Institut de Biologie de l'École Normale Supérieure ENS . CNRS UMR8197 . Inserm U1024 Directeur : Pierre Paoletti

Abstract

Moving towards net-zero emission societies is projected to provide human health co-benefits. However, the magnitude of these co-benefits is poorly documented and might be context specific. Synthesising the evidence on these co-benefits could enhance the engagement of decision makers and populations in climate mitigation actions. We performed database searches of PubMed, Web of Science, and Scopus for studies published between database inception and Jan 1, 2024, identifying 3976 papers. Of these, 58 quantitative studies met our inclusion criteria and were included in this systematic review. These 58 papers explored 125 net-zero emission scenarios and considered various pathways by which climate policies can affect human health. Pathways addressing air quality, physical activity, and dietary changes found substantial health co-benefits, with a median mortality reduction of 1·5%. National or sub-national studies showed that net-zero policies would yield substantial local air quality benefits, independently of the actions taken in neighbouring countries. However, these co-benefits varied with explored emission sector, decarbonisation levers, modelling approach, and location. Studies that included a cost-benefit analysis estimated that monetised benefits outweighed the costs of implementing climate policies. This systematic review highlights the need for a standardised framework to assess and compare health impacts of climate mitigation actions across sectors and confirms that achieving net-zero goals supports far-reaching public health policies.

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Figure 4 sub-title
Sankey diagram showing linkage between type of net-zero scenario, emission sector, co-benefit pathway, and health outcome.
Net-zero scenarios can have links to several emissions sectors, co-benefit pathways, and health outcomes. Air pollution captures ambient air pollution only. lndoor air quality refers to the global quality of the indoor air environment. AFOLU=agriculture, forestry, and other land use. DALYs=disability-adjusted life-years. Several studies focused only on one sector could assess multiple types of scenarios ; similarly, several studiesonly assessing one health pathway could rely on a multisectorial emission model.