What role does the ghost of Marley play in the heralding events to come in the plot?

Marley warns Scrooge to fix his ways before its too late.

Explanation:

“the battle of stalingrad is not a turning point necessarily in strategic terms, because a lot more has to be done before the soviets can be certain of defeating germany,” says renowned world war ii historian richard overy. the germans had fought nearly a thousand miles across the soviet union to get to stalingrad.