The real danger on the cooling side, however, probably isn't the next onset of the glaciation phase of the Ice Age. (realclimate.org)
When temperatures were very cold on the mainland, the oceans remained warm, especially during the periods of intense cooling that took place at the onset of glaciation. (sciencedaily.com)
Also, the onset of glaciation or deglaciation appears to be triggered by orbital effects that have big seasonal / regional impacts but apply almost zero RF in the global mean. (realclimate.org)