Les Jardins de Gally presented the Interreg NWE Groof project at the Salon des Maires et Collectivités Locales in Paris from 19 to 21 November.

The world is facing major climate challenges, with + 7.5 ° C forecast by 2100. City areas will be the first affected, with + 9 ° C to + 15 ° C in built-up areas. Temperatures of 50 ° C will be reached regularly in Paris in 2050!

Faced with this alarming finding, there is good news! In the Paris region, the APUR agency found temperatures - 4 ° C to -8 ° C lower in green spaces (urban parks) than in highly built spaces in the urban center. The plant is a true natural air conditioner. The plant catalyzes the evaporation of water, and consumes some of the solar energy. This consumed energy is no longer available to heat the air and surrounding surfaces. Every day, the plants transpire between 1 and 5 times their weight in water. In fact, this means that a forest of 1 ha has the same air-conditioning power as 1,000 domestic air-conditioning systems.

This is an argument in favor of green roofs, but what about greenhouses on roofs? The construction of greenhouses on the roof can be seen as an artificialization of urban surfaces, which contributes to the heat island effect. But the Groof approach is different! By connecting the greenhouse to the energy and fluid metabolism of the building, the losses and energy consumption of the building are reduced. Greenhouse and roof production is becoming more resilient: it does not require dedicated heating equipment, values the building's CO2 and avoids the artificialisation of soils for peri-urban greenhouse production.

The mayors and the territorial managers were sensitive to these arguments and wish to deepen these subjects, for a coherent agricultural, food, economic and ecological development on the territories!

Sources : CNRS, CEA et Météo France, septembre 2019 /  GIEC /  Jean Jouzel, 2018 /