I imagine my house without me. What would it be like? Well, it would be an empty house, useless and pointless. That's what the Earth without humans would be like, too, useless and pointless. But lots of Earth-first types -- you know, humans are the problem -- are getting their jollies out of Alan Weisman's book "Earth Without Us":
Weisman embarks on an audacious intellectual adventure: He tries to imagine what the world would be like if humans suddenly disappeared. "How would the rest of nature respond if it were suddenly relieved of the relentless pressures we heap on it and our fellow organisms? How soon would, or could, the climate return to where it was before we fired up all our engines? How long would it take to recover lost ground and restore Eden to the way it must have gleamed and smelled the day before Adam, or homo habilis, appeared? Could nature ever obliterate all our traces?"
In the end, Weisman pulls back says, well, we can still save the Earth if we just change our wicked ways:
He calls for mankind to cut its birthrate dramatically by limiting every female to one child. By 2100, we would have reduced the human population to 1.6 billion, back where it was in the 19th century. The only alternative, he strongly implies, may be figuring out how to travel to other planets, either physically or by replicating ourselves remotely, cloning our bodies holographically and e-mailing our minds across the cosmos.
The Earth is our home. And homes get old. My prediction is that we will eventually use this one up and move on. We will figure out how to get to other planets. I'm so confident of this that I invite you to heap scorn on me later if it turns out I am wrong.