The role of green roofs in climate change mitigation. A case study in Seville (Spain)

The intense anthropogenic urban activity generates a phenomenon known as heat island, which is related with high temperatures in cities, as compared against adjacent suburban and rural areas. Due to this effect, the comfort conditions of the citizens deteriorate. In the case of the city of Seville (Spain), several models of climate change forecast increases in the maximum temperatures ranging from 1.5 to 6 degrees C in summer. This article explores the role of green roofs as a supplement to the green spaces of the city, in order to buffer the negative effects of the increase of the maximum temperatures due to climate change. Images from the Landsat 7 ETM+ and Sentinel-2 satellites have been used in order to verify the inverse relationship between land surface temperature and the abundance of vegetation, expressed by the normalized difference vegetation index. For Seville, a green roof surface of 740 ha should be implemented, in the most adverse scenario, which means covering 40.6% of the existing buildings. In the most optimistic scenario, the forecasted green roof surface required is 207 ha (11.3% of the roofs). (C) 2017 Elsevier Ltd. All rights reserved.