March 12, 2025

Warren, Lawmakers to Hegseth: Ending DoD Climate Change Programs Threatens National Security, Puts American Lives and Billions of Taxpayer Dollars at Risk

“As Secretary of Defense, your first duty is to the United States and the Soldiers, Sailors, and Airmen you now lead, not any political mission.”

Climate change threatens DoD operations, strategies, infrastructure, supply chains

Text of Letter (PDF)

Washington, D.C. – U.S. Senator Elizabeth Warren (D-Mass.), along with Senators Mazie Hirono (D-Hawaii), Richard Blumenthal (D-Conn.), and Tammy Duckworth (D-Ill.), all members of the Senate Armed Services Committee, wrote to Secretary of Defense Pete Hegseth, regarding his threats to cut efforts to adapt to climate change at the Department of Defense (DoD), which would put thousands of American lives and billions of American taxpayer dollars at risk.

DoD officials, generals, and admirals have warned that the consequences of climate change may harm the organization, training, equipping, and planning of military services. Climate change threatens instability in some of the most volatile regions of the world and presents significant national security challenges for the United States.

Hegseth recently suggested that the Department of Defense (DoD) will cut “climate programs,” implying that these programs do not contribute to the “business of deterring and winning wars.”

“Surely, as a Secretary of Defense that claims to be ‘laser focused on warfighting,’ you are aware that military experts have highlighted the security implications of climate change and the threat it poses to future operations for years,” wrote the lawmakers.

Storms like Hurricane Katrina, which decimated Ingalls Shipbuilding in Pascagoula, and Hurricane Matthew, which damaged Norfolk Naval Shipyard, highlight the precarious positions of many critical links in the defense industrial base. Over the past decade, extreme weather exacerbated by climate change has also caused billions of dollars of damage to DoD installations and degraded operational readiness. 

Even under the Trump administration, senior Pentagon officials warned about the security implications of climate change. Former Secretary of Defense James Mattis said, “The effects of a changing climate — such as increased maritime access to the Arctic, rising sea levels, desertification, among others — impact our security situation.” 

Just last year, more than 6,500 National Guard members, 250 members of the Army Corps of Engineers, and 100 Marines mobilized to recovery efforts after Hurricanes Helene and Milton devastated the Florida Gulf Coast, while many more responded to fight fires in Oregon, Tennessee, West Virginia, Massachusetts, Texas, and California. 

Recovering from extreme weather caused by climate change has also cost the Pentagon billions. In 2018, hurricanes caused over $8 billion in damage to Camp Lejune and Tyndall Air Force Base, while flooding at Offutt Air Force Base in 2019 has cost over $1 billion to date. The Air Force also estimates the rebuilding of Andersen Air Force Base in Guam, struck by a typhoon in 2023, will cost nearly $9.7 billion. Additionally, these costs do not account for the training time lost or man-hours spent by the Pentagon on recovery operations. 

Climate change presents operational challenges as well. In the Western Pacific, climate change threatens critical locations such as Kawjalein Atoll, home to the brand new billion dollar “Space Fence” surveillance system, and Guam, site of Andersen Air Force Base. Both locations are critical to supporting U.S. operational flexibility in the region.

“As Secretary of Defense, your first duty is to the United States and the Soldiers, Sailors, and Airmen you now lead, not any political mission,” concluded the lawmakers

The lawmakers demanded Hegseth explain his plan to address the threat climate change poses to the DoD by March 26, 2025.

Senator Warren has long been a leading voice calling for action to combat climate change: 

  • In December 2024, Senator Elizabeth Warren and Representative Veronica Escobar (D-Texas) reintroduced the Department of Defense (DOD) Climate Resilience and Readiness Act to address the Pentagon’s contributions to climate change and mitigate climate change’s impact on military readiness. 
  • In April 2024, Senator Elizabeth Warren, along with Representatives Sean Casten (D-Ill.) and Veronica Escobar (D-Texas) urged the Federal Acquisition Regulation (FAR) Council, composed of the Department of Defense (DoD), General Services Administration (GSA), and the National Aeronautics and Space Administration (NASA), urging them to finalize the Federal Supplier Climate Risks and Resilience Rule as quickly as possible.
  • In February 2022, Senator Elizabeth Warren and Congresswoman Barbara Lee (D-Calif.) urged the Department of Defense (DoD) Secretary Lloyd J. Austin, III to ensure that efforts to combat climate change are included in the DoD’s upcoming National Defense Strategy, and called for recommendations for the federal budget that reflect the urgency of the climate crisis.
  • In December 2021, Senator Elizabeth Warren and Representative Veronica Escobar (D-Texas) urged the Department of Defense to take proactive steps to ensure the strength and readiness of DoD assets and installations in the face of the climate crisis.
  • In April 2019, Senator Warren wrote to the Chairman of the Joint Chiefs of Staff, following up on concerns brought forth by eight military leaders about the rising threat of climate change to the United States military's missions, operational plans, installations, and overall readiness.
  • In April 2019, Senator Warren and Senate Armed Services Committee Ranking Member Jack Reed wrote to the Government Accountability Office calling for a review of potential threats to national security resulting from the impacts of climate change on defense contractors and the defense supply chain, and to review the extent to which the Department of Defense can address climate change and other environmental risks during the contracting process.

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