Page - 41 - in Biodiversity and Health in the Face of Climate Change

41 sity will curtail the potential for future responses is unclear. Protecting ecosystems and associated biodiversity through a ‘maintenance of options’ insurance function is important for this reason alone (Díaz et  al. 2018). It is also important for helping to address inequalities and for promoting social and environmental justice (Kabisch Chap. 5, this volume), given that in developing countries there is an even stronger reliance on ecosystems for health and well-being than in the developed world (Roy et  al. 2018). Ironically, despite developing countries containing most of the world’s untapped genetic diversity, developing countries are also where pressures such as urbanisation, demographics and population need, are greatest. Uncertainties remain about some of the evidence for the links between biodiver- sity, human physical health and climate change. However, we know enough about the human health-biodiversity-climate change relationship to argue strongly to pro- tect biodiversity and mitigate against climate change. Conceptual and theoretical work, empirical evidence and process modelling are all contributing to an improv- ing evidence base, with increasing emphasis on integrative methods (Calvin and Bond-Lamberty 2018). Nevertheless, the complexities of environmental, social and governance factors mean that there is some way to go for a more complete under- standing. Underpinning evidence will need to consider a range of settings and scales, including spatio-temporal dynamics in different climate zones and biomes as well as in the distinct urban habitat that now defines the majority of people’s lives. We will also need to further develop our understanding of links between mental and physical health, connections between different body organ systems and the environ- mental determinants of health/ill-health from the perspective of biodiversity and the natural environment (see de Vries and Snep Chap. 8; Marselle et  al. Chap. 9; Cook et  al.  Chap. 11, all  this volume). Studies of the life course also have something to offer here, including environment-focused population cohort studies (see Dadvand et  al. Chap. 6, this volume). Our review reveals that there is still a need for extensive further research into rela- tionships between biodiversity, climate change and human physical health. We still know little about trade-offs and the balance between benefits and harms. Such research is multi-layered and inherently multi-disciplinary. Complexities are com- pounded due to differing perspectives on issues, for example with some researchers using health as a primary starting point and other researchers starting from the per- spective of environmental or ecological processes. The different perspectives are important for developing fuller understandings, but still make the challenges of inte- grated research all the more demanding, especially at the science-practice interface. Ultimately, the most pressing questions also include some recognition of the need for action in the light of climate change projections, biodiversity losses and public health demands (De Young Chap. 13, this volume). It will be important to understand and resolve the web of connecting pathways between biological and functional diversity, and human health and well-being (Box 2.1) to identify the main protective roles and ensure that they are retained and enhanced in a range of ecosys- tems. Given urban growth and economic imperatives, it will be necessary to explore what sort of configurations can be promoted for multiple beneficial ecosystem func- tioning in different geographical, temporal and social settings. It will also be impor- tant to understand how climate change and related stresses will modify functions 2 Biodiversity, Physical Health and  Climate Change: A  Synthesis of  Recent Evidence