My pet theory for a very long time has been that tidal forces from the sun/moon/earth orbits act on the Earths core, which is believed to be mostly solid iron the size of the moon, causing frictional heating that builds up over a period of time. Another effect from this, which I wont go into much now, is a kind of pumping action occurs (I dont buy the conventional convection plume theory).
So after a period of time, say every 12K years, this excess heat eventually causes a weakening of the lithosphere and pressure waves from the cores pumping action opens fissures through which extra molten material finds its way through to the surface in the form of what we call plumes and divergent tectonic plate boundary zones. IMO, this is the simplest explanation and makes the most sense.
Scientists believe frictional heating from tidal force occurs with other bodies in our solar system, such as the moon IO orbiting the planet Jupiter, and a number of icy moons in the solar system with cryovolcanoes.
Active Volcanoes of Our Solar System - Activity Occurs on Earth and on the Moons of a Few Planets
In my Errant opinion, this is strong evidence that a similar process (except the Earth's solid central core is one of the main elements here), is what's occurring within the Earths interior and may explain what drives the Earth back into ice ages, even during warm periods (from the increased ash/SO2/moisture released into the atmosphere from increased volcanic activity).
Keeping in mind this is a complex world, there are other contributing factors in climatic change such as asteroid/comet impacts, solar output variations, changes in the Earth's orbit and inclination through precession, and etc.
It has been pretty thoroughly discussed at Catastrophism that the Younger Dryas was probably caused by asteroid/comet strikes along the Canadian border and perhaps in northern Europe. A well researched book by Firestone, et al. lays out this theory in detail. SC: Give him the reference please.
Once you have checked this out, see how it would affect your theorizing. I am inclined to think that Ice Ages are cause by megavolcanos and large asteroids/comets.
When all the ballyhoo was going on about drowning polar bears, there was submarine volcanic activity in the Arctic Ocean.
Blaming volcanic activity on melting ice is bassackward, imho.
Many moons ago, when people considered the internal heat of this planet the result of nuclear reactions at the core, a colleague and I postulated that the natural reactor at the core would poison itself when the daughter products reached a concentration sufficient to inhibit fission. That concentration (iirc) is fairly low, just a few percent. This would cause a period of quiescence which would allow the material to density stratify (removing daughter products), and then a resurgence when it did, which would account for the cyclical nature of the thermal cycles which drive tectonic activity.
No natural system is ever as 'pretty' as a theory, and the process would be unevenly distributed laterally in the layer of heavy metals near/at the core, but that might account for the thermal pulses apparent over geologic time, delayed and distributed by convection cells in the mantle.
Anyway, melting ice is one symptom of higher heat flow, not the cause thereof. There are other causes, after all, the ice has thermal interfaces on the top as well as the bottom, whereas heat applied from the outside is unlikely to cause volcanic activity without melting a lot more than ice.
The other as yet less than fully understood factor deals with cosmic impacts, and while causation is as easy to blame on cosmic impacts as more humanoid extraterrestrial influences (joking), if one was enough to cause an ELE at the end of the Cretaceous, other, lesser impacts could certainly cause less than ELE climate shifts.
Theory of the possible impact-related formation of the Carolina Bays may account for the Younger Dryas cooling. Either that, or all those Mammoth were cruising the glacial margins in SUVs again. (again, joking).
Melting ice requires the absorbtion of tremendous amounts of latent heat to achieve the phase change, with the effect of cooling surroundings, not heating them. That alone renders the concept that melting ice causes volcanism rather than vice-versa a bit counterintutitve. I would think there are enough examples of alpine glaciers melting prior to eruptions (from increased heat flow from rising magma) to show that cause-effect relationship.
On a global level, volcanism can cause significant atmospheric ash and sulfide levels which can decrease insolation and cause large scale cooling, but again, when the ash settles locally, there is a sufficient albedo change to cause the upper layers of the ice to absorb more heat rather than less, unless the thickness of pyroclastic material is great enough to act as an insulator, a phenomenon often observed in the spring at this latitude with wind-blown sediment, where ice can be preserved into late spring and early summer under a layer of dirt--especially in naturally shaded areas.
For this reason, much like with CO2, I think the researchers may have taken a trailing indicator and attributed causation to it.
Solid theory. Thank you. Very interesting.
Naturally, I’ll respectfully disagree — there’s no possible cause for massive glaciation apart from big impacts from space. Literally nothing else will cause it. I appreciate the deep-seated desire that there’s some kind of classifiable, predictable, cyclical cause, but there just isn’t one.
Even if the crustal displacement or pole shift models had been plausible (most recent advocates of the former are the Flem-Aths, basing their work on that of Charles Hapgood), they amount to trying to tame down catastrophes — look, a way for landmasses to shift into other latitudes with nary a shake or shimmy, barely rattling the dishes in the cupboard.
That said, there’s clearly an altitude shift, such as isostatic rebound when large ice masses melt back into the seas, but the ice didn’t get there gradually over centuries or thousands of years.