Climate change vulnerability is a measure of how strongly people or ecosystems are likely to be affected by climate change. Its formal definition is the "propensity or predisposition to be adversely affected" by climate change. It can apply to humans and also to natural systems (or ecosystems).. In: Climate Change 2022: Impacts, Adaptation and Vulnerability. Contribution of Working Group II to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change [H.-O. Pörtner, D.C. Roberts, M. Tignor, E.S. Poloczanska, K. Mintenbeck, A. Alegría, M. Craig, S. Langsdorf, S. Löschke, V. Möller, A. Okem, B. Rama (eds.)]. Cambridge University Press, Cambridge, UK and New York, NY, USA, pp. 3–33, Issues around the capacity to cope and adapt are also part of this concept. Vulnerability is a component of climate risk. It differs within communities and also across societies, regions, and countries. It can increase or decrease over time. Vulnerability is generally a bigger problem for people in low-income countries than for those in high-income countries.
Higher levels of vulnerability will be found in densely populated areas, in particular those affected by poverty, poor governance, and/or conflict. Also, some livelihoods are more sensitive to the effects of climate change than others. Smallholder farming, pastoralism, and fishing are livelihoods that may be especially vulnerable. Further drivers for vulnerability are unsustainable land and ocean use, marginalization, and historical and ongoing patterns of inequity and poor governance.
There are many different notions of what it means to be vulnerable. An important distinction is between biophysical and social vulnerability. Biophysical vulnerability is about the effects of climate hazards such as heat waves, coastal flooding or tropical cyclones. Social vulnerability, on the other hand, is about the underlying political, institutional, economic and social factors within societies. These factors matter for how and why people are affected, and they put some people and places more at risk than others. People who are more vulnerable include those with low incomes, indigenous peoples, women, children, and the elderly.
Tools for vulnerability assessment vary depending on the sector, the scale and the entity or system which is thought to vulnerable. For example, the Vulnerability Sourcebook is a guide for practical and scientific knowledge on vulnerability assessment. Climate vulnerability mapping helps to determine which areas are the most vulnerable. Mapping can also help to communicate climate vulnerability to stakeholders. It is useful to carry out vulnerability assessments in advance of preparing local climate adaptation plans or risk management plans. Global vulnerability assessments use spatial mapping with aggregated data for the regional or national level.
Definition
Climate change vulnerability has been a central concept in academic research and IPCC assessments since 2001. The concept of vulnerability can refer to a wide variety of different meanings or contexts in climate change research. It can apply to humans or to natural systems (ecosystems), often simultaneously given the interdependence of humans and ecosystems. Vulnerability is a component of climate risk. Vulnerability will be higher if the capacity to cope and adapt is low.
One definition of climate change vulnerability is stated as the "propensity or predisposition to be adversely affected" by climate change. A similar definition is given by the Third IPCC report (2001): "the degree to which a system is susceptible to, and unable to cope with, adverse effects of climate change, including climate variability and extremes".
Early studies focused on biophysical vulnerability to climate change. In other words, the effects of physical climate hazards such as a heat wave or heavy rain events. This direction of research was shaped by earlier natural hazards research and it emphasised physical changes and energy flows in the landscape. It aims to quantify and measure the impacts of an event on the environment and on people. Since (biophysical) vulnerability is interpreted here as the negative outcome of climate change on people or places, it is also sometimes referred to as 'outcome vulnerability'.IPCC, 2014: Annex II: Glossary [Agard, J., E.L.F. Schipper, J. Birkmann, M. Campos, C. Dubeux, Y. Nojiri, L. Olsson, B. Osman-Elasha, M. Pelling, M.J. Prather, M.G. Rivera-Ferre, O.C. Ruppel, A. Sallenger, K.R. Smith, A.L. St. Clair, K.J. Mach, M.D. Mastrandrea, and T.E. Bilir (eds.)]. In: Climate Change 2014: Impacts, Adaptation, and Vulnerability. Part B: Regional Aspects. Contribution of Working Group II to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change [Barros, V.R., C.B. Field, D.J. Dokken, M.D. Mastrandrea, K.J. Mach, T.E. Bilir, M. Chatterjee, K.L. Ebi, Y.O. Estrada, R.C. Genova, B. Girma, E.S. Kissel, A.N. Levy, S. MacCracken, P.R. Mastrandrea, and L.L. White (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, pp. 1757-1776.
An alternative framing focuses on social dimensions of vulnerability that set the context in which climate change happens. These dimensions include the political, institutional, economic and social structures that interact with the physical climate changes. For example, water privatization might affect the ability of people to respond to drought. This direction of research was shaped by human security research and they focus on the current context or 'starting point' for the social and biophysical processes. They are sometimes also referred to as 'contextual vulnerability' approaches. Research in this area focuses on analysing the factors that "put people and places at risk and reduce capacity to respond". See the section on 'Causes' below.
In the Fifth IPCC report, the social context was emphasized. It noted factors such as wealth and employment, access to technology and information, societal values and the role of institutions to resolve conflicts or develop relations among states as important. In: Climate Change 2014: Impacts, Adaptation, and Vulnerability. Part A: Global and Sectoral Aspects. Contribution of Working Group II to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change [Field, C.B., V.R. Barros, D.J. Dokken, K.J. Mach, M.D. Mastrandrea, T.E. Bilir, M. Chatterjee, K.L. Ebi, Y.O. Estrada, R.C. Genova, B. Girma, E.S. Kissel, A.N. Levy, S. MacCracken, P.R. Mastrandrea, and L.L.White (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, pp. 1-32. Vulnerability was defined as a characteristic of people or places independent of physical events. The report included two additional definitions, one of contextual vulnerability and one of outcome vulnerability.
Vulnerability and exposure In the climate change context, exposure is defined as "the presence of people; livelihoods; species or ecosystems; environmental functions, services, and resources; infrastructure; or economic, social, or cultural assets in places and settings that could be adversely affected.".
In earlier definitions of vulnerability to climate change (in the Third IPCC report and Fourth IPCC report) vulnerability was defined as a function of exposure, sensitivity and adaptive capacity. This changed during the Fifth IPCC cycle. In this report, exposure was defined as one of the three interacting elements of climate risk, rather than as one of the external drivers of vulnerability. This change had two main implications. First, it means that vulnerability is understood as independent of exposure (and hazard) but is contextual. Second, it means that vulnerability assessment could focus on indicators for sensitivity and adaptive capacity to understand the current system weaknesses. For example, weaknesses such as the high ground slope of a farmland or marginalization of households in a community would make people or places sensitive to climate impacts. This makes it important to select the most hazard-relevant indicators for any vulnerability assessment. For example, to assess the vulnerability of traditional coastal fishing communities to sea surge, 'distance of dwellings from sea' and 'elevation of dwellings from sea level' would be hazard-relevant indicators.
Types Climate change vulnerability has a wide variety of different meanings and uses of the term have varied and evolved over time. The main distinction is between biophysical and social (or socioeconomic) vulnerability:
Biophysical vulnerability is about the effects of physical climate hazards such as a heat wave or heavy rain events Social vulnerability considers the many political, institutional, economic and social structures that form the context for climate change
Biophysical or (physical) vulnerability Early studies focused on biophysical vulnerability to climate change. In other words, the effects of physical climate hazards such as a heat wave or heavy rain events. This direction of research was shaped by earlier natural hazards research and it emphasised physical changes and energy flows in the landscape. It aims to quantify and measure the impacts of an event on the environment and on people. It plays down the role of people themselves in managing these impacts. Since (biophysical) vulnerability is interpreted here as the negative outcome of climate change on people or places, it is also sometimes referred to as 'outcome vulnerability'.
Physical vulnerability tends to focus on outcomes of monetary loss and disruptions. It is also sometimes defined as the "degree of loss" on a scale of 0 (no loss) to 1 (total loss). In this framework, for example, physical vulnerability to surface water hazards in mountain areas has been widely studied.
Social (socioeconomic) vulnerability Social vulnerability is a more people-centred, holistic perspective on how and why people are affected by climate change. Vulnerability of ecosystems and people to climate change is driven by certain unsustainable development patterns such as "unsustainable ocean and land use, inequity, marginalization, historical and ongoing patterns of inequity such as colonialism, and governance". Therefore, vulnerability is higher in some locations than in others. Certain aspects within a region increase vulnerability, for example poverty, governance challenges and violent conflict. Some types of livelihoods are regarded as particularly climate-sensitive, resulting in a higher level of climate change vulnerability. These include for example smallholder farmers, pastoralists and fishing communities.
At its basic level, a community that is economically vulnerable is one that is ill-prepared for the effects of climate change because it lacks the needed financial resources. Preparing a climate resilient society will require huge investments in infrastructure, city planning, engineering sustainable energy sources, and preparedness systems. From a global perspective, it is more likely that people living at or below poverty will be affected the most by climate change and are thus the most vulnerable, because they will have the least amount of resource dollars to invest in resiliency infrastructure. They will also have the least amount of resource dollars for cleanup efforts after more frequently occurring natural climate change related disasters.M.J. Collier et al. "Transitioning to resilience and sustainability in urban communities" Cities 2013. 32:21–S28