Karachi, showing that it is possible to support similar levels of density in existing informal and substandard dwellings, while also providing better housing and economic opportunity to residents. Some urban slums are located in flood plains or other areas of particularly high climate risk, yet these examples show that deterministically linking urbanization or urban slum residence with heightened vulnerability can miss vital internal variation. Factors associated with population dynamics and development can change the nature of urban exposure.
Mobility and migration Defining vulnerability and exposure only in terms of geography and the built environment leads to the cataloguing of those who move due in part to climate change impacts as a vulnerable group. In this model, people’s mobility in the face of climate change is seen as an outcome of their vulnerability and the extent of climate impacts where they are (e.g., Stern 2006, among many). The hazard occurs, and people are displaced. However, although climate migrants have often been classed as a “vulnerable” group, they are frequently people who have engaged in contextually appropriate adaptive behaviour and have used mobility to reduce their vulnerability. In this way, individuals who have stayed behind in the original location may remain exposed to climate-related hazards (Government Office for Science, 2011). Consensus is therefore growing that migration is an adaptation strategy, rather than a response based on a failure of adaptation (Tacoli, 2009). The discourse and scholarship on these areas is more fully explained in Chapters 2 and 3. One additional point remains, however, regarding the relationship between individual behaviour and aggregate population dynamics. To conceive of migration as part of adaptation, population spatial distribution needs to be incorporated into exposure (and adaptive capacity, as described below). First, even using a narrow definition of exposure, if people change their location, for instance through seasonal migration, and therefore their exposure, then spatial distribution and mobility need to be taken into account. Second, migrants are incorporating climate change into their migration calculations (as they have with environmental change since the first people migrated), meaning that people may move in part based on their perceptions of exposure (International Organization for Migration [IOM], 2009). This is the crux of migration as adaptation, and why seeing migration as simply an outcome of climate change hazards is such an oversimplification. If current or future population spatial distribution is based in part on the geography of expected environmental risk, then separating the two into hazard as cause and migration as effect is problematic. Without the shift in spatial distribution of the population from an outcome of exposure to an ingredient in exposure, these linkages remain hidden.
Engaging with Adaptive Capacity The third component of the IPCC’s definition of vulnerability is adaptive capacity, which it defines as “[t]he ability of a system to adjust to climate change (including climate variability and extremes) to moderate potential damages, to take advantages of opportunities, or to cope with the consequences” (Technical Summary, Box 1). A broader definition is proposed by Brooks et al. (2005, p. 168), who suggest that adaptive capacity is: Po pul at i ng Adap tat i o n I nco rp o rat i ng P o p ul at i o n Dy nam i c s i n C li m at e Ch ange Adap tat i o n P o li c y an d P ract i c e
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