Talking about dry, Mark, you mention there may have been much more passage in the past, with Donkey carts, etc... do you think this may have allowed a tiny bit of greenery or do you think it's always been as polished and desolate as shown? Do you think they might have cut/burnt lots of trees in the area such as Lebanese Cedar (isn't Lebanon not too far "down the road"?) and such over the last centuries - for cooking/building purposes as well as during constant warring?
Dans les grandes choses, les hommes se montrent comme il leur convient de se montrer; dans les petites, ils se montrent comme ils sont.
Annie, the best I can do to answer your question is basically to quote from Wilipedia which sums it us - "It (Jordan) consists of arid plateau in the east irrigated by oasis and seasonal water streams, with highland area in the west of arable land and Mediterranean evergreen forestry."
It's been like this for eons and hasn't really had a climate change since err...... many eons ago. Most of the land around me would have originally been forest though. But now, as you would expect, it's been cleared and fields made. The further south you go from Amman the more desolate it becomes, and generally hotter. The same for east and west until you start going north a little. Then east, west and further north it gets greener. I doubt much south of me would have been vast amounts of wood and forest. Any that was, was probably denuded fairly quickly.
Lebenese cedar does even still grow up in the north west (I think) where the climate is right for it.