Our Common Future Under Climate Change

International Scientific Conference 7-10 JULY 2015 Paris, France

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Wednesday 8 July - 11:30-13:00 UNESCO Fontenoy - ROOM XII

L2.3 - Climatic Variability and the Social and Human Dimensions of Vulnerability

Large Parallel Session

Chair(s): C. Vera (Centro de Investigaciones del Mar y la Atmósfera (CIMA), UMI-IFAECI, CONICET-UBA-CNRS, Buenos Aire, Argentina)

Co-Convener(s): C. Mbow (Institut des Science de l'Environnement, Dakar-Senegal, Senegal)

11:30

Extremes of climate variability and impacts on society: The drought and water crisis of 2014-15 in Southeastern Brazil

J. Marengo (INPE, São Paulo, Brazil), J. Marengo (CEMADEN, San Paolo, Brazil)

Abstract details
Extremes of climate variability and impacts on society: The drought and water crisis of 2014-15 in Southeastern Brazil

J. Marengo (1)
(1) CEMADEN, San Paolo, Brazil

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Deficient rainy season during the austral summers of 2013-14 and 2014-15 over most of southeastern Brazil affected the São Paulo Metropolitan Area (SPMA)-South America’s largest metropolis, home to 20 million people and where 10% of Brazilians live and a third of GDP is produced. Together with high temperatures throughout 2014 and up to January 2015 and a subsequent increase in water demand, the persistent lack of rainfall determined a drought situation, impacting on the use of water for human consumption, hydropower, as well as water for agriculture, creating an acute  “water crisis” situation. In the last 60 years, some extreme dry events have impacted Southeastern Brazil, including the 1953-54 episode and the 2000–2001 as the most intense. Here we intend to assess how extraordinary the recent extreme drought that started in summer of 2013, persisted throughout 2014 and continued up to January 2015 was, and to analyze some of the main factors contributing to it.

 

The hydropower reservoirs—which account for around 70% of the country’s entire hydroelectric power generation- and the rivers feeding the Cantareira reservoir system, which provides almost half of the city of São Paulo’s water, were almost dry by the end of 2014.The severe drought of the summer 2014-2015 was associated with a wide, intense and very persistent high-pressure area placed from surface to the upper troposphere. The anticyclonic system that dominates the atmospheric circulation over eastern South America extended from the sea level to the upper troposphere inhibiting the distinctive seasonal convective activity. This anticyclone lasted 45 days, extremely rare in terms of duration and never previously recorded for that region.

 

The region of Cantareira region experienced the most severe drought during the summer of 2014, and this year corresponds to the warmest year in the region since 1962.  Other drought years, as in 1971 and 2001 were also among the six warmest years during that period. Therefore, the worse water crisis in Sao Paulo during the warmest year during the last 52 years is a relevant example of climate change risk due to rising temperatures due to anthropogenic influences.

 

However, origins of the current water crisis go beyond the rainfall deficiency, to include an array of interconnected factors: the city’s surging population growth in the 20th century; a chronically leaky system that spills vast amounts of water before it can reach homes; and the destruction of surrounding forests and wetlands that have historically soaked up rain and released it slowly into reservoirs. Rainfall over the Cantareira system has been decreasing during the last decades and the levels in 2014 were the lowest since 1940. Longer-term planning by regional governments has fallen short, and many residents are already enduring sporadic water cutoffs, some going days without it. SABESP, the state utility company has reduced its extraction from the reservoir by a third, cut its pump pressure at night, and offered discounts to customers who reduce their consumption.  Some parts of the city are relying on water trucks to maintain their supply.  

11:50

Managing multifunctionnality for Climate Smart Landscapes

C. Mbow (Institut des Science de l'Environnement, Dakar, Senegal)

Abstract details
Managing multifunctionnality for Climate Smart Landscapes

C. Mbow (1)
(1) Institut des Science de l'Environnement, Faculté des sciences et techniques, Dakar-Senegal, Senegal

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This presentation addresses the importance of managing trade-offs for sustainability in the face of climate change and how in particular the integrated landscape approach could be the one way to achieve many climate change related objectives. The presentation suggests a analytics for harnessing the climate smart landscape approach to the emerging climate challenges using some examples of practices that are suited to different contexts. From the historical footprints of the co-evolution between policy and science in the aim of achieving integrated solutions to climate/environmental crisis, we suggest some avenues on how to use landscape management principles in the design and the implementation of multiple goals; and what are the key barriers.

12:10

Human vulnerability and adaptation to extreme events in rapidly changing rural and urban environments

J. Birkmann (Institute for Spatial and Regional Planning, Stuttgart, Germany)

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Human vulnerability and adaptation to extreme events in rapidly changing rural and urban environments
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12:30

Q&A session

C. Vera (Centro de Investigaciones del Mar y la Atmósfera (CIMA), UMI-IFAECI, CONICET-UBA-CNRS, Buenos Aire, Argentina)

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Q&A session
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