Urban heat vulnerability in Great Britain and the US

Research conducted by the Ordnance Survey, the Met Office, and 4 Earth Intelligence has identified significant extreme heat vulnerabilities within Great Britain. The study, which analyzed 71 cities across England, Scotland, and Wales, identified Portsmouth as the most vulnerable city both currently and in the future. Other cities projected to face severe impacts by the end of the century include the City of Westminster, Plymouth, Leicester, and Exeter.

The research highlights that urban areas can become up to 10C hotter than rural regions due to the urban heat island effect. Projections indicate that by 2040, all 71 analyzed cities will reach a high level of heat vulnerability, and by 2100, nearly two-thirds could reach the most severe level, particularly in areas lacking tree cover, green spaces, and waterways.

Broader climate analyses show escalating heat risks in both the United Kingdom and the United States. In the UK, 83 per cent of British cities are currently classified as “highly vulnerable” to urban heat. Concurrently, several US cities have experienced record-breaking numbers of triple-digit temperature days in 2026, with Dallas, Texas, recording 52 days above 100 degrees Fahrenheit. These extreme heat events are attributed to climate change, heat domes, and a strengthening super El Niño pattern.