Characteristics of Vulnerability and Adaptation Analyses

Vulnerability and adaptation analyses can be performed in many contexts and have a wide range of uses. In general, vulnerability analyses assess exposure to and impacts from a disturbance, as well as sensitivity to these impacts and the capacity to reduce or adapt to the negative consequences of the disturbance. These analyses can then be used by decision makers to help decide where, how much, and in what ways to intervene in human or environmental systems to reduce vulnerability, enhance resilience, or improve efficient resource management (Eakin et al., 2009; Turner, 2009). In the context of climate change, vulnerability analyses seek to evaluate and estimate the harm to populations, ecosystems, and resources that might result from changes in climate, and to provide useful information for decision makers seeking to deal with these changes (Füssel and Klein, 2006; Kates et al., 2001; Kelly and Adger, 2000).

A major lesson learned from conventional vulnerability analyses is that they often miss the mark if they focus on a single system or set of interactions—for example, a certain population or ecosystem in isolation—rather than considering the larger system in which people and ecosystems are embedded (O'Brien and Leichenko, 2000; Turner et al., 2003a). The Hurricane Katrina disaster (Box 4.3) illustrates the importance of interactions among the human and environmental components in influencing vulnerability: land and water management decisions interacted with environmental, social, and economic dynamics to make the people and ecosystems of New Orleans and surrounding areas particularly vulnerable to storm surges, with tragic results.

As recognition has grown that vulnerability should be assessed in a wider context, attention has increasingly turned to integrated approaches focused on coupled humanenvironment systems. Such analyses consider both the natural characteristics and the human and social characteristics of a system, evaluate the consequences of climate change and other stresses acting on the integrated system, and explore the potential actions that could be taken to reduce the negative impacts of these consequences, including the trade-offs among efforts to reduce vulnerability, enhance resilience, or improve adaptive capacity (see Figure 4.1) (Eakin and Luers, 2006; Kasperson et al., 2009; Turner et al., 2003a). Integrated approaches that allow the evaluation of the causal structure of vulnerabilities (i.e., the long-term drivers and more immediate causes of differential exposure, sensitivity, and adaptive capacity) can help identify the resources and barriers that can aid or constrain implementation of adaptation options, including

Röaicr;al

Stacked system by scale

Röaicr;al

Stacked system by scale

Exposure

Pre-emptive measures

State of biosphere Global environ mental change

Stressors, Stresses, Perturbations

• Macro political economy

■ Social-structural dynamics

■ Globaiization

• Socioeconomic endowments & entitlements

■ Range of variability & coping capadty

■ Political economy

' Socioeconomic conditions

Exposure

Pre-emptive measures

Coping/ response

RisW impacts

Environmental/ ecological conditions

Adaptation

Stressors, Stresses, Perturbations

State of biosphere Global environ mental change

Human-Environ ment System [with attributes of vulnerability]

. Biophysical/ecological endowments p Range of variability & resilience > Reference state

FIGURE 4.1 A framework for analyzing vulnerabilities, focusing on a coupled human-environment system in which vulnerability and response depend on both socioeconomic and human capital as well as natural resources and changes in the environment. From left to right, the figure includes the stresses on the coupled system, the degree to which those stresses are felt by the system, and the conditions that shape the ability of the system to adapt. SOURCE: Kasperson et al. (2009), adapted from Turner et al. (2003a).

BOX 4.3

Vulnerability of New Orleans to Hurricane Katrina

The Mississippi River, especially in and around New Orleans, has been intensively engineered to control flooding and provide improved access for ships to the port of New Orleans. These hydraulic works significantly reduce the river's delivery of sediments to the delta between the city and the Gulf of Mexico, and thus the land-building processes that would otherwise offset the gradual subsidence and erosion of the delta. In addition, the construction of channels and levees and other changes in the lower delta have affected vegetation, especially the health of cypress swamps. Together, these changes in elevation and vegetation have weakened the capacity of the lower delta to serve as a buffer to storm surges from the Gulf of Mexico.

Various assessments of the condition of the lower Mississippi Delta—which together form a quasi-integrated vulnerability study—revealed that in the event of a direct hurricane strike, the vegetation and land areas south of New Orleans were insufficient to protect the city from large storm surges, and also that various hydraulic works would serve to funnel flood waters to parts of the city (Costanza et al., 2006; Day et al., 2007). Despite this knowledge, little was done to reduce the region's vulnerabilities prior to 2005. When Hurricane Katrina struck in late August of that year, the human-induced changes in the region's hydrology, vegetation, and land-building processes, together with the failure to maintain adequate protective structures around New Orleans, resulted in extensive flooding of the city and surrounding area over the following week (see figure below). This, combined with a lack of institutional preparedness and other social factors, led to a well-documented human disaster, especially for the poorest sections of the city (Costanza et al., 2006; Day et al., 2007; Kates et al., 2006).

While climate change may or may not have contributed to the Katrina disaster (see Chapter 8 for a discussion of how climate change might influence the frequency or intensity of hurricanes and other storms), it does illustrate how scientific analysis can help identify vulnerabilities. The Katrina disaster also illustrates how scientific analyses alone are not sufficient to ensure an effective response.

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