Military Installations and Sea-Level Rise
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July 26, 2019
Military Installations and Sea-Level Rise
The Department of Defense (DOD) manages more than
Figure 2. Relative Sea-Level Change Trends & Military
1,700 military installations in worldwide coastal areas that
Installations in East Coast Congressional Districts, 2017
may be affected by sea-level rise. These installations
support DOD readiness and operations including naval
vessel embarkation and disembarkation, amphibious
training, and special operations forces training. Military
installations on and near the coast are at risk for high-tide
and storm surge flooding amplified by sea-level rise.
Congress may choose to assume a role in preparing military
installations for sea-level rise based on its authority in fiscal
and national security matters.
Sea-Level Rise and Climate Change
Global climate observations from the National Oceanic and
Atmospheric Administration (NOAA) show trends of
increased surface, air, and ocean temperatures that correlate
with sea-level rise. The U.S. Global Change Research
Source: NOAA, Tides & Currents, “U.S. Sea Level Trend Map”; U.S.
Program (USGCRP) reports that global mean sea level
Census Bureau; Homeland Infrastructure Foundation-Level Data
(GMSL) has risen by approximately 7-8 inches since 1900;
Notes: Colored dots are monitoring stations; CD = Congressional
further, GMSL has risen 3 inches of GMSL since 1993 (see
District with coastline; mm/yr = mil imeters per year
CRS Report R43229, Climate Change Science: Key Points,
by Jane A. Leggett).
RSL trends vary across the United States coastline (see
Figure 1 and Figure 2). For example, in 2017, RSL was
NOAA identifies the two major causes of GMSL rise as
rising at a rate of 9-12 millimeters per year along
thermal expansion (water expanding from rising ocean
Louisiana’s Mississippi River Delta where parts of the land
temperature) and melting land ice (ice sheets and glaciers)
surface was sinking (Figure 2), while RSL was dropping
adding water to ocean basins. Factors such as land
along portions of the Pacific Northwest coastline and near
rebounding, sediment compaction, oil and gas extraction,
southern Alaska (Figure 1). With few exceptions, RSL is
and land management influence relative sea level (RSL),
rising along the coastlines of the contiguous United States;
the sea level relative to the land surface from which it is
according to USGCRP, both GMSL and RSL levels are
measured (for more information, see CRS Report R44632,
expected to continue to rise for the foreseeable future.
Sea-Level Rise and U.S. Coasts: Science and Policy
Considerations, by Peter Folger and Nicole T. Carter).
Impacts to Military Installations
Military installations differ in terms of their existing
Figure 1. Relative Sea-Level Change Trends & Military
infrastructure and potential vulnerabilities. A number of
Installations in West Coast Congressional Districts, 2017
coastal military installations already routinely experience
high-tide flooding, and storm surge from recent hurricanes
has exacerbated flooding, disrupted operations and caused
extensive damage to infrastructure. Likewise, infrastructure
outside of military installations, (e.g., mission critical
access roads) can be impacted by sea-level rise, further
impeding military operations.
A study led by DOD’s Strategic Environmental Research
and Development Program (SERDP) observed that sea-
level rise threatens the sustainability of coastal installations
through intensified storm surge, increased flood frequency,
and saltwater intrusion into the groundwater aquifer (see
SERDP study RC-1701). SERDP study RC-2334 found that
U.S. military installations on low-lying atolls in the Pacific
Ocean will be negatively impacted when “mean sea level is
Source: NOAA, Tides & Currents, “U.S. Sea Level Trend Map,”;
0.4 meters higher…the amount of sea water flooded onto
U.S. Census Bureau; Homeland Infrastructure Foundation-Level Data
the island will be of sufficient volume to make the
Notes: Colored dots are monitoring stations; CD = Congressional
groundwater non-potable year-round.” In the 2014 Climate
District with coastline; mm/yr = mil imeters per year
Change Adaptation Roadmap, DOD identified the Hampton
Roads, VA region, which houses the largest concentration
https://crsreports.congress.gov
Military Installations and Sea-Level Rise
of military sites in the world, as vulnerable to projected
military construction policies, forms, and procedures. For
RSL rise of 1.5 feet (0.45 meters) over the next 20 to 50
example, the FY2019 NDAA (P.L. 115-232):
years.
Requires an update of DOD Form 1391; and by
The Government Accountability Office (GAO) describes
extension, UFC 3-201-01, Civil Engineering, to direct
climate change and sea-level rise as issues of “fiscal
planners for new military construction projects to
exposure” (see GAO-19-453). According to the report, the
identify whether they are in the Federal Emergency
2018 hurricane season was especially damaging to DOD
Management (FEMA) 100-year floodplain, and if so,
installations, highlighting that DOD’s worldwide real-estate
requires them to specify mitigation plans and build 2-3
portfolio is vulnerable to extreme weather. Hurricane
feet above base flood elevation (Sec. 2805(a)(B),
Michael damaged every building on Florida’s Tyndall Air
FY2019 NDAA)
Force Base (repair estimate $4.7 billion). Hurricane
Florence dropped 36 inches of rain, flooding three North
Directs the Secretary of Defense to incorporate
Carolina Marine Corps installations (repair estimate $3.6
authorized, site-specific, and long-term climate
billion). While more intense hurricanes have not been
projections, via amendment of UFC 1-200-01, General
confidently linked to climate change, higher sea levels
Building Requirements, and 1-200-02, High
magnify the adverse impact of storm surges (see chapter 1
Performance and Sustainable Building Requirements.
of the Fourth National Climate Assessment).
(Sec. 2805(c), FY2019 NDAA)
DOD Response to Rising Sea Levels
Expands Defense Access Roads authority to improve
DOD has identified climate change as a cause of risk in
critical roads outside installations impacted by sea-level
military operations and to its installations since 2010 (See
rise and recurrent flooding. (Sec 2865, FY2019 NDAA)
2010 Quadrennial Defense Review). In 2014, DOD’s
Congress has required DOD to assess and report installation
Climate Change Adaptation Roadmap named “rising sea
levels and associated storm surge,” as one of four primary
vulnerability to extreme weather and sea-level rise. Sec.
335 of the FY2018 NDAA instructed DOD to assess
climate change related phenomena likely to impact DOD
climate-related impacts to installations, resulting in DOD’s
activities.
2019 Report on Effects of a Changing Climate. Some
Members of Congress requested that DOD revise the report
based on concerns it had not met statutory requirements.
Vulnerabilities to installations include coastal and
DOD complied and issued an addendum in March 2019.
riverine flooding. Coastal flooding may result from
storm surge during severe weather events. Over time,
Possible Issues for Congress
gradual sea level changes magnify the impacts of storm
surge, and may eventually result in permanent
Standard definitions of extreme weather. DOD
installation vulnerability assessments suggest that the
inundation of property. Increasing coverage of land
understanding of extreme weather terms (including sea-
from nuisance flooding during high tides, also called
level-related terms like storm surge) varies across DOD.
“sunny day” flooding, is already affecting many coastal
A standard list of extreme weather definitions could
communities.
assist DOD with assessing and preparing for sea level-
DOD Report on Effects of a Changing Climate, 2019
related and other impacts of extreme weather events on
coastal and non-coastal installations.
In 2016, the Department issued DOD Directive (DODD)
Instructions for incorporating climate projections
4715.21, Climate Change Adaptation and Resilience
into planning. DOD does not have a process for
(updated in 2018), which assigns responsibility to all
evaluating and incorporating the use of climate
organizational entities within DOD to assess the effects of
projections into guidance. UFCs 1-200-01 and 1-200-02
climate change and integrate them into planning. Section
lack guidance on the use of different projections,
2.2 (a) of DODD 4715.21 identifies the Office of the
integration into facilities planning, and the development
Assistant Secretary of Defense for Energy, Installations,
of site-specific climate projections. DOD is in the
and Environment (OASD (EI&E)) as the primary climate
process of developing guidance for incorporating sea-
adaptation official responsible for considering climate
level rise projections into UFCs, but does not have a
change adaptation and resilience in the installation planning
timeframe for incorporating other climate projections.
process. DODD 4715.21 also assigns OASD (EI&E)
Medium and small sites are not required to consider
responsibility to provide direction on technologies,
extreme weather in planning. Presently, only officials
engineering standards, and tools for climate change
at major military installations – defined by the Base
adaptation and resilience, including the Unified Facilities
Structure Report as a large site with a Plant
Criteria (UFC) Program. UFC documents specify
“
Replacement Value (PRV) greater than or equal to
planning, design, construction, sustainment, restoration,
$2.067 billion – are required to incorporate extreme
and modernization criteria,” for military installations in
weather, such as storm surge enhanced by sea-level rise,
accordance with DODD 4270.5 (Military Construction).
into master plans (10 U.S.C. § 2864).
Congressional Actions
Through the National Defense Authorization Act (NDAA),
Margaret Tucker, Research Associate
Congress has exercised oversight of how DOD assesses and
G. James Herrera, Analyst in U.S. Defense Readiness and
prepares for sea-level rise by legislating changes to DOD’s
Infrastructure
https://crsreports.congress.gov
Military Installations and Sea-Level Rise
IF11275
Disclaimer
This document was prepared by the Congressional Research Service (CRS). CRS serves as nonpartisan shared staff to
congressional committees and Members of Congress. It operates solely at the behest of and under the direction of Congress.
Information in a CRS Report should not be relied upon for purposes other than public understanding of information that has
been provided by CRS to Members of Congress in connection with CRS’s institutional role. CRS Reports, as a work of the
United States Government, are not subject to copyright protection in the United States. Any CRS Report may be
reproduced and distributed in its entirety without permission from CRS. However, as a CRS Report may include
copyrighted images or material from a third party, you may need to obtain the permission of the copyright holder if you
wish to copy or otherwise use copyrighted material.
https://crsreports.congress.gov | IF11275 · VERSION 1 · NEW
July 26, 2019
Military Installations and Sea-Level Rise
The Department of Defense (DOD) manages more than
Figure 2. Relative Sea-Level Change Trends & Military
1,700 military installations in worldwide coastal areas that
Installations in East Coast Congressional Districts, 2017
may be affected by sea-level rise. These installations
support DOD readiness and operations including naval
vessel embarkation and disembarkation, amphibious
training, and special operations forces training. Military
installations on and near the coast are at risk for high-tide
and storm surge flooding amplified by sea-level rise.
Congress may choose to assume a role in preparing military
installations for sea-level rise based on its authority in fiscal
and national security matters.
Sea-Level Rise and Climate Change
Global climate observations from the National Oceanic and
Atmospheric Administration (NOAA) show trends of
increased surface, air, and ocean temperatures that correlate
with sea-level rise. The U.S. Global Change Research
Source: NOAA, Tides & Currents, “U.S. Sea Level Trend Map”; U.S.
Program (USGCRP) reports that global mean sea level
Census Bureau; Homeland Infrastructure Foundation-Level Data
(GMSL) has risen by approximately 7-8 inches since 1900;
Notes: Colored dots are monitoring stations; CD = Congressional
further, GMSL has risen 3 inches of GMSL since 1993 (see
District with coastline; mm/yr = mil imeters per year
CRS Report R43229, Climate Change Science: Key Points,
by Jane A. Leggett).
RSL trends vary across the United States coastline (see
Figure 1 and Figure 2). For example, in 2017, RSL was
NOAA identifies the two major causes of GMSL rise as
rising at a rate of 9-12 millimeters per year along
thermal expansion (water expanding from rising ocean
Louisiana’s Mississippi River Delta where parts of the land
temperature) and melting land ice (ice sheets and glaciers)
surface was sinking (Figure 2), while RSL was dropping
adding water to ocean basins. Factors such as land
along portions of the Pacific Northwest coastline and near
rebounding, sediment compaction, oil and gas extraction,
southern Alaska (Figure 1). With few exceptions, RSL is
and land management influence relative sea level (RSL),
rising along the coastlines of the contiguous United States;
the sea level relative to the land surface from which it is
according to USGCRP, both GMSL and RSL levels are
measured (for more information, see CRS Report R44632,
expected to continue to rise for the foreseeable future.
Sea-Level Rise and U.S. Coasts: Science and Policy
Considerations, by Peter Folger and Nicole T. Carter).
Impacts to Military Installations
Military installations differ in terms of their existing
Figure 1. Relative Sea-Level Change Trends & Military
infrastructure and potential vulnerabilities. A number of
Installations in West Coast Congressional Districts, 2017
coastal military installations already routinely experience
high-tide flooding, and storm surge from recent hurricanes
has exacerbated flooding, disrupted operations and caused
extensive damage to infrastructure. Likewise, infrastructure
outside of military installations, (e.g., mission critical
access roads) can be impacted by sea-level rise, further
impeding military operations.
A study led by DOD’s Strategic Environmental Research
and Development Program (SERDP) observed that sea-
level rise threatens the sustainability of coastal installations
through intensified storm surge, increased flood frequency,
and saltwater intrusion into the groundwater aquifer (see
SERDP study RC-1701). SERDP study RC-2334 found that
U.S. military installations on low-lying atolls in the Pacific
Ocean will be negatively impacted when “mean sea level is
Source: NOAA, Tides & Currents, “U.S. Sea Level Trend Map,”;
0.4 meters higher…the amount of sea water flooded onto
U.S. Census Bureau; Homeland Infrastructure Foundation-Level Data
the island will be of sufficient volume to make the
Notes: Colored dots are monitoring stations; CD = Congressional
groundwater non-potable year-round.” In the 2014 Climate
District with coastline; mm/yr = mil imeters per year
Change Adaptation Roadmap, DOD identified the Hampton
Roads, VA region, which houses the largest concentration
https://crsreports.congress.gov
Military Installations and Sea-Level Rise
of military sites in the world, as vulnerable to projected
military construction policies, forms, and procedures. For
RSL rise of 1.5 feet (0.45 meters) over the next 20 to 50
example, the FY2019 NDAA (P.L. 115-232):
years.
Requires an update of DOD Form 1391; and by
The Government Accountability Office (GAO) describes
extension, UFC 3-201-01, Civil Engineering, to direct
climate change and sea-level rise as issues of “fiscal
planners for new military construction projects to
exposure” (see GAO-19-453). According to the report, the
identify whether they are in the Federal Emergency
2018 hurricane season was especially damaging to DOD
Management (FEMA) 100-year floodplain, and if so,
installations, highlighting that DOD’s worldwide real-estate
requires them to specify mitigation plans and build 2-3
portfolio is vulnerable to extreme weather. Hurricane
feet above base flood elevation (Sec. 2805(a)(B),
Michael damaged every building on Florida’s Tyndall Air
FY2019 NDAA)
Force Base (repair estimate $4.7 billion). Hurricane
Florence dropped 36 inches of rain, flooding three North
Directs the Secretary of Defense to incorporate
Carolina Marine Corps installations (repair estimate $3.6
authorized, site-specific, and long-term climate
billion). While more intense hurricanes have not been
projections, via amendment of UFC 1-200-01, General
confidently linked to climate change, higher sea levels
Building Requirements, and 1-200-02, High
magnify the adverse impact of storm surges (see chapter 1
Performance and Sustainable Building Requirements.
of the Fourth National Climate Assessment).
(Sec. 2805(c), FY2019 NDAA)
DOD Response to Rising Sea Levels
Expands Defense Access Roads authority to improve
DOD has identified climate change as a cause of risk in
critical roads outside installations impacted by sea-level
military operations and to its installations since 2010 (See
rise and recurrent flooding. (Sec 2865, FY2019 NDAA)
2010 Quadrennial Defense Review). In 2014, DOD’s
Congress has required DOD to assess and report installation
Climate Change Adaptation Roadmap named “rising sea
levels and associated storm surge,” as one of four primary
vulnerability to extreme weather and sea-level rise. Sec.
335 of the FY2018 NDAA instructed DOD to assess
climate change related phenomena likely to impact DOD
climate-related impacts to installations, resulting in DOD’s
activities.
2019 Report on Effects of a Changing Climate. Some
Members of Congress requested that DOD revise the report
based on concerns it had not met statutory requirements.
Vulnerabilities to installations include coastal and
DOD complied and issued an addendum in March 2019.
riverine flooding. Coastal flooding may result from
storm surge during severe weather events. Over time,
Possible Issues for Congress
gradual sea level changes magnify the impacts of storm
surge, and may eventually result in permanent
Standard definitions of extreme weather. DOD
installation vulnerability assessments suggest that the
inundation of property. Increasing coverage of land
understanding of extreme weather terms (including sea-
from nuisance flooding during high tides, also called
level-related terms like storm surge) varies across DOD.
“sunny day” flooding, is already affecting many coastal
A standard list of extreme weather definitions could
communities.
assist DOD with assessing and preparing for sea level-
DOD Report on Effects of a Changing Climate, 2019
related and other impacts of extreme weather events on
coastal and non-coastal installations.
In 2016, the Department issued DOD Directive (DODD)
Instructions for incorporating climate projections
4715.21, Climate Change Adaptation and Resilience
into planning. DOD does not have a process for
(updated in 2018), which assigns responsibility to all
evaluating and incorporating the use of climate
organizational entities within DOD to assess the effects of
projections into guidance. UFCs 1-200-01 and 1-200-02
climate change and integrate them into planning. Section
lack guidance on the use of different projections,
2.2 (a) of DODD 4715.21 identifies the Office of the
integration into facilities planning, and the development
Assistant Secretary of Defense for Energy, Installations,
of site-specific climate projections. DOD is in the
and Environment (OASD (EI&E)) as the primary climate
process of developing guidance for incorporating sea-
adaptation official responsible for considering climate
level rise projections into UFCs, but does not have a
change adaptation and resilience in the installation planning
timeframe for incorporating other climate projections.
process. DODD 4715.21 also assigns OASD (EI&E)
Medium and small sites are not required to consider
responsibility to provide direction on technologies,
extreme weather in planning. Presently, only officials
engineering standards, and tools for climate change
at major military installations – defined by the Base
adaptation and resilience, including the Unified Facilities
Structure Report as a large site with a Plant
Criteria (UFC) Program. UFC documents specify
“
Replacement Value (PRV) greater than or equal to
planning, design, construction, sustainment, restoration,
$2.067 billion – are required to incorporate extreme
and modernization criteria,” for military installations in
weather, such as storm surge enhanced by sea-level rise,
accordance with DODD 4270.5 (Military Construction).
into master plans (10 U.S.C. § 2864).
Congressional Actions
Through the National Defense Authorization Act (NDAA),
Margaret Tucker, Research Associate
Congress has exercised oversight of how DOD assesses and
G. James Herrera, Analyst in U.S. Defense Readiness and
prepares for sea-level rise by legislating changes to DOD’s
Infrastructure
https://crsreports.congress.gov
Military Installations and Sea-Level Rise
IF11275
Disclaimer
This document was prepared by the Congressional Research Service (CRS). CRS serves as nonpartisan shared staff to
congressional committees and Members of Congress. It operates solely at the behest of and under the direction of Congress.
Information in a CRS Report should not be relied upon for purposes other than public understanding of information that has
been provided by CRS to Members of Congress in connection with CRS’s institutional role. CRS Reports, as a work of the
United States Government, are not subject to copyright protection in the United States. Any CRS Report may be
reproduced and distributed in its entirety without permission from CRS. However, as a CRS Report may include
copyrighted images or material from a third party, you may need to obtain the permission of the copyright holder if you
wish to copy or otherwise use copyrighted material.
https://crsreports.congress.gov | IF11275 · VERSION 1 · NEW