...the flood and the ultimate destruction of the wicked by fire represent the Earth's baptism, first by water, then by fire. And as we're redeemed, so Earth is redeemed. As we escape death, so Earth will be glorified, redeemed and sanctified.
1. The earth was not baptized. The earth didn't commit a sin and need "saving".
2. Baptism was introduced by John the baptist, not before.
3. The whole earth did not receive fire and brimstone, only Sodom and Gomorrah did.