Wednesday, May 4, 2011

Wise decisions and predictions

Daniel Sarewitz is a leader in the Science-Policy interface area, and last year he had this to say in an opinion piece in Nature last year:

If wise decisions depended on accurate predictions, then in most areas of human endeavour wise decisions would be impossible. Indeed, predictions may even be an impediment to wisdom. They can narrow the view of the future, drawing attention to some conditions, events and timescales at the expense of others, thereby narrowing response options and flexibility as well.

Would “projections” also lead to the same trap? According to Kevin Trenbarth, the difference is that a projection makes no effort to start from the actual initial state of the system, and so all that can be evaluated is the change from the assumed initial state. As a result, there is no expectation on the part of the “projector” that the projection will actually come to pass. In contrast, a prediction is made in the expectation that the future will look similar to the prediction, although as far as I can tell, the same tools are used for both. Intriguingly this is yet a third way to define the difference between a projection and a prediction. Either way, I think predictions and projections run the risks described by Sarewitz.

1 comment:

  1. Drew- Caught this post of yours just in time to integrate it into a talk I was giving on the dangers of falling in love with climate change predictions. CC models just bleed uncertainty, and IPCC re-negotiates theirs every chance they can we possibly validate and manage? Some predict less than 1 ft of sea level rise, others almost 6 ft...somewhere between 0-12 degree Celsius temp change...ocean pH dropping between 0 and 2.0 in the next 500 years. Those all have incredibly different effects on Alaskan ecosystems, and instead of worrying about the now, we are looking 500 years into the future and arguing about the magnitude of change. This was a great quote to open some eyes (hopefully).