Seite - 364 - in Biodiversity and Health in the Face of Climate Change

364 Highlights • Protected natural areas in, and adjacent to, cities provide ecosystem benefits and services that support human health and climate change adaptation. • Urban green spaces provide billions of dollars in cost savings for health services. • Partnerships between conservationists, city planners and health authorities are critical for the continued protection of protected nature areas in and around cities. 16.1 Introduction Biodiversity and healthy natural ecosystems underpin and sustain human liveli- hoods and well-being by providing essential services such as food, clean air  and  water, and protection against floods, coastal storms and other natural disas- ters (Dudley et  al. 2010). These functions will become ever more important in help- ing people to cope with, and adapt to, climate change and its impacts. Water scarcity, food security and biodiversity loss will be some of the greatest global challenges over the next few decades; all will be exacerbated by climate change and have con- sequences for human health and well-being. In Africa alone some 75 mil- lion–250  million people are expected to be experiencing water shortages by 2020, with a 50% reduction in yields from rain-fed agriculture, leading to more food shortages, poverty, insecurity and migration (World Bank 2010). In Asia, climate change is projected to lead to decreased freshwater availability and the increased prevalence of water-borne diseases, whereas coastal areas, especially the densely populated delta regions, will be exposed to a greater risk of flooding. These climate- induced changes will have a cost in terms of human health, with more endemic morbidity and mortality due to the rise of diarrhoea and other water-borne diseases and the spread of certain disease vectors (World Bank 2010; Müller et  al. Chap. 4, this volume). Land degradation and the continued erosion of the natural capital that underpins functioning ecosystems  – including soil, water and biodiversity  – are an increasing threat to human health and sustainable livelihoods. The World Health Organisation (WHO) suggests that up to a quarter of all deaths globally could be avoided simply by improved management of environmental issues such as air pollution, water con- tamination and dust from degraded drylands (WHO 2005). Over half of the world’s population now lives in cities, and it is predicted that nearly 70% of people will be living in urban environments by 2050 (United Nations 2014). In the coming decades, 95% of urban expansion is expected to occur in the developing world, including in some of the countries most likely to be impacted by climate change and more erratic weather patterns (United Nations 2014). Cities are not urban ‘islands’; they depend on surrounding natural landscapes and seascapes, including protected areas, to provide critical ecosystem services, such as food, clean K. MacKinnon et al.