What is the significance of time/sequencing in the book?

Flashbacks are used throughout the novel so that the reader can understand the man and his son's past lives, the the way in which the carastrophe unfolds.

"McCarthy does more than offer background information to help us understand the tragedy and the man’s present thought and emotions. Since the flashbacks are not clearly separated from the rest of the narration, they intentionally obscure the story's linearity and reflect the man’s shifting between memory and reality. Just as the flashbacks make the novel's present more difficult for the reader to grasp in some ways, the man drifts in and out of dreams and memories. This disjointed narration technique helps sustain the novel’s mood of confusion and isolation."