I wonder...

[davywavy]

...if the entire human race were to drop dead tomorrow of Bird Flu, how long it would be before there were no visible signs that we'd ever existed?

Comments

Rather quickly I wager

[applez.livejournal.com]

If you mean things like overt architecture, infrastructure and the like...

Consider all those petro-refineries, nuclear power plants, ships at sea, and multiplicity of boilers & fuel systems all over the world that would start massive conflagrations without proper monitoring.

Likewise, most roads and homes in the US, at least, are built so poorly that a decade of floods, frost, and weeds would devastate most recognizable structures.

Otherwise, if one means all traces of humanity, I'm afraid our toxic and nuclear wastes, plus massive species transfers have made a permanent mark. As it is, most near-surface groundwater surfaces have levels of pesticide & herbicide contamination that won't be removed for a century or more.