200,000 years for all trace of Man to vanish from the Earth
By Lewis Smith
Within hours, nature would begin to eradicate its impact. In 50,000 years all that would remain would be archaeological traces. Only radioactive materials and a few man-made chemical contaminants would last longer an invisible legacy.
Homo sapiens has managed just 150,000 years on Earth, and his earliest debatable ancestor only six million. By contrast, the dinosaurs populated the planet for 165 million years.
Mans environmental footprint would, according to a report in New Scientist, begin to deteriorate almost immediately, with light pollution the first to go as power stations ceased to provide energy.
I looked a little around as I admittedly was a little skeptical regarding the given time line. Whether we like it or not we are leaving quite an impression on earth. Given that we (and earlier civilizations, if ever present on earth) have built quite impressive and durable population centers, I was a little surprised to see that the expected most brick/concrete buildings to be gone after only a 1000 years. Especially as there has been found quite a few well preserved stone age villages (up to roughly 10,000 years).
Basically it is what is believed to be the oldest building as yet discovered, and it is dated back about 500,000 years. I would therefore contend that much more numerous and durable structures definitely would leave a trace behind, probably for quite a while.