Desastres naturais no Nordeste do Brasil: aspectos meteorológicos, sociossanitários e populacionais

Abstract

Over the years, climatic variability in the Northeast region of Brazil (NEB) has made extreme weather events more frequent, with periods of excess and deficit of precipitation, causing great impacts on society and being one of the factors that potentiates the numbers of Natural Disasters. The dry seasons and droughts, torrents and floods have been causing great damage to the population. The objective of this study was to analyze the occurrences of natural disasters in the Northeast of Brazil, identifying the potential associated factors, regarding meteorological, social, health and environmental conditions, in addition to estimating the respective risk probabilities to the recorded events. The first article aimed to identify the temporal space distribution of the records of natural disasters in the period from 1991 to 2013, characterizing the occurrences of disasters in the mesoregions, considering the meteorological and sociohealth aspects. The Grade of Membership methodology based on fuzzy logic was used to define the profiles in the region. In the second article, The Generalized Additive Model for Location, Scale and Shape was used in order to estimate the relationship between the events of natural disasters in the face of extreme climatic, socio-sanitary and population conditions, considering the most frequent events for the Region, such as dry seasons/droughts, floods and torrents. Finally, the third article culminated with a case study in order to analyze the atmospheric conditions associated with the event of intense precipitation caused by an Easterly Wave Disturbances (EWD), as well as the environmental conditions related to the mass movement that occurred between June 14th and 15th, 2014, in the district of Mãe Luiza, Natal/RN. The results of article 1 pointed to the characterization of three profiles with different characteristics. Profile 1 presented favorable mesoregions to the indicators of excessive precipitation, with events of torrents and droughts, in addition to better social and health conditions and a higher percentage of urbanization, located in the eastern part of the Northeast of Brazil. Profile 2 aggregated the units that are disadvantaged by the rain regime, have greater occurrences of drought and moderate conditions for the social, sanitary and urbanization aspects, covering part of the boundaries of the Brazilian Semiarid Region. Profile 3 was characterized by conditions conducive to indicators of excessive rainfall, with greater frequency of flooding, low urbanization and disadvantaged in social and health conditions. Article 2 revealed the predominance of drought disasters in the Brazilian Northeast, representing 81.1% of the decrees. The results showed that the components of excessive rain and humid climate conditions are positively associated with torrents and floods and negatively with drought. However, the number of consecutive dry days contributed in an inverse way to torrents and floods, as would be expected. As regarding environmental aspects, inadequate sanitation and garbage collection services contributed significantly to the increase in drought and torrent disasters. As regarding drought, the precariousness of the water supply was also a factor in the increase in drought disasters. In the third article, it was found, based on the analysis of the geological, geomorphological, pedological conditions, defluvium coefficient, vegetation cover and land use and cover, an expressive area classified to have high and very high vulnerability to mass movements that, enhanced by intense rainfall from the EWD, caused the disaster in the neighborhood of Mãe Luiza. Knowledge about the behavior of occurrences of natural disasters over the years and their relationship with socio-health and population factors can support the management of actions and effective public policies for the mitigation of natural disasters.