and distribution within those settlements. Each of these issues relates quite differently to climate change and poses different political and governance challenges. Except in passing, differences between small versus large settlements, mono-centric versus polycentric settlements or cities versus city-regions are not considered. While these differences could well relate to the broader question of how urbanization and climate change trends will combine, and how this will affect the most vulnerable groups, the evidence is too ambiguous to justify the sort of brief summary that could be included in this chapter. Understanding the environmental, economic and social implications of urbanization requires getting its definition straight. The definition of urbanization used in this chapter is the standard demographic one: The level of urbanization is the share of the population living in urban rather than rural settlements, and the rate of urbanization is the annual rate at which this urban population share increases (Poston and Bouvier, 2010). Urbanization is sometimes used loosely to refer to urban population growth or to the conversion of land to urban use. This is statistically incorrect, since urban population growth rates in urbanizing countries are typically about twice the rate of urbanization, the difference being the country or region’s overall population growth rate (United Nations, 2010b). Moreover, with urban population densities declining around the world, urban land areas are expanding far faster than the urban population growth rate (Angel et al., 2010). Defining urbanization in terms of the growth of urban areas or populations is also misleading conceptually in that urbanization is a shift from rural to urban and not a purely urban phenomenon. It involves a relative reduction in the number of people in dispersed rural areas, as well as an increase in comparatively dense urban locations. Increasing the level of urbanization involves a shift towards greater settlement density. The implications of this shift are not at all the same as those of overall population growth and the declining density of urban settlement (or urban sprawl), which together are driving most urban spatial expansion. In particular, the shift has very different implications for greenhouse gas emissions and adaptive capacities.
Rural-urban Migration, Exclusion and Climate Adaptation Some widely cited estimates suggest that climate change will result in hundreds of millions of climate refugees migrating out of the global South, looking for safer places to live (Myers, 2005). This crisis narrative has proved to be an effective means of stirring up press and public concern in the North. Similar estimates could be constructed to stir up fears about climate migrants leaving the countryside and overwhelming the cities of the global South. In both cases, such crisis narratives are in danger of being used to justify tightening controls on migration and diverting attention from the sources of climate change and from the positive role that migration can play in adapting to climate change. The high estimates of international climate migrants have been largely dismissed as unfounded by migration researchers (Black et al., 2008; Piguet, 2010; Tacoli, 2009). It has also been pointed out that this crisis narrative is ideologically rooted and obscures more legitimate concerns about how the burdens of climate change are being distributed (Hartmann, 2010). What is really striking about this narrative, however, is that it takes a Fai r A n d E ffe ct i ve R e s po n s e s to U rban i zat i o n A n d C li m at e Ch a nge : Tap pi ng Sy n e rgi e s an d Avo i d i ng E xc lus i o nary P o li c i e s
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