Over the last decade, heat waves have claimed an increasing number of casualties among the elderly - particularly in southern Europe. Prolonged periods of high temperatures also put a strain on medical resources and place an additional financial cost to society as a whole. High densely built-up areas trap the heat, especially at night, causing what is called Urban Heat Islands (UHI) in which city centers can be up to 10° C warmer than surrounding rural areas. Another consequence of UHIs is that energy consumption rises with the increased use of air conditioners and refrigeration appliance.

ESA has recently launched a set of activities to aid decision and policy makers in mitigating the effects of UHIs through appropriate alert systems and, in terms of reducing risk, through improved urban planning. Within this framework, ESA is funding the Urban Heat Island and Urban Thermography (UHI) project under the DUE - Data User Element - program.

The project started on 1st November 2008 and closed on September 2011. The project analyzed the UHI trends over 10 European cities (Athens, Bari, Brussels, Budapest, Lisbon, London, Madrid, Paris, Seville, Thessaloniki) over the last 10 years, using a multi-sensor approach.

The UHI consortium is composed by 6 organizations from Italy (Planetek Italia, Coordinator), Belgium (VITO - Flemish Institute for Technological Research, EUROSENSE), Greece (NOA-ISARS - National Observatory of Athens - Institute for Space Applications and Remote Sensing with LAP-AUTH - Laboratory of Atmospheric Physics - Aristotle University of Thessaloniki,), Portugal (Edisoft) and Spain (INDRA Spacio).