Climate is complex. Scientists often build mathematical models that represent simple climate systems to aid in understanding the many complex processes that define a regions climate. We gain an understanding of the importance of a certain parameter (for example, cloud cover) by changing that variable in the simple climate model and observing the changes in the model predictions (for example, changes in surface temperature). This is referred to as a sensitivity study. Sensitivity studies help us understand how the planet's temperature is maintained and how human activity can impact climate.