Future scenarios (2021-2050) of extreme precipitation events that trigger landslides – a case study of the Paraitinga River watershed, SP, Brazil

Rodrigo Cesar Da Silva,Gilberto Fisch,Rodolfo Moreda Mendes

doi:10.4136/ambi-agua.2558

Abstract

Global climate change and the consequent occurrence of extreme events will impact societies on a large-scale, with intense rainfall tending to trigger a greater number of hazards caused by climatic events, especially landslides. The incidence of this type of event is conditioned by the combination of several environmental and human factors, such as land use and cover patterns, geomorphological characteristics, and extreme climate. This study analyzed, through the classification of land use and cover and simulation of rainfall, future scenarios in the Paraitinga River watershed, in the southeastern region of Brazil. Precipitation data were used from the MIROC5/Eta model, using the scenario RCP 4.5 (Representative Concentration Pathway) from the IPCC (Intergovernmental Panel on Climate Change) and comparing data from past (1971-2000) and future (2021-2050) periods. The results estimate an increase in consecutive dry days and intense and very intense rainfall, pointing to heavy and concentrated rainfall in the future. An increase of 31.8% in accumulated precipitation over 72 hours that triggers landslides was also predicted, and this increase encompasses 41.6% of the areas of medium and high frequency of incidence of this type of geological event in the study area.

Highlights

Natural disasters related to landslides occur around the world and the losses related to such events range from loss of vegetation, soil and even cases involving deaths in urban areas (Silva et al, 2014)
The results indicate that the southeastern region of Brazil tends to present an increase in average temperatures and extreme rainfall events, which may trigger an increase in the occurrence of natural disasters such as floods and landslides
Land use and land cover (LULC) underwent significant changes between the years 2002 and 2019, with a strong increase in the presence of urbanization and bare soil (221.0%), with most of this increase relative to bare soil due to urbanization processes, which represents a reduction in the quality of land use in the region

Summary

Introduction

Natural disasters related to landslides occur around the world and the losses related to such events range from loss of vegetation, soil and even cases involving deaths in urban areas (Silva et al, 2014). When comparing the increase of urbanization in areas with high slope in California and on the coast of southeastern Brazil, Oliveira-Folharini et al (2018) point out that in both countries the population's vulnerability to landslides is increasing. This is due to the expansion of occupation in high-risk areas, mainly due to precarious construction in Brazilian municipalities, where there is disorderly and unplanned urbanization. This fact is a consequence of poverty and poor living conditions and will tend to affect an increasing number of inhabitants, since climate simulation models predict more intense rains during the summer period

Methods

Results

Conclusion