Heat Hazard Map Supports Resilience Planning

Ordnance Survey and 4 Earth Intelligence (4EI) have created the UK’s first street-level map of areas potentially at risk from extreme weather conditions. The free-at-point-of-use Heat Hazard Postcode data is already being used to plan the provision of urban green spaces, assess vulnerable populations and inform climate change strategy. Early adopters of the data include the Greater London Authority (GLA), numerous local authorities and several central government departments.

Derived from satellite imagery and created using automated algorithms, the 4EI data identifies hot spots, usually within urban areas, where temperatures can be up to 3-4 degrees higher forming what is known as an Urban Heat Island (UHI). An UHI is a metropolitan area that is warmer than its vicinity. Heat created by energy from people, cars, transport and building’s heating, cooling and ventilation systems, interacts with construction materials to elevate temperatures.

“We recognize the danger extreme temperatures pose and the beneficial role space data can play. This is particularly pertinent as we continue to face COVID-19 - undoubtedly the most significant public health challenge in generations,” commented Kristina Guida, Manager at the London Climate Change Partnership, part of the GLA. “The 4EI heat hazard postcode data will help us ensure that we can understand where the hazard lies and will support the mitigation planning for reducing the impact on our most vulnerable populations”

Increased day time temperatures, reduced night time cooling, and higher air pollution levels associated with urban areas can significantly impact human health. It is estimated that the heatwaves of 2019 led to almost 900 additional deaths in England and, with potentially vulnerable households still maintaining self-isolation, it is possible the figures for this year could be higher.