Urban Heat, Vulnerability, and Mitigation in U.S. Cities: A Systematic Review

Extreme heat is increasing globally under climate change, and its impacts are amplified in cities by the urban heat island effect, with disproportionate burdens in low-income, racially marginalized, and other socially vulnerable communities. This PRISMA-guided systematic review synthesizes 50 U.S.-based, peer-reviewed studies at the intersection of intra-urban heat exposure, social vulnerability, and mitigation. Studies were identified in Web of Science, screened using ASReview, and coded for heat metrics, socioeconomic indicators, spatial and temporal resolution, modeling approaches, and whether mitigation strategies were empirically evaluated. The evidence base relies heavily on satellite-derived land-surface temperature (66%) and census-tract aggregation (54%), while income indicators appear in over 90% of studies. Cross-scale aggregation was widespread, with 47 studies (94%) linking, overlaying, or translating data across spatial scales, often from fine-scale heat or land-cover data to census or administrative units. Temporal coverage was uneven: multi-year or interannual studies formed the largest group (40%), but nearly one-third relied on snapshot or event-specific windows. Most studies discuss mitigation without empirical testing (68%), and evaluated interventions are dominated by vegetation-based strategies, with far fewer studies testing roofs, pavements, shading, or multi-strategy portfolios. These patterns can underrepresent lived heat stress, introduce aggregation-related misclassification, and weaken translation to siting decisions. Additional gaps include inconsistent treatment of historic redlining, housing conditions, cooling access, energy burden, distributional outcomes, and displacement risks. The review synthesizes these patterns into eight recurring bias categories and outlines opportunities to improve measurement validity, align spatial units with intervention scales, expand climate and city coverage, and develop equity-aware decision platforms.