The Department of Defense (DoD) has identified climate change as a risk to its infrastructure and is seeking to develop efficient and effective processes to assess the vulnerability of its assets to this risk. In response to this need, this project developed, piloted, and evaluated an approach for vulnerability assessment keyed to DoD decision-making needs and processes at multiple organizations levels. It also developed and tested methods for use in an overall assessment framework, and it outlined a process for assessments at installations that applies extensive stakeholder involvement, a novel approach to providing climate information (plausible future exposure), a range of existing models and approaches for estimating impacts, and decision-making frameworks.

Using research literature on climate change vulnerability (theory, definitions, and processes-in-use), this project tested approaches and methods to assess vulnerabilities in case studies at three DoD mid-Atlantic installations that represent three military Services, differing missions, and differing risks from future climate changes: the U.S. Naval Academy, Joint Base Langley-Eustis, and Fort Bragg. It probed for data and potential indicator to establish baseline conditions and installation characteristics, extracted information about the installations’ future exposure to climate change from sources including regional climate models, established the significance for missions and operations of future climate impacts, and analyzed the potential for integrating climate risks into short- and long-term DoD decision making. This project developed (1) specialized information on impacts-relevant climate variables and a climate outlook approach to providing climate information; (2) a three-tiered framework for DoD vulnerability assessment; and (3) a process for implementing installation-level assessments that emphasize stakeholder engagement, relevance, and communication and impacts evaluation/modeling paired with qualitative analysis of significance for mission attainment.

The major results were the development of a three-tiered framework for DoD-wide vulnerability assessment, an outline of steps to guide the conduct of installation-level vulnerability assessments, and the identification of three sets of methods that are important for such assessments, as well as research needed on aspects of the assessment process.

The project also produced a climate outlook for the mid-Atlantic region, which was useful in identifying and quantifying climate-change impacts relevant to the installation-level priority systems established through stakeholder engagement processes. The climate outlook provides an overview of climate information relevant to vulnerability assessment of military installations. The analyses in the outlook integrate knowledge of current climate trends from observations with sources of information about possible future climates. The outlook integrates expert judgment about the state of science related to climate phenomena that were identified as important to installations in the region through the project’s stakeholder interactions. The information in the outlook can be used with the vulnerability baseline established for an installation to identify potential future impacts of climate change that warrant additional assessment or adaptation planning. The outlook also provides a starting point for building awareness of climate change into extant planning and decision-making processes.

Finally, the project produced insights into impacts modeling approaches/methods and vulnerabilities at each case study location. Specific methods included event history analysis, coastal flooding return period analysis, storm surge modeling, fire risk and ecosystem maintenance, training and flag days, network interdependence analysis, heating and cooling degree days, and decision analysis. Elevation was explored as a proxy for vulnerability to sea level rise and storm surge through the creation of maps that combined elevation data and asset indicators; the web bulb globe temperature, a proxy for outdoor training disruption; and the Keetch-Byram Drought Index, a proxy for fire-prone conditions and disruption of planned controlled burns.

This research supports the following conclusions:

1. Vulnerability assessments provide essential and specialized information needed to determine the susceptibility and consequent risk of climate change to infrastructure assets. The DoD needs such information to successfully and efficiently manage climate risks.
2. Vulnerability should be defined as a function of the characteristics that affect the susceptibility of a site to damage, thus emphasizing sensitivity and adaptive capacity rather than exposure. This definition structures information collection and analysis, and points staff to the dimensions of infrastructure they can prioritize, measure, and manage.
3. A three-tiered assessment approach will increase efficiency and reduce costs while still allowing for detailed analysis where needed. Tier 1 screens all agency sites to set priorities. Tier 2 focuses on more detailed assessments at a smaller number of sites identified as most vulnerable by Tier 1. Tier 3 comprises analysis of adaptation options.
4. An established but flexible process for DoD installation assessments (Tier 2) would provide comparable results and adaptability for varied missions and operations. The case studies suggest a five-step process to meet DoD’s needs: (a) frame the assessment, (b) appraise conditions and identify installation vulnerabilities, (c) analyze future climate exposure, (d) estimate/model potential impacts, (e) evaluate significance and next steps, (f) build assessment into ongoing processes, and (g) document and evaluate the process.
5. No “one size fits all” approach is appropriate for stakeholder engagement. Strategies must be tailored to take advantage of the expertise of staff who know how the installation works.
6. Information on future climate change needs to focus on installation- and area-specific variables, drawing on information sources including observations, projections, and scenarios of climate conditions, downscaling, and modeling of hydrology and other related environmental conditions. Projections should be made using diverse quantitative and qualitative methods.

The framework and process presented here have promise for future implementation, with (1) continued testing and evaluation of methods (for screening, engagement, priority setting), climate information, indicators and thresholds; (2) assessment of opportunities to integrate climate change considerations into ongoing planning and decision-making processes; (3) development of training and technical guidance for participants and users of vulnerability assessments; (4) cataloging of available methods and establishing research programs to develop others; and (5) documenting of experience to perform lessons learned analysis.