While it's true that the relationship is unproven (the only way to really prove it is to see it happen), it's not just an idea, it's a result of modelling. Now

While it's true that the relationship is unproven (the only way to really prove it is to see it happen), it's not just an idea, it's a result of modelling. Now, these models are not entirely correct and still lack elements (climate is a very complex system), but it's not as if no thought had been put into the relationship.