The Lancet Planetary Health, March 2025

Future-proofing cities against negative city mobility and public health impacts of impending natural hazards: a system dynamics modelling study

As the world emerges from the COVID-19 pandemic, it faces increasing risk of more frequent and larger scale natural hazards, including infectious disease outbreaks (IDOs) and climate change-related extreme weather events (EWEs), such as flooding, storms, heatwaves, and droughts, and combined events.

Data indicate that climate-related events, including EWEs, increased from 3656 in 1980–99 to 6681 in 2000–19. Between 2000 and 2019, the number of major floods globally doubled, from 1389 to 3254, and the number of storms leapt from 1457 to 2034. The Intergovernmental Panel on Climate Change’s 2023 report estimates that the frequency of EWEs will increase in the near term due to climate change. Some estimates also indicate that the yearly probability of extreme IDOs (ie, whose death rate is at least 0·001‰ of the global population per year) could increase up to three-fold in the coming decades. Climate change and the risk of IDOs are connected, as many emerging IDOs are facilitated by changes in environmental conditions; population growth; urban ecosystems; and global transport modes, patterns, and connectivity associated with climate change.