Now picture that same beach next summer, destroyed. Perhaps it eroded so much that there's barely room to spread out a towel. Maybe a colossal concrete hotel is being built where the sand dunes used to be. Maybe it has been coated with a slick of spilled oil. Hopefully, your slice of paradise will remain well preserved. But at many beaches around the world, nightmares like these are coming true (just ask anyone who lives on the Gulf Coast).