Below we consider the roles of the various elements in the overall scheme of internal interactions. In reality, this is a very unusual condition, but, nevertheless, it is the simplest way to imagine Earth system interactions. A will cause changes in system B which cause system A to increase further. This can cause a 'cascade' effect which leads to very fast, almost 'step' changes in the overall Earth system. A will cause changes in system B which cause system A to decrease.
Negative feedback helps to damp out variations in the Earth system.
A can occur quickly, but the response of system B may be much slower. This produces an observable lag.