Urban heat: a priority issue and a health challenge in the Mediterranean

Heat is becoming a priority and a health issue in Mediterranean cities. By 2050, it is estimated that heatwaves will have doubled, while by 2100, the rise in temperature in France could reach +4°C. This is known as ‘survival’ urban planning.

Urban heat, a complex, cross-disciplinary issue

The issue of urban heat lies at the intersection of several scales, projects, professions and systems of players, all of which are equally complex. To translate data into concrete action, a proactive and demonstrative policy is needed. In Cuers, in the French department of Var, a pilot town in the implementation of a ‘low-temperature town’, a number of initiatives have been put in place: shading by sails in the main shopping street, light-coloured asphalt for the pavements, debudding of the feet of trees, and planting of more than 70 trees. By the summer of 2024, the results will be: -35°C lower ground temperature under the shades than in full sun, -15°C for the light-coloured asphalt, a cooler feeling in the city, and recognition of the landscape quality of its plant heritage. To support French local authorities, ADEME has developed a decision-making tool called “Plus fraîche ma ville” (‘Cooler my city’). This highly intuitive tool can be used to quickly calculate the costs and benefits of implementing an initiative.

Visite guidée de Cuers par les autorités locales

Individuals at the heart of the system

The issue of urban heat is a question of the overall health of the population. So, according to researcher Franck Taillandier from the INRAE institute, it is a question of creating communities to respond to the question of uses and confronting imaginations: what do local people want? What are their needs? Their fears?

This expert refers to the results of their socio-economic analysis demonstrating the inequalities associated with heat. In the same way as access to green spaces, there is a socio-economic difference between the highest and lowest incomes and access to cooling facilities. Here, heat appears to be a social issue.

Issues of warmth relate to the general perceptions of users of public spaces. Work in environmental psychology provides information on the many criteria that also contribute to well-being: safety, noise, etc.

Pilot projects for adapting to climate change

School grounds are considered to be exemplary projects. Acting as micro-societies, school playgrounds can sometimes be a source of conflict. By taking into account the needs of children and the fears of parents and teachers (particularly with regard to the use of wood shavings and possible accidents), school grounds can once again become places for cooperation and play and show what is possible in a fairer society. In 2024, the CAUE supported 15 schoolyard desilting projects, and the département is interested in rolling out this ambition to all 71 secondary schools in the Var. The Cool Noons project, led by AVITeM, aims to improve thermal comfort in our towns and cities during the hottest hours of the day. To achieve this, 9 partners are working for 33 months to fine-tune our urban spaces and practices to promote coolness. This pilot project is taking place in five Mediterranean cities: Marseille, Lisbon, Imola, Budva and Dubrovnik, all of which are tourist destinations and have to cope with extreme heat in summer. A range of solutions have been devised: nature-based solutions for renaturating public spaces, such as ecological corridors; shading design solutions, such as canopies and veils; water-based solutions, such as fountains and maps of drinking water points in the city; making air-conditioned public buildings more appealing, etc. A project to watch!

The holistic ecosystem of the city in nature

A paradigm shift is needed to address the issue of urban heat: the human/urban being is part of Nature.

Architect Julio Jiménez, from Costa Rica, recalls the underlying paradigm that governs territorial thinking in the West: man sees himself as master and possessor of Nature. He proposes to move away from the engineering approach and bring about a cultural change.

Inspired by the work of Alberto Magnaghi, he stresses the need to design local projects based on bio-geo-climatic factors, in symbiosis with nature and seasonality. In his view, simple, inexpensive and easy-to-implement solutions can be devised if they are inspired by Nature.

Regenerating our degraded urban ecosystems in response to the heat in cities

Three components are essential to urban ecosystems, according to Agnès Hennequin, from the Agence Régionale de la Biodiversité: soil, water and plants.

The soil, in its ability or inability to retain rainwater, to be a living, healthy soil. Water must return to its natural cycle, with infiltration on arrival, slower run-off and open-air rain management.

Plants must also be considered in an ecosystemic way, i.e. in the form of a layer of healthy vegetation in ecological corridors.

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