Garrett Hardin's "The Tragedy of the Commons" is required reading for any environmental and natural resource economist. Its conclusion is usually taken at face value:
Ruin is the destination toward which all men rush, each pursuing his own best interest in a society that believes in the freedom of the commons. Freedom in a commons brings ruin to all.
I was particularly excited to see two of my favorite publications, the Economist and the New Yorker (yes, I also eat arugula), revisiting the idea from different angles this week.
The New Yorker reviews Michael Heller's The Gridlock Economy,
which takes stabs at patent laws and
other "anticommons" that lead to
"underuse and waste," much as the commons lead to "overuse and
destruction." One example is wind:
Wind power...could reliably supply up to twenty per cent of America’s energy needs—but only if new transmission lines were built, allowing the efficient movement of power from the places where it’s generated to the places where it’s consumed. Don’t count on that happening anytime soon. Most of the land that the grid would pass through is owned by individuals, and nobody wants power lines running through his back yard.
I buy that reasoning.
The point isn’t that private property is a bad thing...But property rights need to be limited to be effective.
Good luck finding the right balance, but it's certainly good to have the discussion out in the open.
The Economist takes another tack. It reviews some of Elinor Ostrom's critiques of Harding. She has found several examples, including the "miracle of the Rhine," that showed how the commons can be
managed without selling off every last bit and assigning ownership, the usual solution to Harding's 
problem. Management of Swiss (or Austrian) Alpine pastures is another example. Farmers don't tend to add animals until the ecosystem collapses. Quite the opposite: Many of these pastures have been managed successfully for decades or sometimes centuries, despite belonging to no one in particular.
The Economist also tracked down the 12th Biennial Conference of the International Association for the Study of the Commons last month, where Charlotte Hess spoke about extending the concept of the commons to global public goods like oceans or Antarctica. That's where managing becomes more difficult. Once the entire Earth is the common, like with climate change, it's not as simple as having a handful of farmers divvy up a pasture or establishing unwritten norms for Sahelian nomads.
That said, we are moving towards this kind of management in global climate talks. We are not exactly assigning property rights to the Earth's atmosphere as devout followers of Harding might want to see. (Harding himself purportedly admitted before he died that he should have called his article "The Tragedy of the Unmanaged Commons.") Instead, the next global deal on climate will likely look much closer to an agreement to manage the atmospheric commons than to assign strict property rights.
That's where the clean-up of the Rhine becomes instructive again:
[I]t was not until local pressure groups, city and regional governments and non-governmental organisations got involved that polluters were willing to recognise the costs they were imposing on others, and cut emissions. An inter-governmental body (the International Commission for the Protection of the Rhine) did not have the same effect.
It'll likely take a global deal brokered by UNFCCC to establish the goals (ideally a global cap on emissions) and the framework of how to achieve them, but it will be up to "local pressure groups" -- city, state and national governments, NGOs, or other citizen or business groups -- to help enforce them.
