Urban Heat Island (UHI) is an important urban climate phenomenon in which cities experience higher temperatures than surrounding rural areas. Rapid urbanisation, land use change, loss of vegetation, and increasing energy consumption have intensified UHI effects over the last two and a half decades. This review analyses the global research trend on UHI and its combined impacts on the environment and human health from 2000 to 2025. A systematic bibliometric approach was followed using the Scopus database, and 667 research articles were analysed with R Studio and the Biblioshiny package. The results indicate a substantial increase in global UHI-related publications, particularly after 2015, with more than 60% of the total publications produced during 2015–2025. China contributed the highest number of publications, followed by the United States and several European countries, reflecting a strong geographical concentration of research output. Bibliometric analysis identified “land surface temperature”, “climate change”, “heat stress”, “air pollution”, and “mortality” as the most frequently occurring research keywords. The reviewed studies revealed that UHI intensity in major metropolitan regions commonly ranges between 1 and 7 °C compared to surrounding rural areas, depending on urban density and land-cover characteristics. Environmental impacts associated with UHI include increased cooling energy demand, deterioration of air quality, altered precipitation patterns, and ecosystem disturbance. Human health impacts include increased heat stress, cardiovascular and respiratory diseases, mental stress, and elevated mortality during extreme heat events, particularly among elderly populations, low-income communities, and other socially vulnerable groups. The study highlights the need for integrated urban planning, green infrastructure development, climate-responsive building design, and targeted public health policies. Strengthening interdisciplinary research and improving data integration between environmental and health sectors are essential for building climate-resilient and sustainable cities.
Bera et al. (Tue,) studied this question.