Sensitivity of Mexico’s Farmers: A Sub National Assessment of Vulnerability to Climate Change

Abstract

In ecology and systems theory, sensitivity refers to ability of an environmental system which deals with stress or disturbance s. Sensitivity is degree to which a system is affected, or its ability to respond to a stimulus, in this case, climate stimulus (Smit et al., 2009). Some concepts that have been applied to natural systems are stability, resilience and flexibility, which may well be applied to human systems. Stability refers to ability of a system to remain fixed or unchanged when exposed to a disturbance. Resilience refers to ability of system to rebound from a disturbance that could be experienced. Flexibility is degree of manoeuvrability that exists within system. Despite their application in ecology, boundaries in human systems between these concepts are not clear and kept on being discussed (Smithers and Smit, 2009). But what we can be certain of is that terms described above have gained attention in recent years because they influence internal definition of systems and their vulnerability to changes in climate systems (Klein and Nicholls, 1999). The IPCC recognizes vulnerability to climate change as the degree to which systems are able or unable to address negative impacts of climate change” (Parry et al., 2007), referring to geophysical, biological and socioeconomic systems. They point out that vulnerability may relate to vulnerable system (a city, an agricultural activity), impact on system (flood) or mechanism that drives it (melting). Cutter (1996) and Third Assessment Report of IPCC (McCarthy et al., 2001) identified three components that determine vulnerability of a system or group of people: their exposure, sensitivity and adaptive capacity. In fact, since second IPCC report (1996) it was recognized that the most vulnerable systems are those more sensitive to climate change and with less adaptability. More information on vulnerability analysis can be found in Berry et al., 2006; Bohle et al., 1994, Downing and Patwardham, 2006, Kelly and Adger, 2000; whereas in present work definition of IPCC on vulnerability is used and especially in this chapter on climate sensitivity, a component of vulnerability. The sensitivity, according to IPCC (2007), is the degree to which a system is affected by a disturbance, either adversely or beneficially, by variability or climate change, and points out that effects can be direct or indirect. Sensitivity refers to extent such a system will