An ecosystem service perspective on urban nature, physical activity, and health.

Nature underpins human well-being in critical ways, especially in health. Nature provides pollination of nutritious crops, purification of drinking water, protection from floods, and climate security, among other well-studied health benefits. A crucial, yet challenging, research frontier is clarifying how nature promotes physical activity for its many mental and physical health benefits, particularly in densely populated cities with scarce and dwindling access to nature. Here we frame this frontier by conceptually developing a spatial decision-support tool that shows where, how, and for whom urban nature promotes physical activity, to inform urban greening efforts and broader health assessments. We synthesize what is known, present a model framework, and detail the model steps and data needs that can yield generalizable spatial models and an effective tool for assessing the urban nature-physical activity relationship. Current knowledge supports an initial model that can distinguish broad trends and enrich urban planning, spatial policy, and public health decisions. New, iterative research and application will reveal the importance of different types of urban nature, the different subpopulations who will benefit from it, and nature's potential contribution to creating more equitable, green, livable cities with active inhabitants.

Solidarity for the Anthropocene.

Social solidarity is essential to large-scale collective action, but the need for solidarity has received little attention from scholars of Earth Systems, sustainability and public health. Now, the need for solidarity requires recognition. We have entered a new planetary epoch - the Anthropocene - in which human-induced global changes are occurring at an unprecedented scale. There are multiple health crises facing humanity - widening inequity, climate change, biodiversity loss, diminishing resources, persistent poverty, armed conflict, large-scale migration, and others. These global challenges are so far-reaching, and call for such extensive, large-scale action, that solidarity is a sine qua non for tackling these challenges. However, the heightened need for solidarity has received little attention in the context of the Anthropocene and, in particular, how it can be created and nurtured has been overlooked. In this commentary, we explore the concept of solidarity from inter-species, intra-generational and inter-generational perspectives. We also propose strategies to enhance solidarity in the Anthropocene.

Autonomous Vehicles and Public Health.

Autonomous vehicles (AVs) have the potential to shape urban life and significantly modify travel behaviors. "Autonomous technology" means technology that can drive a vehicle without active physical control or monitoring by a human operator. The first AV fleets are already in service in US cities. AVs offer a variety of automation, vehicle ownership, and vehicle use options. AVs could increase some health risks (such as air pollution, noise, and sedentarism); however, if proper regulated, AVs will likely reduce morbidity and mortality from motor vehicle crashes and may help reshape cities to promote healthy urban environments. Healthy models of AV use include fully electric vehicles in a system of ridesharing and ridesplitting. Public health will benefit if proper policies and regulatory frameworks are implemented before the complete introduction of AVs into the market.

Global Environmental Change and Noncommunicable Disease Risks.

Multiple global environmental changes (GECs) now under way, including climate change, biodiversity loss, freshwater depletion, tropical deforestation, overexploitation of fisheries, ocean acidification, and soil degradation, have substantial, but still imperfectly understood, implications for human health. Noncommunicable diseases (NCDs) make a major contribution to the global burden of disease. Many of the driving forces responsible for GEC also influence NCD risk through a range of mechanisms. This article provides an overview of pathways linking GEC and NCDs, focusing on five pathways: ( a) energy, air pollution, and climate change; ( b) urbanization; ( c) food, nutrition, and agriculture; ( d) the deposition of persistent chemicals in the environment; and ( e) biodiversity loss.

Nature and health.

Urbanization, resource exploitation, and lifestyle changes have diminished possibilities for human contact with nature in urbanized societies. Concern about the loss has helped motivate research on the health benefits of contact with nature. Reviewing that research here, we focus on nature as represented by aspects of the physical environment relevant to planning, design, and policy measures that serve broad segments of urbanized societies. We discuss difficulties in defining "nature" and reasons for the current expansion of the research field, and we assess available reviews. We then consider research on pathways between nature and health involving air quality, physical activity, social cohesion, and stress reduction. Finally, we discuss methodological issues and priorities for future research. The extant research does describe an array of benefits of contact with nature, and evidence regarding some benefits is strong; however, some findings indicate caution is needed in applying beliefs about those benefits, and substantial gaps in knowledge remain.

Climate change: challenges and opportunities for global health.

IMPORTANCE: Health is inextricably linked to climate change. It is important for clinicians to understand this relationship in order to discuss associated health risks with their patients and to inform public policy. OBJECTIVES: To provide new US-based temperature projections from downscaled climate modeling and to review recent studies on health risks related to climate change and the cobenefits of efforts to mitigate greenhouse gas emissions. DATA SOURCES, STUDY SELECTION, AND DATA SYNTHESIS: We searched PubMed and Google Scholar from 2009 to 2014 for articles related to climate change and health, focused on governmental reports, predictive models, and empirical epidemiological studies. Of the more than 250 abstracts reviewed, 56 articles were selected. In addition, we analyzed climate data averaged over 13 climate models and based future projections on downscaled probability distributions of the daily maximum temperature for 2046-2065. We also compared maximum daily 8-hour average ozone with air temperature data taken from the National Oceanic and Atmospheric Administration, National Climate Data Center. RESULTS: By 2050, many US cities may experience more frequent extreme heat days. For example, New York and Milwaukee may have 3 times their current average number of days hotter than 32°C (90°F). High temperatures are also strongly associated with ozone exceedance days, for example, in Chicago, Illinois. The adverse health aspects related to climate change may include heat-related disorders, such as heat stress and economic consequences of reduced work capacity; respiratory disorders, including those exacerbated by air pollution and aeroallergens, such as asthma; infectious diseases, including vectorborne diseases and waterborne diseases, such as childhood gastrointestinal diseases; food insecurity, including reduced crop yields and an increase in plant diseases; and mental health disorders, such as posttraumatic stress disorder and depression, that are associated with natural disasters. Substantial health and economic cobenefits could be associated with reductions in fossil fuel combustion. For example, greenhouse gas emission policies may yield net economic benefit, with health benefits from air quality improvements potentially offsetting the cost of US and international carbon policies. CONCLUSIONS AND RELEVANCE: Evidence over the past 20 years indicates that climate change can be associated with adverse health outcomes. Health care professionals have an important role in understanding and communicating the related potential health concerns and the cobenefits from policies to reduce greenhouse gas emissions.

Energy and human health.

Energy use is central to human society and provides many health benefits. But each source of energy entails some health risks. This article reviews the health impacts of each major source of energy, focusing on those with major implications for the burden of disease globally. The biggest health impacts accrue to the harvesting and burning of solid fuels, coal and biomass, mainly in the form of occupational health risks and household and general ambient air pollution. Lack of access to clean fuels and electricity in the world's poor households is a particularly serious risk for health. Although energy efficiency brings many benefits, it also entails some health risks, as do renewable energy systems, if not managed carefully. We do not review health impacts of climate change itself, which are due mostly to climate-altering pollutants from energy systems, but do discuss the potential for achieving near-term health cobenefits by reducing certain climate-related emissions.

Aging, climate change, and legacy thinking.

Climate change is a complex, long-term public health challenge. Older people are especially susceptible to certain climate change impacts, such as heat waves. We suggest that older people may be a resource for addressing climate change because of their concern for legacy--for leaving behind values, attitudes, and an intact world to their children and grandchildren. We review the theoretical basis for "legacy thinking" among older people. We offer suggestions for research on this phenomenon, and for action to strengthen the sense of legacy. At a time when older populations are growing, understanding and promoting legacy thinking may offer an important strategy for addressing climate change.

More green, less lonely? A longitudinal cohort study.

BACKGROUND: Urban greening may reduce loneliness by offering opportunities for solace, social reconnection and supporting processes such as stress relief. We (i) assessed associations between residential green space and cumulative incidence of, and relief from, loneliness over 4 years; and (ii) explored contingencies by age, sex, disability and cohabitation status. METHODS: Multilevel logistic regressions of change in loneliness status in 8049 city-dwellers between 2013 (baseline) and 2017 (follow-up) in the Household, Income and Labour Dynamics in Australia study. Associations with objectively measured discrete green-space buffers (e.g. parks) (<400, <800 and <1600 m) were adjusted for age, sex, disability, cohabitation status, children and socio-economic variables. Results were translated into absolute risk reductions in loneliness per 10% increase in urban greening. RESULTS: The absolute risk of loneliness rose from 15.9% to 16.9% over the 4 years; however, a 10% increase in urban greening within 1.6 km was associated with lower cumulative incident loneliness [odds ratio (OR) = 0.927, 95% confidence interval (CI) = 0.862 to 0.996; absolute risk reduction = 0.66%]. Stronger association was observed for people living alone (OR = 0.828, 95% CI = 0.725 to 0.944). In comparison to people with <10% green space, the ORs for cumulative incident loneliness were 0.833 (95% CI = 0.695 to 0.997), 0.790 (95% CI = 0.624 to 1.000) and 0.736 (95% CI = 0.549 to 0.986) for 10-20%, 20-30% and >30% green space, respectively. Compared with the <10% green-space reference group with 13.78% incident loneliness over 4 years and conservatively assuming no impact on incident loneliness, associations translated into absolute risk reductions of 1.70%, 2.26% and 2.72% within populations with 10-20%, 20-30% and >30% green space, respectively. These associations were stronger again for people living alone, with 10-20% (OR = 0.608, 95% CI = 0.448 to 0.826), 20-30% (OR = 0.649, 95% CI = 0.436 to 0.966) and >30% (OR = 0.480, 95% CI = 0.278 to 0.829) green space within 1600 m. No age, sex or disability-related contingencies, associations with green space within 400 or 800 m or relief from loneliness reported at baseline were observed. CONCLUSIONS: A lower cumulative incidence of loneliness was observed among people with more green space within 1600 m of home, especially for people living alone. Potential biopsychosocial mechanisms warrant investigation.