By Tom Ellison

Introduction

The Center for Climate and Security’s (CCS) Military Responses to Climate Hazards (MiRCH) tracker now includes 501 deployments in 97 countries between June 2022 and February 2025–averaging more than one every two days. In light of the military response to January’s devastating wildfires in California and ongoing policy debates about US domestic disaster relief, now is a good time to analyze what MiRCH tells us about military responses to disasters such as wildfires, hurricanes, and flooding within the United States. 

The Who, What, When, Where, and Why

Overall, US MiRCH data since 2022 shows 176 military deployments to floods, fires, and hurricanes across about three-quarters of US states and territories. Readers can explore the data further by clicking on the visualizations below.

Who – US National Guards (Mostly)

In the United States, military deployments for domestic disaster relief are predominantly the purview of state National Guard branches, which account for 78% of US MiRCH deployments. US Department of Defense assets augment the Guard when needed, including the Air Force, Army, Coast Guard, Marines, and Navy. January’s southern California wildfires marked the first time since June 2022 that third-country militaries assisted the United States with climate disaster relief, when Mexico and Canada contributed (though Canada, Mexico, and other foreign partner militaries have contributed to US disaster relief in the past).

What – A Range of Preparation, Response, and Recovery

National Guard and Department of Defense deployments provide states with special equipment, logistics capacity, and/or personnel to support wildfire and flooding preparation, response, and recovery. These range from brief deployments of a single aircraft or unit to the mobilizing of thousands of personnel for major disasters (such as Hurricanes Debby, Francine, or Helene, or the Los Angeles wildfires). Examples of common activities include:

• Preparation: Erecting flood barriers ahead of storms and extreme precipitation, monitoring approaching hurricanes, or spraying in anticipation of fire risks.  
• Specialized capabilities: Deploying airplanes and helicopters for wildfire suppression or boats, high-water vehicles, and helicopters for flood search-and-rescue. 
• Public safety and logistics: In large-scale hazards and evacuations, augmenting law enforcement, regulating traffic, or providing facilities, transportation, and other logistics support for food and water deliveries. 
• Recovery support: In especially destructive disasters, remaining in place for weeks or months for debris removal, cleanup, and recovery.

When – A Year-Round Strain, Magnified in Late Summer

MiRCH deployments in the United States are year-round, intensifying in the summer and early fall, a similar pattern to what exists worldwide and coincides with periods of higher wildfire and hurricane risk. Militaries have deployed in US states and territories at least once during 28 of the 32 months since June 2022, but roughly half of the 176 incidents occurred in July, August, or September. These have ranged from short-term responses to long-term commitments, such as the joint military task force that activated for 7 weeks in response to Maui’s 2023 wildfires, handing additional recovery off to the Hawaii National Guard. Summer 2024 saw especially numerous deployments in the United States, in part due to the impact of Hurricanes Helene and Milton across southern and mid-Atlantic states.

MiRCH incidents in the United States by month and hazard type.

Where – Widespread Responses, Within and Across States

Since June 2022, National Guards and other military assets have deployed to climate-related disasters in 37 out of 50 states, as well as the US territories of Puerto Rico and the US Virgin Islands. These deployments have been most common in Florida (34), California (15), and North Carolina (15). From 2022-2024, these states were among those affected by 35 weather-related disasters that resulted in 924 deaths and estimated damages exceeding $350 billion, according to the National Oceanic and Atmospheric Administration’s database of billion-dollar weather disasters. These populous coastal states face a variety of climate hazards and house important military facilities and communities, ranging from Fort Liberty in North Carolina to the Headquarters of Central, Southern, and Special Operations Commands in Florida to Naval Base San Diego (home of the Pacific Fleet) in California. 

Why – Hurricanes, Fires, and Floods

In the United States, militaries have responded predominantly to hurricanes and tropical storms (42%), wildfires (32%), and extreme precipitation/flooding (23%). Still, on rare occasions, the US military has been called to address other climate strains, such as the Army Corps of Engineers intervening to mitigate drought-driven saltwater intrusion in the Mississippi River or the New York National Guard activating over extreme heat. Worldwide, the MiRCH dataset is also dominated by wildfires, hurricanes/tropical storms, and extreme precipitation/flooding in modestly different proportions.

MiRCH deployments by hazard type, in the United States (left) compared to worldwide (right).

Three Issues for the Future

Is All Climate Security Local? 

These data highlight the interdependence between national security and subnational disaster relief and resilience issues. National Guards serve both state governors and the president (for national defense purposes) and must work closely with local authorities (mayors, fire and emergency services, law enforcement, etc.) as well as across state lines. California’s Task Force Rattlesnake, an integration of the National Guard and California Department of Forestry and Fire Protection (CALFIRE) on wildfire prevention, offers a helpful model. Most often, governors activate their own National Guards to deploy within their state, but at times of major disasters also lend their National Guards across state lines. US military capabilities often play a critical role in responding to climate threats to Americans, especially with their logistics capabilities, equipment, and personnel resources. Conversely, strong local resilience stands to reduce these strains on military assets, easing the balancing act between the National Guard’s domestic and national defense roles. 

Politicization and Lack Thereof

National Guard branches are routinely activated by Republican and Democratic governors alike for climate-related disaster response, and military deployments to climate disasters do not correlate with a state’s partisan leanings. National Guards deploy across state lines despite political differences, as when the Wyoming National Guard contributed to January’s California wildfire response. 

Political polarization of climate-driven disasters, however, may strain the apolitical nature of the National Guard’s role. As of 2022, 33% of Americans had experienced recent extreme weather, and the share of Americans who view climate change as a major threat had grown from 44% to 54%. At the same time, however, the partisan split over climate has widened. President Trump has spread climate misinformation, and the White House and Congressional leaders have threatened to withhold wildfire relief from California over recent wildfires–spurring objections and divisions among Congressional Republicans. Politicization of federal responses to climate disasters threatens to undermine resilience and expose the National Guard to more severe and politicized disaster relief. During the response to Hurricane Helene, the National Guard encountered armed militia in North Carolina reportedly mobilized by anti-FEMA misinformation. Amid political polarization, coordinated and even-handed responses to growing climate disasters are critical for US well-being and national security.

Hard Choices and Implications

Hazards such as wildfires and flooding will intensify through 2040 even in an unrealistically optimistic emissions scenario, meaning the United States may face harder choices over the military’s disaster relief and overseas defense functions. These balancing challenges were previewed during Hurricane Katrina in 2005 (when 40% of Guard troops overall and 35% of Louisiana’s Guard were deployed overseas) and in 2020, when roughly 120,000 National Guard troops were deployed, primarily for disaster response, COVID-19 and civil unrest in addition to their overseas missions. Domestic tradeoffs exist too–in January, 500 US Marines were pulled from supporting California wildfire response to the southern border. Such choices will become more complicated if the United States simultaneously faces an overseas conflict demanding major troop commitments. At the peak of deployments in late 2009, the United States had 191,500 armed forces personnel and roughly 40,000 DOD-funded American contractors in Afghanistan and Iraq, according to the Congressional Research Service, and US defense analysts warn that major US troop commitments could be required to defeat or reverse a Russian invasion of the Baltics or Chinese seizure of Taiwan, even as climate disasters intensify. Resolving these tradeoffs with increased resources would need to contend with fiscal constraints, other national priorities, and public opinion (a plurality of Americans believe US military spending is too high). 

Conclusion

Examining the breadth and frequency of domestic military deployments in response to climate hazards in the United States over the past 2.5 years underscores the national security threat of climate change, even to wealthy nations. With floods, wildfires, and extreme storms likely to intensify as temperatures continue to warm, the United States must prepare to address tradeoffs and challenges around domestic resilience, political polarization, and military priorities.