The question is no longer whether [the effects of sea level rise] will manifest, but rather how soon.

The threats posed by rising sea levels can be hard to imagine, especially for people living in the U.S. interior. For them, sea level rise is a distant news story reported as millimeters of rise per year, and who worries about millimeters? The seemingly intangible (or negligible) impacts of rising seas disconnect us from the reality of the threat. So, how bad is the problem? In terms of magnitude, experts have recommended adaptation plans that prepare for 0.5–2 meters of sea level rise by the year 2100. In terms of effects, rising seas will impact coastal and landlocked communities alike. Furthermore, the ocean does not discriminate based on a country’s affluence – wealthy and developing nations will be affected alike.

The impact of rising seas is neither superficial nor isolated, and is severe enough to threaten the national security of the United States and nearly all other countries. Rising seas influence food and water availability, human health, and military operations, among other topics not covered here, but which also pertain to national security (for example, economics, social instability, and energy). The question is no longer whether these effects will manifest, but rather how much, and how soon. We must be prepared with mitigation and adaptation strategies.

Before delving into the concerns posed by rising seas, it is first worth clarifying the meaning of the term “national security.” Simple interpretations of national security evoke military preparation – soldiers, bases, vehicles, and weapons – to defend against hostile foreign powers. While the physical defense of a nation still constitutes a major focus of national security, it is not the only focus. National security is a broader concept, and U.S. National Security Strategies of recent decades have repeatedly invoked the destabilizing effects of environmental problems such as climate change. Clearly, maintaining national security requires safeguarding a nation’s food and water security, public health, economic status, and other factors, alongside maintaining traditional military security.

The national security implications of key environmental and health concerns are manifest in the U.S. defense community’s involvement in the Global Health Security Agenda, a cooperative effort spanning over 50 nations and other stakeholders, all seeking to improve disease surveillance and response. Furthermore, the U.S. State Department maintains an Office of Global Food Security, and the Office of the Director of National Intelligence stressed water security’s implications for U.S. national security in a 2012 report. When it comes to national security threats, recognition of the challenges is required before action can be taken, which is why the effects of sea level rise on water, food, and health security must be clearly delineated.

One of the most alarming national security consequences of rising sea levels is the threat of water scarcity. This may seem counterintuitive, since sea level rise seems to imply that water availability will increase. However, sea water must be treated to meet human consumption needs, and the energy demands and financial costs of desalination remain prohibitive. Furthermore, as ocean levels rise, saltwater intrusion degrades the existing supply of fresh water, contaminating drinking water in coastal areas. Saltwater intrusion will also penetrate farther inland than in the past, affecting not only surface water but also seeping into aquifers and other groundwater sources.

Current measurements and modeled projections suggest that drinking water losses either have occurred or will soon occur in numerous locations around the world. For example, Bangladesh is expected to suffer a shortage of potable drinking water by the year 2050 due to sea level rise-induced saltwater intrusion. Developing countries are not the only ones at risk. Residents of Adelaide, Australia, can expect their water to fail World Health Organization salinity standards on two out of every five days within 20 years, leading to health outcomes which will be discussed later.

Rising seas threaten our food supply, as well. Shortages of clean water affect irrigation water, and thus agricultural capacity, since most plants cannot tolerate high salinity. Saltwater intrusion causes certain crops like rice to experience slow germination rates and difficulties in nutrient uptake. Even fisheries are threatened by saltwater intrusion and sea level rise. More frequent and intense flooding events related to rising water levels will decrease soil fertility, hasten soil erosion, and result in overwatering of many terrestrial crops. Plus, excessive stagnant water will alter a farm environment’s pest composition, changing ecosystem dynamics and having unknown impacts on plants and livestock. These realities threaten the food security of all communities that import food from affected agricultural lands, not to mention the economic security of agricultural exporters. And for the communities themselves—the ones relying on the products compromised by sea level rise—perhaps the hardest hits will be felt at the checkout counter, where the cost of healthier, fresh foods will reflect the trauma felt by farmers.

Any conversation about food and water access challenges is incomplete without considering the obvious implications for people’s health. The consumption of salty water leads to poor public health outcomes. In Bangladesh, for instance, saltwater ingestion due to seawater contamination of drinking supplies has been linked to high blood pressure, as well as preeclampsia and associated maternal death. In western Australia – a more affluent nation resembling the U.S. in terms of adaptive capacity – respiratory illness, vector-borne diseases, and even some mental health cases have been tied to sea level rise. The fact that some diseases harbored by mosquitoes thrive in conditions created by rising seas is of particular concern, as it is not hard to imagine this sort of outcome occurring closer to home, given recent fears over Zika, West Nile virus, and the like. Couple these health effects with loss of medical infrastructure—or infrastructure in general—near coastlines, and the human health costs of sea level rise are glaring.

If the financial costs coupled with physical damages—some of which have already occurred—are not convincing enough evidence of national security threats to warrant action, one wonders what will.

Water and food are the foundations of public health, and rising sea levels threaten both. This is itself a national security problem. Rising seas also increase the potential for violent conflicts due to the increasing scarcity of fresh water, not to mention their indirect – yet related and severe – impacts such as economic turmoil, migration, and social instability. Thus, rising seas are a clear national security threat. However, let us consider for a moment the more direct implications of rising seas for the U.S. military.

Sea level rise will probably affect the U.S. military by increasing the demand for foreign and domestic humanitarian aid and disaster relief operations (made necessary at home or abroad by the water, food, and health challenges detailed previously). An old military aphorism states, “An army marches on its stomach.” Even more so, it marches on the contents of its canteens. The local scarcity of drinking water globally will increase the logistical and energy burden for the U.S. military to provide water to U.S. operations worldwide.

Rising seas will also affect U.S. military installations globally. More attention will need to be paid to contingency plans for bases and their surrounding communities. Adaptation and mitigation planning applies most urgently to coastal bases, which will suffer from more frequent inundations and even land losses. These threaten military infrastructure, including personnel housing, and field testing and training lands, especially at bases on the East- and Gulf Coasts. Such threats have already reached the Alaskan shoreline, where sea level rise-induced coastal erosion has damaged Air Force radar and communication systems, destroyed half a runway so that large planes cannot use it, and reduced access to training areas. In fact, four stations (Naval Air Station Key West, Joint Base Langley-Eustis, Dam Neck Annex, and Parris Island) have estimated risks of losing 75–95% of their land by the year 2100. Considering that Naval Station Key West alone is home to the Joint Interagency Task Force South, responsible for monitoring and preventing illicit drug trafficking, the impacts of such land loss could be felt nationwide. Not surprisingly, the U.S. Navy has the most installations at “very high risk,” with severe threats to piers, electrical substations, and communication utilities. Overall, the estimated value of U.S. naval installations alone which are suffering or which are likely to suffer from sea level rise is a whopping $100 billion. If the financial costs and physical damages – some of which have already occurred – do not convince us that this is national security threat that warrants action, one wonders what will.

To their credit, U.S. defense and emergency management communities have not ignored the realities outlined above, having publicly acknowledged sea level rise threats with greater frequency in recent years. For instance, a 2015 Congressional request tasked the Department of Defense with “[identifying] the most serious and likely climate-related security risks for each Combatant Command.” The report placed near the top of the list flooding and its relationship to public health crises, food insecurity, and associated outcomes such as migration . Furthermore, numerous expert panels, Congressional briefings, and testimonies of national importance over the past year alone have witnessed retired, high-ranking military leaders from all branches of the U.S. military unifying on a common theme: climate change—including, or in some cases explicitly singling out, sea level rise—poses numerous threats to U.S. national security.

As a result, climate change impact assessments on military installations and programs are becoming commonplace within parts of the armed services. For instance, the U.S. Navy’s Task Force Climate Change is responsible for determining the level of risk posed to different Navy installations due to climate stresses which include: sea level rise impacts, water access challenges, and changes in humanitarian response requirements. The Army and Air Force have followed suit with similar assessment strategies to inform future adaptation planning. While these assessments are critical, their goal is not to address the actual, physical mitigation or adaptation outcomes required. Until definitive actions are taken, the battle between U.S. national security and sea level rise heavily favors rising waters. Instead of doing more impact assessments, the government could also experiment with pilot-type projects which seek to provide some proof-of-concept for addressing sea level rise-induced challenges.

One such program is underway in both Norfolk and Virginia Beach, Virginia. It partners the Department of Defense has partnered with local government officials to replace concrete piers at Naval Station Norfolk with double-deck variants. This is one of many community-driven projects in the area. Again, while such partnerships are a step in the right direction, until physical adaptation strategies are given preference over soon-to-be redundant impact assessments, sea level rise will continue to have the upper hand. This will be particularly true as long as physical adaptation strategies fail to address water, food, and health security challenges alongside explicit military-based ones.

The threat of sea level rise and its impending consequences for food and water security, human health, and defense suggest a need for not just acknowledgement on a community level, but rather action on a national one. The sea level rise outcomes discussed here are by no means comprehensive. Economics, infrastructure, and migration were each mentioned tangentially but could merit entire articles themselves. The ecological and biodiversity impacts will undoubtedly be severe.

What should be clear, however, is that both coastal and inland communities are threatened – either directly or indirectly, at home or abroad – by rising sea levels. Rising too, will be the magnitude of the crises to follow. Whether water levels increase by 0.2 or 2 meters is truly a non-issue. Any measurable displacement will turn the theoretical scenarios described here into tangible threats. The time for debate is past; we now have a choice. When it comes to sea level rise, will we sink or swim?



Aubrey Paris is a senior fellow at the Institute on Science for Global Policy. The opinions in this article are those of the author and do not necessarily reflect the views of the U.S. Army War College, U.S. Army, or Department of Defense.

Photo: A Dutch police officer watches the water flowing over a dike in polder Tolberter Petten, north-west of the Netherlands, on January 5, 2012.

Photo Credit:  VINCENT JANNINK/AFP/Getty Images


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