Maybe it’s because of all the science fiction books and films I’ve always enjoyed, but I’ve often wondered how long it would take for all traces of mankind to dissappear from the planet if our species were to suddenly vanish from the face of the Earth. Anyway this article in the Times (taken from New Scientist) sheds some light on the question. Apparantly it would take 200,000 years.
Light pollution would be the first to go, followed by fields, buildings and cities
IF MAN were to vanish from the face of the Earth today, his footprint on the planet would linger for the mere blink of an eye in geological terms.
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.