Is there any effect on the earths rotation due to increase in the number of high rise building reaching to heights of nearly a mile. Especially if they are concentrated in some cities like Manhattan or Dubai.

Scleros

Interesting question.

The only thing I can think of would be that the earth is ever so minisculy more un-balanced because the center of mass has been changed. And, perhaps also by extremely slight crustal deformation due to loading.

I think both are a stretch and probably unmeasurable, but I hope this post gets a geologist's opinion.

ebaines

It is apparent that as you build a tall building you are increasing the moment of inertia of the earth - raw materiels are mined from underground, turned into steel and concrete, and then hoisted far into the air. Hence you would expect that the earth's rotational velocity to decrease - like the ice skater who extends her arms during a spin to slow down. But the effect would be miniscule. Remember that most of the volume of a building is air, so while a building may be 1000 feet tall its mass is no more than that of a 100-foot tall hill.

In fact, I would bet that the erosion of mountains - causing silt to be washed from high altitude down to the oceans - more than makes up for whatever the effect of building construction may be.

asking

Compared to mountain ranges with the mass of the Andes or the Himalayas, I can't imagine that a few buildings scattered here and there would have any significant effect...but I don't actually know! Cool question.