The putative "feral cityâ€ is (or would be) a metropolis with a population of more than a million people in a state the government of which has lost the ability to maintain the rule of law within the city's boundaries yet remains a functioning actor in the greater international system.
In a feral city social services are all but nonexistent, and the vast majority of the city's occupants have no access to even the most basic health or security assistance. There is no social safety net. Human security is for the most part a matter of individual initiative. Yet a feral city does not descend into complete, random chaos. Some elements, be they criminals, armed resistance groups, clans, tribes, or neighborhood associations, exert various degrees of control over portions of the city. Intercity, city-state, and even international commercial transactions occur, but corruption, avarice, and violence are their hallmarks. A feral city experiences massive levels of disease and creates enough pollution to qualify as an international environmental disaster zone. Most feral cities would suffer from massive urban hypertrophy, covering vast expanses of land. The city's structures range from once-great buildings symbolic of state power to the meanest shantytowns and slums. Yet even under these conditions, these cities continue to grow, and the majority of occupants do not voluntarily leave.
Feral cities would exert an almost magnetic influence on terrorist organizations. Such megalopolises will provide exceptionally safe havens for armed resistance groups, especially those having cultural affinity with at least one sizable segment of the city's population. The efficacy and portability of the most modern computing and communication systems allow the activities of a worldwide terrorist, criminal, or predatory and corrupt commercial network to be coordinated and directed with equipment easily obtained on the open market and packed into a minivan. The vast size of a feral city, with its buildings, other structures, and subterranean spaces, would offer nearly perfect protection from overhead sensors, whether satellites or unmanned aerial vehicles. The city's population represents for such entities a ready source of recruits and a built-in intelligence network. Collecting human intelligence against them in this environment is likely to be a daunting task. Should the city contain airport or seaport facilities, such an organization would be able to import and export a variety of items. The feral city environment will actually make it easier for an armed resistance group that does not already have connections with criminal organizations to make them. The linkage between such groups, once thought to be rather unlikely, is now so commonplace as to elicit no comment.
[W]here the police forces of the state have sometimes opted not to enforce the rule of law in certain urban localities, in a feral city these forces will not be able to do so.
The author, Richard Norton, is a professor of national security affairs at the Naval War College, according to his bio. He goes on to say that feral cities would become environmentally toxic, transnational threats both militarily and medically. Los Angeles is still in the green, says Norton, but Mexico City's yellow and Jo'burg is well into the red.
Thanks to Warren Ellis, again, for this one. Wish I was as smart as him. Unrelated to this site's portfolio, you might dig Warren's ongoing comic series Planetary. He's a damn good comic book writer.