In order to predict the climate several decades into the future, we need to understand many aspects of the climate system, one being the role of clouds in determining climate sensitivity.
Clouds affect climate, and are in turn affected by changes in the climate.
The relationship is a complicated system of feedbacks, in which clouds modulate Earth's radiation balance. Clouds cool Earth by reflecting incoming sunlight. Clouds are themselves changed by the warming or cooling of Earth. What is important is the net cooling or warming effect of all clouds on Earth. If Earth should warm due to the greenhouse effect, weather patterns would change.