https://crsreports.congress.gov
July 12, 2022
Climate Change and Adaptation: Department of Defense
Secretary of Defense Lloyd Austin has stated that “to keep
the nation secure, [the Department of Defense (DOD)],
must tackle the existential threat of climate change.” DOD
has released a number of documents outlining how it plans
to adapt to and address climate change, including the 2021
DOD Climate Risk Analysis and the DOD Climate
Adaptation Plan. Congress may conduct oversight of the
implementation of these plans. Congress could also
consider examining possible climate risks and assessing
possible implications for global security, military readiness
and infrastructure, and DOD force structure when
considering authorization, appropriations, and other
legislation.
Implications of Climate Change for the
U.S. Military
DOD Directive (DODD) 4715.21, “Climate Change
Adaptation and Resilience,” took effect in 2016 and
outlines department policy, roles, and responsibilities
related to climate change. The directive defines climate
change as
variations in average weather conditions that persist
over multiple decades or longer that encompass
increases and decreases in temperature, shifts in
precipitation, and changing risk of certain types of
severe weather events.
DOD’s Climate Risk Analysis report concludes that these
variations could produce climate hazards such as sea or
glacial ice retreat, rising sea levels, flooding, drought,
extreme heat, wildfires, and tropical cyclones. Each of these
hazards in turn holds implications for international security.
For example, drought could lead to inadequate water
supplies and adverse impacts on agricultural production.
This could increase competition for, or conflict over,
natural resources in affected areas. Flooding could damage
critical infrastructure and displace populations, which could
in turn cause mass migration or political crises. DOD notes
that such hazards could “[reshape] the geostrategic,
operational, and tactical environments with significant
implications for U.S. national security and defense.”
DOD’s Climate Risk Analysis report further notes that
as the frequency and intensity of [climate] hazards
increase ... [they may] affect the demands on and
functionality of military operations, and increase
the number and severity of humanitarian crises, at
times threatening stability and security.
DOD has sought to increase military readiness and may
propose changes in military equipment or force structure in
anticipation of increased operations due to climate change.
For example, extreme weather events could increase
demand for humanitarian assistance and disaster response
capabilities, while glacial ice retreat could lead to increased
regionial competition in the Arctic, with an increase in
demand for specialized, cold-weather military equipment
for U.S. forces.
According to DOD officials, climate change has growing
implications for the costs of operating U.S. military
installations and associated equipment. DOD maintains
more than 5,000 military installations worldwide. Of these,
more than 1,700 are in coastal areas and have been or may
be affected by sea-level rise or extreme weather events. In
2018, Hurricane Michael caused an estimated $4.7 billion
in damage to Florida’s Tyndall Air Force Base (with more
than 12 F-22 fighter aircraft sustaining damage), while
Hurricane Florence caused around $3.6 billion in damages
to North Carolina’s Marine Corps Base Camp Lejeune. In
2021, winter storms damaged 694 facilities across four
military installations in Texas (Fort Hood), Okahoma (Fort
Sill), Kansas (Fort Riley), and Lousiana (Fort Polk).
Some analysts have argued that rising sea levels, extreme
weather events, and other climate-related factors could
impact transportation routes, port infrastructure, or
manufacturing facilities, which could in turn affect both
commercial and military supply chains.
DOD Climate Adaptation Planning
DODD 4715.21 defines climate adaptation as an
“adjustment in natural or human systems in anticipation of
or response to a changing environment in a way that
effectively uses beneficial opportunities or reduces negative
efforts.” DOD’s Climate Adaptation Plan builds upon
previous DOD climate change-related policies to “ensure
the DOD can operate under changing climate conditions.”
The adaptation plan outlines five lines of effort (LOE):
1. Climate-informed decision-making based on
climate assessments;
2. Train and equip a climate ready force able to
operate in extreme weather conditions;
3. Infrastructure to support military operations
under changing conditions;
4. Supply chain resilience and innovation in austere
locations; and
5. Enhance adaptation and resilience through
collaboration with other federal agencies,
Congress, U.S. allies and partners, and other
stakeholders.
These LOEs and related enablers, such as monitoring and
data analytics, constitute DOD’s Climate Adaptation
Strategic Framework.
