The planetary boundaries framework defines a safe operating space for humanity based on the intrinsic biophysical processes that regulate the stability of the Earth system. Here, we revise and update the planetary boundary framework, with a focus on the underpinning biophysical science, based on targeted input from expert research communities and on more general scientific advances over the past 5 years. Several of the boundaries now have a two-tier approach, reflecting the importance of cross-scale interactions and the regional-level heterogeneity of the processes that underpin the boundaries. Two core boundaries—climate change and biosphere integrity—have been identified, each of which has the potential on its own to drive the Earth system into a new state should they be substantially and persistently transgressed.

Quantitative scenarios are coming of age as a tool for evaluating the impact of future socioeconomic development pathways on biodiversity and ecosystem services. We analyze global terrestrial, freshwater, and marine biodiversity scenarios using a range of measures including extinctions, changes in species abundance, habitat loss, and distribution shifts, as well as comparing model projections to observations. Scenarios consistently indicate that biodiversity will continue to decline over the 21st century. However, the range of projected changes is much broader than most studies suggest, partly because there are major opportunities to intervene through better policies, but also because of large uncertainties in projections.

Enhancing the resilience of ecosystem services (ES) that underpin human well-being is critical for meeting current and future societal needs, and requires specific governance and management policies. Using the literature, we identify seven generic policy-relevant principles for enhancing the resilience of desired ES in the face of disturbance and ongoing change in social-ecological systems (SES). These principles are (P1) maintain diversity and redundancy, (P2) manage connectivity, (P3) manage slow variables and feedbacks, (P4) foster an understanding of SES as complex adaptive systems (CAS), (P5) encourage learning and experimentation, (P6) broaden participation, and (P7) promote polycentric governance systems. We briefly define each principle, review how and when it enhances the resilience of ES, and conclude with major research gaps. In practice, the principles often co-occur and are highly interdependent. Key future needs are to better understand these interdependencies and to operationalize and apply the principles in different policy and management contexts.

Human domination of the biosphere has led to substantial gains in human welfare and economic development, but simultaneously threatens the planetary conditions that underpin societal wellbeing and prosperity 1-3 . Emerging challenges, including water scarcity, food security issues and biodiversity loss, are intractable, interconnected and influenced by a range of crossscale drivers and complex feedback mechanisms 4 . These challenges, and attempts to address them, involve multiple groups of people with different needs and interests and are beset by social, political and administrative uncertainty 5 .Researchers and practitioners alike are turning to knowledge co-production as a promising approach to make progress in this complex space. Conceptually, knowledge co-production is part of a loosely linked and evolving cluster of participatory and transdisciplinary research approaches that have emerged in recent decades. These approaches reject the notion that scientists alone identify the

ABSTRACT. Humanity has emerged as a major force in the operation of the biosphere. The focus is shifting from the environment as externality to the biosphere as precondition for social justice, economic development, and sustainability. In this article, we exemplify the intertwined nature of social-ecological systems and emphasize that they operate within, and as embedded parts of the biosphere and as such coevolve with and depend on it. We regard social-ecological systems as complex adaptive systems and use a social-ecological resilience approach as a lens to address and understand their dynamics. We raise the challenge of stewardship of development in concert with the biosphere for people in diverse contexts and places as critical for long-term sustainability and dignity in human relations. Biosphere stewardship is essential, in the globalized world of interactions with the Earth system, to sustain and enhance our lifesupporting environment for human well-being and future human development on Earth, hence, the need to reconnect development to the biosphere foundation and the need for a biosphere-based sustainability science.

Ecosystem stewardship is an action-oriented framework intended to foster social-ecological sustainability of a rapidly changing planet. Recent developments identify three strategies that make optimal use of current understanding in an environment of inevitable uncertainty and abrupt change: reducing the magnitude of, and exposure and sensitivity to, known stresses; focusing on proactive policies that shape change; and avoiding or escaping unsustainable socialecological traps. All social-ecological systems are vulnerable to recent and projected changes but have sources of adaptive capacity and resilience that can sustain ecosystem services and human well-being through active ecosystem stewardship. A Call for Ecosystem StewardshipHuman actions are having large and accelerating effects on Earth's climate, environment, and ecosystems 1, 2 , thereby degrading many ecosystem services (see glossary) 3 . This unsustainable 2 trajectory demands a dramatic change in human relationships with the environment and lifesupport system of the planet 2,3 . In this paper we address recent developments in thinking about the sustainable use of ecosystems and resources by society in the context of rapid and frequently abrupt change (Box 1).Western resource management paradigms have evolved from exploitation, where sustainability is not an important consideration, to steady-state resource management aimed at maximum or optimum sustainable yield (MSY or OSY, respectively) and efficient production of a single resource such as fish or trees, to ecosystem management to sustain a broader suite of ecosystem services 4 ( Fig. 1). Despite its sustainability goal, management for MSY or OSY tends to over-exploit targeted resources because of overly optimistic assumptions about the capacity to sustain productivity, avoid disturbances, regulate harvesters' behavior, and anticipate extreme economic or environmental events 5 . Ecosystem management seeks to sustain multiple ecosystem services 6 but often uses, as a reference point, historic conditions that are not achievable in a rapidly changing world.Given the challenges of sustainable use of ecosystems during rapid change, we advocate a shift to ecosystem stewardship (Table 1) 7,8 . Its central goal is to sustain the capacity to provide ecosystem services that support human well-being under conditions of uncertainty and change (see glossary). Uncertainty has always characterized social-ecological systems and should therefore not be an impediment to action. Such a paradigm shift entails important tradeoffs, particularly between efficiency and flexibility and between immediate and long-term benefits 9, 10 .Ecosystem stewardship integrates three broadly overlapping sustainability approaches 8,11, 12 (Fig. 2): reducing vulnerability to expected changes [11][12][13] ; fostering resilience to sustain 3 desirable conditions in the face of perturbations and uncertainty 14 ; and transforming from undesirable trajectories when opportunities emerge 15,16 . Adaptive capacity contributes to all three ...

The scale, rate, and intensity of humans' environmental impact has engendered broad discussion about how to find plausible pathways of development that hold the most promise for fostering a better future in the Anthropocene. However, the dominance of dystopian visions of irreversible environmental degradation and societal collapse, along with overly optimistic utopias and business-as-usual scenarios that lack insight and innovation, frustrate progress. Here, we present a novel approach to thinking about the future that builds on experiences drawn from a diversity of practices, worldviews, values, and regions that could accelerate the adoption of pathways to transformative change (change that goes beyond incremental improvements). Using an analysis of 100 initiatives, or "seeds of a good Anthropocene", we find that emphasizing hopeful elements of existing practice offers the opportunity to: (1) understand the values and features that constitute a good Anthropocene, (2) determine the processes that lead to the emergence and growth of initiatives that fundamentally change human-environmental relationships, and (3) generate creative, bottom-up scenarios that feature well-articulated pathways toward a more positive future.

Despite growing interest and investment in ecosystem services across global science and policy arenas, it remains unclear how ecosystem services – and particularly changes in those services – should be measured. The social and ecological factors, and their interactions, that create and alter ecosystem services are inherently complex. Measuring and managing ecosystem services requires a sophisticated systems‐based approach that accounts for how these services are generated by interconnected social–ecological systems (SES), how different services interact with each other, and how changes in the total bundle of services influence human well‐being (HWB). Furthermore, there is a need to understand how changes in HWB feedback and affect the generation of ecosystem services. Here, we outline an SES‐based approach for measuring ecosystem services and explore its value for setting policy targets, developing indicators, and establishing monitoring and assessment programs.