Models of Climate Change Adaptation

In order to gain greater insight into individual decision-making in response to changes in climate, this research turns to wider contributions from the considerable literature on climate adaptation. The impacts of climate change upon human populations are often considered in terms of vulnerability. The vulnerability of a population to the impacts of climate change is reduced with increased adaptive capacity which is, in turn, affected by such factors as economic, human and social capital, institutional processes and access to information (Kniveton et al., 2008). Considering changes of climate from the perspective of adaptation and adaptive capacity permits the inclusion of migration as one potential adaptation strategy available to individuals and households. As such, climate change adaptation models provide a good starting point in the development of a conceptual model of the role of changes in rainfall variability in the migration decision-making process.

Adaptation strategies employed by individuals in response to climatic stimuli depend heavily upon variables such as the nature, duration and intensity of the stimulus, the present status of the individual, their previous experience and the networks to which they belong. In addition, the individual’s perception of the event and their subsequent ability to manage, adapt to or escape from its impacts affects the adaptation strategy chosen. Perhaps as a result of the numerous

contributing factors and their heterogeneous impact upon individuals, there is no explicit formula from which to accurately predict when migration is deemed to be the appropriate course of action. For an individual with the benefit of access to seasonal climate forecasts and information on predicted future climate change, the impact of such change will be assessed according to their perception of the risk posed to their livelihood. According to an individual’s perception of that risk, and the potential for alleviating the risk by relocating to an alternative location, climate change may contribute to the decision of an individual to migrate. However, using an agent-based model, Ziervogel et al. (2005) show that the impact of using forecasts depends upon the level of trust an individual places in the information, a factor both difficult to assess and quantify.

Conceptualising climate change migration as occurring on the basis of prior information, such as seasonal rainfall forecasts, involves the decision-maker adopting a proactive/planned approach to adaptation. As a result, migration may be chosen as an active option that can alleviate the impact of an expected occurrence on the basis of anticipated outcomes. Moser and Ekstrom (2010) present a systematic framework to identify barriers that may impede the process of adaptation to climate change with a focus on the intentional, planned adaptation process.

They suggest that an individual’s choice of a particular scope and scale of adaptation has significant implications for the number and types of barriers activated and encountered. The barriers to which Moser and Ekstrom refer are simply impediments that can stop, delay, or divert the adaptation process. The authors present a graphical representation of the scope and scale of adaptation to climate change, based upon their extensive literature review (Figure 3.4).

When defined according to the scope and scale of adaptation, migration would, in most cases, present something of a last resort adaptation strategy requiring a large investment in time and effort with potentially long term delays before goals are realised.

Figure 3.4: Moser and Ekstrom’s (2010, p.22027) scope and scale of adaptation to climate change.

According to Moser and Ekstrom’s representation of the scope and scale of adaptation, a high input, long term goal adaptation strategy approach such as migration would potentially result in what they term a system transformation. They suggest that such a system transformation will likely require more challenging barriers to be overcome than planning or implementing immediate measures to cope with a climate-driven disaster. In identifying and organising the barriers to such adaptation, Moser and Ekstrom consider the rational decision-making process of adaptation (Figure 3.5). Each of the nine stages in their adaptation decision-making model are systematically used by Moser and Ekstrom to identify potential barriers within the three core phases of understanding, planning and managing the adaptation process.

Figure 3.5: Moser and Ekstrom’s (2010, p.22027) phases and sub-processes throughout the adaptation process.

Moser and Ekstrom’s model presents the phases and sub-processes they deem to be involved in the rational decision-making of a planned adaptation to climate change and is useful as a first step in considering the migration decision. However, although the model breaks the decision down into three distinct sub processes within each of the three phases of the adaptation decision, the detail given for each of the sub processes provides an inadequately detailed basis from which to develop an ABM without considerable further data collection in the field.

Another endeavour to assess vulnerability and adaptive capacity among individual households is provided by Gilbert and McLeman (2010). Using the conceptual framework shown in Figure 3.6, Gilbert and McLeman examine how differential access to economic, social, and human

capital influenced the capacity of households to adapt to severe drought conditions in 1930s rural Canada.

Figure 3.6: Gilbert and McLeman’s (2010, p.11) conceptual diagram of rural household vulnerability.

Gilbert and McLeman’s (2010) study finds that migration patterns witnessed during their study period can be seen as one option amongst the set of adaptations undertaken by the population in response to broader interactions of social, economic and environmental processes. These are described by the authors to result in different levels of vulnerability and adaptive capacity of individual households. Dividing vulnerability into discrete and dynamic exposure/sensitivity and adaptive capacity components and distinguishing between in-situ adaptations and migration are useful steps in developing the migration decision-making model required for this research.

Although Gilbert and McLeman’s conceptual model acknowledges the interacting roles of social, economic and environmental components in causing vulnerability and adaptive capacity, the model is not presented in a state whereby the decision-making process of an actively adapting agent can be established.

Investigating the same concept of vulnerability and adaptive capacity but from the converse perspective of susceptibility, Acosta-Michlik et al. (2008) use security diagrams to measure susceptibility from a socio-economic perspective. On the basis of their security diagrams approach, Acosta-Michlik et al. present a conceptual framework for determining susceptibility

on the basis of socio-economic determinants provided by modernisation theory and trade dependency theory (Figure 3.7).

Figure 3.7: Acosta-Michlik et al.’s (2008, p.154) conceptual framework for socio-economic susceptibility.

Figure 3.7 shows Acosta-Michlik’s interpretation of the economic development and social well-being components that contribute to socio-economic susceptibility to drought. The two components are both broken down into three contributory sub-components. As a result, economic development is seen to be a result of financial resources, dependency on agriculture, and infrastructural development while social well-being results from health condition, educational attainment, and gender inequality. The underlying concept that Acosta-Michlik et al.’s security diagrams and conceptual model emphasise is that the higher the levels of environmental stress and socio-economic susceptibility, the higher the probability that crisis will occur.

The conceptual framework presented by Acosta-Michlik et al. (2008) provides further insight into those components that contribute to an individual’s adaptive capacity or susceptibility to

changes in climate. Developed from a socio-economic perspective the conceptual framework includes important parameters for consideration in the development of a conceptual model of the migration decision but, as with the work of Moser and Ekstrom (2010), requires further contributions in order to both focus upon migration as the adaptation strategy of choice and provide a model basis tailored for translation into an ABM designed to simulate a human system where there is potential for emergent phenomena (Bonabeau, 2002).