Summary: Subversion of the Nuclear Security Enterprise (NSE) undermines the credibility and resiliency of the U.S. nuclear deterrent. One of the external factors that poses a growing risk to the NSE is climate change. Any risk that inhibits production of nuclear weapons, their supporting infrastructure, to include their design and certification, also impacts the credibility of U.S. extended deterrence guarantees. This piece, the first in a two-part series on the nexus of climate change and nuclear security, will examine the impacts of climate change on the NSE, and highlight a handful of circumstances that would undermine the U.S. nuclear deterrent. The second piece will examine the cascading implications that this poses on the risk reduction and nonproliferation regimes. I. Climate Change: A Threat to the Nuclear Deterrent Russia’s invasion of Ukraine has strengthened the NATO alliance, and support for the U.S. nuclear deterrent. Finland and Sweden’s decision to join NATO exemplifies the value of collective defense and the role of U.S. extended deterrence in the reassurance of European allies and partners. As such, the strength and resiliency of the U.S. nuclear deterrent is paramount to not only national defense but also the shaping of global security dynamics. This capability, however, is backstopped by a nuclear security enterprise (NSE) that is increasingly vulnerable to the changing threat landscape: industrial base subversion, sabotage, and, more notably, climate change. With facilities spread across the U.S., the NSE, to include all facilities and infrastructure, must face, to varying degrees, the consequences of drought, water scarcity, earthquakes, wildfires, rising sea levels, flooding, melting polar ice, and catastrophic storms. While seemingly isolated events, each of these phenomena have direct implications on nuclear production capabilities, the resiliency of the U.S. nuclear deterrent, and credibility that underpins numerous strategic partnerships. This paper will examine the broad implications of climate change on the U.S. NSE, and highlight key potential events that will undermine the U.S. nuclear deterrent. II. Climate Change Hazards Effect on Key NSE Laboratories and Sites The NSE comprises Department of Energy (DOE) and National Nuclear SEcurity Administration (NNSA) laboratories, the Nevada National Security Site, production plants, and processing facilities involved in the design, production, and testing of nuclear weapons. Given the geographical variation of these sites, they are susceptible to various natural disasters and the general effects of climate change, including changes in temperature. For example, last February, nuclear officials were altered to a wildfire approaching the Pantex Nuclear Plan. The wildfire near Smokehouse creek, burning northeast of Pantex was recorded as the second largest wildfire in Texas history. Due to the severity and proximity of the fire, operations were ceased and non-essential personnel were evacuated. Although the plant has robust precautions in place to prevent fire from damaging facilities, this scenario provides insight to the challenges that will continue to impact the NSE if climate concerns are left unaddressed. Since 1965, Pantex has been the United States’ sole facility for assembling and disassembling nuclear weapons, making it a single point of failure in the NSE. Climate change has increased the number of wildfires in Texas, and made these a year-long threat rather than seasonal. Additionally, Pantex also handles significant quantities of nuclear material, such as uranium, plutonium, and tritium. Therefore, damage to Pantex could not only halt nuclear weapons production but also lead to a radiological disaster. The threat of wildfires is not isolated to Pantex. The Los Alamos National Laboratory (LANL), one of three NNSA laboratories that supports the U.S. nuclear deterrent mission, and based in the desert of New Mexico, is also extremely vulnerable to wildfires due to the nature of the high desert environment. A report from Pacific Northwest National Laboratory (PNNL) published in 2015, notes a substantial increase in acres burned from 2000-2013. Megafires, fires that are large and highly unpredictable, threaten LANL and surrounding infrastructure. In 2000, the Cerro Grande megafire burned 43,000-48,000 acres in the acres surrounding Santa Fe National Forest from May 4th to May 19th. Though it began as a planned burn at the beginning of wildfire season, the area was in a persistent drought – and due to high winds the fire grew out of control- LANL was forced to evacuate and shut down for over two weeks. These two instances provide some insight into how wildfires can impact laboratory operations. While LANL has developed comprehensive year round wildfire preparedness plans, this does not negate the recurring droughts and high risk status of the surrounding area. This persistent vulnerability has pushed the laboratory to be extremely intentional in ensuring that there are mechanisms in place to protect from these disasters. At the request of the Biden administration in 2022, LANL produced the Climate Change and Vulnerability Assessment and Resilience Plan. The plan described the strong scientific consensus that anthropogenic activity is driving climate change, and in turn is increasing the frequency and severity of extreme weather patterns. All of which pose threats to the operations of LANL, and ultimately LANL’s contributions to the NSE. The dry heat in the Panhandle of Texas and Los Alamos creates vulnerabilities to wild fires, but other sites within the NSE, located on the coast, are at risk to a different kind of natural disaster; hurricanes. The Savannah River Site (SRS) and Savannah River National Laboratory (SRNL) are located in Aiken, South Carolina. Aiken, South Carolina lies between the region’s North Fork Edisto River to the northeast and the Savannah River border with Georgia to the southwest. This makes it vulnerable to hurricanes. As the effects of climate change have become more noticeable, it has increased the severity of hurricanes. According to the Center for Climate and Energy Solutions, climate change is worsening hurricane impacts on the United States by increasing intensity and decreasing the speed they travel. Moreover, the warming sea surfaces intensify the tropical storm wind speeds, increasing the severity of the damage that a hurricane causes. Since 1979-2017, only a 39 year period – the number of majorly devasting hurricanes has increased, whereas, the number of minor hurricanes has decreased. SRS and SRNL are critical facilities for the NNSA. The SRS Tritium Facility contributes to the Defense Programs mission of the NNSA, supplying & processing tritium, an isotope of hydrogen gas that is a vital component of nuclear weapons. SRNL supports SRS in its tritium production, and plays an integral role in the complex’s management of plutonium. Both of these items are vital to the advancement of the nation’s nuclear deterrence. The spike in hurricanes in the U.S. poses threats to these missions, and would undermine the nuclear deterrent if it interferes with the operations of these facilities. In October 2024, Hurricane Helene, a category four hurricane, devastated portions of the Southeastern United States; South Carolina was among one of the states that was critically hit. Most specifically, Hurricane Helene brought devastation the surrounding areas of SRS. Nearly all major roadways at SRS were impacted by debris, fallen trees, or downed power lines. Essential workers in the area worked long arduous hours to bring the site back to its full function. The SRS team worked with Savannah River Nuclear Solutions Site Services, SRS Emergency Response Organization, SRS Fire Department, Centerra-SRS and U.S. Department of Agriculture Forest Service–Savannah River to address the extensive damage and bring the site back to full operability. The site is well equipped to handle these natural disasters, but at what cost? The site remained in a operational emergency status, a status intended to manage any unforeseen complications from addressing the damage from the storm. This status puts a halt on work at the Site and the simple loss of productivity and incurred costs from clean-up are an impact on the enterprise in itself. Ultimately, several of the Labs, Plants, and Sites of the NSE are located in geographically vulnerable areas in the United States. III. Looking Forward Though these Labs, Plants, and Sites are well prepared and equipped to deal with natural disasters, these preparations do not negate the time and resources that the NSE loses by trying to minimize disasters and prevent further damage to infrastructure. The climate threat is only growing. Record-breaking heat waves on land and in the ocean, drenching rains, severe floods, year-long droughts, wildfires, these are just the tip of the iceberg of the more frequent and more intense weather that the globe is experiencing. Pantex, LANL, and SRS are only a few of the sites that comprise the broader NSE, but they were chosen to highlight the risks to vital components of the U.S. nuclear deterrent. Pantex, LANL, SRS/SRNL all have separate but equally critical missions that support the manufacturing, design, credibility, and reliability of nuclear weapons. This is why it is pertinent that we look deeper at the nexus of climate change and nuclear security. Because without understanding the threat climate change poses to the U.S. nuclear deterrent, it is impossible to credibly reassure our allies of the resiliency of the U.S. nuclear umbrella.