How is Scrooge affected by the events in stave 3 and 4 and how has he changed by the end of the novel?

He is shown his own lonely history which has effected his view of Christmas, never having grown in family environment at Christmas. He learns this and that he cannot change the history only the future. With the ghost of Christmas present his eyes are opened when he learns about the scale of want around him and ignorance of those who could do something , even small that can help those in dire need.