I've read about glaciers advancing and retreating as part of a natural earth cycle, on average around every 10,000 years or so. Do you believe this is connected in some way to the global warming we've experienced recently, and if so, couldn't global warming also be considered a process of the natural earth cycle and not necessarily a product of pollution? I'm sure pollution could accelerate the natural cycle but not be the sole cause of it.

Sure.

Scientists currently do not know whether our current global warming situation is a product of pollution or a just part of Earth's natural cycle of global warming and global cooling. You hear most about global warming from environmentalists because they are using it to promote their cause, but nobody has solid evidence of why global warming is occuring now.

The reason it's so hard to determine just what part pollution plays is that we don't relly have much data about previous ages of glacial retreat.

There is no doubt at all that certain pollutants contribute to it.

But no one knows just how much.

It's like asking whether children reach sexual maturity earlier now than they did in the Middle Ages. There are trends in this century that indicate that they are reaching puberty earlier than children a century ago. But there isn't much data about people in the Middle Ages of the type that would answer the question.