What climate models are and what they do is a common source of confusion.
Digital Pictures and Models
Climate models have different resolutions, with higher resolution models dividing the Earth into smaller and smaller pieces. The more pieces and variables you consider in a model, the more complex and detailed the picture is, but this detail comes at a price: you need more expensive computers and more computer time to get to this point. This is similar to digital pictures, with more pixels giving you a more detailed picture with higher quality. Higher resolution models, like higher resolution cameras, are more sophisticated devices that require more in terms of energy, materials, time and expertise to create, and are more expensive.1
Lava Lamp, Weather and Climate Models
In a lava lamp (image right), heat from a bulb causes blobs of goo to move about a cylinder. Earth’s climate is similar, in that heat from the sun causes fluids to move around the planet. In order to understand how the weather works and make forecasts, scientists build models. But predicting tomorrow’s weather is a different science than predicting the average weather conditions in 30 years (the climate). The equivalent of a weather model would be trying to predict where a certain bubble will be in 30 seconds or a minute. The equivalent of a climate model would be trying to predict what would happen if you switched the bulb inside the lamp from 30 to 60 watts. Would the blobs move faster? Would there be more, but smaller, individual blobs moving about the cylinder? Maybe there would be fewer, but bigger, blobs or certain blob shapes become more prevalent.2
- Sub-analogy: This same principle applies to bubbles forming inside a pot of boiling water.3
1. from Bob Henson.
2. Analogy from Keith Dixon, NOAA GFDL.
3. Analogy from Bob Henson.