Posted on | January 18, 2006 | 35 Comments
There’s a good good post on Prometheus about a new paper by anthropologist Myanna Lahsen on the culture of climate modelers. The bottom line is the way modelers tend to believe their own models – to substitute them in their own mind for reality. It reminded me of a paper published last year in which B.G. Hunt and T.I. Elliott model climatic conditions in the Yucatan and use them to discuss drought and its implications for the Maya.
Based on proxy records, some researchers have suggested that drought played a role in the collapse of the Classic Maya (it’s debated), and Hunt and Elliott wanted to model the thing.
It’s an interesting paper, with careful discussion of the model’s shortcomings – like, for example, “its inability to reproduce the observed range of SST (sea surface temperature) anomalies associated with El Niño/Southern Oscillation (ENSO) events.” And then they offer this howler. A set of model-generated figures show rainfall anomalies that seem to match up nicely with the proxy records:
These figures confirm that major rainfall deficiences are a systematic, but irregular, characteristic of the Yucatan region.
No, they don’t. They show that the model exhibits systematic but irregular rainfall deficiencies. What they tell us about the rainfall itself is a bit more epistemologically tricky.
This is a bit of a cheap shot, because much of their discussion is generally more subtle, treating the model as a useful tool in exploring the physical system, rather than a direct representation of it. But in the context of Lahsen’s paper, it’s an interesting slip.