See the Tragedy of the Commons

Warning: Stefan Geens, an expert in the use of Google Earth, has taken a close look at the Zimbabwe photos and he argues that they are the unfortunate result of misinterpreting Google post-processing and updating.  I am not an expert but at the present moment I find his analysis compelling and I have taken down the powerpoints in which I incorporated the flash animation produced by the Center for Global Development.  

A few points of importance.  First, the sharply delineated lines in the photos dividing communal and privately owned land is real and is evidence consistent with the tragedy of the commons.  Geens writes to me:

The observation that the communal farmland seems worse off than the private farmland is a plausible one. And since the Landsat imagery could well have been taken around the year 2000 (or even earlier), Richardson's image can reasonably be used to support the thesis that communal farmland is not as well managed as private land.

What cannot be supported is the "animation" aspect which appears to show but in fact does not show a change over time.  

I should note that I have no reason to think that there was any malfeasance on the part of the Center for Global Development, a great organization, or Craig Richardson who originally brought attention to the photos.  Indeed, my reading of Geens is that without some expert help it would be hard not to make some errors in interpreting Google images, which have a more complicated provenance than one would imagine.  In addition, Richardson emailed me that he showed the images to farmers and government agriculture officials in Zimbabwe who agreed that they were representative of what was going on on the ground.  (See also Geens on this point noting burning.)  Nevertheless, although the redistribution of land in Zimbabwe clearly led to a drop in productivity and output, the animation is not evidence on this point.

One interesting point about this episode is that the story and the flash animation have been on the CGD website for several years but the huge exposure of MR means that we can draw on the expertise of many people around the world. Although I put some work into putting the powerpoints together I am pleased that we were able to correct this so quickly.

Original post follows but with PPs deleted.


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?

Click on the arrow to progress between before and after photos

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.


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