The Black Death and the VoSL
30/03/2012 § 3 Comments
I have been reading about the Black Death, the pandemic that swept through Europe from 1347 to 1350. This has nothing to do with my day job, in case you’re wondering. Wikipedia has this to say (from the Bubonic plague entry):
It is commonly believed that society subsequently became more violent as the mass mortality rate cheapened life and thus increased warfare, crime, popular revolt, waves of flagellants, and persecution.
That seems a pretty uncontroversial statement. As a matter of historical record, there was an increase in manifestations of violence. The violence was directed towards oneself (flagellation) or towards others, and was both petty (crime) and structural (peasant revolts). Historians have connected the dots: life became even nastier, more brutish, and shorter; its value was reduced; the costs of producing violence decreased; therefore, people produced more violence. It’s a simple question of the cost of a factor of production.
That’s a backward look. What if we look forward?
Let’s say that climate change leads to plague and famine. Wouldn’t we expect the same change in the value of a life? Couldn’t we change the sentence above to read, ‘It is commonly believed that society will become more violent as mass mortality cheapens life…?’ It seems, again, relatively uncontroversial to say this.
Now, let’s look at it from the perspective of today. Today, when we are contemplating what to do about climate change, we have in mind or in models some value of a statistical life (VoSL). That is, we put a value on the lives of our descendants. What value should we put on them? If we expect that climate change will lead to a cheapening of VoSL, should we use our current value, or the value we expect to arise in the future?
It’s even worse. Our current actions can affect climate change. We can make it more or less severe. The more severe we make it, the more those future lives may be cheapened, and the less we need to be concerned with the impacts. By taking action to reduce climate change, we are increasing the necessity of taking action. This is, mind you, in a purely in a statistical, intergenerational utility optimising framework.
So whose VoSL should we use, ours or theirs?