Climate Change and Adaptation: Department of Defense
Updated April 6, 2023
Climate Change and Adaptation: Department of Defense
Secretary of Defense Lloyd Austin has stated that “to keep
capabilities, while glacial ice retreat could lead to increased
the nation secure, [the Department of Defense (DOD)],
regionial competition in the Arctic, with an increase in
must tackle the existential threat of climate change.” DOD
demand for specialized, cold-weather military equipment
has released a number of documents outlining how it plans
for U.S. forces.
to adapt to and address climate change, including the 2021
DOD Climate Risk Analysis and the DOD Climate
According to DOD officials, climate change has growing
Adaptation Plan. Congress may conduct oversight of the
implications for the costs of operating U.S. military
implementation of these plans. Congress could also
installations and associated equipment. DOD maintains
consider examining possible climate risks and assessing
more than 5,000 military installations worldwide. Of these,
possible implications for global security, military readiness
more than 1,700 are in coastal areas and have been or may
and infrastructure, and DOD force structure when
be affected by sea-level rise or extreme weather events. In
considering authorization, appropriations, and other
2018, Hurricane Michael caused an estimated $4.7 billion
legislation.
in damage to Florida’s Tyndall Air Force Base (with more
than 12 F-22 fighter aircraft sustaining damage), while
Implications of Climate Change for the
Hurricane Florence caused around $3.6 billion in damages
U.S. Military
to North Carolina’s Marine Corps Base Camp Lejeune. In
DOD Directive (DODD) 4715.21, “Climate Change
2021, winter storms damaged 694 facilities across four
Adaptation and Resilience,” took effect in 2016 and
military installations in Texas (Fort Hood), Oklahoma (Fort
outlines department policy, roles, and responsibilities
Sill), Kansas (Fort Riley), and Louisiana (Fort Polk).
related to climate change. The directive defines climate
change as
Some analysts have argued that rising sea levels, extreme
weather events, and other climate-related factors could
variations in average weather conditions that persist
impact transportation routes, port infrastructure, or
over multiple decades or longer that encompass
manufacturing facilities, which could in turn affect both
increases and decreases in temperature, shifts in
commercial and military supply chains.
precipitation, and changing risk of certain types of
severe weather events.
DOD Climate Adaptation Planning
DOD’s Climate Risk Analysis report concludes that these
DODD 4715.21 defines climate adaptation as an
“adjustment in natural or human systems in anticipation of
variations could produce climate hazards such as sea or
glacial ice retreat, rising sea levels, flooding, drought,
or response to a changing environment in a way that
extreme heat, wildfires, and tropical cyclones. Each of these
effectively uses beneficial opportunities or reduces negative
efforts.” DOD’s
hazards in turn holds implications for international security.
Climate Adaptation Plan builds upon
For example, drought could lead to inadequate water
previous DOD climate change-related policies to “ensure
the DOD can operate under changing climate conditions.”
supplies and adverse impacts on agricultural production.
This could increase competition for, or conflict over,
natural resources in affected areas. Flooding could damage
The adaptation plan outlines five lines of effort (LOE):
critical infrastructure and displace populations, which could
1. Climate-informed decision-making based on
in turn cause mass migration or political crises. DOD notes
climate assessments;
that such hazards could “[reshape] the geostrategic,
2. Train and equip a climate ready force able to
operational, and tactical environments with significant
operate in extreme weather conditions;
implications for U.S. national security and defense.”
3. Infrastructure to support military operations
under changing conditions;
DOD’s Climate Risk Analysis report further notes that
4. Supply chain resilience and innovation in austere
locations; and
as the frequency and intensity of [climate] hazards
5. Enhance adaptation and resilience through
increase ... [they may] affect the demands on and
collaboration
with
other
federal
agencies,
functionality of military operations, and increase
Congress, U.S. allies and partners, and other
the number and severity of humanitarian crises, at
stakeholders.
times threatening stability and security.
These LOEs and related enablers, such as monitoring and
DOD has sought to increase military readiness and may
data analytics, constitute DOD’s Climate Adaptation
propose changes in military equipment or force structure in
Strategic Framework.
anticipation of increased operations due to climate change.
For example, extreme weather events could increase
DOD’s Climate Adaptation Plan additionally states that all
demand for humanitarian assistance and disaster response
department operations, plans, and procedures must include
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Climate Change and Adaptation: Department of Defense
climate change considerations “to ensure the military forces
for operational energy; and $100 million for contingency
of the United States retain operational advantage under all
preparedness.
conditions.” Similarly, Executive Order 14008, signed in
2021, directs the Secretary of Defense and the Chairman of
Considerations for Congress
the Joint Chiefs of Staff to incorporate climate
Installation Plans
considerations into the National Defense Strategy and other
Pursuant to DOD’s Climate Adaptation Plan, DOD
relevant strategy and planning documents.
completed climate exposure assessments on all major U.S.
installations—as defined in 10 U.S.C. §2864–in April 2022
Legislative Activity
and is in the process of finalizing assessments on all major
Congress has conducted oversight of DOD climate-related
OCONUS (outside the continental United States)
activities. In Section 951 of the FY2008 National Defense
installations. Congress may consider the methods and
Authorization Act (NDAA; P.L. 110-181), Congress
results of these assessments as it evaluates military
required that the first National Security Strategy and first
construction funding requests or possible future base
National Defense Strategy prepared after January 2008
realignment and closure processes.
include guidance for military planners to assess the risks of
projected climate change to current and future mission of
Costs
the Armed Forces.
To reduce future costs associated with repairing
installations affected by climate change or extreme weather
Section 335 of the FY2018 NDAA (P.L. 115-91) directed
events, DOD’s FY2024 budget request includes $3.7 billion
DOD to identify and report on 10 installations per service
for installation resiliency measures, which the budget
that were most vulnerable to climate change. This report
request states are to “[adapt] military facilities to withstand
was delivered to Congress in January 2019; however, three
increasingly challenging conditions and [deploy] advanced
members of the House Armed Services Committee
technologies to strengthen the ability to rapidly recover
concluded that the report did not address Section 335’s
from disruptions to public infrastructure” from climate-
specified criteria and formally requested DOD to submit a
induced extreme weather. In considering this request,
revised report. The military services subsequently followed
Congress could consider whether or not to direct an
up in 2019 with responses to questions for the record, in
assessment of the costs of up-front resilience measures
which the Army, Air Force, and Marine Corps each
versus the potential costs of installation repair. Members
identified their 10 most vulnerable installations and the
could also seek additional information to set priorities for
Navy identified its 16 most vulnerable. Section 2801 of the
types, locations, and scheduling of future resilience
FY2020 NDAA (P.L. 116-92) required all major military
measures.
installations to incorporate resilience information into
installation plans, including climate-related threats to
Service Strategies
military installations, assets or infrastructure vulnerable to
In February 2022, the Department of the Army released its
such threats, and lessons learned from previous extreme
Climate Strategy, detailing the service’s plans for adapting
weather events.
to climate change and enhancing resilience across the force.
The strategy outlines a number of metrics by which its
Subtitle C, “National Security Climate Resilience,” of Title
implementation can be assessed (e.g., “field an all-electric
III of the FY2022 NDAA (P.L. 117-81) sought to improve
light-duty non-tactical vehicle fleet by 2027”). Likewise, in
DOD’s climate resilience, defined in the subtitle as “the
May 2022, the Department of the Navy released Climate
capability to avoid, prepare for, minimize the effect of,
Action 2030, which identifies two performance goals—
adapt to, and recover from, extreme weather, or from
building climate resilience and reducing climate threat—for
anticipated or unanticipated changes in environmental
the Navy and Marine Corps. The Department of the Air
conditions, that do (or have the potential to) adversely
Force released its climate action plan in October 2022.
affect the national security of the United States or of allies
and partners of the United States.” Subtitle C directs DOD
Such strategies are not, however, statutorily required. As it
to undertake actions “to ensure that the critical
conducts oversight of climate adaptation and resilience
infrastructure of Department facilities is hardened,
efforts, Congress may consider whether or not to require the
developed, and constructed for quick recovery from natural
services to release climate strategies that detail how the
disasters and the impacts of extreme weather”; requires the
respective service plans to implement overall DOD and
department to include extreme weather events in its reports
executive branch requirements. Congress may additionally
on the health of the national technology and industrial base
consider whether or not to identify more specific goals and
and account for climate and environmental challenges in
evaluative metrics for use by the services.
future planning and development; and requires each
military department to assess climate risks to their
This report was originally co-authored by Hibbah Kaileh,
installations and other facilities.
former CRS Research Assistant.
The President’s FY2024 DOD budget request proposes $5.1
Kelley M. Sayler, Analyst in Advanced Technology and
billion in funding for “enhancing combat capability and
Global Security
mitigating climate risk.” This includes $3.7 billion for
installation resiliency and adaptation; $1.3 billion for
IF12161
research, development, test, and evaluation; $100 million
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Climate Change and Adaptation: Department of Defense
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