Multi-Hazard Risk Analysis Under Climate Change: West Africa Case Studies
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POLITECNICO DI TORINO Repository ISTITUZIONALE Multi-hazard Risk Analysis under Climate Change: West Africa Case Studies Original Multi-hazard Risk Analysis under Climate Change: West Africa Case Studies / Bacci, Maurizio. - (2021 Feb 22), pp. 1- 171. Availability: This version is available at: 11583/2872349 since: 2021-02-24T09:53:48Z Publisher: Politecnico di Torino Published DOI: Terms of use: Altro tipo di accesso This article is made available under terms and conditions as specified in the corresponding bibliographic description in the repository Publisher copyright (Article begins on next page) 11 October 2021 Doctoral Dissertation Doctoral Program in Urban and Regional Development Multi-hazard Risk Analysis under Climate Change: West Africa Case Studies Maurizio Bacci Supervisors Prof. A. Pezzoli Prof. M. Tiepolo Politecnico di Torino January, 2021 This thesis is licensed under a Creative Commons License, Attribution - Noncommercial - NoDerivative Works 4.0 International: see www.creativecommons.org . The text may be reproduced for non-commercial purposes, provided that credit is given to the original author. I hereby declare that, the contents and organisation of this dissertation constitute my own original work and does not compromise in any way the rights of third parties, including those relating to the security of personal data. ………………………………..... Maurizio Bacci Turin, January 20, 2021 1 Summary Developing countries are increasingly challenged to respond to harmful effects of natural disasters under climate change (desertification, floods, climate related hazards, etc.). However, the response to these threats is complex and requires many economic and technical resources, while, in developing countries, responsive local governance for climate adaptation is constrained by weak technical capacity, poor interactions with other institutions, weak observation networks and data quality, weak communication capabilities, and unclear mandates and conflicting priorities between levels and agencies of government. These weaknesses generate serious implications for the poorest and most vulnerable communities that are frequently the most adversely impacted by climate stress. The research activity during my PhD career has focused on the investigation of multi-hazard risk assessment in Sub-Saharan Africa, one of the places on Earth most vulnerable to climate change, with the aim to support decision makers in increasing the effectiveness of their interventions. The thesis contributes to the exploration of new and innovative methodologies by supporting the adaptation process to climate change and disaster risk prevention in least developed countries through the assessment of multi-hazard risk under future climate scenarios. The thesis takes its cue from two papers published during the three years of doctorate which are: i) Multihazard risk assessment for planning with climate in the Dosso Region, Niger, by Tiepolo, Maurizio; Bacci, Maurizio; Braccio, Sarah [1], and ii) Multi-Hazard Risk Assessment at Community Level Integrating Local and Scientific Knowledge in the Hodh Chargui, Mauritania, by Tiepolo, Maurizio; Bacci, Maurizio; Braccio, Sarah; Bechis, Stefano [2]. Both papers deal with the current multi-hazard risk assessment, at a regional scale basis, in these two territories. A part of the chapters 3.1, 3.2, 3.6, 4.1, 4.2, 4.6 and 5 are wrote considering the previous and cited papers. 2 This thesis gathers, with a holistic and interdisciplinary approach, a review of concepts of multi-hazard risk assessment and notions about climate modeling and downscaling techniques, then, starting from the two above mentioned papers, produce the bias-corrected climatic projections datasets and develop the future multi-hazard risk assessment for the two case studies. The future scenarios are compared with the current assessment thus intercepting the most significant trends in risk evolution. The study follows on with a discussion on the obtained results. The last chapter draws conclusions on the sustainability and replicability of the method in similar contexts and its ability to support the medium-long term planning process through the identification of intervention priorities. The investigated case studies are: • Hodh El Chargui Region, Mauritania • Dosso Region, Niger 3 Acknowledgement I’m extremely grateful to Prof. Maurizio Tiepolo and Prof. Alessandro Pezzoli for their support in my PhD career and their help in guiding me in the redaction of this thesis. I would like to extend my sincere thanks to my colleague Vieri Tarchiani, my Directors Giampiero Maracchi, Antonio Raschi, Federica Rossi and Giorgio Matteucci, my CNR-IBIMET and CNR-IBE colleagues, the Italian honorary consul in Niamey Paolo Giglio and all the staff of the National Meteorological Direction of Niger, in particular Katiellou Gaptia Lawan, Aissa Sitta, Ousman Baoua, Labo Moussa, Moussa Mouhaïmouni, Binta Adamou, Aissa Liman for their support in all my activities in Niger. I very much appreciate the support and the kindness of Daniela Belloni during my PhD career and I’d like to acknowledge Sarah Braccio and all the PhD students of Urban and Regional Development and the Sottopalco group. Last but not least, I’d like to thank all my family, Claudia and the three little and terrible ladies: Matilde, Giulia and Teresa. 4 A mamma e babbo 5 Contents 1. Introduction ...................................................................................................... 14 1.1 Context .................................................................................................. 14 1.2 Towards a multi-hazard risk approach .................................................. 15 1.3 Objectives .............................................................................................. 16 1.4 The case studies ..................................................................................... 19 1.5 Organization of the research .................................................................. 21 2. Climate change and risk assessment ................................................................ 22 2.1 Climate projections ................................................................................ 22 2.2 Climate future scenarios ........................................................................ 25 2.3 Application of Bias correction methodology ........................................ 28 2.4 Risk mapping ......................................................................................... 31 2.5 Priorities in the interventions ................................................................. 32 2.6 Characterization of multi-hazard risks .................................................. 33 3. Case study analysis in the Hodh El Chargui Region ....................................... 38 3.1 Multi-hazard risk analysis in the Hodh El Chargui Region .................. 38 3.2 Definition of the current multi-risk zones in the Hodh El Chargui Region ............................................................................................................................ 41 3.3 Local climatic projections in the Hodh El Chargui Region .................. 66 3.4 Application of future projections to the current multi-hazard risk characterization in the Hodh El Chargui Region ............................................... 77 3.5 Comparison of results (present vs. future) and identification of priority intervention areas in the Hodh El Chargui Region ............................................ 79 3.6 Discussion about the Hodh El Chargui Region case study ................... 82 4. Case study analysis in the Dosso Region ......................................................... 86 4.1 The multi-risk approach in the Dosso Region ....................................... 86 4.2 Definition of the current multi-risk index in the Dosso Region ............ 92 4.3 Local climatic projections in the Dosso Region .................................. 117 4.4 Application of future projections to the current multi-risk characterization in the Dosso Region ......................................................................................... 127 4.5 Comparison of results (present vs. future) and identification of priority intervention areas in the Dosso Region ............................................................ 131 6 4.6 Discussion about the case study in the Dosso Region ......................... 134 5. Discussion: Identification of priority areas .................................................... 138 6. Conclusions .................................................................................................... 152 7. References ...................................................................................................... 156 7 List of Tables Table 1: Climate models and Institution ......................................................... 27 Table 2 Correlation precipitation-ephemeral wetland surface....................... 45 Table 3 Meteorological number of drought years and drought probability for the 13 communities of the Hodh El Chargui. ......................................................... 48 Table 4 Average of the August-Sept. rainfall during the 3 years with lowest water accumulation in the mares (mm) ................................................................. 50 Table 5 Hydrological drought probability for the 6 ephemeral wetlands in the Hodh El Chargui. ..................................................................................................