What is the major cause of erosion on the Earth’s surface?

Question

What is the major cause of erosion on the Earth’s surface?

Landslides
Moving water
Moon’s pull on the coast lines
Glacial action

Answer 1

Water...

* Liquid water, eg in rivers and coasts (in the sea this is largely caused by the gravitational effect of the moon);
* Liquid water is a major cause of landslides - soil becomes over-saturated and therefore loses its adhesion to the soil or rock beneath;
* The action of freeze-thaw where liquid water seeps into cracks, expands when it freezes thereby widening the crack and ultimately splitting rocks apart;
* Frozen water in the form of glaciers grinding away at mountains;

Other causes of erosion include:-
* the wind, especially when it blows sand particles with it which erode rocks;
* the Sun which alternatively heats and cools rocks so that they split in much they same way as freeze-thaw (especially in desert areas);
* humans - we contribute to many of the above processes by our own actions, eg deforestation prevents the soil from holding as much water so landslides become more likely; over-farming creates deserts which are subject to wind and sun; coastal "management" often results in more rapid erosion of some areas of coastline

Answer 2

People's misunderstanding of deforestation is the main cause. Harvesting timber as a renewable resource is not the same thing as deforestation. Deforestation is is part of the maturation process of a civilization. Deforestation is no longer happening in the U.S. There are more acres of forested land in the U.S. than there was when Columbus discovered the Americas. When people learn the difference between deforestation and timber harvest there will be lots less deforestation.

Answer 3

Water

Answer 4

The major cause is Deforestation.
Landslides, new flow of massive moving water are the effects of deforestation.

Answer 5

I would think water with wind a close second.

Answer 6

Deforestation. We keep removing vegetation. The root systems help keep everything in it's place.

Answer 7

Can't sell short wind action

Answer 8

Humans...

Answer 9

all of the above

Answer 10

nuclear warheads