Combining models of urbanization and climate change scenario to improve the environmental urban footprints. A case of study: Tandil city, Argentina

PICONE, NATASHA

Nueva York

Conferencia; ICUC 10; 2018

City College of New York, AIUC y American Meteorological Society

The 50 % of the world population lives in urban areas nowadays, and this proportion is expected to increase to 80 % by 2050. Argentina is not an exception, with 92 % of the present population living in urban areas. Studding the way cities will grow is the key to understand how the climate change will impact them. This paper evaluates the environmental consequences of urban growth using two prospective models that combine two urbanization trends and two scenarios of climate change. Modelling future scenarios is important to identify the growth patterns that exhibit the highest resilience to climate change, and to generate a more sustainable urban footprint. The study focuses on the cityof Tandil, a middle-sized Argentinian city that constitutes an excellent example of the accelerated growth rates that have been observed during the last two decades at the national scale.Methods combine remote sensing, GIS and modelling to analyze the current state of cities and to determine how its footprint can evolve following different growing patterns. These techniques are increasingly used in developing countries due to the lack of information on urbanization processes. We used satellite images from Landsat mission and WUDAPT methodology to determine the past (2002) and current (2017) urbanization state. Patterns of urban growth and urbanization characteristics related to the environmental modifications (in particular surface temperature, runoff and vegetation cover) were determined based on the changes detected in this 15-year period. Future climate change scenarios were estimated using the Climate Change Adaptation Model (CCAM ? TerrSet). First, we run three different scenarios (RCP 2.6, RCP 4.5 and RCP 6.5, each one represents different increase of energy in the climatic system) from 2017 to 2050. Second, we model two trends of Local Climate Zones changes using the same period of time.From these, one model assumes continuity of current change trends and the other assumes a more sustainability scenario based on increasing vegetation and pervious areas with a densification of green infrastructures. The response of each growth pattern to different climate change scenarios was determined by combination of the different models. Results revealed that two combinations of models may consistently improve the sustainability of the city. Both combinations include the sustainability scenario of urban growth, as it promotes the densification of green areas andtherefore contributes to regulate air temperatures and to increase infiltration rates. Combined with the RCP 2.6 model, the sustainability scenario shows a great improvement in the city environment compared to the current state.Environmental improvements under the RCP 4.5 scenario are also notable, although they appear comparatively less important. The worst scenario combines the RCP 6.5 model with the current pattern of growth. In this case, the urban heat island intensifies, the capability of temperature regulation decreases and runoff rates increase.