When I was in college a couple years ago I read a very interesting book, it had some theories that really made sense to me. The book in titled The Canopied Earth by Dr. Dennis Lindsay.
In this book he talks about how the earth was before the great flood in Noah's time. The earth actually had what they call a canopy. It was an outer layer in the atmosphere that was very dense and watery.
According to this theory it would cause a greenhouse effect, which would cause the earth to maintain an average temperature of I believe it was 70 something. This is the explanation for the plants being found in antartica and other places, now frozen.
There was also large underground resevoirs of water, which would come up out of the ground as a mist watering the plants, there was no rain, no snow and no wind.
The bases for this idea is in the book of Genesis in the Bible, it says that God seperated the waters below from the waters above and this was called the sky.
Some interesting things about the canopy is that they claim it would make the sky more of a pinkish color instead of blue. Also it would cause the oxygen level to be more compacted, causing everything to breath in more. The canopy also protected against harmful UV rays which cause people not to age as quickly. In short people were healthier and younger feeling and looking. This also affected the size of things, such as animals and humans. Thats why you sometimes find remains of giants and fish, and other animals and plants that were much larger then present day.
This theory was actually proven correct by Dr. Carl Baugh in Glenrose Texas. He built a building and adjusted the atmosphere inside to match that of what the earths would have been, the result was plants and animals grew much much larger and healthier.
The theory for the death of the canopy was that a meteor or something broke the canopy causing the water to pour down upon the earth. This meteor also caused the waters underground to begin to pour out of the earth. All of this extra water then flooded the entire earth, this is during Noah's time.
When the water withdrew it froze on the north and south pole, causing what is known as the ice age.
These catastrophic events also messed up the weather, wind and rain came from the earth trying to restore itself back to the previous way, which it actually will not be able to get back to that.
If you would like to read more about this I recommend you get the book. You can purchase it at CFNI.org in the bookstore. Dr. Lindsay has I believe 9 books published. Also you can read some of Dr. Carl Baugh's materiels or Ken Ham (who just opened the creation museum in Kentucky).