>Long ice age intervals did not just suddenly occur.

I agree and I didn't state otherwise. As you agreed at least for the most recent glaciation, the asteroid impact is just the first step in a series of steps that lead to glaciation.

As I mentioned, a specific cause for global cooling is the sequestering of carbon dioxide that occurred over millions of years due ultimately to the asteroid impact. There is no doubt in the environmental community today that carbon dioxide is a major factor determining the global temperature. Some would say it is the single most important factor regulating the temperatures of the earth (I would disagree that it is the single most important factor but the point is that mainstream science recognizes the importance of carbon dioxide in regulating troposheric temperatures.)

Everything you have said in the previous post concerning ice ages and glaciation, I agree with and these views are represented on my terracycles web site. Ice ages are a complex combination of interelated systems. And like all systems that repeat themselves (cycles), given enough time the system finds a resonant frequency and tends to oscillate with a more or less regular time interval. This time interval is what I call the terracycle.

Dave