“The Army will never need to fight in a megacity.”

Over the past few months, MWI has published several articles exploring combat in megacities and examining the Army’s preparation for such an operating environment. The response these articles have produced has brought into the open a debate—ongoing and almost shockingly intense—not about whether the Army is prepared for the unique complexities of dense, urban terrain, but about whether there would ever be a reason for the Army to even consider entering a megacity. A not insignificant minority—including some very smart and experienced people—has voiced some variation of the opinion above in comments sections, on social media, and in direct conversation. Although these opinions are at odds with the views of Army Chief of Staff Gen. Mark Milley—who has said that the explosive growth of megacities gives him “very high degrees of confidence” that the Army will be fighting in urban areas in the future—they are typically thoughtful and always well-meaning. But they are also wrong.

The arguments that the Army need not devote time, manpower, or money to better preparing to operate in megacities are not uniform in their objections. But they do share a series of assumptions on which they’re based, the flaws of which become apparent on closer examination.

Assumption: Megacities are just big cities, and thus pose the same challenges as cities but on a bigger scale.

By the simplest measures, megacities are big cities—defined by the United Nations as cities with more than ten million residents. Nevertheless, as Dr. Russell Glenn, a senior U.S. Army Training and Doctrine Command advisor recently pointed out, this definition fails miserably to define the special character and unique challenges of the world’s megacities.  Megacities are complex adaptive systems, and a defining characteristic of complexity is that there is no immediately apparent relationship between cause and effect. The dense population, complicated structural patterns, and vast infrastructure systems of a megacity makes it a system of systems with no easily identifiable cause and effect; pressure on one point of the system yields reaction and counter-pressure elsewhere, but the megacity’s constant state of change makes even linking action and reaction immensely difficult. Moreover, the megacity’s scale interconnects it with both regional and global economic, security, and stability dynamics.

Take, for instance, Lagos and Shanghai.  Nigeria’s commercial capital, Lagos, is the country’s principal port, through which more than 75 percent of the country’s general cargo and most of its oil exports flow.  It represents massive and vital infrastructure to Nigeria, the largest oil producing country in Africa.  With over 1 percent of China’s population, Shanghai serves as the largest base of Chinese industrial technology, one of the country’s most important seaports, and China’s largest commercial and financial center.  A number of megacities “now have substantially more economic weight, international connectivity, and diplomatic influence on the world stage than dozens of nations.”  A disruption to any of these megacities will have major—but more importantly, unpredictable—impacts on global geopolitical, financial, trade, telecommunication, and security networks.

Assumption: The United States does not have national security interests that warrant taking action in megacities.

Despite this assumption’s seeming defiance of logic and history, the authors have heard this response from audiences and senior leaders during briefings and discussions about military operations in megacities.  These leaders don’t argue that there are no US interests in megacities, but that there are no interests that would drive the US government, after a cost-benefit analysis, to commit military forces to solve problems in that environment. Essentially, given the scale of the problem and the size of our forces, these operations are impossible.

To say there are no interests in megacities so vital as to commit military forces to protect them fails to appreciate US role in world.  The current National Security Strategy lists four enduring national interests:

  • The security of the United States, its citizens, and US allies and partners;
  • A strong, innovative, and growing US economy in an open international economic system that promotes opportunity and prosperity;
  • Respect for universal values at home and around the world; and
  • A rules-based international order advanced by US leadership that promotes peace, security, and opportunity through stronger cooperation to meet global challenges.

These interests are global and, in many regions, their nexus is in megacities. To cordon off areas of the world where we say it is just too hard represents a failure to provide the president with options.  The reality is that megacities create conditions that increase the likelihood of future military operations.

Megacities are more susceptible to both natural and manmade disasters.  Many of the world’s megacities are coastal and consequently vulnerable to a range of weather and geological phenomena.  Tokyo, Osaka, and Manila received the highest rating of risk of exposure to natural disaster by the United Nations.  Twenty-four megacities are located in the less developed “global south.” China alone is home to six megacities, while India has five.  The ten additional cities projected to become megacities by 2030 are all located in developing countries. The high population density, low quality of life and sanitation conditions, and inability of governments to provide services to vast swaths of megacities also put them at high risk to the rapid spread of diseases like the Zika and Ebola viruses. Megacities are military humanitarian aid and disaster relief operations waiting to happen.

Additionally, Americans live in all of the world’s megacities.  US combatant commanders’ command priorities include the protection of these Americans living abroad.  While it is difficult to determine the precise number of US citizens that live in megacities, of the estimated 7.6 million Americans living overseas, many call these international hubs of activity home.  There are estimated to be more than 17,000 in Tokyo, 9,000 in Seoul, and more than 4,000 in Mumbai (and many more times these numbers if short-term visitors or, especially in the case of Seoul, military members and dependents are added).   Plenty of scenarios could lead to the requirement for noncombatant evacuation of US citizens in these and other megacities.

Finally, the US economy’s global connections and reliance on a stable international system add to US interests in megacities.  Many of them, such as Cairo, Shanghai, and São Paulo are critical hubs of this international system: they provide commodities and natural resources, serve as critical ports through which global trade passes, and house institutions that represent nodes in global financial networks.   This is not to say that the United States must take action in the event of any crisis in a megacity, but clearly instability in many megacities has the potential to severely impact the US economy and put at risk other vital interests that could warrant a wide range of military operations.

Assumption: Megacities can be cleared of civilian population before commencing operations.

Much of the difficulty of conducting operations in a megacity stems from the masses of noncombatants in the environment. The easy fix? Just relocate the people. In theory, this is a workable solution, very much a shaping operation that will create a less complex battlespace; it’s been done by combatants throughout the history of modern war in some form or another, from Stalingrad to Mosul. In practice, this is not a practical option for a host of reasons.

Encouraging a city’s population to temporarily relocate is clearly within the bounds of acceptable norms for US operations. In Iraq and Afghanistan, we have regularly broadcast messages warning an area’s residents of impending operations and encouraging them to leave the area. But forcible relocation is something we have increasingly refused to undertake—despite historical evidence that it can work. During the British army’s successful counterinsurgency campaign in Malaya, half a million people were forced into “new villages” behind barbed wire. And yet such a proposal was never seriously considered in our post-9/11 wars, even at the height of America’s counterinsurgency struggles in Iraq.

Even if a crisis scenario that overcame American normative resistance to mass relocation emerged—US forces in Vietnam tried a small-scale and short-lived version of it—the scale of such a challenge in megacities offers immense practical impediments. If war broke out on the Korean Peninsula, for example, and North Korean forces were to advance on Seoul and turn the city into a battlefield, the logistical barriers alone would make emptying the city of noncombatants virtually impossible. To get a sense of the size of such a task, it would require 128,000 fully loaded eighty-passenger buses to relocate the civilian population of Seoul alone (almost twenty times as many buses as actually exist in the city). Add in the entire metropolitan area, and the number jumps to 320,000 buses. And this relocation would take place in a country that has a much lower ratio of surface road length to land area than other advanced countries, and a city that has been actively removing major highways in the city over the past fifteen years. The infrastructure in less developed countries, where the majority of the world’s megacities exist, would be even less capable of supporting massive population relocation. Clearly, the feasibility of even partial relocation is a dangerous assumption.

Even if time permitted such a massive undertaking, or US planners were content simply to expect noncombatants to evacuate themselves, a range of equally daunting challenges would necessarily follow. Where will evacuated civilians be housed? How will their basic need be met—food, water, medical care, security? Because pursuit of economic opportunity is a key driver of urbanization, increasing congregation of people in megacities brings with it a resource shift, leaving the areas to which evacuees will move less prepared to absorb them. The challenges faced by maintaining the Zaatari refugee camp in Jordan are instructive—and it houses about 80,000 displaced Syrians, just a fraction of one percent of the population of a megacity.

Framed as a question of the Army’s mission variables, METT-TC (Mission, Enemy, Terrain and weather, Troops and support available, Time available, and Civil considerations), this assumption essentially reduces megacities’ complexity to a single variable (“C”), to be dealt with before actual operations commence. In reality, relocating millions of people, or even hundreds of thousands, from such complex terrain would be a complicated, time- and manpower-intensive operation on its own—one that is far from a guaranteed option in the event of a crisis.

Assumption: Nuclear weapons are an option.

This is not an erroneous assumption, in itself. If nuclear weapons were not in fact an option, much of the theory of strategic deterrence in the nuclear age would be essentially proven false. Certainly, the nuclear threshold—a figurative, nebulous line beyond which nuclear weapons use by a combatant becomes conceivably possible—falls within the bounds of potential real-world conflict. But where this assumption breaks down is in its failure to account for what might be called an “interests threshold” and, more importantly, the gap between the two.

In almost any scenario in which military action is called for, nuclear weapons are clearly not—be it humanitarian assistance, noncombatant evacuation operations, counter-WMD, or even large-scale conventional (Korea, First Gulf War) or counterinsurgency (Vietnam, Iraq, Afghanistan) operations. The US military has undertaken these missions in jungles, deserts, and mountains, in rural areas, villages, and cities. Why? Because policymakers have deemed conducting them in our national interest. That similar interests simply do not exist in megacities is clearly insensible (see above). Therefore, this assumption only holds up if the “interests threshold” and nuclear threshold align properly—which, of course, would require that evacuating US citizens from a megacity under siege from an enemy force, or locating and securing stolen WMD materials, could somehow be undertaken (or even facilitated) by employing a nuclear weapon.

Of course, many considerations factor into any decision to use military force, including terrain complexity. And the incredible complexity of dense, urban terrain exerts upward pressure on the “interests threshold.” Simultaneously, near-peer potential adversaries like Russia are actively lowering their nuclear threshold, which, if deterrence is to remain a relevant strategic concept in the 21st Century necessarily pushes our own threshold downward.

And yet, the assumption that nuclear weapons offer an alternative to ground forces operating in a megacity necessitates that there be no gap between the points at which US interests require safeguarding and nuclear weapons will be used. Given the evidence, that’s more of a hope than a justifiable assumption.

Assumption: The military is already prepared for megacities.

It isn’t inherently illogical to believe that, because the Army has a long history of operating in cities, it will adapt to the megacity environment if required—a view buttressed by the earlier assumption that megacities are in fact just large cities. US forces conducted combat operations in Baghdad for over eight years, so the lessons learned there should translate to Bangalore.   However, even with its more than four million inhabitants in 2003, Baghdad is exponentially less complex than any of the world’s megacities.  It has few buildings above twelve floors, no subterranean transportation system, and no major connections to global economic, information, or political networks.

Operating in megacities presents a long list of challenges to military forces in three general areas:

  • The challenge of the physical terrain. The vertical terrain of skyscrapers and other structures creates urban canyons that prevent or disrupt visibility, concealment, line of site, and satellite navigation and communication equipment. The complicated networks of streets and alleys vastly increase potential enemy avenues of approach, while windows and rooftops at every elevation create a multitude of places to be attacked from. The subterranean dimension of subways, utilities, and sewers exacerbates both of these challenges. Furthermore, narrow thoroughfares, packed with vehicles, constrain ground movement, while vertical structural density limits landing and pickup zones and flight routes for aerial assets, to include unmanned aerial systems.
  • The challenges of the human population. The threat of high civilian casualties is omnipresent. Essential services and resource requirements provide a layer of complexity on top of military objectives. The volume of electronic signatures creates a saturation of big data. Indigenous enemy forces easily blend in amongst the millions of residents. Chaos and disruption have the potential to spark massive humanitarian concerns, overburden the systems that maintain order, and bring domestic productivity to a screeching halt.
  • The challenges of understanding. Each megacity is a unique entity and understanding their complexities and connections is a massive undertaking.  David Kilcullen argues they should be treated like living organisms complete with their own flows and metabolism.  Research conducted by the 2014 Chief of Staff of the Army Strategic Studies Group concluded that each city should be its own unit of analysis studied through a framework of context, scale, density, connectedness, and flows.  Without understanding a city’s unique characteristics, national security authorities have no basis on which to assess the impact or requirements at the strategic, operational, or tactical level.

But despite all of these unique challenges, the US military has no school, no doctrine, no specialized equipment, and no tailored framework for operations in megacities. There is no megacities studies institute or training site to learn, train, plan, or prepare to operate in megacities. Much of the Army’s force design, training, and equipment fielding practices assume an ability to adapt to the environment. This may be true, to an extent, but it cannot be argued that the Army is already prepared to operate in megacities. And failing to do so is a strategic risk that will cost considerably when, not if, military forces are called upon to conduct any mission in these environments.

Building a Prepared Force

Ultimately, the likelihood that the US Army will find itself operating in megacities is dependent on our adversaries. If they are willing to operate in dense urban terrain, refusing to do so ourselves is tantamount to ceding to them the initiative in their preferred operational environment. And make no mistake, this would be a fundamental shift. We have faced threats and the need to protect vital interests in a host of domains and complex battlespaces, and we have recognized that backing away from such a challenge is not an option. We maintain a Northern Warfare Training Center, Mountain Warfare School, Desert Warrior Course, and Jungle Operations Training Center to be prepared to operate in uniquely challenging conditions. We invest resources to safeguard interests in space and cyberspace. And in each of these environments and domains we don’t make assumptions similar to those above. We don’t assume an arctic war would be the same as a desert war, only colder. We don’t assume we have no security interests in a particular place because of environmental considerations. We don’t create an Internet kill switch and stop actively operating in cyberspace. And we don’t assume we’re prepared and that no refinement of our preparation is required.

The US Army cannot afford to be unprepared for megacities. An urban warfare school deserves serious consideration. Specialized units—manned, trained, and equipped to operate in megacities—should be an option, as well. But first, we must dispel with the idea that we can simply choose not to operate in an environment that features so centrally in the current and future security environments. Sooner or later, we will be forced to operate in megacities. We better be ready.


Maj. John Spencer is a scholar with the Modern War Institute at West Point. A former Ranger Instructor, he has held the ranks of private to sergeant first class and lieutenant to major while serving in ranger, airborne, light, and mechanized infantry units during his 23 years as an infantryman. He looks forward to connecting via Twitter: @SpencerGuard.

John Amble is the editorial director of the Modern War Institute at West Point. He is a military intelligence officer in the US Army Reserve and a veteran of Iraq and Afghanistan wars. Follow him on Twitter: @johnamble.

The views expressed in this article are those of the authors and do not reflect the official policy or position of the Department of the Army, Department of Defense, or the US government.


Image credit: Jorge Láscar (adapted by MWI)