Because the earth is older than 6000 year old. but man has only been on the earth a little under 6000 years. Gen I is not when the earth was made, it was went it was reformed for man.
Dinosaurs lived on the earth for years before man was created.
Gen 1:1 In the beginning God created the heaven and the earth. when was that beginning?
how many years passed before Got reformed the earth as you can see in the next verse, the earth was already here it was with out form
Gen 1:2 And the earth was without form, and void; and darkness was upon the face of the deep. And the Spirit of God moved upon the face of the waters.
Satan when he was still an angel before he rebelled and became demoniac was on the earth.
You can read when the earth was first made in john.
Joh 1:1 In the beginning was the Word, and the Word was with God, and the Word was God.
Joh 1:2 The same was in the beginning with God.
Joh 1:3 All things were made by him; and without him was not any thing made that was made.
That is before man Gen 1:1, then God reformed the earth after Satan's rebellion and the earth became decade dead with out life. God makes nothing in disarray. it became that way, Just as man is doing to the earth by following Satan's influence
Global warming has nothing to do with whats happening to the world now it falling into decay because of disobedience.
Read all of Lev.26 ... the first 1/2 would be are blessings for obeying the last 1/2 is what is happening now by following Satains influnce