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Contexto Internacional

Print version ISSN 0102-8529On-line version ISSN 1982-0240

Contexto int. vol.39 no.2 Rio de Janeiro May/Aug. 2017  Epub May 08, 2017 

Think Piece

The Enabling Power of the Oceans

Antonio Ruy de Almeida Silva1 

1Brazilian War College (ESG), Rio de Janeiro–RJ, Brazil;


The importance of the oceans to humankind has been studied throughout the centuries, including in the fields of co-operation and conflict. This think piece synthesises discussions in international politics of some of the characteristics of oceans, especially discussions in the strategic-military domain, It contests those who consider oceans as a “barrier”, and alternatively defends that oceans are a critical enabler that allows the generation of wealth, projection of military forces, and the influence of the international politics in war or peace.

Keywords International Politics; International Security; Military Power; Sea Power; Naval Power

He that commands the sea is at great liberty,

and may take as much and as little of the war as he will.

Francis Bacon


The oceans are paramount enablers to make Earth home to humankind. They cover 75% of its surface and their physical, chemical and biological properties make the marine environment critical to the existence of life in our planet. As pointed out by the United Nations, ‘our rainwater, drinking water, weather, climate, coastlines, much of our food, and even the oxygen in the air we breathe, are all ultimately provided and regulated by the sea’ (2017:1).

Oceans have played an important role in the history of civilisations. Their characteristics generate the conditions of possibility to exploit or influence the political, economic, social, environmental, and military domains. Their importance has evolved, mainly, thanks to the possibilities the maritime spaces offer for trade, natural resources exploitation, transport of persons, military operations and – especially in the past – the spread of ideas. According to Bertrand Russel, philosophy and science first appeared in Miletus, as the city was an important commercial seaport in which people of different cultures could meet, thus contributing to the diversity of ideas (Russell 2001).

The oceans have also become an important source of biological and energy resources and minerals. This importance tends to grow as new research and technologies demonstrate the potential of ocean resources and enable their economic exploitation. The influence of the sea extends even to the coastal areas, where most of the world’s population lives, and is subject, therefore, to the climatic changes that affect the marine environment. According to the United Nations, ‘over three billion people depend on marine and coastal biodiversity for their livelihoods’ (2017: 1).

The purpose of this contribution is to defend what I call ‘the enabling power of the oceans’, characterised by their role in maintaining human life on Earth, in generating wealth for nations, in allowing the circulation of goods and people, and in facilitating military power projection. I do not repeat here what is well known about the three first characteristics of the oceans. My focus is rather on the strategic-military aspect of the seas. Nevertheless, since wealth, trade and maritime power are interlinked, I mention them whenever it is necessary to support my argument. I first describe, very briefly, the relation between sea power, trade and globalisation, and then explain how the enabling power of the oceans allows nations to use their military power to exert influence in situations of war and peace.

Maritime trade, sea power, and globalisation

Although technological advances and the emergence of post-industrial societies are reducing the importance of geographical factors, the physical environment remains a significant element to understand international politics (Dougherty and Pfaltzgraff 2003). In this context, the oceans stand out because they are an important enabler to generate wealth, maintain sea lanes of communication between the continents, and project military power around the world.

To Alfred T. Mahan, the sea is a great path, open to all, which allows the free flow of people and goods. He points out that the history of sea power shows an enormous influence of maritime transportation on commerce, wealth and power of nations, and, at the same time, reveals how disputes and economic competition involving the sea often culminated in armed conflicts. So, he states, ‘the control of the sea is and has been a great factor in the history of the world’ (Mahan 1987: iii).

However, Mahan does not define the concept of sea power precisely. Sometimes he refers to it as the ability of the military power in its naval expression to control the sea, and sometimes he uses it as the set of commercial maritime activities, the access to markets and the possession of colonies contributing to a nation’s wealth and power (Crowl 1986). To make the concepts clear, I define sea power as the ability of a state to exploit or influence the range of sea-related activities in the political, economic, social, environmental, and military domains. Naval power is the military component of sea power.

According to Mahan, trade and politics are interlinked, and nations are bonded by their interests in such a way that the whole forms an articulated system (1987: 144). This system is what has been called today globalisation. This phenomenon has dramatically increased the flow of information and of financial and trade transactions, while increasing the interdependence between nations, with direct consequences on the flow of world trade – which, in turn, has fostered an extraordinary development of shipping (Silva 2007). Moreover, the oceans are an important source of energy. Offshore oil production has increased to one-third of the total world oil production, and new methods of exploration now ‘allow the search for oil and gas to a depth of 12 kilometers below the ocean floor’ (World Ocean Review 2017: 1).

Globalisation and sea power are, therefore, closely interlinked. Whenever the process of globalisation intensifies, maritime power develops, and vice-versa. Regarding its economic importance, globalisation has increased the flow of commercial transactions, yielding an extraordinary development of maritime transport, which accounts for approximately 80% of the total world trade as measured by volume, and 70% of the total world trade as measured by value. According to a report of the United Nations Conference on Trade and Development (UNCTAD), in 2015 there were 89.464 commercial vessels in service at the sea. This system is so important that it can be said that ‘maritime transport remains the backbone of international trade and globalisation’ (2015: 22).

The process of globalisation has contributed to the expansion of the world maritime system. As stated by Reason and Freyman, ‘all the economies of the world […] depend for their prosperity upon uninterrupted worldwide commerce’ (1998?: 17). Although most nations participate and benefit from this system, those with greater sea power are the ones that have the greatest benefits.

Mahan (1987) considers that the main elements affecting a nation’s sea power are its geographic position, the size of its coast and the number of areas suitable for good ports, the number of its population and its population’s inclination for sea-related activities, and its government’s ability to produce good policies. More recently, Erik Grove (1990) has updated these elements by dividing them into first-order elements: economic strength and technological capacity, and socio-political culture; and second-order elements: geographical position, dependence on maritime trade, and the resources of the sea and government policies and perceptions. So, there is a virtuous circle in which a nation’s economic strength and technological capacity foster the improvement of its sea power, which, in turn, contributes to reinforce the nation’s economic strength and technological capacity.

The expansion and the importance of economic and financial activities linked to globalisation have also brought up consequences to the post-Cold War international security and defence system. Although, on the one hand, the world trade market facilitates co-operation among nations, on the other hand, it fosters competition that may lead to conflict. Warships and navies, initially created to protect the maritime trade of the earliest civilisations of the Mediterranean (Stevens and Wescott 1958), are now primarily responsible for the security of this globalised maritime system. The United States of America, whose economy heavily depends on international trade and benefits the most from the maritime trade system, has committed itself with the task of maintaining the security of the seas and exploiting the enabling power of the oceans to its military power projection, in order to exercise its leadership in world politics.

The enabling power of the oceans and military power

The enabling power of the oceans, which allows the free flow of people and goods, as discussed above, is also critical to allow the projection of military power around the globe. The oceans favor the mobility of naval forces to operate in international waters and the access to maritime areas near the coastlines, where ‘half the world’s population lives within 60 km of the sea, and three-quarters of all large cities are located’ (UNEP 2017: 1). The United Nations Convention on the Law of the Sea safeguards freedom of navigation, so naval forces can legally operate in international maritime areas or approach a nation’s territorial waters using the right of innocent passage – ‘so long as it is not prejudicial to the peace, good order or security of the coastal State’ (United Nations 1982: 41).

Mobility allows the naval forces to operate for long periods at long distances while preparing for combat. These forces are versatile, in the sense that they can undertake several types of tasks and regulate the use of force according to specific situations and necessities. Furthermore, they have the flexibility to shape the naval units in small or bigger task forces, depending on the mission to be accomplished. These missions are usually designed to control maritime areas, precluding the opponent to make use of the sea and hence to project its naval military power to influence events taking place on land.

According to Julian S. Corbett,

Since men live upon the land and not upon the sea, great issues between nations at war have always been decided—except in rarest cases—either by what your army can do against the enemy’s territory and national life, or else by the fear of what a fleet makes it possible for your army to do. The paramount concern, then, of maritime strategy is to determine the mutual relations of your army and navy in a plan of war (2004: 14).

The crucial role of land forces in war does not reduce the importance of the other components of military power. War usually depends on all armed forces branches, so a maritime strategy has to be developed as part of a whole in which land, air and space strategies are integrated in order to succeed. The effects of the use of maritime power to influence events on land are strategic, contributing to the nation’s political objectives in war and in peace (Gray 1994). According to George Moldelsky and William Thompson, ‘in global war conditions, navies have proved decisive in winning the contest in global proportions’ (1988: 12).

World War II is a clear example of the strategic contribution of sea power to events occurring on land. During the dispute over sea control, both sides attempted to weaken the economic power of the opponent. When the Allies established a certain grade of control of the sea, the army forces – transported by the sea – were projected on land to fight the battles that led to victory. In the campaigns of the Pacific War, the control of the sea by the United States allowed the economic suffocation of Japan. Therefore, both methods of a maritime strategy by which the naval forces are used to exert control over the opponent – that is, economic suffocation and the projection of power over land – are paramount to win a war (Wylie 1989). Even Mearsheimer, who defends the primacy of land power, recognises that the control of the sea by the United States was, along with the land battles, ‘a deciding factor in that conflict’ (2003: 113). The victory in World War II would not have been possible without the vital contribution of sea power, and of the exploitation of its potential to ‘manipulate the placement, the timing, and, in great measure, the weight of the strategic centers of gravity on land’ (Wylie 1989: 132).

According to Colin Gray, the sea is the only way by which a sea power can transport a great amount of heavy and bulk goods in case of a regional or global conflict. Moreover, naval power has an important advantage: ‘the ability to control the geostrategic terms of engagement in war; depending upon who controls the sea, water is a highway or a barrier’ (1992: xi-xii). The enabling power of the oceans can be exploited by any nation able to develop a great sea power. Norman Friedman, for instance, considers that the United States will only be threatened by a hostile country that is able to develop a great economic and technological capacity that may allow it to become a global sea power: ‘Only then can an enemy gain sufficient strength to turn the natural barrier of the oceans into an invasion route, and use that route to place a decisive force in North America’ (2001: 15). In this framework, the concept of the ‘stopping power of water’, defended by Mearsheimer, is more related to an incapacity of a state to develop a powerful sea power which might be able to control the sea and to project power over land than to a particular characteristic of the oceans that might influence war in a critical aspect.

The maritime waters are highways for those nations who are capable of exploiting the enabling power of the oceans for peace or for war. These highways allow a sea power to have sea borders with all the coastal states of the globe and to project its military power all over the world, influencing international politics. The capacity of global reach is paramount to a great power to protect its interests, influence other countries and maintain the international order. As Moldelsky and Thompson put it, ‘Sea power is the sine qua non of action in global politics because it is the necessary (though not the sufficient) condition of operations of global scope’ (1988: 13).


The oceans are critical to our life on Earth in such fields as the political, economic, environmental and military domains. The physical, chemical and biological properties of the marine environment are paramount to the existence of life in our planet. Furthermore, the oceans are a source of energy and other natural resources and highways, which interconnect continents, contributing to the globalisation process and the wealth of the nations. These characteristics give them what I call the enabling power of the oceans. In war as well as in peace this power plays a crucial strategic role in world politics, further influencing events on land. To those nations able to control the sea, the oceans are considered highways, whilst to those not capable to do so, they may be seen as a barrier. So, ‘the stopping power of water’ is more a state’s incapacity to control the sea and to project power over land than a characteristic of large bodies of water, which allegedly makes the oceans a ‘forbidding barrier’, as defended by Mearsheimer (2001). The enabling power of the oceans will continue to provide the nations able to become a great sea power with the advantage of controling and making use of the oceans in war and in peace, in order to influence global politics.


Crowl, Phillip A. 1986. ‘Alfred Mahan: the naval historian’. In: Peter Paret (ed), Makers of modern strategy from Machiavelli to the Nuclear Age. Nova Jersey: Princeton University Press. pp. 444-480. [ Links ]

Dougherty, James E and Robert L Pfaltzgraff. 2003. Relações internacionais: as teorias em confronto [International Relations: different theories in debate]. Lisboa: Gradiva. [ Links ]

Friedman, Norman. 2001. Seapower as Strategy: Navies and International Interests. Annapolis: Naval Institute Press. [ Links ]

Gray, Collin S. 1992. The Leverage of Sea Power: The Strategic Advantage of Navies in War. New York: Free Press. [ Links ]

Gray, Collin S. 1994. The Navy in the Post-Cold War World. University Park: Pensylvania State University Press. [ Links ]

Grove, Eric. 2003. The Future of Sea Power. Annapolis: Naval Institute Press. [ Links ]

Mahan, Alfred Thayer. 1987. The Influence of Sea Power Upon History. New York: Dover Publications, Inc. [ Links ]

Mearsheimer, John J. 2001. The Tragedy of Great Power Politics. New York and London: W.W. Norton & Company. [ Links ]

Modelsky, George and William R Thompson. 1988. Seapower in Global Politics, 1494-1993. London: The Macmillan Press LTD. [ Links ]

Reason, Paul J. and David G Freymann. 1998. ‘Sailing New Seas’. Newport Paper no. 8. Newport: Naval War College. [ Links ]

Russell, Bertrand. 2001. História do Pensamento Ocidental. Transl. Laura Alves and Aurélio Rebelo. Rio de Janeiro: Ediouro. [ Links ]

Silva, Antonio Ruy de Almeida. 2007. ‘A Globalização e Segurança Marítima’. Revista Marítima Brasileira, 127 (10/12). [ Links ]

Stevens, William Oliver and Allan F Wescott. 1958. História do poderio marítimo Transl. Godofredo Rangel. São Paulo: Companhia Editora Nacional. [ Links ]

United Nations. 1982. Convenção das Nações Unidas sobre o Direito do Mar [United Nations Convention on the Law of the Sea]. Rio de Janeiro: Department of Hydrography and Navigation, Navy of Brazil. . [ Links ]

United Nations. 2016. ‘Healthy oceans, healthy planet’. Available at: [accessed on 24 January 2016]. [ Links ]

United Nations. 2017. ‘World Ocean Day’. Available at [accessed on 01 February 2017]. [ Links ]

United Nations Conference on Trade and Development (UNCTD). 2015. ‘Review of Maritime Transport 2015’. Available at [accessed on 01 February 2017]. [ Links ]

United Nations Environment Program (UNEP). 2017. ‘Cities and Coastal Areas’. Available at: [accessed on 06 February 2017]. [ Links ]

World Ocean Review. 2017. ‘Wor 3 in Short’. Available at [accessed on 01 February 2017]. [ Links ]

Wylie, Joseph Caldwell. 1987. Military Strategy: A General Theory of Power Control. Annapolis: Naval Institute Press. [ Links ]

Received: February 10, 2016; Accepted: February 14, 2017

Antonio Ruy de Almeida Silva is Rear Admiral, senior professor and special advisor of the Brazilian War College (ESG), Brazil. He holds a PhD in International Relations from the Pontifical Catholic University of Rio de Janeiro (PUC-Rio), and a PhD (with distinction) in Maritime Policy and Strategy from the Brazilian Naval War College. He also holds a BA degree from the United States Naval War College (Class of 2000), and a MA degree in Arts (International Relations) from Salve Regina University, USA. He was the 60th Director of the Brazilian Naval War College (EGN). He has published several articles on International Security, Nuclear Proliferation, Sea Power, “New Threats”, South Atlantic, Defence Diplomacy, Piracy, among others.

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