Unintended Consequences of Messing with Complex Systems

Ecosystems are complex. When you try to intervene and “fix” one discrete part of an interconnected ecosystem, you’ll likely incur unintended and unpredictable consequences elsewhere. An ecosystem can be a biological community; it can also refer to a large company or even an entire economy. I love Arnold Kling’s metaphor of a country’s economy being like a rainforest. It’s a metaphor that should humble any policymaker who thinks he can simply turn a knob here or a knob there to shape economic outcomes.

In a recent episode of Econtalk on free market environmentalism, there’s an interesting story about wolves in Yellowstone. When wolves were taken out of Yellowstone park, all sorts of weird things happened. A very cool 5 minute video summary (with some beautiful imagery) explains.

3 Responses to Unintended Consequences of Messing with Complex Systems

  1. Rolf Wasén says:

    LET THE CHAOS OF NATURE BE IN PEACE

    I remember inviting Danish scientist Erik Mosekilde to Saab and Linköping in the 1990-ties for lecturing on chaos in simple and complex systems and related things having to do with more or less unpredictable consequences of so called (strong) nonlinearities.

    My brother Håkan, who is a journalist, made an interview with Mosekilde and afterhand wrote the article: LET THE CHAOS OF NATURE BE IN PEACE!!

    I also remember participating in a small workshop on complex natural and artificial systems in Abisko in Artctic Lapponia in Sweden.

    One message was that over-reliance on “technical methods” for fire protection in forest parks had unexpected (negative) consequences. Efficiently fighting the small fires led to accumulation of material prone to take fire and a large fire out of control!

    The second message was that humans are effectively unable to control the number of certain animals in a natural park.

    A third message is that mathematical models are notoriously uncertain predicting the life and birth of animals interacting with each other. Still, they might of course learn us something. Also to be more modest.

    We might hope that economists and politicans take a more humble approach to their undertakings, as you suggest in your comment. Otherwise it might still happen that systems recovers despite of their great and influential intervenings!!!

    Greetings from Sweden
    Rolf Wasén

  2. Chris says:

    The video makes for a great story (Tyler Cowen would want us to be suspicious). I have a close ecologist friend who spent a winter tracking wolves in Yellowstone, and he felt that the video overstated it’s case. See this journal article on the issue. It notes:

    “…scientists now disagree about whether wolf-related behaviorally-mediated-trophic cascades in Yellowstone are really occurring or at least whether that hypothesis has been rigorously tested (Kauffman et al., 2010). At most, that well-publicized claim may not be correct at all. For example, the whole question of possible willow increase in Yellowstone after wolf restoration is rife with controversy.”

    The story is still a great example of unintended consequences. However, the lesson to me seems to be that economies and ecosystems are both incredibly complex making it very difficult to identify causal relationships.

  3. DaveJ says:

    I have been thinking about a thesis related to this that we don’t really know much at all about causality in complex ecosystems (which I refer to as “singletons” since we can’t really reproduce experiments in any controlled fashion). In general, we rely on some combination of rationalistic theory, anecdotes, ethical preferences, and other factors to take a position on matters for which we have simply no ability to predict outcomes (i.e., no knowledge).

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