Cities must adapt to climate change

Major disasters are wake-up calls from which people must draw the right conclusions. The fires in the US are a wake-up call related to the structure of large cities and climate change. The catastrophic fires in Los Angeles, exacerbated by the effects of climate change, call into question less the systematic use of wooden houses than the uncontrolled urban expansion of this city designed for cars, according to statements to AFP by architect and urban planner Nicolas Michelin. While the long months of drought in 2024 and winds that gusted up to 160 km/h are largely responsible for the scale of the disaster, the proliferation of housing in areas vulnerable to fires has only worsened the situation, believes Nicolas Michelin, involved in the ecological transition of architecture. He stressed the need to bury "extremely old" overhead power lines located near vegetation to prevent fires from starting, and said that Los Angeles is first and foremost the archetype of a "out of context" city. "In the US, as in Europe, we have built many cities without any connection to the environment, telling ourselves "the place is beautiful, I will put my house there, my building here', but without taking into account the topography, the winds, the sun or the history of the place," commented the architect who advocates "measured" urban planning. In Los Angeles, urban expansion in the second largest city in the United States has brought houses closer together, eliminating natural barriers to fire. Many homes engulfed in flames, located on hillsides, were inaccessible to fire and rescue services. "We consider the land to be ours, so we expand, and we build roads every time to get there, while the place is what makes the project, and the project is what makes the rules," added Nicolas Michelin, founder of the ANMA agency. For a long time, in the United States, as in Europe, architects have tended to create projects "that impose themselves on their environment," he recalls, adding that this is the legacy of the architect and urban planner Le Corbusier, a symbol of modernity that is currently being severely tested by the effects of global warming. The "urban prevention" urbanism promoted by Nicolas Michelin applies to all natural risks, especially floods. In Valencia, the scene of the tragic floods at the end of October that killed 231 people, "the river was diverted so that it would not flood the city center, putting asphalt and dams everywhere, and we saw the result." In addition to urban planning, the type of architecture also raises questions. In the United States, the massive use of wood, used for 93% of new homes built by 2023, according to the National Association of Home Builders (NAHB), appears to be one of the aggravating factors of the fires in Los Angeles. "This is a real problem, but it does not call into question wood construction in general, to the extent that we can encapsulate the wood with gypsum board or fiber cement to protect it from fire," emphasizes the architect, who claims that he is not a fan of "concrete bunkers". According to him, the risk is less related to the materials used, but to choosing an inappropriate location, such as "at the edge of a forest" or "in the middle of vegetation". Faced with the challenge of increasing the density of residential areas, building up to the maximum limit allowed by urban planning documents can also present risks.