A live demonstration of the tragedy of the commons


G. Economou 22-jul-2009
We all have read about the tragdey of the commons, the famous lose-lose situation created when some common or public resource is devoured in a race by everyone to get his share before someone else does. In this image from the island of Naxos in Greece, we have a clear live demonstration of exactly this phenomenon! the subject here is overgrazing of open or public land. Overgrazing is a very severe problem in Greek islands. It destroys emergent plant cover that would otherwise stabilise rocky slopes from erosion, keeping the land permanently barren. Plant cover not only stabilizes the ground from erosion, it also improves water retention, water infiltration and aquifer recharge, and through shade cover reduces surface temperatures and reduces evaporation losses. Rainfall is scant and precious, and most of the islands have a problem of water. Overgrazing is a critical part of the problem in that it prevents the regrowth of trees and other plant cover which would in turn improve the water situation. In the image, we see hilly country used as open grazing land for primarily goats and sheep, and small quantities of cattle. Relevant to the matter is that traditionally and today in Greece, the grazing of animals on open land is permitted without restriction. Even private property, if not fenced or specifically cultivated as a field, orchard, etc, is legally open to grazing of animals. Naturally, the owners of the animals have every incentive to graze as much as possible, because it is basically free. But here is the problem: there is no incentive for the owner of animals to lose his own profits or even livelihood in order to improve conditions in the future for his island. He needs money now, and grazing makes money. Now, not all the land on the island is public and open for grazing. Much of it is also privately owned, but still grazed. Do people who own animals use the same practices when grazing on their own land versus when they range their animals over open land? Certainly not! Look closely in the picture below. You will see several regions of land enclosed by old walls. Notice that the enclosed areas are much greener and even have more trees in them. Also notice that the enclosed areas are still grazed- this is not a simple case of no animals in one area and animals in another. The enclosed areas are still covered largely or even entirely by short grasses- the kind of growth that results from repeated grazing of animals- but they are still greener than the surrounding open land. Why is this? Because when grazing animals on one's own land, the owners understand that the total productivity is better when the plant cover is managed for conservation. Graze for a while, then move the animals somewhere else to allow for regrowth. Especially in the dry summers, leaving the plants to grow back will preserve more moisture and result in higher total productivity. Out in the open range, though, there is no incentive to conserve- if your animals don't eat every last blade of grass someone else's will anyway, so you might as well. Even if most animal owners agree not to overgraze, even a single one of them doing so ruins the environment for everyone. Legal restrictions on overgrazing will never be sufficient because they do not change the incentive. Even with draconian enforcement, they will merely provide another channel for pressure toward corruption, by creating a conflict of interest. A system of renting rangeland would create the right incentive structure for animal owners, but would create the wrong incentive for government, which would sooner or later permit overgrazing as inevitable pressure to increase rental income is felt. Only total outright banning of grazing in certain open regions would work as a policy measure. Traditional societies had tools available to them to prevent this kind of abuse (sometimes) which we do not have today- click to see the image in higher resolution
This file and all other content on the VAXpower.org site copyright 2008 by G. Economou