Climatic characteristics of the 2010-2016 drought in the semiarid Northeast Brazil region.

José A Marengo,Lincoln M Alves,Ana Paula Cunha,Osvaldo L.L Moraes,Sheila Brito,Regina C.S Alvala

doi:10.1590/0001-3765201720170206

Abstract

This study discusses the climatological aspects of the most severe drought ever recorded in the semiarid region Northeast Brazil. Droughts are recurrent in the region and while El Nino has driven some of these events others are more dependent on the tropical North Atlantic sea surface temperature fields. The drought affecting this region during the last 5 years shows an intensity and impact not seen in several decades in the regional economy and society. The analysis of this event using drought indicators as well as meteorological fields shows that since the middle 1990s to 2016, 16 out of 25 years experienced rainfall below normal. This suggests that the recent drought may have in fact started in the middle-late 1990s, with the intense droughts of 1993 and 1998, and then the sequence of dry years (interrupted by relatively wet years in 2007, 2008, 2009 and 2011) after that may have affected the levels of reservoirs in the region, leading to a real water crisis that was magnified by the negative rainfall anomalies since 2010.

Highlights

The first two decades of the 21st Century are being characterized by extreme climatic events that have led to natural disasters in central South America: drought in Northeast Brazil (NEB) during 20102016; drought in southeastern Brazil in 2014-15; droughts in Amazonia in 2005, 2010 and 2016; floods in Amazonia in 2009 and 2014; drought in Bolivia in 2016, with some of them almost
The meteorological and oceanic mechanisms that lead to circulation and rainfall changes responsible for drought in NEB have been reported elsewhere, and they refer to the occurrence of El Nino, or to an anomalously warm tropical North Atlantic, or a combination of both (Nobre et al 2016, Coelho et al 2012, 2015a, b, Marengo et al 2012, 2014, 2015, 2016a, b, Silva et al 2013, Rodrigues and McPhaden 2014)
This suggests that the recent drought may have started in the middle-late 1990s, with the intense droughts of 1993 and 1998, and the sequence of dry years after that have affected the levels of reservoirs in the region

Summary

Introduction

The first two decades of the 21st Century are being characterized by extreme climatic events that have led to natural disasters in central South America: drought in Northeast Brazil (NEB) during 20102016; drought in southeastern Brazil in 2014-15; droughts in Amazonia in 2005, 2010 and 2016; floods in Amazonia in 2009 and 2014; drought in Bolivia in 2016, with some of them almost synchronized, for example, intense floods in in Amazonia and drought in NEB in 2012-13. Security and subsistence agriculture in regions such as NEB, and Southeast Brazil, while in Amazonia it can impact biodiversity and population and increase the risk of fires. These regions have multiple stressors on natural and human systems derived in part from significant changes in climate variability/ climate change and exacerbated by land use change. Extremes of climate variability at various time scales have been affecting social and natural systems and high socio-economic vulnerability of people living in the semiarid region in NEB and along the shores of main Amazon region rivers (Marengo et al 2015, Vieira et al 2015). The region is vulnerable to the observed extremes of interannual climate variability, mainly droughts, and climate change scenarios indicate that the region will be affected by rainfall deficit and increased aridity in the second half of 21st century (Marengo and Bernasconi 2015, IPCC 2012, 2014, CGEE 2016)

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Conclusion