All of these feedback loops are similar in principle to the feedback loops that regulate and moderate earth's climate. Many climate feedback loops are in a delicate balancing act that is sensitive to small changes. If altered, systems such as the water vapour feedback system or the carbon dioxide thermostat system, have the potential to significantly change earth's climate.

By definition, feedbacks affect a system from within that system, whereas forcings impact a system from outside of that system. However, forcings can set feedback loops out of balance and into motion. In this lesson, we will focus on feedback systems, such as the polar albedo feedback, and examine how forcings, such as anthropogenic emissions of greenhouse gases, can set them off balance.