Oh, by the way, people here seem to belive that the Ice-age meant that the globe was simply frozen over.
Not so, it was mostly in the north. Lookie:
Now, your Ice-age has quite a span. Dozens of thousands of years. Roll into it and you'd better move to...N-Aussieland.
But seriously, Ice and SL is a good indicator of what is actually happening. And what we know is that SL does not rise without some water being added. Which goes rather in harmony with the land-based Ice that is added. Bear in mind that sea-ice melting does NOT raise SL, while the melting of it is a good indicator of what is going on.
Freezing over apparently takes a lot less time than thawing. (Well, any northerly working farmer will tell you that!). Anyway, once ice starts piling up, it bounces back the sun-heat and accelerates things into some equilibrum of an ice-age, that then stays and will give in when conditions are more....warm. So, that's how it looked:
Not a completely uninhabitable planet, but somewhat different from today.
So....what are 3 inches in 50 years?? They actually indicate the same melting as 80.000 years of Ice-age did on the opposite. Except that the Ice-age started much faster. And yet not, for most of the melting that has occured does NOT cause a rise in SL, since that ice is already in the water.
You may ask....so what? Okay, look at the Ice-age map again. Plenty of habitable space on earth. Then see this one, - a classic example of what greenhouse gases are capeable of doing.....not much life there and no Wallmart.
Hot, ain't she???