Page - 18 - in Biodiversity and Health in the Face of Climate Change

18 Highlights • Biodiversity, health and climate change have multi-scale and interdependent links. • Few studies explicitly connect climate change with biodiversity and physical health. • The full extent of human health impacts from biodiversity losses is unclear. • Action is needed due to climate projections, biodiversity losses and health demands. • New research agendas demand ambitious, multi-disciplinary and cross-sector approaches. 2.1 Introduction Few would now dispute that important links exist between the natural environment and human physical health. Nevertheless, despite considerable progress in concep- tualising and understanding relationships, there is still much to learn about particu- lar connections, their underlying mechanisms, causality and inter-relationships (Sandifer et  al. 2015; Ziter 2016; Cameron and Blanusa 2016). Biodiversity is considered one of the underlying requirements for beneficial functioning of ecosystems for human health and well-being and is enshrined as such within policy-focused arenas (Lovell et  al. 2014; Sandifer et  al. 2015). However, the many interpretations of the term biodiversity, the ways in which it is measured and its inter-relationships with other factors, including climate, present considerable challenges for building and testing hypotheses (Schmeller et  al. 2018). Where hypotheses relate to impacts on human health, there are still more elements to con- sider, including an appreciation of direct and indirect pathways, relevant controls and the interdependencies between psychological and physiological processes. Climate change is known to be modifying the natural environment and how it functions in relation to human health (Bonebrake et  al. 2018). For example, climate affects ecological states and processes. As climate changes, it affects the function- ing of ecosystems in terms of the quantity and quality of functions with a beneficial role for human physical health. Climate change is also affecting the relative balance of benefits and disbenefits. Furthermore, it has been implicated as one of the mecha- nisms driving global biodiversity loss, though in fact it is just one of a suite of fac- tors that remove and degrade associated ecosystems. Data from 63 protected areas in Germany collected over 29  years has shown a three-quarters reduction in the biomass of flying insects, a much higher loss than previously supposed (Hallmann et  al. 2017). However, analysis of climate variables suggested no strong climate signal to explain the decline. While not all climate-related factors could be dis- counted, other large-scale factors were also thought to be contributing, in this case agricultural intensification. Similarly, although climate change leads to health impacts, such as through climate extremes like high temperatures and climate- related S. J. Lindley et al.