As climate change fuels more frequent and intense heatwaves, over 1.7 billion people globally are now at risk, according to the European Commission’s Joint Research Centre (JRC). The issue is particularly acute in cities, where rising temperatures, combined with dense infrastructure, create urban heat islands (UHIs) pockets of significantly higher heat that threaten public health, infrastructure, and productivity. In fact a study published in The Lancet by the EARLY-ADAPT project found that more than 4% of summer deaths in European cities are linked to UHIs.
To combat this growing crisis the EU-backed CityCLIM project is offering a promising way forward. Led by Stephan Holsten, head of the Earth Observation Missions and Applications department at OHB System in Germany, the project merges high-resolution data and real-time modelling to empower both citizens and city planners to respond more effectively to extreme urban heat.
CityCLIM rolled out pilot initiatives in Karlsruhe, Luxembourg, Thessaloniki, and Valencia tailoring services to each city’s specific needs. These efforts used a combination of data from professional sensor stations, citizen science networks like bike-mounted mobile sensors, and satellite-based Earth Observation tools. The project’s standout feature is its operational urban weather model, capable of providing 100-metre resolution forecasts. These forecasts factor in temperature, humidity, pollution, and vegetation cover to create a highly detailed urban heat map.
Tools for Citizens and City Planners
For residents, CityCLIM developed the Heat Island Identification Service, which helps vulnerable groups navigate extreme heat by predicting which city areas are likely to be hottest. This allows citizens to plan their movement or take necessary precautions.
City planners, on the other hand, now have access to the Heat Island Simulation and Mitigation Service. This tool allows them to test how various urban planning decisions like replacing green spaces with pavement will impact heat levels. It’s an evidence-based way to prioritise cooling interventions like tree planting or reflective surfaces.
Scalable, Transferable Climate Services
What makes CityCLIM stand out according to Holsten is the diversity and adaptability of the tools developed. The platform is cloud-based, scalable can easily be extended to address other climate hazards beyond urban heat. “Our solutions are not just theoretical,” Holsten says, “they’re practical tools aligned with what cities actually need and they can be applied in other cities around the world.”
As global temperatures continue to rise, scalable solutions like CityCLIM offer cities a vital chance to prepare for extreme heat while empowering residents and decision-makers alike with the knowledge to act before it’s too late.