What's Causing the "Earth Without Us" Craze in New Scifi Movies?

Following on the tail of the hit book The World Without Us by Alan Weisman, and the documentary Life After People, Hollywood seems determined to make scifi movies that explore the same theme. Certainly we've had "Earth without most of us" flicks like I Am Legend, but two movies that were on proud display at WonderCon, Wall-E and Journey to the Center of the Earth were literally about an Earth that has no humans at all. In Wall-E all the humans have flown off in spaceships, left the garbage bots to clean up their messes, and have never returned. In Journey, the main characters discover an "Earth" that has never evolved human life. Why are we so obsessed by alternative Earths without humans right now? I've got four reasons why.

1. Environmental Guilt. Many people are paralyzed by guilt over how much we've trashed the environment, and though they try to buy green and recycle they are overwhelmed with a sense of hopelessness. Trying to cope with this, people yearn for stories about a world where humans aren't around anymore to muck things up.

2. Future Ennui. Sometimes it seems like we do nothing but plan for the future: You have to do everything from balancing your homework load so you can get into college, to balancing your checkbook so you'll have retirement savings. Living your daily life while planning for tomorrow can be a huge drain on your mental resources. You're constantly asking yourself about what to do now to make the future work out. Which politician should we vote for to improve our neighborhoods or our nation? How can we plan for a perfect vacation, a perfect wedding, or a perfect science project? Stories about a world without people are relaxing. We don't have to worry what we would do because we're just not there.

3. Fear of Extinction. OK, this one is obvious. We may be sick of planning for the future, but we're also scared shitless that the future will smack us on the head and wipe us all out. Who could have predicted Hurricane Katrina or the Asian Tsunami? What if next time the disaster is global in scale? We imagine the world without ourselves as a coping mechanism, a way to accustom ourselves to the idea that no matter how much we plan, we still may not make it as a species.

4. Evolution Degree Zero. A world without humans is a world where we've hit the reset button. All our mistakes are undone, and we can start fresh. Maybe humans will evolve again, better this time.