9.4 Measures of Vulnerability and Mapping

Vulnerability associated with exposures to climate-related hazards is closely tied to place. While an understanding of the individual-level factors associated with vulnerability is essential to assessing population risks and considering possible protective measures, understanding how potential exposures overlap with the geographic location of populations of concern is critical for designing and implementing appropriate adaptations. Analytic capabilities provided by mapping tools allow public health and emergency response workers to consider multiple types of vulnerability and how they interact with place. The development of indices that combine different elements of vulnerability and allow visualization of areas and populations experiencing the highest risks is related to improved geographic information systems (GIS) capabilities.1

Approaches to Assessing Vulnerability


Figure 9.4: Mapping Social Vulnerability

Figure 9.4: Mapping Social Vulnerability

CDC Social Vulnerability Index (SVI): This interactive web map shows the overall social vulnerability of the U.S. Southwest in 2010. The SVI provides a measure of four social vulnerability elements: socioeconomic status; household composition; race, ethnicity, and language; and housing/transportation. Each census tract receives a separate ranking for overall vulnerability at the census-tract level. Dark blue indicates the highest overall vulnerability (the top quartile) with the lowest quartile in pale yellow. (Figure source: ATSDR 2015)13

There are multiple approaches for developing vulnerability indices to identify populations of concern across large areas, such as state or multistate regions, or small areas, such as households within a county or several counties within a state.2 The Social Vulnerability Index (SVI) developed by the CDC aggregates U.S. census data to estimate the social vulnerability of census tracts (which are generally subsets of counties; Figure 9.4). The SVI provides a measure of overall social vulnerability in addition to measures of elements that comprise social vulnerability (including socioeconomic status, household composition, race or ethnicity, native language, and infrastructure conditions). Each census tract receives a separate ranking for overall vulnerability and for each of the four elements, which are available at the census-tract level for the entire United States. A similar methodology has been used to develop a vulnerability index for climate-sensitive health outcomes which, in addition to socioeconomic data, incorporates data on climate-related exposures and adaptive capacity.3

Application of Vulnerability Indices

GIS—data management systems used to capture, store, manage, retrieve, analyze, and display geographic information—can be used to quantify and visualize factors that contribute to climate-related health risks. By linking together census data, data on the determinants of health (social, environmental, preexisting health conditions), measures of adaptive capacity (such as health care access), and climate data, GIS mapping helps identify and position resources for at-risk populations.4,3,5,6,7,8 For instance, heat-related illnesses have been associated with social isolation in older adults, which can be mapped by combining data for persons living alone (determinants of health data), distribution of people aged 65 and older (census data), and frequency and severity of heat waves (climate data).

Vulnerability mapping can also enhance emergency and disaster risk management.9,10 Vulnerability mapping conducted at finer spatial resolution (for example, census tracts or census blocks) allows public health departments to target vulnerable communities for emergency preparedness, response, recovery, and mitigation.11 Geographic characteristics of vulnerability can be used to determine where to position emergency medical and social response resources that are most needed before, during, and after climate change related events.9,10,11

Emergency response agencies can apply lessons learned by mapping prior events. For example, vulnerability mapping has been used to assess how social disparities affected the geography of recovery in New Orleans following Hurricane Katrina.12 Maps displaying the intersection of social vulnerability (low, medium, high scores) and flood inundation (none, low, medium, high levels) showed that while the physical manifestation of the disaster had few race or class distinctions, the social vulnerability of communities influenced both pre-impact responses, such as evacuation, and post-event recovery.12 As climate change increases the probability of more frequent or more severe extreme weather events, vulnerability mapping is an important tool for preparing for and responding to health threats.


  1. ATSDR, cited 2015: Social Vulnerability Index (SVI) Mapping Dashboard. Agency for Toxic Substances & Disease Registry. URL | Detail
  2. Blaikie, P., T. Cannon, I. Davis, and B. Wisner, 1994: At Risk: Natural Hazards, People’s Vulnerability, and Disasters. Routledge, 284 pp. | Detail
  3. CSDH, 2008: Closing the Gap in a Generation: Health Equity through Action on the Social Determinants of Health. Final Report of the Commission on Social Determinants of Health. 247 pp., World Health Organization, Geneva. URL | Detail
  4. Ebi, K., P. Berry, D. Campbell-Lendrum, C. Corvalan, and J. Guillemot, 2013: Protecting Health from Climate Change: Vulnerability and Adaptation Assessment. 62 pp., World Health Organization, Geneva. URL | Detail
  5. Finch, C., C. T. Emrich, and S. L. Cutter, 2010: Disaster disparities and differential recovery in New Orleans. Population and Environment, 31, 179-202. doi:10.1007/s11111-009-0099-8 | Detail
  6. Friel, S., M. Marmot, A. J. McMichael, T. Kjellstrom, and D. Vågerö, 2008: Global health equity and climate stabilisation: A common agenda. The Lancet, 372, 1677-1683. doi:10.1016/s0140-6736(08)61692-x | Detail
  7. Gubler, D. J., P. Reiter, K. L. Ebi, W. Yap, R. Nasci, and J. A. Patz, 2001: Climate variability and change in the United States: Potential impacts on vector- and rodent-borne diseases. Environmental Health Perspectives, 109, 223-233. doi:10.2307/3435012 | Detail
  8. Hutton, D., 2010: Vulnerability of children: More than a question of age. Radiation Protection Dosimetry, 142, 54-57. doi:10.1093/rpd/ncq200 | Detail
  9. Keim, M. E., 2008: Building human resilience: The role of public health preparedness and response as an adaptation to climate change. American Journal of Preventive Medicine, 35, 508-516. doi:10.1016/j.amepre.2008.08.022 | Detail
  10. Manangan, A. P., C. K. Uejio, S. Saha, P. J. Schramm, G. D. Marinucci, C. L. Brown, J. J. Hess, and G. Luber, 2014: Assessing Health Vulnerability to Climate Change: A Guide for Health Departments. 24 pp., Climate and Health Technical Report Series, Centers for Disease Control and Prevention, Atlanta, GA. URL | Detail
  11. Preston, B. L., E. J. Yuen, and R. M. Westaway, 2011: Putting vulnerability to climate change on the map: A review of approaches, benefits, and risks. Sustainability Science, 6, 177-202. doi:10.1007/s11625-011-0129-1 | Detail
  12. Smit, B., O. Pilifosova, I. Burton, B. Challenger, S. Huq, R. J. T. Klein, and G. Yohe, 2001: Adaptation to climate change in the context of sustainable development and equity. Climate Change 2001: Impacts, Adaptation and Vulnerability. Contribution of Working Group II to the Third Assessment Report of the Intergovernmental Panel on Climate Change, J.J. McCarthy, Canziani, O.F., Leary, N.A., Dokken, D.J., and White, K.S., Eds., Cambridge University Press, 877-912. URL | Detail
  13. Turner, B. L., and others, 2003: A framework for vulnerability analysis in sustainability science. Proceedings of the National Academy of Sciences of the United States of America, 100, 8074-8079. doi:10.1073/pnas.1231335100 | Detail