An undersea art gallery that ensnares illegal trawlers

I don’t think that’s true.

The issue here is that land that no one has authority over means that there is also no enforcement and that it’s a race to the bottom as to who will manage to exploit it to the point where it is destroyed and useless to anyone anymore. And why wouldn’t you, morals aside? It’s basically free resources for the exploiter with externalities shared by everyone. It doesn’t mean the solution is private ownership. Look at national parks, they’re publicly owned but they’re not a no man’s land so a government has authority to enforce conservation rules there and punish those who pollute/damage the park.

That’s what parent comment was perfectly illustrating: “not EU waters, not EU trawlers, why even lift a finger if Africa is too corrupt or financially unable to protect these ecosystems and the Chinese too cynical to refrain themselves?”

Angus's own rebuttal claims, among other points that "it’s shocking to realise that he provided no evidence at all to support his sweeping conclusions. He claimed that the “tragedy” was inevitable — but he didn’t show that it had happened even once."

This is in fact false as even a casual reading of the original essay will show.

Hardin's principle concern was population and the risk of global overpopulation. That presents his first example given the best available knowledge at the time he published the essay:

Has any cultural group solved this practical problem at the present time, even on an intuitive level? One simple fact proves that none has: there is no prosperous population in the world today that has, and has had for some time, a growth rate of zero.

A second more trivial example, involves public parking:

A simple incident that occurred a few years ago in Leominster, Massachusetts, shows how perishable the knowledge is. During the Christmas shopping season the parking meters downtown were covered with red plastic bags that bore tags reading: "Do not open until after Christmas. Free parking courtesy of the mayor and city council." In other words, facing the prospect of an increased demand for already scarce space, the city fathers reinstituted the system of the commons.

Two more substantial examples follow immediately:

Even at this late date, cattlemen leasing national land on the western ranges demonstrate no more than an ambivalent understanding, in constantly pressuring federal authorities to increase the head count to the point where overgrazing produces erosion and weed-dominance.

And, in the same paragraph:

Likewise, the oceans of the world continue to suffer from the survival of the philosophy of the commons. Maritime nations still respond automatically to the shibboleth of the "freedom of the seas." Professing to believe in "the inexhaustible resources of the oceans," they bring species after species of fish and whales closer to extinction (9).

And a fourth:

The National Parks present another instance of the working out of the tragedy of the commons. At present, they are open to all, without limit. The parks themselves are limited in extent--there is only one Yosemite Valley--whereas population seems to grow without limit. The values that visitors seek the parks are steadily eroded.

The fifth is pollution, to which Hardin sees no market-based solution:

The tragedy of the commons as a food basket is averted by private property, or something formally like it. But the air and waters surrounding us cannot readily be fenced, and so the tragedy of the commons as a cesspool must be prevented by different means, by coercive laws or taxing devices that make it cheaper for the polluter to treat his pollutants than to discharge them untreated.

What Hardin's self-described critics seem to miss is that Hardin isn't arguing against commons per se but unregulated commons. That regulation may be provided by the market, through taxation or other incentives, through behavioural restrictions, quota systems, or even social mores. Hardin does suggest that property rights seem to be one of the more effective mechanisms available, but does NOT declare that this is the One True Way to manage all commons.

He, and his commons-defending critics, are in fact arguing for the same thing: a regulated commons serving the interests of the broader community, not of avaricious individuals.