Talking of Climate Models, there is another great Climate Audit post titled "Unprecedented" Model Discrepancy where Richard Betts, once again, provides cartoon inspiration in the comments.
It’s a bit like watching a ball bouncing down a rocky hillside. You can predict some aspects of it behaviour but not others. You can predict it will generally go downhill, and if you see a big rock in it’s path you can be reasonably confident that it will hit it and bounce off, but you can’t predict the size and direction of all the little bounces in between.