Fostering mental health and pro-environmental behaviour through nature exposure and nature connectedness – An umbrella review

The concepts of nature exposure, nature connectedness, mental health, and pro-environmental behaviour are theoretically linked. However, evidence across disciplines remains fragmented and inconclusive. Numerous reviews cover various aspects of the relationships between the four concepts. Yet a synthesis of these reviews is lacking. This umbrella review aims to consolidate review evidence to assess the association between nature exposure and nature connectedness, and their association with mental health outcomes and pro-environmental behaviour, as well as the association between mental health and pro-environmental behaviour. Drawing on 150 reviews across disciplines, we identified key processes through which direct interaction with natural environments supports psychological wellbeing and fosters sustainable behaviours. The results show consistent associations between nature exposure and improved mental health, including reduced stress, reduced symptoms of anxiety and depression, and better cognitive functioning. However, causal pathways remain ambiguous due to heterogeneous definitions of the analysed constructs and the predominance of cross-sectional study designs. Moreover, increased nature exposure is associated with higher levels of nature connectedness, which is positively associated with mental health and pro-environmental behaviour. Nature connectedness plays a key role in mediating pathways from nature exposure to wellbeing and from nature exposure to pro-environmental behaviour. Engagement in (outdoor) pro-environmental behaviour may also support mental health through restorative processes. However, conceptual inconsistencies, methodological limitations (e.g. reliance on cross-sectional study designs), and population biases (e.g. prevalence of Western, urban and student samples) restrict the generalisability of the findings. Future research should prioritise standardised measures, longitudinal and experimental designs across diverse populations. Our findings highlight the potential of nature-based activities and interventions for enhancing mental wellbeing and supporting environmental stewardship. Beyond synthesising the evidence, this review contributes theoretically by proposing an integrative framework that reconciles existing theories and highlights nature connectedness as a key mediating mechanism underpinning reciprocal relationships between wellbeing and sustainable behaviour.