Is man now more important than nature in shifting soil and rocks around the planet?

Question

Just a few years ago I remember reading that mankind had finally overtaken nature in the volume of rock and earth which is shifted each year. That is to say, using earth-movers etc we move more material around the planet than all the natural agencies such as rivers, glaciers, the wind, currents etc

Can anyone point me in the direction of an article on this? I haven't been able to find one yet - wrong search terms!?

Answer 1

I don't know about any articles on this, but as a practising geologist, I can safely say that man's role in shifting soil and rocks is still miniscule compared with natural processes. Consider the amount of wind-blown sand in deserts or the amount of sediment carried down via rivers, deltas etc into the sea. The amounts of material are staggeringly huge!

On the other hand don't believe any pseudo-religious mumbo jumbo about such rates of erosion being so huge that the continents would have been levelled. People who peddle this stuff rarely have any real knowledge about geology. The rates of erosion ARE huge, but they are not consistent and therefore it's not appropriate to use modern-day average rates. A lot of erosion can happen in a short space of time (think landslips, floods, catastrophic climate events) separated by periods of relative quiescence. However, these huge rates of erosion are easily are offset by uplift due to continental collision, (plate tectonics) and isostacy (or "buoyancy" of the continents whereby when rocks are eroded, the continents will uplift to compensate for their reduced weight) - This is, of course, putting it very simply. But these are proven processes, not theories or religious dogma!

Answer 2

I think natural erosion is likely still winning.

Nevertheless, sedimentologists have researched many of the world’s rivers and calculated how fast the land is disappearing. The measurements show that some rivers are excavating their basins by more than 1,000 mm (39 inches) of height in 1,000 years, while others move only 1 mm (0.04 inches) in 1,000 years. The average height reduction for all the continents of the world is about 60 mm (2.4 inches) per 1,000 years, which equates to some 24 billion tonnes of sediment per year (Table 1).5 That is a lot of top dressing!

On the scale of one human life-span, these rates of erosion are low. But for those who say the continents are billions of years old, the rates are staggering. A height of 150 kilometres (93 miles) of continent would have eroded in 2.5 billion years. It defies common sense. If erosion had been going on for billions of years, no continents would remain on Earth.

This problem has been highlighted by a number of geologists who calculated that North America should have been levelled in 10 million years if erosion has continued at the average rate.6 This is a ridiculously short time compared with the supposed 2.5-billion-year age for the continents. To make matters worse, many rivers erode the height of their basins much faster than average (Table 1). Even at the slowest rate of 1 mm (0.04 inches) reduction in height per 1,000 years, the continents, with an average height of 623 metres (2,000 feet), should have vanished long ago.



http://www.creationontheweb.com/content/view/230

Answer 3

ya