[atlime (OP)]

Greetings.

Sarcastic title aside, what I want to find out is if we assume all the ice melts, how much will the water will it expand by?
1) Assuming ocean / salt water and taking a very large piece of ice block, say 10 000 ton piece in the middle of the arctic ocean, what % of the ice block is below the surface of the ocean?
2) In the case of that ice block, compared to its frozen state and turned water, by how much does the volume decrease?
3) And the end question, does the total water level rise, stay or drop due to the ice block melting.

[alancalverd]

When floating ice melts, the water level initially drops because the density of water is greatest at 4 deg C, not zero.

Problem with "all the ice in the world" is that a lot of it isn't floating on the sea but piled up on top of Greenland and Antarctica, or frozen into permafrost from which the water will run into rivers.

The world won't drown completely. It has been a lot hotter in the past. But life will become very uncomfortable because something like 80% of the human population lives within 100 miles of the sea, and the loss of a mile of coastline or the movement of a river delta will require a mass migration.

[Outcast]

Can an advanced society arise on a planet completely covered with liquid water?
Many life forms thrive in the oceans....lighting the campfires would appear to require a roomful of Einsteins...LOL

[evan_au]

One suggestion is that if all ice melted, oceans would rise by about 70m.
- This is similar to the sea level rise since the last ice age.

Since there are are areas of land more than 70m above current sea level, not all land will be inundated, and we won't need to grow gills.
See, for example: https://www.amnh.org/explore/ology/earth/ask-a-scientist-about-our-environment/will-the-world-ever-be-all-under-water