It is often thought that humanity will leave no trace of its existence for the next civilization that will come, say, 20 million years from now. But I'd submit that unless something catastrophic happens very soon, one of the signs that "something" happened will be this sudden discontinuity in species history where suddenly the laws of genetics were thrown out the window for some reason, leaving its evidence both in the fossil record and in the attempts to plot out species trees based on genetic similarity.
What today we are pleased to panic about in the "Holocene extinction" may in fact just be the opening act to an explosion of diversity, and the two events would not be distinguishable in the historical record.
> It is often thought that humanity will leave no trace of its existence for the next civilization that will come, say, 20 million years
We have pretty good Trilobite fossils from 400+ million years ago. Why would they leave a trace and humanity not? (given all the stuff we produce: cities, cars, etc.)
Many human artifacts don't need to be fossilized and could be preserved for millions of years (e.g. a gold ring, a stone bracelet, concrete). Also humans deliberately bury their dead (and lots of other stuff), which in some cases might help with fossilization and preservation.
If humanity were wiped out tomorrow, I think it would leave plenty of traces that could be found and understood in millions of years by a later civilization with paleontologists are as active as ours. It's just that those traces would be relatively small and/or buried, like human fossils with jewelry and caissons (with geometric iron oxide deposits from the rebar!) from the foundations of large buildings. No monuments or cities, but enough to indicate that we were here and had technology.
What today we are pleased to panic about in the "Holocene extinction" may in fact just be the opening act to an explosion of diversity, and the two events would not be distinguishable in the historical record.