These people thrive in crises. They can't just live happily because then they become unnecessary. So they invent endless problems out of whole cloth and then heroically fight them. In the end the threat doesn't materialize and they reward each other for the job well done. For details see Lisa and her rock that keeps tigers away.
But if we want to get technical, it's doable too. 70% of Earth surface is water, and the mean radius of the planet is 6,371.0 km. A partial hollow sphere with the inner radius 6371 km and the outer radius 6371.001 km (for water rise of about 3.3', or 1 meter) and 70% coverage has volume of:
4/3 * π * (6371.0013 - 6371.0003) * 70%
That gives the answer: 377 thousand cubic kilometers, or a hundred million billion gallons, or 29 times larger than the volume of Lake Superior.
Now, let's calculate - just for fun - how much energy is needed to melt that much ice (assuming that the temperature was and remains at zero degrees Celsius.)
The heat of fusion for water is 333.55 kJ/kg, and we just calculated that we need 3.57×1017 liters of water. Let's ignore the difference in density here, it's small. The energy needed to melt that much ice is ...
3.57×1017 * 3.3355×105 = 1.19×1023 Joules.
To compare, this energy release is equivalent to about two million explosions of the Castle/Bravo, the largest thermonuclear device that was ever exploded by the USA.
In order to justify the existence of their make-work jobs fabricated out of the whole-cloth of environmental catastrophism...
Oh it could melt.
And, in 100 years, IF - big “if” there! - current sea level increases continue at their current rate - it “might” raise sea levels by a whole 20 inches.
The entire report is meant to control and to scare the readers. NEVER in this article is the real number mentioned. Because the writers don’t want the real number mentioned.