For Whom the Bell Tolls: Vulnerabilities in a Changing Climate

Document Type

Book Chapter

Publication Date



Center for Sustainability Education



Publication Title

Climate Change and Vulnerability


People have evolved ways of earning livelihoods and supplying their needs for food, water, shelter and other goods and services that are adapted to the climates of the areas in which they live. But the climate is ever variable and changeable, and deviations that are too far from the norm can be disruptive, even hazardous.

Now the climate is changing due to human actions. Despite efforts to abate the human causes, human-driven climate change will continue for decades and longer (IPCC, 2001a). Who is vulnerable to the changes and their impacts? For whom does the bell toll? We ask, against the oft-quoted advice of the poet John Donne, because understanding who is vulnerable, and why, can help us to prevent our neighbour's home from washing into the sea, a family from suffering hunger, a child from being exposed to disease and the natural world around us from being impoverished. All of us are vulnerable to climate change, though to varying degrees, directly and through our connections to each other.

The propensity of people or systems to be harmed by hazards or stresses, referred to as vulnerability, is determined by their exposures to hazard, their sensitivity to the exposures, and their capacities to resist, cope with, exploit, recover from and adapt to the effects. Global climate change is bringing changes in exposures to climate hazards. The impacts will depend in part on the nature, rate and severity of the changes in climate. They will also depend to an important degree on social, economic, governance and other forces that determine who and what are exposed to climate hazards, their sensitivities and their capacities. For some, the impacts may be beneficial. But predominantly harmful impacts are expected, particularly in the developing world (IPCC, 2001b).

To explore vulnerabilities to climate change and response options in developing country regions, 24 regional and national assessments were implemented under the international project 'Assessments of Impacts and Adaptations to Climate Change' (AIACC). The case studies, executed over the period 2002-2005, are varied in their objectives, geographic and social contexts, the systems and sectors that are investigated, and the methods that are applied. They are located in Africa, Asia, Latin America, and islands of the Caribbean, Indian and Pacific Oceans. The studies include investigations of crop agriculture, pastoral systems, water resources, terrestrial and estuarine ecosystems, biodiversity, urban flood risks, coastal settlements, food security, livelihoods and human health.

One factor that is common to most of the studies is that they include investigation of the vulnerability of people, places or systems to climatic stresses. Vulnerability studies take a different approach from investigations of climate change impacts. The latter generally emphasize quantitative modelling to simulate the impacts of selected climate change scenarios on Earth systems and people. By contrast, vulnerability studies focus on the processes that shape the consequences of climate variations and changes to identify the conditions that amplify or dampen vulnerability to adverse outcomes. The climate drivers are treated as important in vulnerability studies, but drivers related to demographic, social, economic and governance processes are given equal attention. Understanding how these processes contribute to vulnerability and adaptive capacity in the context of current climate variations and extremes can yield insights regarding vulnerability to future climate change that can help to guide adaptive strategies (Leary, 2002).

This volume presents a collection of papers from the AIACC case studies that address questions about the nature, causes and distribution of vulnerability to climate change. In this first chapter we introduce the case studies and present a synthesis of lessons from our comparison of the studies. A companion to this volume, Climate Change and Adaptation (Leary et al, 2008), explores options for adapting to climate change, capacities for implementing these and obstacles to be overcome.

Our synthesis of lessons about vulnerability is a product of a week-long workshop held in March 2005. During the workshop we applied a three-step risk assessment protocol previously used by Downing (2002). In the first step we identified domains of vulnerability that correspond to resources or systems that are important to human well-being, are very likely to be affected by climate change, and are a focus of one or more of the case studies. Four major domains were selected, around which we organized our discussions in the workshop and which have been used to structure both this chapter and the book as a whole: 1) natural resources, 2) coastal areas and small islands, 3) rural economy and food systems, and 4) human health.

In the second step, outcomes of concern within each domain were identified and ranked as low-, medium- or high-level concerns. In selecting and ranking outcomes, we attempted to take the perspective of stakeholders concerned about national-scale risks. Outcomes are included that our studies and our interpretation of related literature suggest are plausible, and that would be of national significance should they occur. Our rankings of low-, medium- and high-level concerns are based on the following criteria: potential to exceed coping capacities of affected systems, the geographic extent of damages, the severity of damages relative to national resources, and the persistence versus reversibility of the impacts. The rankings do not take into account the likelihood that an outcome would be realized. They represent the degree of concern that would result if the hypothesized outcomes do materialize. While we have not formally assessed the likelihood of the different outcomes, each is a potential result under plausible scenarios and circumstances.

In step three we identified the climatic and non-climatic factors that create conditions of vulnerability to the outcomes of concern within each domain. Where climatic and non-climatic drivers combine to strongly amplify vulnerability, the potential for high-level concern outcomes being realized is greatest. Conversely, where some of the drivers interact to dampen vulnerability, outcomes of lower-level concern are likely to result.

The lessons produced from this protocol are presented below in this chapter. The case studies from which they are derived are elaborated on in the chapters that follow.


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