Human vulnerability to global environmental change
Definitions and Attributes
The susceptibility of populations, resources, and places to harm associated with global environmental change is evaluated through the concept of vulnerability. Vulnerability is a complex term, and is used differently depending on the disciplinary context. Nevertheless, in the multidisciplinary domain of literature on global environmental change and, more specifically, climate change, vulnerability is most often described in terms of three primary attributes: 1) the exposure of a particular population, place, or system (e.g., an “exposure unit”) to a threat, or suite of threats associated with global environmental change; 2) the sensitivity of the population, place or system to the threat(s) and 3) the capacities of the population, place or system to resist impacts, cope with losses and/or regain functions when exposed to global environmental change. Exposure and sensitivity increase vulnerability, while capacity acts to decrease it.
While the inter-relationship and relative importance of these three attributes is ambiguous and openly debated, together these three attributes capture both internal and external dimensions of vulnerability. The internal dimensions of vulnerability have been described as the innate features of the exposure unit that in part affect capacity to adjust, cope and adapt and in part determine its sensitivity to exogenous shocks. The internal dimensions of vulnerability thus may include the ways in which risk is perceived by an individual or population, cultural attributes of a population that affect its willingness to act in relation to threats and intrinsic attributes such as sex, age, or health that alter the exposed unit’s sensitivity to potential impacts. In contrast, the external dimensions of vulnerability refer to the characteristics of the exogenous hazard or threat (e.g., frequency, magnitude, spatial extent of impact). External dimensions may also refer to the structural socio-economic and institutional conditions of a particular place or population that affect who or what is exposed to hazards as well as the likelihood that particular activities, populations and places will suffer loss.
The existing theory of vulnerability to global environmental change is derived primarily from two research traditions: hazards research in human geography and political-economic perspectives on development and poverty. The hazards research perspective, or the “hazards paradigm,” is reflected in much of the early work on vulnerability to climate change that emerged in the 1980s. The hazards paradigm emerged from the pioneering research of Gilbert White of the University of Chicago on the theorization of human exposure to environmental extremes (so called ‘natural disasters’) and the social processes and human behaviors that lead to ineffective disaster management policy. The point of departure of a hazards perspective on vulnerability is with the hazard itself and, as a proxy, vulnerability is measured as the hazard’s outcome for a population such as lives lost, area flooded, or yield decline. On this basis, vulnerability is interpreted primarily as a function of exposure to a specific set of exogenous biophysical threats arising from global environmental change, and thus the characterization of the threat(s) and the nature of exposure (e.g., the number of people or value of property that may potentially suffer impacts) are the focus of research.
Over the course of the 1990s, numerous critiques emerged of the hazards paradigm, initially in relation to inadequacy of the paradigm in explaining the causes and consequences of disasters such as the famines in the Sahel in mid 1980s. One of the strongest critiques came from post-structural and political-economic interpretations of hazard vulnerability. In this perspective, vulnerability is not solely, or even primarily the result of exposure to specific environmental threats such as changing rainfall patterns or rising temperatures. Instead, vulnerability is presented as an existing (although dynamic) and latent characteristic of a place or population, associated with historical patterns of resource allocation at different spatial scales, relationships of social privilege and economic marginality and the political disempowerment of particular social groups.
The political-economic paradigm of vulnerability has been particularly influential in theorizing food insecurity and the incidence of famine, drawing on the theoretical contributions of the economist Amartya Sen. Sen’s “capabilities approach,” entailing an evaluation of populations’ endowments (the set of goods, resources, or ‘capitals’ within the command of the population) and entitlements (the institutions that govern what the population can do with its endowments), is now commonly used in the vulnerability research emerging from this critique. In this perspective the point of departure of analysis is not the hazard or threat but rather the attributes of the exposure unit: its resources and assets, and the institutional framework that circumscribe its capacities, sensitivities and exposure to risk.
The inevitable tension between the two perspectives on vulnerability has been the source of considerable conceptual debate and discussion in the global environmental change literature. The predominance of the hazards’ paradigm in analyses of climate change impacts, for example, has led to the characterization of vulnerability as an ‘end-point,’ or outcome of process of global change. The vulnerability of a population to sea level rise thus may be described in terms of the residual damage that is likely to result from an event of a given magnitude (e.g., a 1 meter [m] rise in sea level), after any actions are taken to mitigate the event (e.g., the construction of a protective sea wall). In contrast, political-economic perspectives on vulnerability are more likely to characterize vulnerability as an existing and dynamic social-environmental state that limits capacities, enhances sensitivities or increases exposure to particular threats. In this perspective, the hazard serves as a ‘trigger’ or stimulus that acts synergistically with existing (socioeconomic and biophysical) structural conditions to shift a population into a situation of crisis. This latter characterization of vulnerability is similar to the way vulnerability is used in the development economic literature in reference to the susceptibility of households to welfare loss or poverty.
Over the last two decades, research on vulnerability has benefited from insights from two fields of inquiry that were initially quite distinct in focus, but increasingly reflect common theoretical ambitions: resilience ecology and sustainable livelihoods. Resilience ecology is based in systems theory, employing the term ‘resilience’ to describe the condition of an ecological system that enables it to re-organize and regain core functions following significant disturbance. In application to social systems, resilience has led to the development of the idea of ‘coupled social-ecological systems’ which describe human activities and environmental processes as mutually dependent, co-evolving and linked through complex feedback relationships. Resilience captures many features of vulnerability as has been used in global environmental change research—particularly the issue of a population, individual or place’s capacity to resist, cope with or recover from shocks and stress.
This focus on capacity is echoed in the very different domain of asset-and-actor based approaches to sustainable development. In recognition of the failure of many projects to improve livelihood security and welfare in the developing world, and the additional threat that global environmental change implies for economically marginalized populations, asset-and-actor based approaches focus on enhancing human agency to mitigate risk. Here the emphasis is on understanding how vulnerability is experienced and perpetuated through the organization of both tangible and intangible (e.g., social capital) resources, and the factors that enable a population to mobilize to alter its relationship with exogenous sources of stress—whether biophysical (such as climate) or socioeconomic (such as globalization).
In short, there is general agreement that vulnerability is neither an outcome nor a static internal condition but rather a dynamic property emerging from the structure of human relations, the internal attributes of specific populations and places, and the nature of social-environmental interaction. In this light, vulnerability assessments, while inevitably focused on a particular attribute of concern (a particular economic activity, population, geographic region), are also inherently contextual, requiring an analysis of system interactions, structural conditions, and the internal dimensions of perception, values, social meanings associated with identity and place (Box 1).
|Box 1: Core Questions of Vulnerability Assessments|
The last decade of research on vulnerability to global environmental change has identified a series of core concerns that are now defining the vulnerability research agenda:
- The interaction of multiple, interacting stressors in creating vulnerability
- The high degree of socioeconomic and biophysical uncertainty associated with identifying, measuring and reducing vulnerability
- The need for metrics and approaches that account for cross-scalar influences and outcomes
- The importance of social equity and justice in addressing vulnerability
The term “multiple stressors” has emerged through a close examination of the external dimensions of vulnerability. Empirical research has repeatedly demonstrated that vulnerability to global environmental change cannot typically be understood through an examination of a single stressor (e.g., a significant decline in precipitation) and the response of an exposed population to that stressor. Globalization, epidemic disease and changes in local institutional settings for social action are just a few types of stressors that have been identified as significant drivers of vulnerability, independently and in interaction with environmental change. Social-ecological systems, communities or individuals often experience these stressors simultaneously and sometimes synergistically. Their responses are thus conditioned not only by their perception of one particular source of change, but the aggregation of a diversity of stressors operating together.
The interaction of multiple stressors introduces the potential for surprise outcomes and unanticipated consequences, and thus a significant degree of uncertainty in characterizing vulnerability. For example, while the United States is considered to have significant technological and financial capacity to deal with extreme climate events and more gradual environmental change, in the case of Hurricane Katrina the combination of regional institutional weaknesses, shifts in administrative priorities at the federal level, and the politics of environmental policy combined with an unusually strong hurricane to create an unprecedented disaster. Anticipating the trajectory of technological change, political priorities and the socioeconomic conditions that can lead to changes how resources are distributed or used is part of the process of assessing future vulnerability. Nevertheless, scientists generally have far less confidence in projections of socioeconomic change than they do in their models of the temporal trajectories of biophysical processes.
Vulnerability research is also challenged by problems of scale. The recognition that the susceptibility to harm of a particular system is not exclusively or even largely determined by local or immediate conditions requires analyses that incorporate the influence of vulnerability drivers and outcomes at different spatial and temporal scales. Researchers have traditionally used qualitative methods to explore cross-scalar interactions of this nature. Currently a number of different quantitative modeling approaches are being developed to explore the relationships between global drivers and local outcomes, and, conversely, local responses and regional and global environmental change. The contribution of resilience ecology to vulnerability analysis has been instrumental in this process. Resilience has led to the use of complex systems models and associated computational tools to evaluate emergent properties and interactions in sensitive systems.
Perhaps most important, as the analysis of vulnerability to global environmental change has moved from a more abstract academic domain to the policy and planning sphere, issues of social equity and justice have assumed increasing prominence. Attention to these concerns has long been a feature in hazards research. Global environmental change if anything has increased concern over how the distribution of key resources globally, as well as within regions and communities, will affect the impacts of global change and response capacities. Complicating research on equity and global change is the recognition that vulnerability to global change is embedded in histories of institutional development and political-economic relations, and that these histories have a significant influence on how present and future vulnerability is experienced and addressed.
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