Thursday, March 18, 2010

Tragedy of the Zimbabwe commons

From Marginal revolution.

A must read for Environmental Economics students.

See the Tragedy of the Commons [Marginal revolution]

In 2000 Zimbabwe began to forcibly redistribute land from private but predominantly white-owned commercial farms to much poorer black farmers who toiled on communal lands. Stunning pictures from Google Earth collected by Craig Richardson show the result.

Take a look at the Before picture. The communal land on the left is dry, dusty and unproductive compared to the private farmland on the right which is green and dotted with blue ponds and lakes. Why? There were two theories to explain this difference.

* The Tragedy of the Commons – the farmers on the communal lands did not have the incentives to invest in the land and thus the land eroded and turned to desert.

* The land on the right (which was owned mostly by whites) was better quality land.

Both theories could be true. Regarding the latter explanation, however, notice that the dry communal lands on the left are sharply delineated from the green private farms on the right--so sharply that soil quality and rainfall alone are unlikely to explain the difference.

So what happened after the land was redistributed beginning in 2000 and all of it made communal?

After reform the land quality worsened everywhere. In particular, note that the blue lakes and ponds on the right became dry and empty as farmers no longer had an incentive to invest in maintaining these resources. The tragedy of the commons.

This excellent visual look at the tragedy of the commons was produced by Todd Moss at The Center for Global Development based on pictures and ideas from Craig Richardson. Of course Zimbabwe had many problems before and after this forcible land redistribution. You can find more pictures, background information and a lengthier discussion of this episode here.

In addition, I have included the shifting graphic in a set of PowerPoint slides which could be incorporated in a classroom discussion of the tragedy of the commons. Feel free to modify these slides as you wish and thanks to the Center for Global Development for helping me to create the slides.

This post is an example of the material available at a new website designed for anyone teaching principles of economics and called, SeetheInvisibleHandBlog. At the new website you can can find videos, powerpoints, ideas, blog posts and much more. The material is nicely linked up with our textbook, Modern Principles, but we think that this website will be useful to anyone who teaches principles of economics.

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