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Global agreement on 30×30 means an unprecedented last push to define how much nature will be left on the planet. At the same time that space for nature is being defined, climate change will be moving nature around. Species are now on the move to track climate change both on land and in the oceans, a process that is accelerating under dramatic new extreme events. This is an opportune time to review conservation recommendations made early in the millennium, to see how many have been taken on board over the past 20 years, and how much is left to be done to adapt to climate change as conservation pushes toward 30×30. The history of Climate Change–Integrated Conservation Strategies begins with two papers published by a group of prominent climate change biologists in 2002. The importance of including adaptation to climate change in conservation was underscored by the first estimates of extinction risk due to climate change in 2004. Subsequent literature has developed concepts such as velocity of climate change and assisted migration. Regional modeling of biodiversity change, expanding protected areas to facilitate species range movements, and managing productive landscapes to facilitate species movements are all now considered "business as usual" for conservation planning for climate change. Regional coordination of conservation efforts to ensure that species on the move are managed for climate change consistently across their range, on the other hand, is under-represented in literature and practice. Improving both theory and practice of regional coordination for climate change is an important priority for conservation now and in the future. Conservation for climate change has focused mostly on warming scenarios, but failure to act on climate change emissions reduction means that meeting Paris Agreement targets will almost certainly have to include both warming past those targets and subsequent cooling back to the target. Managing this double transition is a second critical point of emphasis for climate change biology as the world moves to 30×30. [ABSTRACT FROM AUTHOR]

Urban climate policy offers a significant opportunity to promote improved public health. The evidence around climate and health cobenefits is growing but has yet to translate into widespread integrated policies. This article presents two systematic reviews: first, looking at quantified cobenefits of urban climate policies, where transportation, land use, and buildings emerge as the most studied sectors; and second, looking at review papers exploring the barriers and enablers for integrating these health cobenefits into urban policies. The latter reveals wide agreement concerning the need to improve the evidence base for cobenefits and consensus about the need for greater political will and leadership on this issue. Systems thinking may offer a way forward to help embrace complexity and integrate health cobenefits into decision making. Knowledge coproduction to bring stakeholders together and advance policy-relevant research for urban health will also be required. Action is needed to bring these two important policy agendas together. [ABSTRACT FROM AUTHOR]

In the 1980s and 1990s, a series of publications, including Saskia Sassen's landmark book The Global City, triggered a new current of research aiming to link a cycle of globalized financial and tech capitalism to a new type of city, analogous to what the industrial city had been in the past. This article first reviews this literature in relation to the history and sociology of the world city. It then reviews criticism and sociological questions advanced by the global city literature and, in particular, research by Saskia Sassen and Manuel Castells. It argues that claims about the uniqueness of the global city were not validated empirically. Nonetheless, the issues this literature raised became central to research on globalizing cities, in particular in relation to the role of finance and financial capitals. Finally, this article argues that different forms of globalization give rise to different types of globalizing cities. A new cycle of research is now underway in relation to the climate crisis and pandemics, as the climate crisis becomes the most important global phenomenon. [ABSTRACT FROM AUTHOR]

Africa's fossil record of late Cenozoic mammals documents considerable ecological and evolutionary changes through time. Here, we synthesize those changes in the context of the mechanisms proposed to account for them, including bottom-up (e.g., climate change) and top-down (e.g., hominin impacts) processes. In doing so, we (a) examine how the incompleteness of the fossil record and the varied spatiotemporal scales of the evidence complicate efforts to establish cause-effect relationships; (b) evaluate hypothesized drivers of long-term ecological and evolutionary change, highlighting key unknowns; and (c) synthesize major taxonomic and functional trends through time (e.g., downsizing of faunal communities) considering the proposed drivers. Throughout our review, we point to unresolved questions and highlight research avenues that have potential to inform on the processes that have shaped the history of what are today the most diverse remaining large mammal communities on Earth. The study of late Cenozoic African mammal communities is intertwined with questions about the context, causes, and consequences of hominin evolution. The fossil record documents major functional (e.g., loss of megaherbivores) and taxonomic (e.g., rise of the Bovidae) changes over the past ∼7 Myr. Complexities inherent to the fossil record have made it difficult to identify the processes that drove ecological and evolutionary changes. Unanswered questions about the drivers of faunal change and the functioning of past ecosystems represent promising future research directions. [ABSTRACT FROM AUTHOR]

Food insecurity affects an estimated 691–783 million people globally and is disproportionately high in Africa and Asia. It arises from poverty, armed conflict, and climate change, among other demographic and globalization forces. This review summarizes evidence for policies and practices across five elements of the agrifood system framework and identifies gaps that inform an agenda for future research. Under availability, imbalanced agriculture policies protect primarily staple food producers, and there is limited evidence on food security impacts for smallholder and women food producers. Evidence supports the use of cash transfers and food aid for affordability and school feeding for multiple benefits. Food-based dietary guidelines can improve the nutritional quality of dietary patterns, yet they may not reflect the latest evidence or food supplies. Evidence from the newer food environment elements, promotion and sustainability, while relatively minimal, provides insight into achieving long-term impacts. To eliminate hunger, our global community should embrace integrated approaches and bring evidence-based policies and practices to scale. [ABSTRACT FROM AUTHOR]

Climate change poses a significant occupational health hazard. Rising temperatures and more frequent heat waves are expected to cause increasing heat-related morbidity and mortality for workers across the globe. Agricultural, construction, military, firefighting, mining, and manufacturing workers are at particularly high risk for heat-related illness (HRI). Various factors, including ambient temperatures, personal protective equipment, work arrangements, physical exertion, and work with heavy equipment may put workers at higher risk for HRI. While extreme heat will impact workers across the world, workers in low- and middle-income countries will be disproportionately affected. Tracking occupational HRI will be critical to informing prevention and mitigation strategies. Renewed investment in these strategies, including workplace heat prevention programs and regulatory standards for indoor and outdoor workers, will be needed. Additional research is needed to evaluate the effectiveness of interventions in order to successfully reduce the risk of HRI in the workplace. [ABSTRACT FROM AUTHOR]

This article reviews the present state of insects, describing their taxonomic position, cost, and value as well as the threats to their well-being. Insects are an important source of both ecosystem services and ecosystem disservices. Recent studies have indicated a worrying decline in insect species, especially in flying insects in the northern temperate region, and this has spawned much media attention. Some decline has occurred, it is clear, due to agricultural intensification, urbanization, overuse of pesticides, and global climate change. A decline would seriously affect the ecosystem services that insects provide. However, there is too little data to warrant the belief that all insects are declining everywhere. There is a pressing need for more basic research on insect diversity in the context of a changing world. [ABSTRACT FROM AUTHOR]

Biodiversity conservation requires conserving evolutionary potential—the capacity for wild populations to adapt. Understanding genetic diversity and evolutionary dynamics is critical for informing conservation decisions that enhance adaptability and persistence under environmental change. We review how emerging landscape genomic methods provide plant conservation programs with insights into evolutionary dynamics, including local adaptation and its environmental drivers. Landscape genomic approaches that explore relationships between genomic variation and environments complement rather than replace established population genomic and common garden approaches for assessing adaptive phenotypic variation, population structure, gene flow, and demography. Collectively, these approaches inform conservation actions, including genetic rescue, maladaptation prediction, and assisted gene flow. The greatest on-the-ground impacts from such studies will be realized when conservation practitioners are actively engaged in research and monitoring. Understanding the evolutionary dynamics shaping the genetic diversity of wild plant populations will inform plant conservation decisions that enhance the adaptability and persistence of species in an uncertain future. [ABSTRACT FROM AUTHOR]

Coral reefs are both exceptionally biodiverse and threatened by climate change and other human activities. Here, we review population genomic processes in coral reef taxa and their importance for understanding responses to global change. Many taxa on coral reefs are characterized by weak genetic drift, extensive gene flow, and strong selection from complex biotic and abiotic environments, which together present a fascinating test of microevolutionary theory. Selection, gene flow, and hybridization have played and will continue to play an important role in the adaptation or extinction of coral reef taxa in the face of rapid environmental change, but research remains exceptionally limited compared to the urgent needs. Critical areas for future investigation include understanding evolutionary potential and the mechanisms of local adaptation, developing historical baselines, and building greater research capacity in the countries where most reef diversity is concentrated. [ABSTRACT FROM AUTHOR]

Within the past decade, the attribution of extreme weather events and their impacts has enabled scientists, the public, and policymakers alike to connect real-world experiences of extreme weather events with scientific understanding of anthropogenic climate change. Attribution studies of recent extreme weather events have formed a new and important line of evidence in the most recent Intergovernmental Panel on Climate Change (IPCC) assessment report understanding present-day impacts of climate change. IPCC studies using different methods of event attribution have been assessed together, highlighting that these differences are smaller than the academic discourse on the methods suggests. This development raised two important research questions the science needs to answer: First, how do we formally combine attribution statements using highly conditional methods with probabilistic assessments of how climate change alters the likelihood and intensity of extreme weather events? Second, under what circumstances are individual attribution studies still necessary and to what extent do existing attribution studies provide enough information to answer societal questions? Furthermore, the scientific development still leaves important gaps, particularly in countries of the Global South, leading to ethical questions around the need and requirement of attribution of extreme events in policy contexts, informing adaptation and loss and damage and the role of vulnerability. [ABSTRACT FROM AUTHOR]

Polarization in the United States and around the world is of growing concern. Polarization is about more than just differences in opinions in society. It occurs when groups increasingly diverge in either actual or perceived differences in opinion and can involve both disagreements about issues and negative views of other groups. Since most environmental problems are collective action problems, polarization may interfere with the kinds of deliberation and collaborations needed for effective environmental decision-making. In this review, we examine how polarization influences environmental decision-making and what strategies could be useful for preventing or reducing the negative consequences of polarization. Evidence about the extent of polarization among citizens suggests the current situation may be less severe than is sometimes assumed. The coevolution of individual views, network interactions, and social media that cause polarization is complex and subject to rapid change. However, there are interventions that seem to be effective at reducing polarization. [ABSTRACT FROM AUTHOR]

Qualitative research methods examine a wide range of topics in the study of environment and resource management. This first review on the topic highlights innovative and impactful research over the past few decades, drawing from social science disciplines that include sociology, geography, anthropology, political science, public policy, and psychology. We describe qualitative research methods that have addressed five scientific goals: (a) describing what the world is like, (b) predicting what the world can be like, (c) acknowl-edging researcher positionality and reflexivity and diversifying ways of knowing in theorizing and research designs, (d) integrating imaginaries into empirical research and building narratives to make sense of possible futures and to broaden our view of scientific inquiry, and (e) helping scholars grapple with the deep complexity of socioecological systems. As we explore these themes, we explain foundational qualitative approaches and highlight examples of environmental qualitative research that apply them. [ABSTRACT FROM AUTHOR]

Coastal systems are sensitive to direct and indirect impacts of climate change. Approximately 90% of all coastal areas will be affected by climate change to varying degrees. Nearly half of the world's major cities are located within 50 km of a coast, and coastal population densities are 2.6 times greater than those of inland areas, with a steep rise over the years. While coastal critical infrastructure is expanding, more social and physical systems are increasingly exposed to climate-induced hazards. The interconnectedness and interdependencies of critical infrastructure systems increase their systemic instability and fragility, resulting in greater dynamic risk and cascading impacts. Coastal critical infrastructure systems on several continents are at risk from the effects of climate change, including sea level rise, storm surges, and extreme weather events. Therefore, it is necessary to build and run climate-resilient infrastructure that is planned, designed, implemented, and operated to predict, be prepared for, and adapt to changing climatic circumstances. This review provides an up-to-date, objective, and critical assessment based on the literature to help determine what is known and what needs the future attention of researchers. [ABSTRACT FROM AUTHOR]

Sky islands are unique geologic formations, home to populations of organisms that have weathered climate change since the Pleistocene. Long-term isolation and climatic differences between sky islands and adjacent mountain chains result in natural laboratories well suited for examining the direct effects of climate change. Here, we review the global sky island literature to examine how taxa have responded to climate change. Results show lineage formation, reduced genetic variation, and trait evolution across taxa driven by genetic drift and natural selection. These effects continue today due to ongoing habitat reduction and steep selective gradients on sky islands relative to mountain chains. Comparative studies and experimental manipulations are needed to build broad inference into how past climate change has shaped the structure and function of whole ecosystems. The next era of sky island research is poised to create a model for climate change responses and eco-evolutionary dynamics, with profound conservation implications. [ABSTRACT FROM AUTHOR]

Over 70% of soil organic carbon (SOC) is stored at a depth greater than 20 cm belowground. A portion of this deep SOC actively cycles on annual to decadal timescales and is sensitive to global change. However, deep SOC responses to global change likely differ from surface SOC responses because biotic controls on SOC cycling become weaker as mineral controls predominate with depth. Here, we synthesize the current information on deep SOC responses to the global change drivers of warming, shifting precipitation, elevated CO2, and land use and land cover change. Most deep SOC responses can only be hypothesized because few global change studies measure deep soils, and even fewer global change experiments manipulate deep soils. We call on scientists to incorporate deep soils into their manipulations, measurements, and models so that the response of deep SOC can be accounted for in projections of nature-based climate solutions and terrestrial feedbacks to climate change. [ABSTRACT FROM AUTHOR]

Using the results of more than 20 different global models with a particular emphasis on two rapidly growing large countries (China and India), this paper discusses the cost estimation methods that are used in setting up information for organizing models and to illustrate their global applicability to China, Korea, Japan, India, Indonesia, Europe, Latin America, the Middle East, Africa, and the United States. Some clear points emerge from the intermodal comparison exercise. First, no single technology can play a leading role in global emission mitigation. Second, although participation of all the regions is important, regions where future demographic and economic growth is concentrated will share a large part of this burden. Third, different technologies are important for different regions for mitigating emissions in the most cost-effective way. Fourth, if stringent climate policy targets are to be met, then emission-reduction actions need to be undertaken as soon as possible. [ABSTRACT FROM AUTHOR]

The extent to which natural capital can be substituted with manufactured or human capital in production is a key determinant of the possibility of long-run sustainable economic development. We review empirical literature pertaining to the degree of substitutability between natural capital and other forms of capital. We find that most available substitutability estimates do not stand up to careful scrutiny. Moreover, accurate substitutability estimates are even more difficult to produce for unpriced or mispriced resources. Finally, we provide evidence from industrial energy use, and agricultural land use, that suggests substitutability of natural capital with other forms of capital may be low to moderate. [ABSTRACT FROM AUTHOR]

To appreciate the beauty or the fragility of our environment and our cultural responses to it, we need to understand how artists have portrayed the environment in the past and how they are continuing to portray it in the present. Environmental art is presented in this paper as a new genre to describe works of art that are not only directly representational of the environment (e.g., Constable's Cloud Series or Monet's London Series) but also works of art that are clearly nonrepresentational and performative, such as Long's A Line Made by Walking or Turrell's Skyspaces. The need for an overarching new genre to describe nonrepresentational performative environmental art is more obvious because there has been a host of labels given to this type of art since the late 1960s, such as land art, earthworks, site-specific art, destination art, ecological art, eco-art, and environmental sculpture. The review is also concerned with the potential of environmental art for communicating climate change. [ABSTRACT FROM AUTHOR]

This paper focuses on the desirability, from an economic perspective, of setting fixed and relatively short-term targets and timetables, such as those contained in the Kyoto Protocol, as a means of achieving longer-term climate change mitigation goals. The paper argues that whatever long-term policy goals are adopted, greater flexibility lowers implementation costs. Lower implementation costs, in turn, increases the likelihood that the policies will actually be followed and the goals achieved. Importantly, the Kyoto Protocol incorporates key elements of both “what” and “where” flexibility. That is, the “Kyoto basket” includes all six of the major greenhouse gases plus sinks, and the Protocol incorporates several mechanisms that allow emission reductions to take place at the least-cost geographic location, regardless of nation-state boundaries. The Protocol also provides substantial “how” flexibility in the sense that countries can use a variety of means to achieve domestic policy goals. However, the Protocol does not allow emission reductions to take place at a point in time when they can be achieved at lowest cost as long as they are consistent with the long-term environmental goals (“when” flexibility). Additionally, it does not allow the use of efficient price-based policy instruments to define targets and, thereby, balance environmental goals and compliance costs (which could be thought of as a broader version of “when” flexibility). Instead, the Protocol relies exclusively on strict, short term quantity targets. The relative inflexibility of the Protocol with respect to the timing of reductions and definitions of the targets may derive, in part, from a misplaced analogy between the global warming issue and the highly successful effort to phase out CFCs under the Montreal Protocol. The lack of when flexibility may be a key barrier to achieving the broader goals of the K... [ABSTRACT FROM AUTHOR]

This review considers sociological perspectives and research on the outcomes and implications of forced and refugee migration for migrants and communities of settlement. Analytic constraints and opportunities posed by concepts of forced and refugee migration and migrants for empirical research are underscored. The tendencies for research on forced and refugee migration to serve policy and programs are addressed in relationship to the conceptualization of processes of displacement as well as research design. A social demographic lens is used to illustrate a record of research on the consequences of forced and refugee migration and settlement. Accordingly, we review empirical literature on patterns of spatial mobility, health and well-being, social and economic integration, and family and community dynamics at different scales. Implications of global issues such as climate change and the COVID-19 pandemic are considered. Analytic issues emerge from the intersections, and lack thereof, between forced migration, refugee studies, and migration policy analysis and provide critical opportunities for contributions by sociologists and social scientists more generally. [ABSTRACT FROM AUTHOR]

From the earliest studies examining the impacts of the coal-powered Industrial Revolution, the field of sociology has possessed an intimate, if often implicit, interest in the interconnectedness of fossil fuels and modernity. With the looming climate crisis, the world must rapidly wean itself from these resources in favor of others that emit little to no greenhouse gasses. And while this energy transition will likely have profound social implications, it has only recently begun to receive sustained attention from sociologists across subfields. Consequently, although debates have emphasized the technological and market dimensions of this shift, its relational dimensions and human aspects have remained relatively marginal. In this article, we review research on the social impacts of fossil fuel production and transitions to renewables. Such work is critical and urgent, since the main barriers to combating the climate crisis are neither technological nor economic; they are, instead, deeply social. [ABSTRACT FROM AUTHOR]

A recent wave of research in political science examines the past using statistical methods for causal inference and formal theory—a field widely known as historical political economy (HPE). We examine the development of this field. Our survey reveals three common uses of history in HPE: understanding the past for its own sake, using history as a way to understand the present, and using history as a setting to explore theoretical conjectures. We present important work in each area and discuss trade-offs of each approach. We further identify key practical and analytical challenges for scholars of HPE, including the accessibility of data that do exist and obstacles to inference when they do not. Looking to the future, we see improved training for scholars entering the field, a heightened focus on the accumulation of knowledge, and greater attention to underexplored topics such as race, gender, ethnicity, and climate change. [ABSTRACT FROM AUTHOR]

The timing of ice ages over the past ∼2,600 thousand years (kyr) follows pacing by cyclical changes in three aspects of Earth's orbit that influence the solar energy received as a function of latitude and season. Explaining the large magnitude of the climate changes is challenging, particularly so across the period of time from ∼1,250 to 750 ka—the Mid-Pleistocene Transition or MPT. The average repeat time of ice age cycles changed from an earlier 41-kyr rhythm to longer and more intense glaciations at a spacing of about 100 kyr. Explaining this change is very difficult because there was no corresponding change in the orbital pacing that would trigger a change in timing. While the first generation of hypotheses looked largely to changes in the behavior of Northern Hemisphere ice sheets, more recent work integrates ice behavior with new data capturing the evolution of other important aspects of past climate. A full explanation is still lacking, but attention increasingly focuses on the ocean carbon cycle and atmospheric CO2 levels as the crucial agents involved in the MPT. The pattern of climate changes connected to the ice ages of the past few million years changed radically between about 1,250 and 750 thousand years ago, a time known as the Mid-Pleistocene Transition or MPT. While the glacial cycles were ultimately triggered by cyclical changes in Earth's orbit, the changes across the MPT came from changes in the Earth system itself, most likely in the form of a change in the carbon cycle. The dramatic change in many essential aspects of climate—ice volume, temperature, rainfall on land, and many others—in the absence of an external change suggests how important feedbacks are to the climate system. [ABSTRACT FROM AUTHOR]

A science-based understanding of climate change and potential mitigation and adaptation options can provide decision makers with important guidance in making decisions about how best to respond to the many challenges inherent in climate change. In this review we provide an evidence-based heuristic for guiding efforts to share science-based information about climate change with decision makers and the public at large. Well-informed decision makers are likely to make better decisions, but for a range of reasons, their inclinations to act on their decisions are not always realized into effective actions. We therefore also provide a second evidence-based heuristic for helping people and organizations change their climate change–relevant behaviors, should they decide to. These two guiding heuristics can help scientists and others harness the power of communication and behavior science in service of enhancing society's response to climate change. Many Earth scientists seeking to contribute to the climate science translation process feel frustrated by the inadequacy of the societal response. Here we summarize the social science literature by offering two guiding principles to guide communication and behavior change efforts. To improve public understanding, we recommend simple, clear messages, repeated often, by a variety of trusted and caring messengers. To encourage uptake of useful behaviors, we recommend making the behaviors easy, fun, and popular. [ABSTRACT FROM AUTHOR]

Extreme weather events are expected to increase due to climate change, which could pose an additional burden of morbidity and mortality. In recent decades, drought severity has increased in several regions around the world, affecting health by increasing the risk of water-, food-, and vector-borne diseases, malnutrition, cardiovascular and respiratory illness, mental health disorders, and mortality. Drought frequency and severity are expected to worsen across large regions as a result of a decrease in precipitation and an increase in temperature and atmospheric evaporative demand, posing a pressing challenge for public health. Variation in impacts among countries and communities is due to multiple factors, such as aging, socioeconomic status, access to health care, and gender, affecting population resilience. Integrative proactive action plans focused on risk management are required, and resources should be transferred to developing countries to reduce their vulnerability and risk. [ABSTRACT FROM AUTHOR]

Climate change is a threat multiplier, exacerbating underlying vulnerabilities, worsening human health, and disrupting health systems' abilities to deliver high-quality continuous care. This review synthesizes the evidence of what the health care sector can do to adapt to a changing climate while reducing its own climate impact, identifies barriers to change, and makes recommendations to achieve sustainable, resilient health care systems. [ABSTRACT FROM AUTHOR]

The impacts of climate change, such as sea-level rise and extreme weather events, are expected to increase and alter human migration and mobility. Climate-related mobility is not inherently a crisis; it can provide a pathway for adaptation to climate change. However, a growing body of research identifies health risks and some opportunities associated with climate-related mobility. This review examines recent research (published since 2018) on the climate change–mobility–health nexus; this research focuses largely on in-country mobility in Asia, Africa, and Pacific Island countries. It considers the links between human mobility and anthropogenic climate change and documents the findings of empirical research that addresses the health consequences of displacement, planned relocation, migration, and migration into sites of climate risk. The findings highlight the need for climate-sensitive and migrant-inclusive health care in a heating world. [ABSTRACT FROM AUTHOR]

There is intense interest in using genome editing technologies to domesticate wild plants, or accelerate the improvement of weakly domesticated crops, in de novo domestication. Here, we discuss promising genetic strategies, with a focus on plant development. Importantly, genome editing releases us from dependence on random mutagenesis or intraspecific diversity, allowing us to draw solutions more broadly from diversity. However, sparse understanding of the complex genetics of diversity limits innovation. Beyond genetics, we urge the ethical use of indigenous knowledge, indigenous plants, and ethnobotany. De novo domestication still requires conventional breeding by phenotypic selection, especially in the development of crops for diverse environments and cultures. Indeed, uniting genome editing with selective breeding could facilitate faster and better outcomes than either technology alone. Domestication is complex and incompletely understood, involving changes to many aspects of plant biology and human culture. Success in de novo domestication requires careful attention to history and collaboration across traditional boundaries. [ABSTRACT FROM AUTHOR]

The ocean holds vast quantities of carbon that it continually exchanges with the atmosphere through the air-sea interface. Because of its enormous size and relatively rapid exchange of carbon with the atmosphere, the ocean controls atmospheric CO2 concentration and thereby Earth's climate on timescales of tens to thousands of years. This review examines the basic functions of the ocean's carbon cycle, demonstrating that the ocean carbon inventory is determined primarily by the mass of the ocean, by the chemical speciation of CO2 in seawater, and by the action of the solubility and biological pumps that draw carbon into the ocean's deeper layers, where it can be sequestered for decades to millennia. The ocean also plays a critical role in moderating the impacts of climate change by absorbing an amount of carbon equivalent to about 25% of anthropogenic CO2 emissions over the past several decades. However, this also leads to ocean acidification and reduces the chemical buffering capacity of the ocean and its future ability to take up CO2. This review closes with a look at the uncertain future of the ocean carbon cycle and the scientific challenges that this uncertainty brings. [ABSTRACT FROM AUTHOR]

This article undertakes a comprehensive review of tourism's impacts on social-ecological systems and the use of the local to global commons. It examines a wide range of issues from climate change and air travel to biodiversity loss, pollution, and overtourism. It reinforces that tourism in modernity has pursued a dominant growth-driven paradigm of development and market expansion that is unsustainable. The review raises critical questions about how to move forward in the Anthropocene, where climate change is an existential threat to which travel and tourism must adjust. We offer directions for knowledge creation to develop nature-positive tourism that decouples from greenhouse gas emissions and seeks the regeneration of natural capital and communal health and well-being. This direction includes rethinking the purposes and values of tourism by addressing equity and ethical issues. It also calls for inclusivity of diverse worldviews and knowledge systems, including traditional and Indigenous knowledge. Such a pluralistic paradigm replaces the unsustainable modernist tourism paradigm that has dominated its evolution. We conclude with suggestions for research to advance nature-positive tourism. [ABSTRACT FROM AUTHOR]

Understanding why people do what they do is central to advancing equitable and sustainable futures. Yet, theories about human action are fragmented across many social science disciplines, each with its own jargon and implicit assumptions. This fragmentation has hindered theory integration and accessibility of theories relevant to a given challenge. We synthesized human action theories from across the humanities and social sciences. We developed eight underlying assumptions—metatheories—that reveal a fundamental organization of human action theories. We describe each metatheory and the challenges that it best elucidates (illustrated with climate change examples). No single metatheory addresses the full range of factors and problems; only one treats interactions between factors. Our synthesis will help researchers, policymakers, and practitioners gain a multifaceted understanding of human action. [ABSTRACT FROM AUTHOR]

Rapid Arctic environmental change affects the entire Earth system as thawing permafrost ecosystems release greenhouse gases to the atmosphere. Understanding how much permafrost carbon will be released, over what time frame, and what the relative emissions of carbon dioxide and methane will be is key for understanding the impact on global climate. In addition, the response of vegetation in a warming climate has the potential to offset at least some of the accelerating feedback to the climate from permafrost carbon. Temperature, organic carbon, and ground ice are key regulators for determining the impact of permafrost ecosystems on the global carbon cycle. Together, these encompass services of permafrost relevant to global society as well as to the people living in the region and help to determine the landscape-level response of this region to a changing climate. [ABSTRACT FROM AUTHOR]

Population-based solutions are needed to stabilize and then reverse the continued upward trends in obesity prevalence in the US population and worldwide. This review focuses on the related, urgent issue of disparities in obesity prevalence affecting US racial/ethnic minority and other socially marginalized populations. The review provides background on these disparities from a health equity perspective and highlights evidence of progress in equity-focused obesity efforts. Five recommendations for advancing equity efforts are offered as potential approaches to build on progress to date: (a) give equity issues higher priority, (b) adopt a health equity lens, (c) strengthen approaches by using health equity frameworks, (d) broaden the types of policies considered, and (e) emphasize implementation science concepts and tools. Potential challenges and opportunities are identified, including the prospect of longer-term, transformative solutions that integrate global and national initiatives to address obesity, undernutrition, and climate change. [ABSTRACT FROM AUTHOR]

Reducing emissions from deforestation and forest degradation (REDD++) policies, projects, and interventions are among the most prominent of recent attempts to mitigate climate change. Because REDD++ projects focus on forests, they simultaneously affect socioeconomic and ecological outcomes at local, subnational, national, regional, and global levels. This review assesses the promise of REDD++ for the continued ability of forests to provide multiple benefits to human societies at multiple scales. We survey REDD++ efforts at different levels, examining them through an actor-oriented approach. The article highlights the criticality of collaborative action to enhance desired outcomes of REDD++ efforts. In summarizing major REDD++ future trends, the paper emphasizes the need to learn from past forestry, agricultural, biodiversity, and development policies, and for adaptive policy making. [ABSTRACT FROM AUTHOR]

Aerosols are suspensions of solid and//or liquid particles in the atmosphere and modify atmospheric radiative fluxes and chemistry. Aerosols move mass from one part of the earth system to other parts of the earth system, thereby modifying biogeochemistry and the snow surface albedo. This paper reviews our understanding of the impacts of aerosols on climate through direct radiative changes, aerosol-cloud interactions (indirect effects), atmospheric chemistry, snow albedo, and land and ocean biogeochemistry. Aerosols play an important role in the preindustrial (natural) climate system and have been perturbed substantially over the anthropocene, often directly by human activity. The most important impacts of aerosols, in terms of climate forcing, are from the direct and indirect effects, with large uncertainties. Similarly large impacts of aerosols on land and ocean biogeochemistry have been estimated, but these have larger uncertainties. [ABSTRACT FROM AUTHOR]

This paper explores how long-term energy forecasts are created and why they are useful. It focuses on forecasts of energy use in the United States for the year 2000 but considers only long-term predictions, i.e., those covering two or more decades. The motivation is current interest in global warming forecasts, some of which run beyond a century. The basic observation is that forecasters in the 1950–1980 period underestimated the importance of unmodeled surprises. A key example is the failure to foresee the ability of the United States economy to respond to the oil embargos of the 1970s by increasing efficiency. Not only were most forecasts of that period systematically high, but forecasters systematically underestimated uncertainties. Long-term energy forecasts must make assumptions about both technologies and social systems. At their most successful, they influence how people act by showing the consequences of not acting. They are useful when they provide insights to energy planners, influence the perceptions of the public and the energy policy community, capture current understanding of underlying physical and economic principles, or highlight key emerging social or economic trends. It is true that at best we see dimly into the future, but those who acknowledge their duty to posterity will feel impelled to use their foresight upon what facts and guiding principles we do possess. Though many data are at present wanting or doubtful, our conclusions may be rendered so far probable as to lead to further inquiries… (), p. 4. [ABSTRACT FROM AUTHOR]

Growing international pressure to curb greenhouse gas (GHG) emissions has focused attention on existing policies that may, either by design or by effect, subsidize fossil fuel production and consumption. This paper reviews existing studies of fossil fuel subsidies within the United States, as well as assessments of the potential impact of subsidy reform on GHG emissions. Evaluating the differences across the studies, it highlights the most important disparities in subsidy definition and valuation in order to clarify the conclusions that can be drawn from this body of work. We then present some of the tools used to provide transparency in environmental regulation. We conclude that many of these approaches can be used to improve the transparency of fiscal policy, with important benefits within the context of climate change and beyond. [ABSTRACT FROM AUTHOR]

Discounting plays a central role in decisions about global environmental change that affect the well-being of future generations. Discounting the future more heavily tilts decisions toward the present, making it less likely that society will undertake actions to mitigate climate change or other global environmental change. This article reviews the standard economics approach to discounting that emerges from solving for optimal savings and investment through time. Discounting depends on the pure rate of time preference and differences in consumption levels across time, giving rise to different marginal utilities of consumption. Discounting for problems like climate change that impact future generations involves an ethical dimension. This article includes discussions of ethical dimensions of discounting related to intragenerational and intergenerational equity and also covers behavioral economics, ecological economics, and mainstream economics approaches to discounting. The article closes with a review of the debates over discounting in climate change policy. [ABSTRACT FROM AUTHOR]

Coastal settlements, home to more than three billion people and growing rapidly, are highly vulnerable to climate change. Increasingly, there are calls for climate adaptation that goes beyond business-as-usual approaches, transforms socioeconomic systems, and addresses underlying drivers of vulnerability. Although calls for transformational adaptation are growing, greater clarity is needed on what transformation means in context in order to bridge the gap between theory and practice. This article reviews the theoretical literature on transformational adaptation, as well as practitioner frameworks and case studies of urban coastal adaptation. The article discusses specific challenges for transformational adaptation and its governance in coastal cities. In doing so, this review contributes to the growing debate about operationalizing the concept of transformational adaptation in the context of coastal cities and offers insights to ensure that transformation processes are inclusive and equitable. [ABSTRACT FROM AUTHOR]

In recent years, machine learning has proven to be a powerful tool for deriving insights from data. In this review, we describe ways in which machine learning has been leveraged to facilitate the development and operation of sustainable energy systems. We first provide a taxonomy of machine learning paradigms and techniques, along with a discussion of their strengths and limitations. We then provide an overview of existing research using machine learning for sustainable energy production, delivery, and storage. Finally, we identify gaps in this literature, propose future research directions, and discuss important considerations for deployment. [ABSTRACT FROM AUTHOR]

Environmental factors, particularly those related to climate change, are stranding or could strand assets across different sectors and geographies with significant implications for economies, companies, financial institutions, communities, and workers. In this review, we focus on physical climate change, biodiversity loss, and litigation related to environmental factors as causes of stranded assets. We also review the emerging literature on the consequences of asset stranding for society before turning to some of the key supervisory responses that are emerging to ensure that stranded assets are measured and managed, particularly by financial institutions. These are among the areas of the stranded assets literature that have been growing most rapidly since 2015, and we focus on the literature produced since then. [ABSTRACT FROM AUTHOR]

The knowledge, values, and practices of Indigenous peoples and local communities offer ways to understand and better address social-environmental problems. The article reviews the state of the literature on this topic by focusing on six pathways by which Indigenous peoples and local communities engage with management of and relationships to nature. These are (a) undertaking territorial management practices and customary governance, (b) contributing to nature conservation and restoration efforts with regional to global implications, (c) co-constructing knowledge for assessments and monitoring, (d) countering the drivers of unsustainable resource use and resisting environmental injustices, (e) playing key roles in environmental governance across scales, and (f) offering alternative conceptualizations of the interrelations between people and nature. The review shows that through these pathways Indigenous peoples and local communities are making significant contributions to managing the health of local and regional ecosystems, to producing knowledge based in diverse values of nature, confronting societal pressures and environmental burdens, and leading and partnering in environmental governance. These contributions have local to global implications but have yet to be fully recognized in conservation and development polices, and by society at large. [ABSTRACT FROM AUTHOR]

Despite three decades of political efforts and a wealth of research on the causes and catastrophic impacts of climate change, global carbon dioxide emissions have continued to rise and are 60% higher today than they were in 1990. Exploring this rise through nine thematic lenses—covering issues of climate governance, the fossil fuel industry, geopolitics, economics, mitigation modeling, energy systems, inequity, lifestyles, and social imaginaries—draws out multifaceted reasons for our collective failure to bend the global emissions curve. However, a common thread that emerges across the reviewed literature is the central role of power, manifest in many forms, from a dogmatic political-economic hegemony and influential vested interests to narrow techno-economic mindsets and ideologies of control. Synthesizing the various impediments to mitigation reveals how delivering on the commitments enshrined in the Paris Agreement now requires an urgent and unprecedented transformation away from today's carbon- and energy-intensive development paradigm. [ABSTRACT FROM AUTHOR]

The budget of reactive nitrogen (Nr; oxidized and reduced inorganic and organic forms of nitrogen) has at least doubled since the preindustrial era due to human activities. Excess Nr causes significant detrimental effects on many terrestrial and aquatic ecosystems; less is known about the impact on the open ocean. Nr deposition may already rival biological N2 fixation quantitatively and will likely continue to rise. However, it is unclear how much of the Nr currently deposited to the ocean is external in origin. Understanding the importance of ocean Nr emissions versus external Nr deposition is key to quantifying the influence of deposition on ocean biogeochemistry and climate. This article reviews our understanding of the impacts of Nr deposition on the open ocean and the emissions of Nr from the ocean, placing particular emphasis on stable isotopes as a tool to investigate the surface ocean–lower atmosphere Nr cycle and its variations over time. The ocean has a dynamic exchange of reactive nitrogen with the atmosphere and is not just a passive recipient of nitrogen pollution from land. Tracing anthropogenic nitrogen deposition to the ocean is a challenge due to overlapping geochemical signatures with other nitrogen inputs. However, studies suggest an imprint of external (anthropogenic) nitrogen deposition in the Mediterranean Sea and North Pacific Ocean. Climate change will impact nitrogen emissions from the ocean through warming, acidification, stratification, and changes in food webs. [ABSTRACT FROM AUTHOR]

Food production is affected by climate change, and, in turn, food production is responsible for 20-30% of greenhouse gases. The food system must increase output as the population increases and must meet nutrition and health needs while simultaneously assisting in achieving the Sustainable Development Goals. Good nutrition is important for combatting infection, reducing child mortality, and controlling obesity and chronic disease throughout the life course. Dietary guidelines provide advice for a healthy diet, and the main principles are now well established and compatible with sustainable development. Climate change will have a significant effect on food supply; however, with political commitment and substantial investment, projected improvements will be sufficient to provide food for the healthy diets needed to achieve the Sustainable Development Goals. Some changes will need to be made to food production, nutrient content will need monitoring, and more equitable distribution is required to meet the dietary guidelines. Increased breastfeeding rates will improve infant and adult health while helping to reduce greenhouse gases. [ABSTRACT FROM AUTHOR]

Signals of local adaptation have been found in many plants and animals, highlighting the heterogeneity in the distribution of adaptive genetic variation throughout species ranges. In the coming decades, global climate change is expected to induce shifts in the selective pressures that shape this adaptive variation. These changes in selective pressures will likely result in varying degrees of local climate maladaptation and spatial reshuffling of the underlying distributions of adaptive alleles. There is a growing interest in using population genomic data to help predict future disruptions to locally adaptive gene-environment associations. One motivation behind such work is to better understand how the effects of changing climate on populations' short-term fitness could vary spatially across species ranges. Here we review the current use of genomic data to predict the disruption of local adaptation across current and future climates. After assessing goals and motivationsunderlying the approach, we review the main steps and associated statistical methods currently in use and explore our current understanding of the limits and future potential of using genomics to predict climate change (mal)adaptation. [ABSTRACT FROM AUTHOR]

Climate change decision-making has emerged in recent decades as an area of research and practice, expanding on an earlier focus on climate policy. Defined as the study of decisions relevant for climate change, it draws on developments in decision science, particularly advances in the study of cognitive and deliberative processes in individuals and organizations. The effects of climate, economic, social, and other framings on decision-making have been studied, often showing that nonclimate frames can be as effective as, or more effective than, climate frames in promoting decision-making and action. The concept of urgency, linked to the ideas of climate crisis and climate emergency, has taken on importance in recent years. Research on climate decision-making has influenced numerous areas of climate action, including nudges and other behavioral interventions, corporate social responsibility, and Indigenous decision-making. Areas of transformational change, such as strategic retreat in the face of sea-level rise, are emerging. [ABSTRACT FROM AUTHOR]

Cities are particularly vulnerable to extreme weather episodes, which are expected to increase with climate change. Cities also influence their own local climate, for example, through the relative warming known as the urban heat island (UHI) effect. This review discusses urban climate features (even in complex terrain) and processes. We then present state-of-the-art methodologies on the generalization of a common urban neighborhood classification for UHI studies, as well as recent developments in observation systems and crowdsourcing approaches. We discuss new modeling paradigms pertinent to climate impact studies, with a focus on building energetics and urban vegetation. In combination with regional climate modeling, new methods benefit the variety of climate scenarios and models to provide pertinent information at urban scale. Finally, this article presents how recent research in urban climatology contributes to the global agenda on cities and climate change. [ABSTRACT FROM AUTHOR]

Despite their heterogeneity, small island developing states (SIDS) are recognized as being particularly at risk to climate change, and, as they share numerous common traits, the United Nations recognizes them as a special group. SIDS have been quite vocal in calling attention to the challenges they face from climate change and advocating for greater international ambition to limit global warming. Here, we unpack factors that are helpful in understanding the relationship between climate change and SIDS through a review of studies that span disciplines and methodologies. We assess patterns of hazards, exposure, and vulnerability; impacts and risks; awareness and knowledge; adaptation planning and implementation; mitigation; loss and damage; and climate justice to provide an overarching review of literature on climate change and SIDS. [ABSTRACT FROM AUTHOR]