I love how this one slowly hits you. At first you think, "why would they be scuba diving in the desert?" Then you finally understand... because there is no more water. Now, while I think that if the Earth ever got this bad we would be dead before we ever took up desert scuba diving, the message is not lost on me. Anytime I take a shower longer than three minutes I start to get worried about the planet. I live in Southern California which as been in a drought since the 20s. Seriously, until we learn how to drink salt water, this could be a serious issue.
I don't think this is how the end of the world would go down though. A lot of people have the desert depiction in their head, but I think a huge wave will swallow us all before we ever completely dry up. Isn't this fun to talk about?