Extreme heat in the United States: vulnerabilities, health impacts, and the policy gaps that sustain a national crisis

Extreme heat is the leading cause of weather-related mortality in the United States, though it remains structurally under-recognised in disaster governance. The review synthesises multidisciplinary scholarship on extreme heat impacts, vulnerability, and policy response to assess what is currently known, to connect these findings to existing U.S. policy, and to identify research gaps that must be addressed to inform effective policy intervention. While substantial research has been conducted across disciplines, existing studies remain siloed, limiting the development of integrated strategies for what is increasingly a public health emergency. This fragmentation has obscured key dimensions of compounding vulnerability and constrained policy innovation. The review identifies four critical gaps in the literature: (1) how individuals perceive and understand extreme heat, (2) how they manage and cope with its effects, (3) how adaptation is shaped by socio-political constraints, and (4) how governments can design responsive, equity-centred policies for vulnerable populations. The review argues that reducing the impacts of extreme heat requires reframing it as a federally recognised disaster and embedding interdisciplinary insights into coherent, long-term governance. Future research must bridge disciplinary divides and elevate community knowledge to develop interventions that reflect the lived realities of those most affected. As climate risks intensify, an integrated approach is essential to confront preventable risks.