Measuring the Natural Environment - Wellbeing in non-'green' Climates.

Mental health conditions are a growing public health concern, by 2030 it is projected that mental health conditions will be the leading cause of mortality and morbidity globally (WHO, 2011). The biophilia hypothesis proposes that humans have evolved alongside nature to have an affinity for natural environments, this hypothesis has led to the Attention Restoration Theory (ART) and the Stress Reduction Theory (SRT) which indicate different mechanisms by which human health might be affected by time spent in nature. Additionally, there are multiple ways in which nature can impact health, such as reduced exposure to pollutants, increasing social connections, and providing opportunities for physical exercise. Current research indicates a strong association between positive mental health and aspects of the natural environment such as the broadly defined 'greenspace'. More recently the research has turned to focussing on naturalness and connection to nature over 'greenspace', finding associations between nature exposure and cognitive function, brain activity, blood pressure, mental health, physical activity, and sleep. However, much of the current research is limited to Eurocentric urban/suburban greenspace studies in climates where open space is habited by vegetation (Astell-Burt, Mitchell & Hartig., 2014, Van den Burg et al., 2016, Xu et al., 2019).

The limitations of current studies create challenges when applying the research globally, the aim of this project is to develop a more inclusive measure of the natural environment and investigate its impact on wellbeing. For this project secondary data from the Australian study "45 and Up" will be used. 45 and up is a longitudinal study that began in 2005 and follows over 250,000 individuals in urban, rural and remote areas in order to develop an understanding of ageing and other factors that may impact good health and wellbeing. The study has collected geospatial data and information regarding physical activities (type and duration) and health (physical and mental health), as well as data on how long participants spend outdoors daily and whether the individuals engage in regular walking sessions outdoors.

The three objectives of this project are to: 1) Develop a more inclusive measure of the natural environment including diverse data (such as topography, distance to blue space, surface cover, population density, vegetation cover) that considers geographical variation in different countries and regions. 2) Investigate how predictive this measure is of wellbeing in a geographically diverse sample using the Australian Study "45 and Up". 3) Investigate the role of behavioural mediators (e.g., levels of physical activity) and their potential mediator effects on the relationship between the natural environment and wellbeing.

Implementing green space initiatives for improving mental health, such as the NHS Forest project, are proving to be successful in areas where the climate supports growth of green shrubs and evergreen trees, however projects such as these will not be sustainable if implemented in hot dry climates. Therefore, this project aims to identify potential alternative characteristics of the environment that can mediate the relationship between nature and wellbeing, particularly in climates where open space is not habited by vegetation.