The verses in question (that are said to prove God will obliterate the Earth and the heavens) are from 2 Peter 3:10-13. Here they are from the CLNT:
"Now the day of the Lord will be arriving as a thief, in which the heavens shall be passing by with a booming noise, yet the elements shall be dissolved by combustion, and the earth and the works in it shall be found.
11 At these all, then, dissolving, to what manner of men must you belong in holy behavior and devoutness,
12 hoping for and hurrying the presence of God's day, because of which the heavens, being on fire, will be dissolved, and the elements decompose by combustion!
13 Yet we, according to His promises, are hoping for new heavens and a new earth, in which righteousness is dwelling."
I like to find proofs from the scriptures-in the scriptures. I know there are many who take this portion of scripture and use it to prove the elements in question are the elements that make up the Earth and heavens. I do not believe that is the case (and Horan, there are many who believe in the reconciliation of all who believe this Earth and the heavens are going to be obliterated, and God will create all new). These elements that Peter speaks of are found in the writings of Paul.
Galatians 4:3, 9: "Thus we also, when we were minors, were enslaved under the elements of the world." "Yet now, knowing God, yet rather being known by God, how are you turning back again to the infirm and poor elements for which you want to slave again anew? And in
Colossians 2:8, 20: "Beware that no one shall be despoiling you through philosophy and empty seduction, in accord with human tradition, in accord with the elements of the world, and not in accord with Christ." "If, then, you died together with Christ from the elements of the world, why, as living in the world, are you subject to decrees."
And Hebrews 5:12: "For when also, because of the time, you ought to be teachers, you have need again of one to teach you what are the rudimentary elements of the oracles of God, and you have come to have need of milk, and not of solid nourishment."
All of these elements have to be destroyed in order for all to be all in God. The Earth and the heavens do not have to be destroyed, as Wanda pointed out from Genesis 8:21. Fire is always used to purge, cleanse, each of us will be salted with fire (Mark 949), our God is a consuming fire (Hebrews 12:29). We are told that we who believe are a New Creation in Christ (2 Cor. 5:17). At present we, the believers, are being purged of these elements as we are being formed in His image. There will come a time when all will be purged of these elements, those in the heavens, on the Earth, and under the Earth.
That is a brief synopsis of my understanding.