2.3.3 Defining coping ranges
The coping range of climate (Hewitt and Burton, 1971) is described in the TAR as the capacity of systems to accommodate variations in climatic conditions (Smith et al., 2001), and thus serves as a suitable template for understanding the relationship between changing climate hazards and society. The concept of the coping range has since been expanded to incorporate concepts of current and future adaptation, planning and policy horizons, and likelihood (Yohe and Tol, 2002; Willows and Connell, 2003; UNDP, 2005). It can therefore serve as a conceptual model (Morgan et al., 2001) which can be used to integrate analytical techniques with a broader understanding of climate-society relationships (Jones and Mearns, 2005).
The coping range is used to link the understanding of current adaptation to climate with adaptation needs under climate change. It is a useful mental model to use with stakeholders – who often have an intuitive understanding of which risks can be coped with and which cannot – that can subsequently be developed into a quantitative model (Jones and Boer, 2005). It can be depicted as one or more climatic or climate-related variables upon which socio-economic responses are mapped (Figure 2.3). The core of the coping range contains beneficial outcomes. Towards one or both edges of the coping range, outcomes become negative but tolerable. Beyond the coping range, the damages or losses are no longer tolerable and denote a vulnerable state, the limits of tolerance describing a critical threshold (left side of Figure 2.3). A coping range is usually specific to an activity, group, and/or sector, although society-wide coping ranges have been proposed (Yohe and Tol, 2002).
Risk is assessed by calculating how often the coping range is exceeded under given conditions. Climate change may increase the risk of threshold exceedance but adaptation can ameliorate the adverse effects by widening the coping range (right side of Figure 2.3). For example, Jones (2001) constructed critical thresholds for the Macquarie River catchment in Australia for irrigation allocation and environmental flows. The probability of exceeding these thresholds was a function of both natural climate variability and climate change. Yohe and Tol (2002) explored hypothetical upper and lower critical thresholds for the River Nile using current and historical streamflow data. The upper threshold denoted serious flooding, and the lower threshold the minimum flow required to supply water demand. Historical frequency of exceedance served as a baseline from which to measure changing risks using a range of climate scenarios.