The US Military on the Front Lines of Rising Seas (2016)

Rising seas will increasingly flood many of our coastal military bases.

Sea levels are rising as global warming heats up the planet. Many military bases along the US East Coast and Gulf of Mexico are at risk of permanently losing land to the ocean in the decades ahead.

As the seas rise, high tides will reach farther inland. Tidal flooding will become more frequent and extensive. When hurricanes strike, deeper and more extensive storm surge flooding will occur.

The US Armed Forces depend on safe and functional bases to protect the national security of our country. We must prepare for the growing exposure of our military bases to sea level rise.

Naval Station Norfolk—the largest naval installation in the world—is projected to face 4.5 feet to nearly 7 feet of sea level rise this century.  
Photo: US Navy

Military bases at risk

Military installations included in this analysis

18 military installations are included in this analysis. Each location's changing exposure to flooding is projected through the end of the century:

Key findings

The military is at risk of losing land where vital infrastructure, training and testing grounds, and housing for thousands of its personnel currently exist.

  • By 2050, most of the installations in this analysis will see more than 10 times the number of floods they experience today.
  • By 2070, half of the sites could experience 520 or more flood events annually—the equivalent of more than one flood daily.
  • By 2100, eight bases are at risk of losing 25 percent to 50 percent or more of their land to rising seas.
  • Four installations—Naval Air Station Key West, Joint Base Langley-Eustis, Dam Neck Annex, and Parris Island—are at risk of losing between 75 and 95 percent of their land by the end of this century.
  • Flooding won’t be confined to the bases. Many surrounding communities will also face growing exposure to rising seas.

Naval Air Station Key West is at risk of losing 70 percent to 95 percent of its land to the sea by the end of this century.
Photo: US Navy

Planning for rising seas

The gap between the military’s current preparedness for sea level rise and the threats outlined here is large and growing.

To plan effectively for the long term, military decision makers with authority over these bases need to understand how sea level rise may permanently alter the landscape and where the threat of storm surge may become intolerable.

To take action, however, individual installations will need more detailed analysis and resources to implement solutions.

Congress and the Department of Defense should, for example:

  • Support the development and distribution of high-resolution hurricane and coastal flooding models
  • Adequately fund data monitoring systems such as our nation’s tide gauge network
  • Allocate human, financial, and data resources to detailed mapping and planning efforts at military installations.
  • As adaptive measures are identified, allocate resources for these projects, many of which will stretch over decades.

Our defense leadership has a special responsibility to protect the sites that hundreds of thousands of Americans depend on for their livelihoods and millions depend on for national security.

About this analysis

Each base's exposure is calculated based on the National Climate Assessment’s midrange or “intermediate-high” sea level rise scenario (referred to in this analysis as “intermediate”), which projects a global average increase of 3.7 feet above 2012 levels, by 2100; and a “highest” scenario based on a more rapid rate of increase, which projects a global average increase of 6.3 feet.

The highest scenario is especially useful when making decisions with a low tolerance for risk. Moreover, recent studies suggest that ice sheet loss is accelerating and that future dynamics and instability could contribute significantly to sea level rise this centu­ry.

This analysis includes an executive summary; key findings; and fact sheets for each location, which can be downloaded via the links above. You can also download all of the materials as a single PDF. For more, please see the detailed methodology and key caveats for this analysis.

Authors and contributors

Authors: Erika Spanger-Siegfried, lead author and project manager, is a senior climate analyst in the UCS Climate and Energy Program. Kristina Dahl, lead analyst, is a consulting climate scientist in the program. Astrid Caldas is a climate scientist in the program. Shana Udvardy is a climate preparedness specialist in the program.

Contributors: Sarah Pendergast is a legislative assistant with the Climate and Energy Program. Alyssa Tsuchiya is a climate policy analyst with the program. Pamela Worth is a UCS staff writer.

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