Thank you for starting a new thread!
I have no idea re: math into this, either, and I could most definitely be wrong. But, at the end of the day, the chief input re: heat on Earth is the sun.
If more of the Earth's surface is reflecting more sunlight back into space (and dissipating heat more readily at nighttime as well), I would think that actually has a *larger* impact than changes in GHGs, which alter the distribution of heat retained by the Earth, not the overall amount of heat it actually takes in. The only things that can alter the latter are A) changes in the sun's output or B) changes in the Earth's reflectance/albedo.
Given this, I suspect that we have vastly underestimated albedo's impact on overall global climate. Even if the amount of land that is snowcovered in a given year only increases by 10%, that is an absolutely *huge* amount of solar energy (~3% of planetary total!) that is now being deflected back into space.
If someone can provide more concrete numbers or throw my ideas into the garbage can either would be appreciated.
Of course, we currently are dealing with shrinking amounts of Arctic sea ice, which also has significant impacts re: albedo and most certainly is a huge contribution to overall warming and the seemingly runaway melt we are now seeing up north.
To my eyes, this will continue until there is almost no ice up north, and the Arctic will continue taking up more and more heat until there is enough snow on the continents to counteract the differential.
The key thing to note here is that though the Earth may have vastly more ocean than land, the impact of losing the ice up north can indeed be more than countered by expansion of snowpack over land in terms of raw area (e.g., we currently have 13.5M KM2 of icepack; it is certainly not inconceivable that if this dropped another 50% during wintertime, that the 6.75M KM2 differential is more than made up for by increased extent and duration of overland snows).
Consider that the Arctic bears the brunt of solar input during summer -- so the albedo impact of its losses are most felt during this time when it takes in energy -- but areas lower in latitude deal with much more solar energy earlier and later in the year (especially the Himalayas). That means that while the loss of Arctic icepack albedo is very detrimental during summer, it is somewhat less relevant to total global energy uptake vs. mid-upper latitude snowfall changes, which matter much more in spring/fall.
Final note: the increase in snowfall also has implications for the oceans/sea ice. It seems to my eyes that the only areas of sea ice that are holding steady or increasing on an annual basis are those in the upper-mid-latitudes (Hudson Bay, Labrador Sea, Sea of Okhotsk). This adds a relatively minimal amount of sea ice, but this too contributes to the reflectance of solar energy back into space, in areas that receive much more sunlight than the Arctic much earlier in the year. Of course, they still melt out, but the contribution is not insignificant.