1. Green roofs: a green deposit or a real contribution to nature in the city

1.1 Combating land artificialisation: a priority

More than three-quarters of Europeans now live in cities. In France, land artificialisation has been steadily increasing over recent decades, at a rate of between 16,000 and 60,000 hectares per year. . Artificialization is one of the factors driving the decline in biodiversity. It also contributes to climate change. In response, the French government and local authorities are looking at ways to reduce the pressure of urban development on natural, agricultural and forestry areas, notably through the zero net artificialization (ZAN) objective.