How much is enough?

By Jack Scott

Sea glass is a finite resource. It may not seem like it to those who visit famous glass beaches around the world, former dumping grounds now covered so thickly in sea glass that you can barely see the sand below, but it's true. Communities no longer dump their trash (including discarded glass) onto beaches so the beaches are not getting replenished with glass as quickly as it is taken by sea glass hunters.

At some point, every collector has experienced the disappointment and frustration of returning empty-handed from a beach that was full of treasure on the previous visit. Of course, it's hard to be too disappointed or frustrated during a pleasant stroll on the beach, but it remains an unpleasant reality that the more you take today, the less the next beachcomber finds tomorrow. And that beachcomber may be you.

This kind of problem is hardly unique to beachcombing, and it's known as the "Tragedy of the Commons." Ecologist and philosopher Garrett Hardin coined this term in an article of the same name where he fleshes out the theory: the "tragedy" occurs anytime a group of people who share a resource, each acting in their own best interest, end up completely depleting that resource, resulting in everyone being worse off than if each had consumed the resource at a sustainable rate. The problem is that the scarcity of the resource does not discourage any individual from using it: in fact, that scarcity is the very reason why everyone ends up greedily taking what they can for themselves.

The classic example is overfishing. If everyone were to limit their fishing so that reproduction could completely restore the population, then everyone would have a steady supply of fish. However, from the point of view of one fisher, the impact of their own actions on the entire fish population is negligible, and so they take as much as they please, seeing as it has no immediate effect on their next hauls. In addition, when the fish population does inevitably start to decline, they have even less reason to pace themselves, since they want to catch as many fish as they can before they're all gone. There are countless further examples of the tragedy of the commons in action, including deforestation, overpopulation, water shortages, and even things like network congestion caused by computers on shared Wi-Fi. And, there are numerous examples in beachcombing, including taking too many shells from one location, removing all the driftwood from beaches, and over-collecting fossils.

If everyone is willing to sacrifice a little, then everyone can reap the benefits. But, from the individual's perspective it is hard to make that sacrifice: if everyone is filling up buckets full of sea glass on every outing, then there will soon be none left, whether you do the same or not. And if everyone is being prudent and acting with restraint, then you can fill buckets to your heart's content.

Being so widespread, the tragedy of the commons naturally has spawned some solutions. The most obvious approach is for an outside body to regulate the consumption of the limited resource. In our beachcombing case, this has been done in some locations: for example, at the Glass Beach in Fort Bragg, an ordinance prohibits beachcombers from taking sea glass home. However, this clearly isn't really a viable solution for most beaches, and it's difficult to enforce. And, after all, we still want to be able to take some treasures for our collections, especially those in our favorite colors and shapes. But we shouldn't take so much that others are left with nothing.

Without an outside force telling us what to do, the only option we are left with is self-governance. Work by political scientist Elinor Ostrom on the tragedy of the commons shows that small and tightly connected groups are best at overcoming the problem. The beachcombing community can save our collective selves from our impulses, reminding and encouraging each other to take a reasonable amount and to leave some treasures for future beachcombers to find.

In the end, self-control is the easiest way to make a difference. In the moment, it may seem like a waste to leave even one piece of sea glass behind, but just remember that there are many others who are thinking the exact same thing. Maybe we can all leave a few on the beach so there's sea glass to find for generations to come. #leavesomeforothers

Jack Scott studied computer science and philosophy at Stanford University.