The city of Basel in Switzerland has implemented an incentive program to promote green roofs as both a mitigation measure to save energy and hence reduce emissions, and an adaptation measure, lowering indoor temperatures and absorbing rainwater, thus reducing flood risk. There are also biodiversity and social aesthetic benefits. Climate projections suggest that by the 2050s, the temperature in the Basel region could increase by 2 C in winter and 2.5 C in summer. Extreme rainfall events are also likely to increase in frequency and severity. Why city of Basel implemented green roof project? What is the impact of the global warming in the societies?