Urban riks. Concepts and definitions

Urban concentration creates urban risks: that's how Jean-Jacques Rousseau summed it up in his famous reply to Voltaire, who had written a poem about the Lisbon disaster, an earthquake on November 1 ^er 1755 that destroyed the lower part of the city and claimed more than 20,000 victims. The disaster had indeed provoked numerous reactions among European philosophers, and two sentences in particular, in Rousseau's reply to Voltaire, have gone down in history: "Without leaving your subject of Lisbon, agree, for example, that nature had not assembled there twenty thousand houses of six or seven storeys, and that, if the inhabitants of this great city had been dispersed more evenly and more lightly housed, the damage would have been much less and perhaps nil. Everything would have fled at the first tremor, and they would have been seen the next day twenty leagues away, just as cheerful as if nothing had happened". A little further down, in the same letter dated August 18, 1756, we add two other essential sentences: "You would have liked the earthquake to have occurred at the bottom of the desert rather than in Lisbon. Is there any doubt that earthquakes also occur in deserts? But we don't talk about them, because they do no harm to the gentlemen of the cities, the only men we take into account". In short, if we follow Rousseau, risk is only urban. Under these conditions, the expression "urban risks" would in fact be a pleonasm, although it must be said that it has been regularly used, at least in France, over the past few decades.

The aim of this article is to retrace the French history of the notion of urban risk since, and even slightly before, its appearance in academic literature in the 1990s, and to show how it has evolved and become more complex, in line with technological, economic and political developments. In the first section, we return to the foundations on which the notion was apparently built in the 1980s: the entry into the "risk society", coupled with the significant decentralization of political power in France, and the re-emergence of "urban engineering". The 1990s (section 2 ) saw a gradual focus of research on the city and its technical networks, with the term "urban risks" making its first appearance in academic literature. The issue became more complicated for the first time in the 2000s...