Though the Bible does not give us specifics, it does tell us that Jehovah God will not allow the Earth to become overpopulated.
God's original purpose was clear when He said to Adam and Eve: “Be fruitful and become many and fill the earth and subdue it." (Gen. 1:28) Notice how God said "fill", not overfill.
Whatever situations are presented in the future, we can be assured that God will make everything all right:
“You are opening your hand and satisfying the desire of every living thing.” (Psalm 145:16)
"But the meek ones themselves will possess the earth, And they will indeed find their exquisite delight in the abundance of peace." (Ps.37:11)
Jehovah God has never failed to fulfill his promises. As the Scriptures say of ancient Israel: “Not a promise failed out of all the good promise that Jehovah had made to the house of Israel; it all came true.” (Joshua 21:45)
For more, see:
What Is God’s Purpose for the Earth?
Search For Bible Truths - ARCHIVE
Search For Bible Truths - Search Guide