Adjust the sliders to explore how climate responds to changes in four factors: incoming solar energy, the albedo (or reflectivity) of land, the albedo of ice-covered regions, and the intensity of the greenhouse effect. Average annual temperatures in 18 latitude bands are indicated by color on the globe and numerically in the right margin. Snowflakes mark areas where the temperature is low enough to allow permanent accumulation of ice and snow. Choose your favorite temperature scale (Kelvin, Celsius, or Fahrenheit) with the buttons at the upper right. For more info see the American Scientist column and the bit-player blog post. There's also a bibliography. And you can download the source code.