I was going to say that desert cultures certainly know that there are places without grass, and that there was probably a time when there was not any grass at all, but Foxy Freedom beat me to it.
Most cultures have stories about how this or that thing that exists now came about. In Native American lore there are stories about the origins of corn, a crop they themselves domesticated thousands of years ago. Does not take any secret knowledge from a god to make up a story using what you already know about the world. And given enough stories, some will happen to have some truth to them. but information that could not have been known at the time? Not so apparent. 
In the Quran, paradise is often described in poetic terms as the place where abundant water brings forth life.
Now, how did those ancient Arabs know that water was the source of life? Modern science only discovered that humans are descended from fish in the past century. Allah must have been telling those desert people things that they could not possibly have figured out by themselves....
Or, maybe being desert people, the Arabs associated water with paradise because a) no living thing can survive long without water and b) water is really scarce, rare and valuable in a desert.
Nah, had to be magical whisperings from a god.
What discoveries that have not yet been made are predicted in the bible? Please enlighten us.