CONICET | Buscador de Institutos y Recursos Humanos

The dimensions and shape of the Plata River (PR) estuary create quasi maritime dynamical conditions. Thus, storm winds produce surges that when enhanced by astronomical tides lead to extreme water levels. Most of the Argentine coastal area is subject to recurrent storm surge floods, which will become more frequent as the mean sea level rises due to global warming. This coast is a dense populated area that includes the metropolitan region of the Buenos Aires city. Very low areas, which will be likely permanently flooded by 2070/2080, are now scarcely populated because they are frequently flooded by storm surges. As a result of this adaptation to present storm surge conditions, the social impact of future permanent flooding will be small. Then, climate change vulnerability in this coastal zone is mostly conditioned by future exposure to extreme surges. Coastal neighborhoods that currently have relatively low recurrence of floods, and because of that are densely occupied, are those where the storm surge recurrence changes will create the greater impact. They are now inhabited by different social stratus, ranging from upper middle class to socially vulnerable population. Thus, these changes will lead to social damages as well as to important real estate losses. Assessment of vulnerability took into consideration both physical as well as social conditions. Storm surge levels were adequately represented by a two-dimensional hydrodynamic model with high spatial (2.5 km) and temporal resolution (1 minute). The model was calibrated to astronomical tides and storm surges. In addition, was able to reproduce the statistical water level distribution at the Buenos Aires port for 1990-1999 period. After confidence in its capacity to reproduce the basic features of storm surges was gained, the tuning of the model allowed estimating extreme tide values along the coast of the RP, thus overcoming the lack of basic data. Future scenarios of mean water level were constructed forcing the model with the mean sea level from scenarios of the IPCC 2001 Report and with winds calculated from global climate models selected from the IPCC webpage. For calculating the return periods of floods over land, a data set of surface levels, based on GPS measurements, satellite radar data and previous maps was developed.. Finally, physical and social data were integrated in a geographical information system. If no change in population is assumed, by the end of the century, the people occupying the area with a risk of flood with a return period of 100 years will be around 900.000. Current real state damage is estimated in 30 M USD/year and if no socioeconomic changes are assumed, it would reach 100 and 300 M USD/year in 2030/2040 and 2070/2080, respectively.