Earth - human = ?

A pretty fascinating piece in the New Scientist attempts to sketch a world in which homo sapiens simply vanishes. Imagine the fishing...
Money Quote:

Ocean sediment cores will show a brief period during which massive amounts of heavy metals such as mercury were deposited, a relic of our fleeting industrial society. The same sediment band will also show a concentration of radioactive isotopes left by reactor meltdowns after our disappearance. The atmosphere will bear traces of a few gases that don't occur in nature, especially perfluorocarbons such as CF₄, which have a half-life of tens of thousands of years. Finally a brief, century-long pulse of radio waves will forever radiate out across the galaxy and beyond, proof - for anything that cares and is able to listen - that we once had something to say and a way to say it.