And here are the plots (found here, hat-tip to NSIDC):
I think it illustrates how problematic the increase could become over time. The sheer % rise year over year in 2018 is something that is impossible with sea ice because the starting point for NH snow is much lower.
But what about with even more sea ice loss? Does that lead to rapid recurring annual wintertime double digit % losses beginning in the Arctic while we see the same y-o-y increase between 2017->2018 in snowcover also begin to repeat with more frequency?
As the GHG load on the atmosphere increases I think this is a very plausible solution as it is the most effective way for the increased dissipation of planetary heat under ever-increasing GHGs. The increase in heat also comes with an increase in the efficiency of the heat *engine* which is the coupled continental ice sheet-sea ice albedo system.
When the planet is within an ice age, the system responds rapidly to losses in sea ice (i.e. albedo), and with more heat distributed each and every year, *when major extant ice sheets exist* the continents compensate until the annual increase in heat is minimized and the heat engine loses some steam.
Thus I think we must look at the *derivative* of increase rather than the increase itself as another important factor in determining change. When the system is effectively resolving more heat, planetary temps drop, and sea ice begins to form once more.
But as we see several more decades of guaranteed major sustained annual GHG increases, that is not going to happen. Instead, the extra heat is going to be resolved by the destruction of most polar sea ice with new continental ice sheets probably forming by the 2030s. Perhaps the amount of heat injected / natural feedbacks thereafter could be sufficient to plunge the planet into something worse than the last major maximum.
This will have the fortunate side effect of shutting off the primary mechanism behind the GHG releases, however.
Food for thought: current record low March NHEM ice volume is approximately 20,000 KM^3. This has dropped from 27,000 KM ^ 3 in 2002 (26%).
This March saw a maximum SWE near 4,500 KM^3. That is about 50% above the normal maximums observed within the past few years. It is a stand out but as years like 2007 and 2012 have shown WRT sea ice, black swans may start as isolated ducklings but they quickly turn into angry honking flocks.
If we roll forward based on a 30% decrease in March ice volume over the next 15 years (probably reasonable based on comp w/02), we end up at 14,000 KM ^ 3 of ice.
Looking at SWE, another 50% increase from 2018 would be approximately 6,750KM ^ 3. Again, we pass 10,000 KM ^3.
What if another major tipping-point is hemispheric snow-water-equivalent surpassing its total volume of sea ice?
We seemingly have answers behind what happened at the end of all the previous ice ages, yet the actual question of onset is always beset by silly thoughts re: solar cycles etc. These are all coincidental to TIPPING POINTS when extant continental ice sheets co-exist with sea ice.
Neven thank you for the animations. In terms of extent 2018 seems to be with the high years in North America and with the low years in Siberia, but not exceptional in any case.
As for the quoted post, I don't even know where to begin (again).
Yes we might get more snow depth because of more open water. Will we get more snow extent? It doesn't seem like it.
Will the snow last longer on the ground? My research above, Rob's calculation above, and plain old common sense regarding a warming climate say a strong no.
Does the snow create its own weather? No. The heat comes from elsewhere to melt the snow. An elsewhere where GHGs drive up temps, and there is no albedo effect. The snow is not protected from that heat.
"When the planet is within an ice age, the system responds rapidly to losses in sea ice (i.e. albedo), and with more heat distributed each and every year, *when major extant ice sheets exist* the continents compensate until the annual increase in heat is minimized and the heat engine loses some steam." - so during ice ages the proposed cycle is loss of sea ice leading to growth in continental ice sheets? I say pure fantasy. Sea ice does not shrink while increased glaciation is ongoing, as it is too cold for that. To claim otherwise requires extraordinary proof.
"When the system is effectively resolving more heat, planetary temps drop, and sea ice begins to form once more." - I concur that perhaps the snow is a way for the system to shed some extra heat. But it doesn't cool the system below where it started. It uses some of the excess energy for precipitation, that's all.
"But as we see several more decades of guaranteed major sustained annual GHG increases, that is not going to happen. Instead, the extra heat is going to be resolved by the destruction of most polar sea ice with new continental ice sheets probably forming by the 2030s. Perhaps the amount of heat injected / natural feedbacks thereafter could be sufficient to plunge the planet into something worse than the last major maximum." This defies all common sense. In this theory too much heat causes the continental ice sheets to form. But the snow feedback is not strong enough, cannot be strong enough for that. If it snowed over the whole earth including oceans and equator, and that snow lasted extra time, then perhaps somehow you could get a strong feedback. Pure fantasy.
"We seemingly have answers behind what happened at the end of all the previous ice ages, yet the actual question of onset is always beset by silly thoughts re: solar cycles etc. These are all coincidental to TIPPING POINTS when extant continental ice sheets co-exist with sea ice." Indeed we have answers. Milankovitch cycles. Summers become shorter and cooler, snow lasts on the ground, you get an ice age.
Snow depth is not a feedback in terms of albedo, neither is sea ice volume. The albedo effect is achieved by area multiplied by insolation. NHEM sea ice during insolation season equinox to equinox is currently ~1.5 million km2 less than it was in the 1980s. Is snow extent higher by 1.5 million km2 sustained during the whole season? No. So where is the feedback? Nowhere to be found.
My only serious question, as this is a science forum, is why this "glaciation due to a warming climate" theory is popping up again and again almost on a daily basis. Sorry if I sound harsh, but this does test one's patience, especially as the theory's proponent does seem well versed in science.
Personal resolution: I will try to refrain from posting rebuttals on the subject from now on.