Seite - 370 - in Biodiversity and Health in the Face of Climate Change

370 space has clear benefits for physical health, while nature can reduce feelings of anger, sadness and anxiety (Hartig et  al. 2014). A growing body of evidence is also demonstrating that the sense of connected- ness with nature that results from positive nature-based experiences, whether in a city, a national park, or another natural ecosystem, leads to the development of posi- tive attitudes and behaviours towards nature and its protection (Wright and Matthews 2014; Teisl and O’Brien 2003). Policies and programmes that create opportunities for greater access to nature thus have the added benefit of building public support for biodiversity conservation and political will for the protection of intact natural ecosystems that underpin human health and well-being (for more information, see Davies et  al. Chap. 12, this volume). 16.3 Nature and  Health in  an  Urban Setting Many of the benefits that derive from protected areas in the broader landscape also apply to natural spaces in urban settings. Urbanisation both intensifies biodiversity loss and presents its own unique health and lifestyle challenges and opportunities. Cities are dependent on surrounding natural landscapes and protected areas to pro- vide critical ecosystem services, but parks, waterways and river corridors can pro- vide links and ‘stepping stones’ from cities to the broader landscape. Maintaining natural habitats and green and blue spaces within cities can also provide ecosystem services that are important for climate change adaptation. Urban parks, green spaces and wetlands absorb rainwater and stormwater run-off and alleviate air pollution. The roles and benefits of natural ecosystems as green infrastructure will become more important with climate change (Beatley 2014). Tree cover in urban settings has been shown to reduce rainwater run-off and reduce flood risk. A study of street trees in Manchester, UK, found that surface runoff was up to 62% lower in asphalt plots with a tree planted in the middle compared to asphalt plots with no trees. Grass plots almost completely prevented surface runoff, and therefore reduced flood risk (Armson et  al. 2013; Lindley et  al. Chap. 2, this volume). Similarly, urban green spaces can help reduce air pollution. More than three million people globally die each year from outdoor  air pollution (WHO 2016). A study by the University of Exeter’s medical school into the impact of urban green- ery on asthma suggests that respiratory health can be improved by the expansion of tree cover in very polluted urban neighbourhoods (Alcock et  al. 2017). In the UK, over 5.4  million people receive treatment for asthma, with an annual cost to the National Health Service of around £1  billion; asthma is estimated to lead to over 1,000 deaths a year. The findings of these studies provide strong evidence for pro- moting the role of trees in urban planning and public health policy. Increasing urbanisation and changing lifestyles have resulted in more people spending less time in nature, doing less physical activity, and experiencing greater stress, and negative health outcomes such as greater obesity and physical and men- K. MacKinnon et al.