The covenant with Noah is clearly a renewal of the covenant of Creation (1:1), and that tells us that God sees Noah’s salvation as a fresh start for His original creation.
After being expelled from the Garden, Adam’s and Eve’s descendants were divided into two lines of descent, an ungodly line through Cain and a godly line through Seth. But ten generations later ungodliness ruled over both lines, prompting God to declare that he would wipe mankind from off the earth.