Clippo

Firstly, to get Poptech out of the way, he/she wrote:-
That’s not an explanation of the ‘mechanism’ of ice melting/ sea-level change. It’s the usual sceptic doubt generating diarrhoea from the usual gang of crackpots.
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You’ve nearly answered your own doubts C-Steam with your final comments:-

Where I think you are at fault is your assumption that air and/or water temperature is the main criteria. You should rather consider the heat capacity of water and air.
For example, water can hold more heat than an equivalent mass/volume of air.
There are several different measures of heat capacity but as a generalisation water can hold about 4 times as much heat as air by any measure.
For the intellectually challenged, a practical example is that a human can walk in sub-zero temperatures for hours (with reasonable protective clothing) but how long would that human survive after falling into an icy lake?
(The icy lake has a greater capacity to remove heat from a human body than cold air – and I don’t want to get into the semantics of this being a reverse example)

So back to the Arctic situation. You have to identify where the heat is coming from to cause melting.
Consider land ice initially.
There is no significant source of heat from the underlying rocks (okay a small volcanic hot-spot has recently been found in NE Greenland I think but it’s significance in ice melting is small according to consensus of scientists studying it).
The only other source of heat is solar radiation. Don’t quote me accurately on these figures but I think overall measurements suggest 1.3 KW of ‘heat’ fall on every sq. m. of the Earth per day without cloud or aerosol interference. However, ice has a high reflectivity, or albedo, and the actual amount absorbed by ice is about 0.1 i.e. 1%
Considering arctic sea - ice,
Once again, solar radiation is a source but the same comments apply.
The second source of heat is obviously from the ocean waters below the ice. I have already explained how water has a greater heat capacity than air and thus it is the heat in the water which is melting the arctic ice much, much faster than land ice.
Where does the heat come from initially in the arctic ocean ? Well, you now have to bring into play the ocean circulations, particularly the ‘thermohaline circulation’. (This is also known by several other names but in Climate science circles the name Meridional overturning Circulation- abbrev. MOC is widely preferred).
I don’t propose to go into the detail of this. If you are curious, you can do a google search or go to Wiki which has a very balanced account of the science of this:-
Thermohaline circulation - Wikipedia, the free encyclopedia
Essentially, the MOC in the north Atlantic is continually bringing tropics-warmed water to the arctic ocean and since, due to the greenhouse effect, the surface waters of the tropics are warming even more there is a positive feedback effect in eventually accelerating the arctic sea ice melt.

So, to repeat, I think you had the germ of an explanation in your own last statement.

I think your estimate of 25% of 39%, if I’ve interpreted it correctly, is grossly inflated and I’m not going to hesitate a guess. There is no doubt that some of the Greenland ice sheet is melting but if you want to find out how much, in proportion to the sea ice, I suggest you do some research first through respectable science articles & peer-reviewed papers – as I had to do originally.
Lastly, on this topic I want to point out 2 important secondary effect of sea- ice melting.
a) Whereas, the ‘albedo’ of sea-ice is high, e.g. virtually an insignificant amount of melting results from solar radiation, when the ice has gone, the resulting ocean has virtually no Albedo, e.g. most solar radiation (1.3 KW / m2 per day) is absorbed into the water. This is another positive feedback.
b) Both in the Arctic & Antarctic, the presence of sea ice is thought to have slowed the flow of glaciers to the sea. Melting of sea ice has removed that impediment and at both poles glaciers are now flowing to the sea at increased rates.

I’m getting bored with this. I can’t remember what the current rate of sea rise is and I don’t have time now to look. As I said earlier, why don’t you do some google or other searches. What I do know is that in the last IPCC report there a number of scenarios were presented. The experts in these subjects have in fact criticised the IPCC for being too conservative. Obviously, the writer of your original article link is in this camp – as I am.