Given the rhetoric coming from today’s military leaders, you’d be right to think climate change and sustainability has been tossed aside. The nation’s 2025 National Security Strategy labeled climate change a “disastrous” ideology. “The Defense Department is not in the business of climate change, solving the global thermostat. We’re in the business of deterring and winning wars,” said Secretary of Defense Pete Hegseth. And yet, there is still progress on sustainability being made; only now, it’s been rebranded as resiliency. At an Army base at Fort Polk in Louisiana, a renovation promises a cleaner, less carbon-intensive future, as well as a better living situation for servicemembers and their families. Completed in early March, the base represents a first-of-its-kind, $30 million investment in modernizing traditionally outdated and poorly maintained housing. It includes the installation of a large-scale geothermal energy system, all using U.S.-made equipment. It’s the first such geothermal installation at a U.S. military base, and an investment in reducing the installation’s carbon footprint.  “What they get out of it is a much more efficient system that responds to their needs a lot better,” says John Plack, Senior Vice President of Engineering and Implementation at Ameresco, the contractor that oversaw the retrofit. “We’re directly eliminating fossil fuel for heating.” [Photo: courtesy Ameresco] Now, the 3,600 homes on base will see their energy bills slashed by 30%. The upgrades are projected to reduce the Fort Polk family housing portfolio’s annual electrical consumption and deliver more than $2.6 million in annual utility and operational cost savings. Beyond delivering long-term savings to the installation, the initiative fostered local economic growth by investing in the community and supporting the local workforce.  Resilient housing on the rise The military has a lengthy history of making substantial investment in more sustainable and resilient buildings and housing, even during the current administration. As far back as 2003, during the George W. Bush administration, the Department of Defense was commissioning reports on climate risks.  Typically it has viewed this issue through the lens of resiliency: adapting bases to rising sea levels, making installations more self-sufficient, and cutting the military’s massive reliance on unstable oil supplies.  Right now, Tyndall Air Force Base in Panama City, Florida, is being rebuilt as a demonstration of resilient military construction, in response to a 2018 storm that caused $5 billion in damages. New buildings rest more than a foot above the ground, roofs have been hardened to survive 165–mile-per-hour winds, and a manmade oyster reef offshore is meant to break up waves. It’s one of a number of resiliency-focused projects that have continued under the current administration. The military has continued this work set in motion during previous administrations, despite policy shifts coming from the White House and Pentagon, for resilience and budget reasons. A Bloomberg Law analysis found that roughly $400 billion in federal assets, mostly in the Defense Department, stand at risk of a major flood or storm. Ameresco, which does a lot of federal work with groups like Veterans Affairs or the General Services Administration, built Fort Polk’s geothermal system by taking advantage of a program called ESPC, or Energy Savings Performance Contracts.  Enacted as part of the Energy Policy Act of 1992, it’s a way to invest in energy performance/efficiency upgrades on federal property without specific congressional appropriations, as long as there’s no upfront capital costs. The funding is structured as such that the base pays the private contractor over 25 years via the energy savings achieved by the installation.  So when a contractor like Ameresco comes in—bringing drill rigs into the backyard, trenching around utilities, and running piping through buildings—they’re paid as a down payment on future energy systems. According to the Army’s own reporting, it’s a great way to upgrade outdated military and other government facilities without spending government money, and it tends to exceed projected savings. It’s a massive program—the latest batch of funding for these kinds of projects, ESPC IV, was worth $3 billion —and Ameresco is working on a number of other, similar programs, including an array of energy-saving additions including solar and battery storage. Plack says that over the last few decades Ameresco has been doing this work, the projects have become more sophisticated, as technology has improved. A recently finished project in Petaluma, California, retrofitted the Coast Guard training facility to be more resilient in the event of a grid failure; a new microgrid, with solar panels and a storage battery, was added in response to a previous fire that left the installation without power for five days. When it comes to the Armed Forces and sustainability, practicality tends to be a consistent objective.  “We’re able to be very flexible with the technologies that fit the specific base or use case,” says Plack. “We’re pretty technology agnostic. It’s really what fits best.”