Over recent years there has been a growing body of evidence and consensus that global climate change is occurring, with warming in New Zealand likely to be comparable to the projected global mean (1.1 to 6.4°C) by the end of the 21st century. Although the impacts and consequences of climate change are likely to be many and complex, there is evidence that climate change is already affecting human health and well-being through a myriad of environmental consequences. There is a need for authorities to be able to assess, anticipate, and monitor human health vulnerability to climate variability and change to plan for, or implement action to avoid, these eventualities. Due to the multidisciplinary nature of studying the impacts of climate change on health, the complexity of many interacting factors, and the numerous uncertainties involved, there are significant research gaps in this field at present.
Therefore, the purpose of this research was to explore the complex relationships between climate change and human health in the New Zealand context, in a structured way by developing environmental health indicators as a tool that could be used to assess and monitor the impacts of climate change on human health. A tool such as this applied to climate change does not currently exist for New Zealand.
The research aim was to develop the tool using a process of critical evaluation to select 1) an existing framework, 2) two environmentally-related (sentinel) infectious diseases, 3) the appropriate environmental health indicators that could be used to support the assessment and monitoring of the impacts of climate change (cause) on the sentinel diseases (health effect) in New Zealand. Once selected the environmental health indicators were developed, and 4) the potential utility of environmental health indicators as a tool were discussed.
As a result of the critical evaluation processes the tool was developed by selecting 1) the Driving force-Pressure-State-Exposure-Effect-Action framework from 11 frameworks 2) salmonellosis and cryptosporidiosis as the two environmentally-related (sentinel) infectious diseases, 3) 18 environmental health indicators (14 for salmonellosis; 13 for cryptosporidiosis) from over 50 possible environmental health indicators. These 18 environmental health indicators were developed covering the components of the Driving force-Pressure-State-Exposure-Effect-Action framework to describe the environmental health causal chain/network for the sentinel diseases to assess and monitor the impacts of climate change on health. Finally, 4) the tools development process provided sound results and thus evidence that as a construct environmental health indicators could be used to assess and monitor the impacts of climate change on human health for New Zealand provided quality data can be accessed.
The resulting environmental health indicators can be used as a tool to enhance our knowledge when assessing human health vulnerability, aid in the design and targeting of interventions, and measure the effectiveness of climate change adaptation and mitigation activities on human health. It can also provide baseline information for assessing and monitoring temporal and spatial variability of risks, enabling projection scenarios of how the current situation may evolve. A tool such as this derived from environmental health indicators will provide a comprehensive picture of important environmental health issues related to climate change that are of concern now and will continue to be so in the future. An environmental health indicator tool such as this applied to climate change is the first of such an approach for New Zealand. The tool has the potential to be expanded to include other diseases and to be applied in other countries.