Residential and routine mobility dynamics and weather extremes under changing climate – MobiClimEx

MobiClimEx calls for a better understanding of both physical and social processes involved in flash floods. In order to integrate both aspects and combine social and natural data together, we will use a space-time framework to account for scaling issues specific to flash flood events (Holling, 2001; Creutin et al 2009). On the one hand, daily mobility's variability will be confronted to the extremely rapid and violent dynamic of hydrological phenomena in order to estimate and model individual exposure in the space and time of the event. On the other hand, a longer term exposure will be addressed, observing the interactions between public policies (and their impacts on residential mobility) and long term dynamics and recurrence of flash flood phenomena. This observation will consider the situation in the Gard Department from 1958, date of one of the worst flash floods, to current time. Retrospective scenarios will be proposed to explore this long term dynamical process.

The reconstitution of past events is coherent with Naulin et al. (2013). The temporality of road cuts appears as inescapable for assessing the exposure of home-work mobility. Moreover, the main factors of migration are linked with the size of municipalities, their economic profil and location. The collected data show that for the municipalities regularly exposed to floods, the urbanization was made independently from the risk. This will certainly have an impact on residential mobility in the context of a reinforcement of extrem phenomena.

Forthcoming

Forthcoming

Climate change prompts Human Society to develop adaptive capacities in front of extreme weather events, which are expected to increase in frequency in many regions of the world, while social vulnerability also evolves.

MobiCLIMEx addresses the question of human exposure to short fuse weather events, more precisely to flash floods associated to storms in the Mediterranean area.

Exposure describes the complex relationship across space and time scales between population mobility (daily and residential) and the development of storms and floods (flood dynamics and flood frequency). In other words, exposure to dangerous circumstances varies within minutes because of daily mobility under stormy conditions, but it also varies at larger time pace (i.e. decades) with the residential mobility under changing climatological conditions.
In order to analyze the coincidence (and avoidance strategies) between space-time patterns of mobility and hydrometeorological extremes MobiCLIMEx will focus in a first step on two embedded space-time scales:

- At small scales, we will consider how exposure across the day is shaped by pattern of routine mobility, and how mobility patterns are affected by extreme events. It includes investigating: i) patterns of individual and household’s routine activities and travels with respect to their susceptibility to flooding, ii) the pace of behavioral adaptation with respect to the flooding dynamics, iii) the set of circumstances and triggering factors enhancing coping capacity.

- At large scales, we will focus on residential mobility considering: i) residential dynamics in relation with the changes in the frequency of extremes events and risk governance practices, ii) its impacts on the development of road infrastructures and exposition of routine travels patterns to flash flood risk.

Our second step will be to understand better and represent the interaction of both environmental and social dynamics across these two space-time scales. The definition of an adapted framework and methodology will be tested with the elaboration of current situation scenarios, taking into account past dynamics. We plan to develop tools that could be used in the future for the elaboration of scenarios of human exposure in 2030 or 2050.

MobiCLIMEx is rooted in a well-defined case study: the Gard department. This region is frequently hit by flash flood events either perturbing social activities or causing major damage and fatalities. In the recent history, the Gard was affected by two catastrophes of similar intensity in 1958 and 2002. Since 2002, several other smaller scale or more localized events took place in 2005, 2008 and 2011. This pilot case will be used: i) to model the change of residential and travel exposure to flash floods between 1958 and 2002 (and 2012); ii) to investigate the influence of various external factors (socio-demography and economy, risk policy and governance, land costs and land use) on daily and residential mobility and exposure iii) to simulate scenarios of the exposition of the Gard population to hydro-meteorological events during the last 50 years.