When Rising Tides Don’t Raise All Ships

The Difference of a Few Degrees on Shipbuilding in the US Navy

“A ship in a harbor is safe, but that’s not what ships are for” [1] could very well be the unofficial slogan of the US Naval Service.  While this is certainly true, the reactor servicing, propulsion plant maintenance, and weapons systems work that are performed in a shipyard are critically important to maintaining naval fleet readiness [2].  The naval shipyard can be seen as the last-mile portion of a supply chain that brings materials, equipment, and skilled technicians to a ship in need of maintenance.  This process begins when personnel at the US Naval Supply System apply technical requirements to an order with a vendor, and terminates when that equipment has been successfully installed onboard a warship at a shipyard under the oversight of the US Naval Sea Systems Command [3].

An essential characteristic of this last mile is the dry dock, a large container that a ship can be sailed into such that the ship is surrounded on all sides.  The dry dock can then be sealed off from the ocean by means of a caisson, a large watertight plug that allows the dry dock to be drained, permitting work to be performed that requires cutting the ship’s hull below the waterline.  Because dry docks are located by necessity at sea level, rising ocean levels pose a threat to the US Navy’s ability to use them to maintain ships—in the vicinity of some Naval shipyards, sea levels are anticipated to rise between 3.5 feet and 5 feet by 2100 [4].  Given that some US Navy shipyards already flood during exceptionally high tides [5], naval shipyards and their dry docks in particular are in danger of becoming inoperable as global temperature rises.

There’s no quick fix for a dry dock that is slipping beneath the waves of a rising tide.  As significant capital investments, dry docks see high demand and continuous use over the course of many years.  For example, Dry Dock 1 at Norfolk Naval Shipyard, built in 1833, was the first dry dock built in the western hemisphere and is still used today to house US Navy ships during maintenance [6]. Other dry docs are similarly old—the average age of a dry dock owned by the US Navy is greater than 80 years [7].  Given this lengthy time horizon, it is not entirely surprising that current dry docks were not constructed with a rising global temperature in mind.  To complicate matters, defense budgets that prioritize funding current operations over maintaining infrastructure have resulted in dry docks that are desperately in need of maintenance and modernization [7].  These circumstances present a bleak picture of Naval preparedness for climate change—most dry docks were built before rising sea levels were anticipated, re-fitting dry docks to accommodate higher sea levels will be expensive, and funds with which to do so are in short supply.

This is not to say that the US Navy has neglected to prepare for climate change entirely. The Navy is currently working to relocate roads and buildings that are threatened by rising sea levels, and stringently requires justification, flood barriers, and backup systems when a planned new building is within two meters of sea-level-rise forecasts [8].  Additionally, the US Navy is working to build higher piers to allow docking ships in higher seas [9]; while many maintenance items could be performed at these higher piers, any work that requires hull cuts beneath the waterline would still require use of a dry dock.  Taking an attitude of prevention, the US Navy has also worked to reduce its own carbon footprint by increasing the use of biofuels [8].  However, the U.S. Navy has been publically silent regarding its plan to prepare dry docks for rising sea levels, either near-term or long-term.

While current actions taken by the US Navy in response to rising sea levels are appropriate, additional work must be performed to ensure that rising sea levels do not prevent naval ships from receiving essential maintenance that can only be provided in dry docks.  Specifically, studies should be undertaken immediately to determine if existing dry docks can be modified (e.g., constructing flood barriers and embankments, augmenting existing dry dock drain systems, extending the height of caissons) to accommodate higher sea levels, or if new dry docks must be constructed.  Given the long-term construction and use of capital investments at naval shipyards, it would be prudent to begin this effort before waters rise too much higher.

The risk posed to dry docks by rising sea levels also begs an additional important question: What other shoreline naval infrastructure is at risk of sinking in the next hundred years? (770)


[1] Fred R. Shapiro, The Yale Book of Quotations (New Haven, CT: Yale University Press, 2006), Section John A. Shedd, p. 705.

[2] “US Naval Shipyards: Supporting the Fleet Today and Preparing for the Future”, Undersea Warfare 52 (Fall 2013): 4-13.

[3] US Naval Supply System, “Naval Supply Chain Management,” https://www.navsup.navy.mil/ public/navsup/wss/nscm, accessed November 2017.

[4] Union of Concerned Scientists, “On the Front Lines of Rising Seas: Portsmouth Naval Shipyard, Maine”, http://www.ucsusa.org/global-warming/global-warming-impacts/sea-level-rise-flooding-portsmouth-naval-shipyard-maine#.WgtBDrQ-fld, accessed November 2017

[5] National Geographic, “Who’s Still Fighting Climate Change? The U.S. Military”, https://news.nationalgeographic.com/2017/02/pentagon-fights-climate-change-sea-level-rise-defense-department-military, accessed November 2017.

[6] US Naval Sea Systems Command: Norfolk Naval Shipyard, “250 Years of Excellence”, http://www.navsea.navy.mil/Home/Shipyards/Norfolk/About-Us/History/, accessed November 2017

[7] LT Sean Getway, USN; ”80-Year-Old Drydocks Don’t Cut It”, US Naval Institute: Proceedings Vol. 143/6/1,372 (June 2017)

[8] Reinhardt, Forest L. and Toffel, Michael W., “Managing Climate Change: Lessons from the U.S. Navy”, Harvard Business Review (July-August 2017 issue): 102-111.

[9] Copp, Tara, “Pentagon is still preparing for global warming even though Trump said to stop”, https://www.militarytimes.com/news/your-military/2017/09/12/pentagon-is-still-preparing-for-global-warming-even-though-trump-said-to-stop, accessed November 2017


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Student comments on When Rising Tides Don’t Raise All Ships

  1. Dry docks’ becoming inoperabble due to rising sea levels and causing supply chain problems in ship maintenance, especially in the US Navy, is a climate change consequence that I have never thought of until I read this essay. Thank you for this very interesting perspective. As you also mentioned, the US Navy is probably working on various measures and plans to modify its infrastructure (like roads and buildings on the shores) in order to prepare them for a certain amount of change in sea levels. I can also understand that necessary financial investments for preparing old dry docks or building new ones might be significant. Therefore I agree with you on the importance of conducting studies to identify those problems and develop solutions as early as possible.

    You also touch on a great point with your essay by mentioning the preventive solutions. I think that the US Navy, as world’s largest vessels, aircrafts, and land vehicles operator and with its significantly high share in greenhouse gases (GHG) emissions, could do much more in terms of renewable energy sources and preventive solutions. By doing so, it could reduce GHG emissions and thus contribute to slowing the climate change down, not only earning more time for planned preparations but also reducing the amount of necessary investments. To your last question regarding other naval infrastructures, I can only think of the sinking of some tiny islands in some regions of the world, changing the local geopolitical borders and causing new challenges for the US Navy.

  2. Great and thoughtful post. This also makes me wonder how the US Navy is able to navigate long-term planning for climate change when certain parts or entire administrations may be opposed to addressing potential issues regarding climate change. In particular, I wonder do they face budget approval issues when it comes to the long-term preventative maintenance for their existing sea-level infrastructure? Based on this post, it seems they are still able to get budget approval regarding these issues. I also wonder if their latest focus on renewable energy for their vehicles is done as stated to reduce reliance on foreign fuel sources or if it is in relation to climate change and an attempt to reduce emissions.

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