Today, 25 finalists for the C40 Cities Bloomberg Philanthropies Awards 2017 were announced. The fifth-annual C40 Cities Awards, will celebrate the best projects across five categories. ‘The Rotterdam Roofscape’ project was nominated in the category Cities4Tomorrow and will compete against projects from Washington D.C. (US), San Francisco (US), Wuhan (China) and Hong Kong (China). The projects represent the most ambitious and innovative projects by mayors of the world’s great cities to tackle climate change. Each category of the C40 Cities Bloomberg Philanthropies Awards 2017 will have a winner from an American city and a city from the rest of the world.

“In 2015 I had the honor to receive a C40 Award for the Rotterdam Adaptation Strategy (RAS) at COP21 in Paris,” says Mayor Ahmed Aboutaleb. “Its large scale and holistic approach makes The Rotterdam Roofscape an unique project which will contribute to the resilience and sustainability of Rotterdam. There are so many unused rooftops in the world. This project will generate new knowledge and insights that we will share with other world cities so we can learn from each other.”

‘The Rotterdam Roofscape’ programme has developed schematics for four different classifications of multifunctional roofs. ‘Blue roofs’ emphasize water retention, ‘green roofs’ cultivate biodiversity, ‘yellow roofs’ provide clean energy production, and ‘red roofs’ work towards social cohesion. By installing a mix of roof types, the City has been able to approach climate action with a holistic mindset. This means several problems can be tackled at ones. The plan is clear and specific and has an itemised list of 40 specific steps falling into 7 action lines –– which break down into goals of informing, inspiring, stimulating, developing policy, connecting, and innovating.

In total, the project aspires to build 1 million m2 of multifunctional roofs by 2030, creating a second layer in the city. In 2017 and 2018, the initiative hopes to install 10,000 m2 of yellow roofscapes and 80,000 m2 of green roofscapes, retaining up to 2,000 m3 of water. Water retention reduces water treatment costs and alleviates the burden of runoff from the sewage system in the city centre, reducing the local flood risk. The project has already built 250,000 m2 of green roofscapes.

“Congratulations to every city that has been selected as a finalist of the C40 Cities Bloomberg Philanthropies Awards 2017,” said Mayor of Paris and Chair of C40, Anne Hidalgo. “The urgency of the climate crisis facing the world means that we need to be constantly recognising the best ideas in how cities can tackle climate change. Every one of these projects deserves to be closely studied by mayors and city leaders around the world. I wish each city the very best of luck.”