[svcw]

Hum. I am not seeing that. How would it block enough sun light to cause a permanent ice age?
Its not that I am saying you are incorrect (I mean I was a pych major in collage), I am just not getting it.

[Alter Kaker]

How would it block enough sun light to cause a permanent ice age?

Because they block and reflect sunlight. Small, temporary rings 35 million years ago may have blocked as much as a third of all visible light, leading to mass extinctions. Additionally, rings on earth would most likely be the result of a large meteor strike kicking back debris into earth orbit, which could itself be disastrous.

[jongaltsr]

How would it block enough sun light to cause a permanent ice age?

Eggheads.......
The ring would block 10% (or greater) of the sunlight striking the earth.
What is the absolute (cold) temperature on an object in space if no light strikes it surface?
Take that temperature (Near Absolute Freezing) take 10% of the difference between that and average earth temperatures see what the surface of the earth would decrease by.
Of course there are numerous other factors to consider but reduction of 10% (or even 5%) would turn the earth very cold.