He would destroy it because of all the evil, hate, sin, etc. Earth is like Sodom & Gomorrah. Just sinful & wicked. So God destroyed it. God promises he will return & take us all up to heaven & make a new one. At least that's what my preacher has said.
The Bible sheds light on this. For one thing it reveals that the earth, the planet itself will not be destroyed. This is revealed at Ecclesiastes 1:4 which states that the earth will stand forever. Another indication of the earth's permanence is found at Psalm 37:29 which shows that right hearted people will live upon the earth forever. A close examination of what the Bible says at 2 Peter 3 vs 5-13 show that what was destroyed in the flood of Noah's day will be the same thing destroyed by the fire of God's anger in our time. The wicked world of mankind, the systems of things on this planet not in harmony with God's arrangement. But the earth, the planet itself will not be destroyed.
The world belongs to satan. By human choice satan has dominion over it and God allows it for now because it is human choice. Everything that does not belong to Him when the time comes will be destroyed. Some believe it will be made new and perfect again as in Eden and heaven will actually be on a perfect, sinless earth which will be inhabited by those who chose to follow Him. Currently, tho, everything is of sin and evil. There is very little for Him to keep. If a potter is creating a pot in the wheel and a flaw appears that warps the rest of the work he doesnt keep going. He smashes the work and starts over. If you have a car that breaks down you might fix it once or twice but eventually the cost becomes insupporrable and you get rid of it. The world is broken - in more ways than one and getting continuously worse both physically and spiritually. Soon it will be time to junk it and get the new model.
Ecclesiastes 1:4 tells us that "the earth is standing to time indefinite." Jehovah would never destroy the earth. However, He does speak of destroying this wicked "system of things." I invite you to follow this link. It has helped many who wonder the same thing!
God is referring to the system of things. Imagine if you had bad tenants in your home. If you wanted them removed, would you simply get rid of the tenants or would you burn the house down? Obviously, you would get rid of the tenants because there is nothing wrong with the earth! The earth has been described as a jewel in our solar system. At Isaiah 45:18 it refers to God in the following way says, "the Creator of the heavens, He the true God, the Former of the earth and the Maker of it, He the One who firmly established it, who did not create it simply for nothing, who formed it even to be inhabited." He wants the earth to be enjoyed the way he intended for it to be. I hope this helps.
God is not the blame, He gave mankind a perfect start, but humans have chosen to ignore God's requirements and decide for themselves what is good and what is bad. By doing this, they have come under the influence of wicked superhuman forces. "We know that we are children of God and that all the rest of the world around us is under SATAN'S power and control." 1John 5:19. ( Living Bible). "Follow the steps of the godly instead, and stay on the right path, for only good men enjoy life to the full; evil men lose the good things they might have had, and they themselves shall be destroyed." Proverbs 2:21-22 (Living Bible) "The godly shall be firmly planted in the land ,and live there forever, The godly man is a good counselor because he is just and fair and knows right from wrong." Psalms 37:29-30. (Living Bible)