Experts call for scale-up of climate and health intervention trials

Researchers from the London School of Hygiene & Tropical Medicine and Aga Khan University argue in a comment piece published in Nature Medicine, that rapid and ambitious adaptation and mitigation actions are urgently needed to address the growing impacts of climate change on health. 

Evidence from the Pathfinder Initiative shows that the majority of existing evidence on the health outcomes of climate mitigation actions is modelled evidence. While the Pathfinder Initiative Climate and Health Evidence Bank highlights case studies of evaluated implemented actions, further real-world examples are needed to improve understanding of what works in which contexts. 

The comment is part of broader efforts by the Pathfinder Initiative and partners to support the implementation and develop guidance for the evaluation of complex climate and health interventions. 

The experts note that while randomised trials provide the gold standard for testing new drugs and treatments, trials are underused in the assessment of climate and health interventions. 

The researchers state: “Important lessons can also be learnt from advances in the design, interpretation and governance of clinical trials for the evaluation of climate and health interventions”, adding that trial registries should be expanded to include climate and health interventions.

The authors highlight the importance of integrating adaptation and mitigation actions, and for evaluations to consider the implications for both adaptation and mitigation. For example, widespread use of air conditioning as an adaptation strategy to rising temperatures can increase energy demand if powered by fossil fuels, as well as contributing to the heat island effect, where urban areas experience significantly higher temperatures than their surrounding areas.

The researchers also highlight the potential for evaluations to bring economic benefits of climate action to the fore. They say: “Many current arguments against net-zero policies focus on the need to cut costs, but the economic costs of inaction, including those that arise from the effects of climate change on human health, are often poorly accounted for in policy decisions. Well-designed studies can bring the economic benefits of climate action including reduced health costs, into focus.”

The authors say that large scale interventions across sectors are required such as carbon pricing, withdrawal of fossil fuel subsidies, and policies to promote active travel and public transport. They also note trade-offs of poorly planned interventions that can increase inequity, for example if energy price increases due to investments in renewables affect consumers rather than being addressed by taxing fossil fuel profits. 

The authors call for a global initiative involving researchers, funders, development banks, the WHO and other United Nations agencies, to support the scaling up of intervention research and advance the climate and health agenda. 

Read the full comment in Nature Medicine.