SURVIVORS   Suppose that the worst has happened. Human extinction is a fait accompli.   Not by nuclear calamity, asteroid collision, or anything ruinous enough to also wipe out most everything else, leaving whatever remained in some radically altered, reduced state.   Not by some grim ecoscenario in which we agonisingly fade, dragging many more species with us in the process.   Instead, picture a world from which we all suddenly vanished.   Tomorrow.  Unlikely perhaps, but for the sake of argument, not impossible.   Say a Homo sapiens-specific virus — natural or diabolically nano-engineered — picks us off but leaves everything else intact.  Look around you, at today’s world.   Your house, your city.  The surrounding land, the pavement underneath, and the soil hidden beneath that.   Leave it all in place , but extract the human beings.   Wipe us all out and see what’s left.  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 or must have gleamed and smelled the day before Homo sapiens appeared?   Could nature ever obliterate all our traces?     Alan Weisman – The world without us.