>[!citation] >Tackle, E. S. (1995). *Forecast models for weather and climate*. Iowa State University. https://www.meteor.iastate.edu/gccourse/model/basic/images/pinball.html >[!abstract] >An astute observer of weather and weather forecasts might raise the point that since 10-day forecasts are essentially useless for planning purposes, it is audacious and absurd for meteorologists to pretend they can predict anything 1 year, much less 50 years, into the future. > >To understand the concept of a climate model and to clarify the concept of climate predictions as compared to weather predictions, we consider the "pinball machine analogy". This is not a real model for simulating climate but only an analogy that will help distinguish weather from climate and observe how changing certain conditions changes the climate statistics. The accompanying sketch shows the result of many outcomes of dropping balls through the pinball matrix. If the matrix is very large there will be many, many individual paths to the bottom. The exact positions of the pegs determine the distribution of balls at the bottom. A slight change in peg position will have some influence on the distribution of possible paths, with some pegs being more influential than others.