The earth's desserts are all only thousands of? years old. We know this from their rate of growth and historical record (ancient literature) which tells us places that were abundant with trees and plantlife in the past are now dessert
No you don't know that. Just because there are place that are desert now doesn't mean that there were no deserts before. There is something called desertification which is an observed phenomena. Deserts are not static, enviroments are not static, they move, they change, they always have, and none of that proves there was a giant flood.
The polar caps have tropical plant fossils under thier ice sheets. This has been discovered by scientists.
No it wasn't, in fact there is nothing under the north pole but water, there is no landmass at the north pole, so how is it that "This has been discovered by scientists" when it is a know fact that there is no land at the north pole? Has for Anartica it is quite possible but it doesn't prove fuck all about a global flood or an ice canopy.
It? was Ice above the atmosphere
Which would have left the earth below as a frozen wasteland trapped in an constant ice age. If such a thing had fallen to earth the gravitational pontential energy released would have have turned the ice into superheated steam long before it reached the ground, with the net result being Noah and his merry boat full of animals being boiled alive as the entire surface of the planet was steralized in a worldwide steam cleaning that would leave theplanet totally and completely lifeless. Don't try to use science to explain your mythology, it never, ever works in your favor and always leave people like yourself sitting there looking stupid.