As the model is a easy description to show the structure or working of an object system or concept, as it has some advantages and weaknesses too which are.
ADVANTAGES:
it allows scientists to analyse and simplify complex system,input can be changed and outcomes can be observed without waiting for the actual event,and last but not the least results can be shown to the scientists an to the public.
WEAKNESSES:
they may not be accurate as climate models are highly complex in number of factors and accuracy is lost in the process of oversimplification, they depend on the expertise of the people making them,and different people expound them in different ways.