I found a couple of threads on the subject, but they didn't really give me the answers I was looking for. I'm working on a project where earth has become a global desert. The statue of liberty surrounded by wasteland, New York City barren and covered with sand, same story everywhere else on earth, basically a very dry setting. There are however pockets of water, underground lakes and rivers, where humans have built settlements which are violently contested. My question is are there any plausible scenarios where the amount of water on earth has been drastically reduced in a relatively short (a hundred years or so) span of time? I do realize that water normally doesn't just disappear, so, I was hoping somebody here could come up with a clever way to explain its absence.