Before the next ice age can begin, we have to wait until the current ice age ends. We are right smack dab in the middle of the Pleistocene Ice Age, and have been for the last 2.5 million years, or so. read more
Actually we can't head into an ice age at this point in time because we are already in one. Technically this is an interglacial period within the current ice age, ie. this is not "Earth Normal" climate, which is much hotter. Interglacial means "between glacations" and is about as unstable a climate as possible on this planet. read more