Until 13 July 2025, the 3rd edition of the Biennale d’architecture et de paysage d’Île-de-France is taking place in Versailles, with exhibitions, conferences and study days under the banner of ‘The Living City”. Those who missed the event can catch up: AA has been following the highlights. In particular, we focused on the Four degrees Celsius between you and me exhibition, designed by architects Sana Frini and Philippe Rahm as a catalogue of architectural solutions inspired by subtropical climates.

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Chloé Carissimi

11:30:53 SEOUL: 43° –  11:34:07 MEXICO CITY: 41° –  11:39:08 BAGDAD: 53°  – 11:42:51 PARIS: 44°

Like a clock radio reminding us of the reality of everyday life, these digital segments scroll across imposing orange curtains. In this atmospheric airlock installed in the Grande Nef of the École Nationale Supérieure d’Architecture de Versailles, we are reminded of the reality of a near future with an additional 4°C, a horizon of the year 2100, in which cities all over the world will be sweltering. Given the devastating heatwaves and droughts that many of them are already experiencing today, there is growing concern about the future of life in urban areas. It’s against this backdrop of a dystopian world that the exhibition opens.

Looking south

What avenues can be explored by those who think about and build the city? For Sana Frini and Philippe Rahm, co-curators of the exhibition, the answer is clear: the solutions lie to the south. The projections are clear. In 75 years’ time, the temperate climate of cities like Paris will give way to a subtropical climate, similar to that of northern Africa, Mexico or southern Spain. It seems only logical that architects, landscape architects and urban planning professionals should turn their attention to these latitudes with their already warm climates in order to draw inspiration – with all the humility that this implies – from the know-how, techniques and architectural models that have been optimised for centuries to enable entire populations to live with such temperatures. This is precisely the aim of this exhibition, which argues that this insight could guide solutions for adapting northern cities to these new climatic realities.

Refresh the city

Even before entering the exhibition hall, the tone is set: the architects, landscape architects and students taking part in the exhibition are looking for solutions to cool down the city. Indeed, that’s what visitors could guess from the two pavilions in the centre of the Cour des Fontaines adjoining the Grande Nef. The ‘Mud Trianon’, designed by Andrés Jaque, is made up of dolia, large, human-sized amphorae made of terracotta, a material known for its heat-regulating properties. Just behind it is ‘Atrapaviento’, a futuristic tent-like installation designed by the Mexican agency Colectivo C377, which explores the potential of air convection using a system of solar chimneys. The chimneys increase the ascent of the hot air, bringing down the temperature below, where visitors can rest on swings.

Past and present for the future

4° Celsius between you and me is an exhibition in three parts. The past is embodied in the models, drawings and various objects displayed on the shelves, testifying to the richness of vernacular architecture from before the era of air conditioning, particularly in subtropical and Mediterranean regions. At the centre of the exhibition, contemporary architects present their projects for living in the city in 2100, inspired by these timeless skills. Finally, a large wall features projections by architects, critics, historians and philosophers. All of which sketch out a Paris in 2100 that has learnt the lessons of these architectural solutions. Of particular note is a cartography by the architect Gael Biache of a Paris whose surface would be repainted with 30% white paint to reduce the temperature by 2 degrees.

Nature as a solution

Water, earth and air. The scenography of the 4° Celsius between you and me exhibition, organised around these three elements, explores a wide range of architectural solutions designed to cope with this inevitable heat. Each of them is approached according to its potential, but also its associated challenges and risks.
Although blue gold can be used to cool buildings (particularly through evaporation), it is above all an increasingly scarce resource, at the heart of major human and climatic crises. Madrid-based Husos Arquitecturas has managed to overcome this ambivalence with its proposal for a green façade fed by grey water. This ingenious prototype meets the dual challenge of naturally cooling the home while providing a practical response to the drought that is so prevalent in Spain today, and will certainly be just as prevalent in France tomorrow. ‘The recycled water feeds the plants, which act as a thermal cushion: they naturally cool the house during the hot seasons and retain heat in winter,’ explain the architects.

At the centre of the central exhibition space sits a unique installation in the shape of a soil silo, topped by a glass pane that visitors can open as they wish. This is ‘Trombe d’été’, designed by the Barcelona agency Takk, which exploits the refreshing properties of earth and air in the same way as the Trombe wall. The curators of the current Catalan Pavilion at the Venice Biennale describe the prototype as follows: ‘A thick wall of compacted earth absorbs the heat of the day, preventing it from penetrating. Vents at the top and bottom create an air flow, allowing hot air to escape and cool air to enter. At night, the wall vents any stored heat to the outside, while the door and windows remain open, allowing air to circulate and keeping the interior cool.

All in all, 4°C Between You and Me is a refreshing exhibition that looks at the architectural and urban planning challenges posed by climate change. Without being alarmist, it proposes concrete approaches, based on vernacular know-how from regions already facing hot climates. It’s an approach that encourages us to anticipate rather than suffer – and to build and live in cities differently.

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4°C entre toi et moi
à l’ÉNSA Versailles
5 avenue de Sceaux, 78000 Versailles
→ Jusqu’au 13 juillet 2025
Plus d’informations sur le site de la Bap!