Many climate change adaptation efforts aim to address the implications of potential changes in the frequency, intensity, and duration of weather and climate events that affect the risk of extreme impacts on human society That risk is determined not only by the climate and weather events (the hazards) but also by the exposure and vulnerability to these hazards Therefore, effective adaptation and disaster risk management strategies and practices also depend on a rigorous understanding of the dimensions of exposure and vulnerability, as well as a proper assessment of changes in those dimensions This chapter aims to provide that understanding and assessment, by further detailing the determinants of risk as presented in Chapter 1 

The first sections of this chapter elucidate the concepts that are needed to define and understand risk, and show that risk originates from a combination of social processes and their interaction with the environment (Sections 22 and 23), and highlight the role of coping and adaptive capacities (Section 24) The following section (25) describes the different dimensions of vulnerability and exposure as well as trends therein Given that exposure and vulnerability are highly context-specific, this section is by definition limited to a general overview (a more quantitative perspective on trends is provided in Chapter 4) A methodological discussion (Section 26) of approaches to identify and assess risk provides indications of how the dimensions of exposure and vulnerability can be explored in specific contexts, such as adaptation planning, and the central role of risk perception and risk communication The chapter concludes with a cross-cutting discussion of risk accumulation and the nature of disasters

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Determinants of risk: Exposure and vulnerability

The repercussions of climate change will be felt in various ways throughout both natural and human systems in Sub-Saharan Africa. Climate change projections for this region point to a warming trend, particularly in the inland subtropics; frequent occurrence of extreme heat events; increasing aridity; and changes in rainfall—with a particularly pronounced decline in southern Africa and an increase in East Africa. The region could also experience as much as one meter of sea-level rise by the end of this century under a 4 °C warming scenario. Sub-Saharan Africa’s already high rates of undernutrition and infectious disease can be expected to increase compared to a scenario without climate change. Particularly vulnerable to these climatic changes are the rainfed agricultural systems on which the livelihoods of a large proportion of the region’s population currently depend. As agricultural livelihoods become more precarious, the rate of rural–urban migration may be expected to grow, adding to the already significant urbanization trend in the region. The movement of people into informal settlements may expose them to a variety of risks different but no less serious than those faced in their place of origin, including outbreaks of infectious disease, flash flooding and food price increases. Impacts across sectors are likely to amplify the overall effect but remain little understood.

Climate change impacts in Sub-Saharan Africa: from physical changes to their social repercussions

Eutrophication and nutrient release in urban areas of sub-Saharan Africa--a review.

[1] Flood-related fatalities in Africa, as well as associated economic losses, have increased dramatically over the past half-century. There is a growing global concern about the need to identify the causes for such increased flood damages. To this end, we analyze a large, consistent and reliable dataset of floods in Africa. Identification of causes is not easy given the diverse economic settings, demographic distribution and hydro-climatic conditions of the African continent. On the other hand, many African river basins have a relatively low level of human disturbance and, therefore, provide a unique opportunity to analyze climatic effects on floods. We find that intensive and unplanned human settlements in flood-prone areas appears to be playing a major role in increasing flood risk. Timely and economically sustainable actions, such as the discouragement of human settlements in flood-prone areas and the introduction of early warning systems are, therefore, urgently needed.

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Flood fatalities in Africa: From diagnosis to mitigation

In this chapter, two different types of impacts on human and ecological systems are examined: (i) impacts of extreme weather and climate events; and (ii) extreme impacts triggered by less-than-extreme weather or climate events (in combination with non-climatic factors, such as high exposure and/or vulnerability). Where data are available, impacts are examined from sectoral and regional perspectives.

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Changes in impacts of climate extremes: Human systems and ecosystems

Many of the urban poor in Africa face growing problems of severe flooding. Increased storm frequency and intensity related to climate change are exacerbated by such local factors as the growing occupation of floodplains, increased runoff from hard surfaces, inadequate waste management and silted-up drainage. One can distinguish four types of flooding in urban areas: localized flooding due to inadequate drainage; flooding from small streams within the built-up area; flooding from major rivers; and coastal flooding. ActionAid undertook participatory vulnerability analysis in five African cities, to explore local people's perceptions of why floods occur, how they adjust to them, who is responsible for reducing the flood risk and what action the community itself can take. While local people adapt to floods, recognition of local, national and international governments' and organizations' responsibility to act to alleviate flooding and its causes, especially the consequences of climate change, is urgently needed.

https://journals.sagepub.com/doi/pdf/10.1177/0956247808089156

Louise Mclean

Papers

Unjust waters: climate change, flooding and the urban poor in Africa

Unjust waters: climate change, flooding and the urban poor in Africa