http://www.timesonline.co.uk/article/0,,3-2399972,00.html

200,000 years for all trace of Man to vanish from the Earth
By Lewis Smith

http://www.timesonline.co.uk/article/0,,3-2399972,00.html

200,000 years for all trace of Man to vanish from the Earth
By Lewis Smith

http://www.timesonline.co.uk/article/0,,3-2399972,00.html

200,000 years for all trace of Man to vanish from the Earth
By Lewis Smith

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.

Man’s 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.

By tomorrow, street lights and house lights left on by their former
occupants would start to go out.

Streets and cultivated fields would be the next to go. Within 20 years
village streets and rural roads would have vanished under a matting of
weeds; fields would be overgrown within months. Urban streets would
take a little longer, but even in huge man-made sprawls, such as
London and Birmingham, plants would have taken over in about 50 years.

Buildings would decay rapidly. Wooden structures would collapse first,
assaulted by bugs and grubs. All such homes would be gone in a
century.

Glass and steel tower blocks that create city skylines would mostly
fall down within 200 years. Brick, stone and concrete structures would
last longer. With exceptions — the pyramids are already 3,000 years
old — by the next millennium there would be little more left than
ruins.

“If tomorrow dawns without humans, even from orbit the change will be
evident almost immediately,” Bob Holmes, of New Scientist, said. “With
no-one to make repairs, every storm, flood and frosty night gnaws away
at abandoned buildings and within a few decades roofs will begin to
fall in and buildings collapse.”

Ronald Chesser, of Texas Tech University, said: “The most pervasive
thing you see are plants whose root systems get into the concrete and
behind the bricks and into door frames and so forth and are rapidly
breaking up the structure.”

Wildlife would thrive in the absence of Man. Most of the 15,589
threatened species will begin to recover immediately towards
historical populations.

Carbon dioxide emissions wouldcontinue to cause climate change for
another 100 years, but after 1,000 years all would be back to
pre-industrial levels, with all man-made traces vanishing in 20,000
years.

However, the most radioactive of untreated nuclear waste would not be
safe for up to two million years, John Large, an independent nuclear
consultant, said. Man-made chemicals, especially perfluorinated types,
would not break down for up to 200,000 years, although it is thought
that they would have been buried long before then.

If, 50,000 years hence, an alien archaeologist were to land on an
Earth without Man, it might be quite frustrated by the paucity of
evidence that we were here at all.

Click here for a graphic showing how man's influence would disappear

http://www.

Light pollution would be the first to go, followed by fields,
buildings and cities