So to summarize, the region of the Earth outside of the tropics is a chaotic system. The variation in this chaotic system accounts for the vast majority of general climate variation over the eons. So a slight temperature rise in the tropics caused by green house gasses could trigger a runaway warming. But it could also trigger the opposite. Or no change could trigger either one. Such is the behavior of chaotic systems. They behave near randomly. Your inputs will have something to do with how they behave, but you can't know how.

So when they say greenhouse gasses could lead to runaway warming, that is a very cheap statement. Of course it could. But parking your car somewhere different could lead to your neighbor having a heart attack in a month.