In 2019, IDA began developing an internally funded interdisciplinary climate security capability within its cadre of research personnel. One of the first results of this effort is a demonstration analysis mapping global changes in an estimated Wet Bulb Globe Temperature (WBGT) Index derived from the most recent ensemble of Community Earth System Models to a publicly available dataset of the Defense Department’s current installation infrastructure. We then estimate the anticipated activity limitations for personnel expected to wear body armor on these installations using common work/rest restriction policies. We find that several global regions, as well as important military training installations, are likely to experience increased WBGT levels that could impose meaningful operational limitations. For commanders seeking to avoid these limitations, innovating new cooling technologies and infrastructure, inventing operational concepts that lower the expected physical strain on body armored servicemembers, reducing operational limitations by removing body armor, or simply accepting operational gaps created by these changes may be their only options.