustainability. Our five levers are general and systemic interventions used in policy or governance to simultaneously address multiple leverage points and social variables ( Figure 2).
There are also important interactions between levers and leverage points, considered in the Section 4. Following the logic that there are no governance panaceas for social-ecological sustainability (Ostrom, 2007), implementation would surely vary considerably across contexts.

| Leverage point 1. Visions of a good life
Embracing visions of a good life that go beyond those entailing high levels of material consumption is central to many pathways. Key drivers of the overexploitation of nature are the currently popular vision that a good life involves happiness generated through material consumption [leverage point 2] and the widely accepted notion that economic growth is the most important goal of society, with success based largely on income and demonstrated purchasing power (Brand & Wissen, 2012). However, as communities around the world show, a good quality of life can be achieved with significantly lower environmental impacts than is normal for many affluent social strata (Jackson, 2011;Røpke, 1999). Alternative relational conceptions of a good life with a lower material impact (i.e. those focusing on the quality and characteristics of human relationships, and harmonious relationships with non-human nature) might be promoted and sustained by political settings that provide the personal, material and social (interpersonal) conditions for a good life (such as infrastructure, access to health or anti-discrimination policies), while leaving to individuals the choice about their actual way of living (Jackson, 2011;Nussbaum, 2001Nussbaum, , 2003. In particular, status or social recognition need not require high levels of consumption, even though in some societies, status is currently related to consumption (Røpke, 1999).
An oft-touted implication is that conventional economics is unsuitable as a sole source of guidance for improving people's lives or measuring those improvements (e.g. GDP; Stiglitz, Fitoussi, & Durand, 2018

| Leverage point 2. Total material consumption and waste
Beyond improved efficiencies and enhanced production, all pathways intended to achieve biodiversity targets entail reducing or reversing the growth of aggregate material production, as a function of population size and per capita consumption and waste (Aguiar et al., in review). Per capita material consumption has risen alongside income, putting further pressure on nature (Dietz, Rosa, & York, 2007;Ehrlich & Holdren, 1971;Ehrlich & Pringle, 2008;Rosa, Dietz, & York, 2004). Since 1970, human population has doubled while total resource extraction rates have more than tri- this may also help reduce unsustainably high rates of population growth in many regions if coupled with education and empowerment of women (Schultz, 1994).
In contrast to the unhelpful but common argument about whether 'the problem' is population growth or consumption, it is not novel to argue that the prob-   (Loorbach, 2010). For instance, a relational value of responsibility to do no harm to others may extend in its application from a mainly interpersonal context to also include environmental impacts from purchases expressed through supply chains, which impacts also affect people (Chan, Anderson, Chapman, Jespersen, & Olmsted, 2017). Promoting action may often include intervening at multiple levels to remove barriers, align incentives, impose constraints or otherwise facilitate action (Geels, 2011;Kemp, Loorbach, & Rotmans, 2007) [e.g. employing levers A and E]. Relational values of concern and responsibility are strongly held in several if not many populations (Klain, Olmsted, Chan, & Satterfield, 2017). Thus, the lack of large-scale environmental action is likely not due to a lack of concern but because conditions impede the expression of that concern, for example, via inappropriate or missing infrastructure and institutions, or powerful opposing forces with vested interests in the status quo Maller & Strengers, 2014;Shove & Walker, 2010

| Leverage point 4. Inequalities
Reducing inequalities is central to many sustainable pathways.
Inequality often reflects excessive control and/or use of resources or power by one or more sectors of society at the expense of others. As societies develop and aim to 'catch up' in economic growth, inequality often emerges through control and distribution of unequal shares of finite resources and appropriation of 'inexpensive' labour through reduction in resource access. This distribution and appropriation contribute to unjust social conditions, environmental degradation and environmental injustices (Cáceres, 2015;Stiglitz, 2012).
Although assessments of inequality often focus on income, there are many dimensions of societal inequalities such as distributive, recognition, procedural and contextual inequities (Leach, Reyers, & Bai, 2018). These inequalities cross many social differences, including gender, where inequality is an important driver of population growth and natural resource management (Ehrlich, Kareiva, & Daily, 2012). Therefore, addressing societal inequities-especially crippling poverty-is not only important for its own sake for moral reasons but also for its role in facilitating the protection of nature and achieving sustainable development (Knight & Rosa, 2011

| Leverage point 5. Justice and inclusion in conservation
Just and inclusive approaches to conservation and restoration will be needed to attain sustainable pathways. Sustainable trajectories that achieve biodiversity targets and sustainable de- (c) linking of local efforts with larger connected landscapes/ seascapes to enable sustainable use of biodiversity and ecosystem services at local and broader scales (Ban et al., 2013) and ( It is certainly not new to bring attention to historical injustices associated with biological conservation (Brockington, Duffy, & Igoe, 2008;Chapin, 2004;Dowie, 2011;Neumann, 1998), but these issues continue to manifest in new ways (Bennett, Govan, & Satterfield, 2015) and proactively addressing them will be especially key as conservation efforts necessarily address more populated landscapes (Sayer et al., 2013).

| Leverage point 6. Externalities and telecouplings
Achieving global sustainability goals will require a targeted focus to elucidate and internalize the distant effects of local actions (i.e.
telecouplings), such as housing booms triggering distant deforestation via demand for wood products (Liu et al., 2013(Liu et al., , 2015Marques et al., 2019). Many existing environmental policy frameworks enable jurisdictions to meet targets by externalizing impacts to other jurisdictions (e.g. national greenhouse gas emissions and water use can and have been reduced in part by importing GHG-and waterintensive agricultural commodities rather than producing them; Pascual, Palomo, et al., 2017

| Leverage point 7. Technology, innovation and investment
Pathways to a desirable societal future entail a regime change towards affordable technologies that reduce negative environmental impacts and towards those with net-positive impacts (Aguiar et al., in review

| Leverage point 8. Education and knowledge generation and sharing
Promoting knowledge generation and sharing in general, and particularly via learning and knowledge systems for sustainability, is central to sustainable pathways. Education and knowledge transmission are often heralded as a necessary albeit insufficient route to sustainability via maintenance or change in behaviours and attitudes, but their role in sustainability can be even more fundamental, as a precursor to well-functioning societies (Sachs, 2015). Furthermore, education will only serve either role if conceived much more broadly than as imparting information or cognitive skills. Rather, education that leads to sustainable development and enduring change in knowledge, skills, attitudes and/or values builds from existing understandings, fosters social learning and embraces a 'whole person' approach (Heimlich & Ardoin, 2008;Wals, 2007 but it is also a keystone to cultural integrity and the maintenance of collective identity (Turner, 2005(Turner, , 2014. Societies with welldeveloped individual psychosocial skills, including empathy, resilience and ethical values, are more likely to have the capacity for civic engagement and to support the collective solutions, individual sacrifices and management necessary for sustainable development (Orr, 2004;Sachs, 2015). Thus, what is called for here is not simply more education of any kind, but rather a nurturing of knowledge transmission and education systems for sustainability in both management and citizenship (Orr, 2004;Tábara & Pahl-Wostl, 2007  Vatn, 2010). It is clear, however, that voluntary incentive programmes such as payments for ecosystem services are limited in their applicability, and constrained to where sufficient capacity exists (Wunder, 2013). As such, capacity building enables conservation and sustainable development, both on its own and by enhancing the effectiveness and equity of incentive programmes [leverage point 4] (Bennett, Lemelin, Koster, & Budke, 2012;Dougill et al., 2012;Gross, Erickson, & Méndez, 2014

| B, Coordination across sectors and jurisdictions
Integrating management across administrative silos and regions is widely recognized as an important mechanism to realize cobenefits and avoid trade-offs among competing sustainability goals and objectives (Aguiar et al., in review). Achieving multiple SDGs, biodiversity targets and Paris objectives demands policy coherence (Nilsson, Griggs, & Visbeck, 2016)  In this sense, ensuring consistent incentives across multiple levels of governance (e.g. local including traditional, provincial, federal, regional) is also key (Kemp et al., 2007). Not all action toward a given objective will simultaneously benefit all other objectives, so an integrated approach enables harmonization that achieves multiple targets (McLeod & Leslie, 2009). Additionally, achieving global objectives will take cooperation among disparate governing bodies (Chester, 2006;Karlsson-Vinkhuyzen, Kok, Visseren-Hamakers, & Termeer, 2017

| C, Pre-emptive action
Sustainable pathways generally entail addressing emerging risks in a precautionary or pre-emptive way, which may be well before systemspecific proof of impact has been established. This may entail imposing constraints to slow rates of change in natural systems or resources, or to cap the scale of changes, in the absence of precise knowledge of causal relationships or maximum allowable change in those relationships. Social-ecological systems frequently involve phase shifts that are difficult to predict (Rocha, Peterson, Bodin, & Levin, 2018) or reverse (Folke et al., 2004;Leadley et al., 2014;Walker & Meyers, 2004), and for which it is difficult to determine the key driving forces in advance (Burgess, Polasky, & Tilman, 2013;Hastings & Wysham, 2010;Levin, 1992). Moreover, there is often a long time-lag between scientific attention to a phenomenon and consensus about causality (let alone proof; Ludwig, Hilborn, & Walters, 1993;Oreskes, 2004), such that phase shifts can be better prevented and managed via proactive and precautionary approaches.
As above (lever B), this lever is rarely implemented, likely because precaution is often seen as at odds with

| D, Adaptive decision-making in the context of resilience and uncertainty
Policies, programmes, bottom-up initiatives and management agencies that seek optimal outcomes while assuming linear or equilibrium ecosystem dynamics are likely to result in undesirable surprises, as nature often operates in nonlinear ways (Chapin, Chapin, Kofinas, & Folke, 2009). Policies, programmes and initiatives may be more effective in the long term if designed as follows: to be robust to uncertainty (performing well across variation in both ecological and socio-economic dynamics); to learn and adapt (despite potential inefficiencies); and to cultivate system resilience to maintain critical functions in the face of disturbance and change (e.g. via diversity and redundancy; Folke, Hahn, Olsson, & Norberg, 2005;Levin & Lubchenco, 2008;Tàbara et al., 2010;Walters, 2002). Where ecosystems have been degraded (Jackson et al., 2001), investing in their rehabilitation and transformation can in many cases pay substantial dividends (Lorimer et al., 2015;Pringle, 2017). In many contexts, retaining and enhancing ecological diversity can guard against shocks and help maintain ecosystem services (Oliver et al., 2015).
As above (levers B and C), this lever is rarely implemented despite its strong and long-standing scientific basis (Walters & Hilborn, 1978). It remains important.
Whereas adaptive management is often understood as being learning (about ecosystems) by doing (Berkes et al., 2003), here we side with those from management and other social literatures who emphasize that the needed learning is also social learning towards sustainability-learning about ourselves, our institutions and our processes in the context of complexity and ecological limits (Chapman, LaValle, Furey, & Chan, 2017;Lee, 1994;Tábara & Pahl-Wostl, 2007).

| E, Environmental law and implementation
Consistent enforcement of laws (including those governing rights and responsibilities, that is, strong rule of law) is a vital prerequisite to reducing the deterioration of nature and protecting human and ecosystem health (Morita & Zaelke, 2005;Schmitz, 2016;Wang & McBeath, 2017). Rule of law is thus key for protecting the rights of the public and future generations from incursion by private interests.
Stronger international laws, constitutions and domestic environmental law and policy frameworks, as well as improved implementation and enforcement of existing ones, are key for protecting nature and its contributions to people (Boyd, 2011;Suckling, Greenwald, & Curry, 2012;Westwood et al., 2019). This is particularly true for vulnerable and marginalized populations who bear a disproportionate share of the burden of adverse environmental impacts (e.g. pollution) and are more likely to lack access to basic environmental services (e.g. clean water and adequate sanitation). Respecting differences in context, much can be learned from legislation, policies and instruments with demonstrated successes, while still maintaining opportunities for regulatory experimentation and innovation (Evans et al., 2016;Hutchings, Stephens, & VanderZwaag, 2016;McDonald et al., 2015).
In many nations, strong environmental legal frameworks have been and continue to be weakened in favour of neoliberal and voluntary approaches (Pellizzoni, 2011). This analysis sides with the abundant environmental legal scholarship demonstrating the importance of regulations, also for structuring voluntary approaches (Bean, Bonnie, & Wilcove, 1999;Bonnie, 1999). Beyond calling out problems of corruption, this analysis points to the foundational role of strong, functional government institutions (e.g. courts, independent judges) and consistent enforcement of laws (UN Environment, 2019a, 2019b).

| D ISCUSS I ON
While each lever and leverage point contains claims that are now familiar, our contribution is to provide a first comprehensive and rigorous articulation of a set of elements for transformative change towards sustainable pathways, including a discussion of the facets of each lever and leverage point and possible interrelationships between them. In some cases, individual leverage points have innovative aspects (e.g. 3, latent values of responsibility). In other cases, novelty stemmed from combinations of ideas (e.g. lever A, where we packaged incentives within a call for broad subsidy reform). While no single lever or leverage point is wholly novel, such is the nature of knowledge synthesis, where the novelty is at a coarser level, in tracing the origins and uptake of ideas across literatures, and-most importantly-in the connections between various levers and leverage points in the set.
While there have been efforts to identify similar points of intervention for global climate solutions (Farmer et al., 2019;Otto et al., 2020;Tàbara et al., 2018), we know of no similar efforts for the biosphere including climate and aspects of sustainable development.
Given the diversity of intervention options and the scale and complexity of the problem, there is no objective way to categorize or verify levers and leverage points. As such, the set identified here should be taken for what it is-one comprehensive effort that stemmed from a thorough scenario and pathway analysis (detailed in Aguiar et al., in review) and the combination of the authors' many years of experience culminating in an iterative group process and associated literature review. Others doing the same exercise might well have expressed levers and leverage points in different terms, and they may have identified additional levers and leverage points or overlooked some of these, particularly those that were largely implicit in scenarios. However, we are confident that those we have identified are meaningful and important. The set here is consistent F I G U R E 3 Eight featured leverage points and five levers of transformative change towards sustainable pathways, overlaid on a simplified version of the IPBES Conceptual Framework (graphical details are depicted slightly differently to accommodate the levers and leverage points, which are themselves represented in short form for graphical simplicity; Díaz et al., 2015). The leverage points (1-8) and levers (A-E) are placed at their primary sites of action, where relatively small changes in indirect drivers could influence other elements to effect large changes in outcomes for nature and its contributions to people. Although the leverage points and levers vary in many dimensions, all pertain somewhat to institutions (both formal and informal), and in most cases how these institutions influence other elements of the Conceptual Framework (including 1 Visions of a good life, where the change would originate with institutions). Many levers and leverage points could be situated within 'Institutions, …', but most do pertain especially to direct drivers-including 'Technology, …', which has impact via Anthropogenic assets. 'Values in action' occurs in two places, affecting human action in the Direct drivers via 'Institutions, …' and also 'Anthropogenic assets' (e.g. infrastructure). Colours correspond to those in Figure 4 Good quality of life with the Global Assessment's Summary for Policymakers (IPBES, 2019a(IPBES, , 2019b, which was approved by IPBES' 132 member nations. While all levers and leverage points address indirect drivers, they do so in ways that affect different elements of social-ecological systems, and different components of the IPBES Conceptual Framework ( Figure 3). The five levers are applicable broadly (not only at the eight leverage points), and desired changes at the leverage points might require additional policy tools or intervention approaches (not only the levers). As such, this analysis offers a prioritization of several key approaches and points of intervention, not a comprehensive treatment of every action that might or must be taken. Pathways to sustainable futures involve considerable flexibility in how to promote positive changes in leverage points such as consumption or inequalities, which would entail substantial variation across contexts ).
Although we were inspired by and benefited greatly from Meadows (1997), our levers and leverage points do not conform to her typology or its derivatives (Abson et al., 2017;Meadows, 1997 (Meadows, 2009, p. 41). In general, Meadows' typology also does not seem well suited to social systems, where individuals and groups have competing and evolving purposes. Thus, while we and many others have found great value in Meadows' typology for insights into systems, it is not clear that it is the most useful framework for guiding social-ecological practice and policymaking.

| From levers and leverage points to real change
Although these various actions and changes may seem daunt-

| Initiating transformations, building support
The joint product of effectively applying the levers and leverage points is a global sustainable economy-that is, an economy that is sustainable at all scales, including planetary ones. It would entail large-scale legal reform across many jurisdictions to achieve a renewable-based, low-impact circular economy. That is, an economy in which wastes are used as resources and goods are repaired and reused, but also one where extraction, production and processing have at most small negative impacts on nature and its contributions to people, and where these impacts would in turn be mitigated.
Although the IPBES Global Assessment's Summary for Policymakers (IPBES, 2019a(IPBES, , 2019b boldly seeks such a future, its approval does not itself entail that reform. As such, much of the work of transforming towards sustainability will need to first build political support at a range of scales. In the cases described above (Boxes 1 and 2) and others in Chan et al. (2019), political opportunity was created in part by various actors intervening in creative ways to enable broad and focused public support. By leveraging further corporate and government action, individual and local efforts might be scaled up to transformative change for sustainability, and these can be initiated by the private sector, civil society and governments at all scales.
Many initiatives already address the aforementioned leverage points and levers, at least partly (Bennett et al., 2016). Analysing these initiatives using the levers and leverage points lens may highlight system components and changes not usually addressed, which might facilitate transformative changes towards sustainability. For example, there is a great deal of attention to reforming investment and technological innovation for a low-carbon economy (e.g. via carbon pricing), but few efforts simultaneously internalize comprehensive impacts on nature and its contributions to people-as suggested above [six externalities and telecouplings, seven technologies, innovation and investment; throughout this section, in square brackets, numbers 1-8 pertain to leverage points and letters A-E to levers].
Addressing the leverage points partially (e.g. only carbon as but one externality) can be counterproductive, for example, potentially incentivizing other kinds of externalities and impacts on nature including via land use change, water quality and quantity and soil retention (e.g. Díaz et al., 2019;Hof et al., 2018). As one example of the limited role of values to date in sustainability initiatives, many behaviour-change programmes encounter one of two major obstacles to fostering system transformation. First, campaigns often appeal only to a small minority of self-identified environmentalists based on a narrow set of environmental values (Moisander, 2007). This can impede behaviour change among broader publics due to negative stereotypes and the narrow reach of social norms (Chan, Anderson, et al., 2017; (Fischer & Fox, 2012;Jaccard, 2020); extending beyond carbon to include water (Molle & Berkoff, 2007), land use or conversion and other metrics of damage or threat to nature and its contributions to people; and ensuring that incentive programmes are designed to foster relational values, not just 'buy' behaviour change (Chan, Anderson, et al., 2017;

BOX 2 Seychelles
Seychelles is among the world's leaders in the percentage of its land that is designated as protected, at over 42% (World Bank, 2018 Examples include renewable electricity mandates for utility companies or zero emission vehicle mandates for automobile manufacturers. The third gap identified is the little attention paid in practice to structuring governing institutions so that they are coordinated, adaptive, precautionary and addressing the resilience of social-ecological systems [B, C, D]. Of particular relevance is aligning governance structures to promote consistent goals, especially transformation, which is generally opposed by powerful interests vested in the status quo (e.g. fossil fuel companies lobbying and marketing against climate policies). Multi-stakeholder non-governmental organizations-as associated with certification systems-offer some promise to leverage change within commodity sectors (e.g. palm oil, soy, cotton, rubber and fisheries), provided power inequities are addressed (e.g. so that smallholders have a substantial voice) and consumers are Much writing about sustainability and even about transformative change might lead one to believe that transformative change to sustainability is as simple as scaling-up and out existing sustainability initiatives. Perhaps as a community of environmental and sustainability professionals, we have been too wary of disappointing those who are seeking sustainability by acting locally via incremental change in business or policy. The IPBES Global Assessment made it clear that neither transformative change nor sustainability is so easily achieved. This analysis of levers and leverage points extends that assessment, building upon its framework for concerted structural change that could actually bring about harmony with nature and the 'future we want'.

| CON CLUS ION
The approach presented here, using the language of levers and leverage points, provides a framework for imagining pathways to sustainability in the context of complex, multidimensional global futures, where uncertainty is extreme and accurate predictions are not feasible. Although there is no objective means of identifying or validating levers or leverage points at the global scale, we hope that this intensive, systematic synthesis effort will enable innovation in policymaking and interdisciplinary research for sustainability. For policymakers, this paper builds upon and complements the IPBES Global Assessment in offering a foundation for prioritizing efforts across sectors and government agencies in pursuit of the recognized need for transformative change. For researchers, we offer a deeply interdisciplinary synthesis that provides a starting point for assessing pathways towards a sustainable future.

ACK N OWLED G EM ENTS
This first many drafts of this work were conducted via the IPBES Global Assessment, so we owe much to IPBES Chair Robert

DATA AVA I L A B I L I T Y S TAT E M E N T
As a review-based analysis, this article does not include data.