Step 3: Assess Vulnerability

Assess the vulnerability of the Tribe’s key concerns to better understand how species, resources, and assets may be affected by climate change and to support the development of adaptation actions.

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Step 3 Checklist

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Step 3 tribal Examples

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Activity 1: Select Vulnerability Assessment Approach

 A vulnerability assessment deepens the community’s understanding of how different species, resources, and assets could be affected by climate change and supports the Tribe’s development of actions to adapt to climate change.

“Yurok elders have a good understanding of how the environment has changed over a relatively short period of time (less than 200 years). While not always attributable to climate change, these changes often reflect ecosystem loss and environmental degradation that resulted from the loss of autonomy and self-determination regarding management of resources, lands, waters, and ecosystems within the last 150 years. Additionally elders’ experience provides a benchmark of how less disturbed ecosystems should function.”

Guiding Questions

Helpful questions to consider during this activity.

Considerations for integrating and protecting
Traditional Knowledges during this activity.

There are many approaches that the Tribe can use to assess vulnerability. Vulnerability is the degree to which a key concern is susceptible to adverse effects of climate change as determined by climate exposure, sensitivity, and adaptive capacity (Figure 3). The concerns that are more sensitive and less able to adapt or respond are more vulnerable while those that are less sensitive and more able to adapt or respond are less vulnerable.

Figure 3. Components of Vulnerability

Vulnerability is determined by climate exposure, sensitivity, and adaptive capacity. This figure defines and highlights the relationships between vulnerability, climate exposure, sensitivity, and adaptive capacity.

Each vulnerability assessment approach is slightly different, but most include two components: 

  • Assessing vulnerability: combining exposure, sensitivity, and adaptive capacity; and
  • Selecting initial planning areas: assessing risk or using a multi-criteria approach to identify the potential magnitude of impact.

Available funding and selected approaches for adaptation planning determine how much time and effort Tribes can dedicate to each component of their vulnerability assessments. Tribes and Tribal organizations approach vulnerability assessments in different ways (Table 8).

Table 8. Summary of Five Different Vulnerability Assessment Approaches

This table summarizes five different approaches that Tribes have used to assess climate vulnerability and prioritize adaptation planning efforts.

This section provides five Tribal case studies that further explore different approaches that Tribes have used to assess climate vulnerability and prioritize adaptation planning efforts (as summarized in Table 8).

Case Study 1: Qualitative Staff Input

The Tohono O’odham Nation

Case Study 2: Vulnerability & Risk

The Confederated Salish and Kootenai Tribes

Case Study 3: Guided Staff Input

Jamestown S’Klallam Tribe

Case Study 4: Vulnerability Index

Shoshone-Bannock Tribes

Case Study 5: Multi-Criteria Analysis

Swinomish Indian Tribal Community

Activity 2: Determine Relative Climate Change Vulnerability

Relative vulnerability rankings can help focus the Tribe’s adaptation planning efforts on the most vulnerable key concerns.

“Many cultural resources are non-renewable resources. They can be one day or thousands of years old. Their destruction is a gross violation of everything we value.”

Guiding Questions

Helpful questions to consider during this activity.

Considerations for integrating and protecting
Traditional Knowledges during this activity.

Relative vulnerability rankings are a key input in deciding where to focus the Tribe’s adaptation planning efforts. Key concerns that are more vulnerable may need immediate attention while those that are less vulnerable could be addressed in the future. There may be instances where climate change creates areas of opportunity that current conditions do not support. Relative climate change vulnerability can be assessed either quantitatively or qualitatively and depends on the climate exposure, sensitivity, and adaptive capacity. See how five Tribes assessed relative vulnerability.

Climate Exposure includes everything from more frequent heavy rainfall events and coastal or riverine flooding to higher temperatures and more intense periods of drought. Changes in the extent, magnitude, and frequency of extreme weather events can have significant effects on the things the Tribe cares about. Using existing resources available for climate projections, it is possible to identify quantitative projections for many of these climate exposures. Where quantitative projections are not available, exposure can be qualitatively assessed (i.e., identifying direction and magnitude). Step 2: Activity 4 has more guidance on collecting and summarizing relevant and actionable climate exposure information.

Sensitivity depends on the nature of the key concerns and the climate exposure variables. A particular concern may be very sensitive to changes in water availability but only slightly sensitive to changes in temperature. For example:

  • Pinyon pine and douglas fir, tree species that live near each other in dry coniferous forests, will likely be exposed to the same increases in temperature and potential drought conditions. However, each species has a different level of tolerance of drought conditions and thus can be more or less sensitive to those conditions.[16] 
  • Due to physiology, Elders and youth are more sensitive to extreme heat events than young adults and adults.[17]

Adaptive Capacity of a key concern is critical in determining the impacts of climate and extreme weather events. Identifying key limitations to adaptive capacity can help determine how to design and focus adaptation actions to reduce those limitations and help the species, asset, or system respond positively to projected changes. For example:

  • With changing food supplies in a particular habitat, a generalist species that eats a variety of plants will likely have a higher adaptive capacity than a specialist species that relies on only one or two plants for survival.
  • A drinking water supply system that has two water sources (groundwater and surface water) and two sets of pumps has a higher adaptive capacity than a water supply system dependent on a single water source, because it is better prepared to shift between sources if one is affected by changing precipitation patterns.

The Tribe can use relative vulnerability rankings to help determine where to focus adaptation planning efforts. Assigning sensitivity and adaptive capacity scores for the range of climate exposures can be used to calculate the relative vulnerability of each of the key concerns. One way to do this is by using a relative vulnerability matrix. A relative vulnerability matrix (Figure 10) ranks components of vulnerability on different axes in order to visualize and identify the degree of vulnerability for each key concern relative to the others. The Tribe can use this information to focus planning efforts.

Figure 10. Example Relative Vulnerability Assessment Matri

This matrix, used by the Jamestown S’Klallam Tribe, shows relative vulnerability assessment rankings by color.[18]


Vulnerability assessment resources used by and developed for Tribes, including examples of resources from Tribes that have completed vulnerability assessments.

Once the Tribe has completed the relative vulnerability assessment process, pause and have the climate change planning team evaluate the reality of the assessment results. In many (but not all) cases, climate change will increase current vulnerabilities. Members of the climate change planning team may already have a sense of the relative vulnerabilities between the key concerns, and it makes sense to review and ground truth these results. If the results are different than expected, investigate why it may be so in order to confirm the results of, identify errors in, or identify necessary modifications to the assessment. Consider the following questions: 

  • Do the final results of the relative vulnerability assessment make sense? If not, why not?
  • Are there any significant surprises that cannot be explained?
  • Were Traditional Knowledges included in the right manner, according to Tribal policy and accurately following Tribal cultural protocols?
  • Are there any gaps where more input, data, or expertise is needed?

Finally, it is important to understand the limitations of and assumptions inherent in the chosen vulnerability assessment approach. Quantitative approaches may be limited by the detailed inputs available to run the tools or models. Qualitative assessments may be limited by the expertise of the people consulted or involved in the assessment. Knowing these limitations can aid in understanding the results.

Activity 3: Select Priority Planning Areas

Given limited time and resources, determine priorities to begin taking action to enhance resilience.

“We chose to start the climate change adaptation planning process by focusing on three sectors that are likely to be affected by these changes in the near future – Water Resources, Human Health, and Emergency Management.”

Guiding Questions

Helpful questions to consider during this activity.

Considerations for integrating and protecting
Traditional Knowledges during this activity.

Planning efforts are always limited in some way by time, money, or other resources. So, it is useful to pick a place to start taking action. This does not imply that the areas selected are more important than other concerns, merely that these planning areas are good opportunities for the Tribe to start taking action. Tribes have used different approaches to focus their adaptation planning efforts (Step 3: Activity 1).

A risk assessment is the process of identifying the probability of occurrence multiplied by the magnitude of consequences of an adverse event or impact. Using a risk assessment, or other approach, to assess the consequences of changes in climate can help determine which issues will have the greatest impact on the community. Some Tribes use explicit consideration of risk to help determine where to focus their adaptation planning efforts. Others incorporate consideration of risk into a multi-criteria assessment process. Either way, the goal is to use the information to determine where to focus the Tribe’s adaptation planning efforts.

Use either a traditional risk assessment focused on the likelihood and consequence of an impact (see Case Study 2 about The Confederated Salish and Kootenai Tribes and Case Study 5 about the Swinomish Indian Tribal Community) or a multi-criteria analysis that includes a variety of factors—such as the unique value of the species or the magnitude and irreversibility of potential impacts (see Case Study 3 about the Jamestown S’Klallam Tribe and Case Study 4 about the Shoshone-Bannock Tribes) to assess the potential impacts to the community with each key concern. Rely on input from the planning team, community members, and partners to complete the risk assessment process. 

No matter which approach the Tribe uses, it is important to be consistent across the assessment and use the same variables to assess risk so that the risks can be compared. These variables may include, but are not limited to: 

  • Impacts to people (e.g., loss of life, physical injury, and mental health), 
  • Impacts to infrastructure (e.g., loss of homes, impacts to businesses, and impacts to infrastructure), 
  • Impacts to cultural significance (e.g., loss of culturally important plant and animal species, and limited access to cultural sites or resources). 

The likelihood and magnitude of exposure to climate change may be similar across several key concerns; however, depending on which impacts are considered (e.g., the number of buildings or miles of roadway in the flood zone) the consequences (direct and indirect) of that change may differ among those concerns.


Resources to help determine magnitude of consequences and identify priority climate vulnerabilities.

Tribal Examples

See how the Red Lake Band of Chippewa Indians assessed vulnerability and categorized risk in their vulnerability assessment.

The results of the risk assessment will guide the selection of priority planning areas. In some cases, these planning areas may be pre-determined by the adaptation planning approach or may be further refinements of the initial planning areas identified in Step 1: Activity 1. In other cases, they may be a subset of those initial areas focusing on the highest vulnerability, highest risk, or near-term opportunities for action (depending on the criteria used in the assessment). This selection of planning areas to focus on (or the refinement of key concerns to focus on within a planning area) can help target funding, resources, and time on the areas where investment is most needed. 

Collaborate with the appropriate members of the planning team, community, partners, and others in the assessment process to determine the criteria for selecting planning areas to move forward into the planning for action phase. For example, consider whether key concerns above a certain risk ranking (e.g., high risk) should be prioritized. Or, consider whether low vulnerability or low consequence items would be best left for a future phase of the Tribe’s adaptation planning work. Narrowing the focus of the assessment will allow the Tribe to use a finite set of resources effectively.

Tribal Examples

Learn more about how the St. Regis Mohawk Tribe completed their Climate Change Adaptation Plan for Akwesasne (the Mohawk Nation Territory) in 2013.