This work aims to provide a dynamic assessment of flood risk and community resilience by explicitly accounting for variable human behaviour, e.g. risk-taking and awareness-raising attitudes. We consider two different types of socio-hydrological systems: green systems, whereby societies deal with risk only via non-structural measures, and technological systems, whereby risk is dealt with also by structural measures, such as levees. A stylized model of human-flood interactions is first compared to real-world data collected at two test sites (People's Republic of Bangladesh and the city of Rome, Italy) and then used to explore plausible trajectories of flood risk. The results show that flood risk in technological systems tends to be significantly lower than in green systems. However, technological systems may undergo catastrophic events, which lead to much higher losses. Furthermore, green systems prove to be more resilient than technological ones, which makes them more capable of withstanding environmental and social changes.

Abstract. Throughout history, the socio-economic development of the city of Rome has been intertwined with the magnitude and frequency of flooding events from the Tiber, one of Italy's largest rivers. Ancient Rome mostly developed on the hills, while the Tiber's floodplain was mainly exploited for agricultural purposes. A few small communities did settle in the riparian areas of the Tiber, but they had a relatively peaceful relationship with the frequent occurrence of flooding events. Instead, numerous people live nowadays in modern districts in the Tiber's floodplain, unaware of their exposure to potentially catastrophic flooding. This research work aims to explore the dynamics of changing flood risk between these two opposite pictures of ancient and contemporary Rome. To this end, we carried out a sociohydrological study by using long time series of hydrological (extreme flood events) and social (human population dynamics) processes, along with information about human interactions with the environment (flood defence structures). The historical analysis showed how human and water systems have been co-evolving over time, while being abruptly altered by the occurrence of an extreme flood event in 1870, just before Rome became the capital of a recently unified Italy. The outcomes of this study were then compared to the results of a socio-hydrological model simulating the dynamics emerging from the mutual shaping of floods and societies.

This paper offers an analysis of the supply of Airbnb accommodation in Rome, one of the main tourist destinations in the world, the third-largest city in Europe, by the number of Airbnb listings. The aim is to focus on the recent spatial trend of Airbnb listings, including the period of the COVID-19 pandemic, and highlight the main housing and socioeconomic characteristics of the neighbourhoods associated with a strong presence of Airbnb listings. The study is developed with quantitative methods and spatial regression (spatial lag and spatial error using OLS as a benchmark), based on data collected from the Inside Airbnb and Tomslee websites. In the period 2014–2019, the listing trend in Rome has been increasing in absolute numbers. After the start of the pandemic, the trend became negative, and the decline of Airbnb offerings is more substantial for shared accommodation. Airbnb supply is related to the distance from the city centre, the average income of the area, empty apartments, singles and the share of foreign residents coming from high-income countries. A signal of spatial diffusion of Airbnb listings emerges in the coastal area, even if they are increasingly concentrated in the historic centre, where there is a monoculture of short-term renting.