The impact of humans on the degradation of biodiversity is no longer in doubt. “75% of the earth’s surface is significantly altered by human activity. More than 85% of wetlands have disappeared. A million species are threatened with destruction. On a global scale, local varieties and breeds of domesticated plants and animals are disappearing”, warns the latest 2019 report from IPBES, the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services.

What we owe to biodiversity can be summed up in three words, according to the Millennium Ecosystem Assessment commissioned by the UN in 2000: climate (its regulation, CO2 storage, the fixation of atmospheric particles, the infiltration of water into the soil and its filtration, the regulation of diseases), supply (of materials, food, clothing), culture (entertainment, the pleasure of beauty, social ties). In particular, the more biodiversity decreases, the greater the risk of a pandemic: a study by University College London, published on 5th August 2020 in the journal Nature, reveals that the fewer species there are, the less likely it is that transmission of the virus will be blocked.

The term biodiversity “is often assimilated with all living species,” declared Gilles Bœuf in December 2013, during his inaugural lecture at the Collège de France. “But it can in no way be assimilated with mere inventories or catalogues of species.” It is “the totality of all relationships established between living beings, among themselves and with their environment”.

It would be irresponsible to build a city without fostering these relationships, in order to respond to the environmental and ecological emergency, especially since social demand and political orders are moving in this direction. The question of how remains. How can living spaces be better managed for humans and animal and plant species? What type of cohabitation, what interactions should be brought about to avoid reducing nature to a technical solution for repairing human damage? How can we make the city a sustainable ecosystem in which new uses can emerge? All those involved in urban planning will have to meet these expectations, together with the inhabitants.

For its part, the French government will provide “more than 20 billion euros” so that “by the end of 2021, all territories will have ecological development contracts”, including “concrete action plans” [such as development of cycle paths and the fight against soil artificialisation, included in the national biodiversity plan in July 2018], the Prime Minister said in mid-July 2020.
Environmental activist Rob Hopkins, the initiator of the international Cities in Transition movement, has no doubt about it: “we are going to experience the most remarkable ten years of ecological transformation in history,” he announced in Le Monde of 22nd August 2020.
