<p>As @gerrit commented, a precise calculation would need to incorporate a litospheric model to account for isostatic <a href="https://en.wikipedia.org/wiki/Post-glacial_rebound" rel="noreferrer">post-glacial rebound</a>. But the "blurry approximation" you want, can be obtained based only on topographic data. This approximation would be reasonably accurate if the melting of the ice happens quickly.</p>

<p>For this, we need topographic data of the current surface, and of the bedrock topography. That's the bare ground below the ice. The only source of such data at a global scale (at least that I'm aware of) is <a href="https://www.ngdc.noaa.gov/mgg/global/global.html" rel="noreferrer">ETOPO1</a>, at a resolution of 1 arc-minute (roughly 1.8 km).</p>

<p>A visualization of current surface data from ETOPO1, using an equal-area projection (Eckert IV) and setting the sea level at 0 m looks like this:</p>

<p><a href="https://i.sstatic.net/nPFXt.png" rel="noreferrer"><img src="https://i.sstatic.net/nPFXt.png" alt="enter image description here"></a></p>

<p>And if we measure sea and land areas, it says that <strong>currently, a 70.97% of the global surface corresponds to oceans</strong>, pretty consistent with the figure you have. Be aware that this simple approach does not consider lakes or rivers, only oceans. It would also misinterpret below sea level dry land as ocean. However, all those factors are arguably minor contributions at a global scale.</p>

<p>Now, if we use the bedrock version of ETOPO1, and set the sea level at <a href="https://www.sciencedirect.com/science/article/pii/B9780444635242000051" rel="noreferrer">66.5 m, consistent with the best estimates of water stored in land ice</a>. The globe would look like this</p>

<p><a href="https://i.sstatic.net/MSFPJ.png" rel="noreferrer"><img src="https://i.sstatic.net/MSFPJ.png" alt="enter image description here"></a></p>

<p>In this case, <strong>if all the ice melts, the fraction of the Earth's surface covered by water would be 75.18%</strong>. Equivalent to an increase of 4.21% relative to the current value.</p>

CC BY-SA 4.0
2019-03-13T22:25:22.547Z
2019-03-16T17:23:11.173Z
2019-03-16T17:23:11.173Z
Camilo Rada
<p>At the present time, about 70% of the earth's surface is liquid water (perhaps that includes floating ice around Antarctica, and the Arctic Ice cap).</p>

<p><strong>What percentage of the Earth's surface would be water if ALL the ice had melted?</strong></p>

<p>I've seen illustrations of the new shoreline, and I've seen estimates of the rise in sea level, but no answer to my question.</p>

CC BY-SA 4.0
2018-11-28T10:38:55.453Z
An accurate calculation would need to consider post-glacial rebound.
gerrit
CC BY-SA 4.0
2018-11-29T20:33:18.670Z
I'm just interested in a blurry approximation.
Jim Brenneman
CC BY-SA 4.0
2018-11-30T21:31:48.520Z
https://earthscience.stackexchange.com/questions/7228/how-much-of-earths-surface-would-be-covered-by-water-if-all-ice-melted
Keith McClary
CC BY-SA 4.0
2021-12-31T03:17:24.453Z
keep in mind melting ice is not the only thing causing sea level rise, thermal expansion of the ocean water accounts for far more rise.
John
CC BY-SA 4.0
2022-04-04T20:12:25.850Z
Ice does not obey the law of archemedes, it is buoyant, it is also an exception to the rule of thermal expansion as it expands when frozen thereby taking up more space when frozen. Liquid molecules are more densely packed than gaseous molecules and less densely packed than solid matters molecules. Water also always flows to the lowest point which to me is the compounds most prevalent characteristic. In doing this it creates things we know called stalactites and stalacmites and underneath every inch of surface on this planet we have a thing called a water table, i think the answer to this quest
Mark Lawlor
CC BY-SA 4.0
2022-04-07T16:53:40.867Z
I am still just asking for a "blurry approximation"  - If all the Ice in Glaciers and Ice Caps were to melt - and none were to go into aquifirs and none were to evaporate - 
What would be the approximate rise of sea-level? How High up would that water go? How much land area would be lost?

This is purely hypothetical.

Does anyone know the answer? Or are we only capable of explaning why this simple question will never be answered? 

I hope  someone will quit making excuses and just give a simple answer.
Jim Brenneman
CC BY-SA 4.0
2022-10-09T01:03:12.757Z
I cant believe with all the clever people around no one can give the answer the gent is asking for - I too would like to see the figures of how much the depth or rise of water would be if all the ice melted. it should be a fairly easy calculation, but no one is willing to give an actual answer. the answer should be calculated by area covered by ice multiplied by the average heigh or thickness of ice above sea level spread out over the total area of the oceans just a ball park figure would be good enough - i cant find a reasonable answer to how much ice water would be added.
nigel fenton
<oceanography><geography><glaciology><sea-level><topography>
If ALL the ice melted, what percentage of the Earth's surface would be water?
Jim Brenneman
# If ALL the ice melted, what percentage of the Earth's surface would be water?

(Asked by: username_0 on 2018-11-27)

At the present time, about 70% of the earth's surface is liquid water (perhaps that includes floating ice around Antarctica, and the Arctic Ice cap).

**What percentage of the Earth's surface would be water if ALL the ice had melted?**

I've seen illustrations of the new shoreline, and I've seen estimates of the rise in sea level, but no answer to my question.

**Tags:** oceanography, geography, glaciology, sea-level, topography

> **Comments:**
> **username_1**: An accurate calculation would need to consider post-glacial rebound.  
> **username_0**: I'm just interested in a blurry approximation.  
> **username_2**: https://earthscience.stackexchange.com/questions/7228/how-much-of-earths-surface-would-be-covered-by-water-if-all-ice-melted  
> **username_3**: keep in mind melting ice is not the only thing causing sea level rise, thermal expansion of the ocean water accounts for far more rise.  
> **username_4**: Ice does not obey the law of archemedes, it is buoyant, it is also an exception to the rule of thermal expansion as it expands when frozen thereby taking up more space when frozen. Liquid molecules are more densely packed than gaseous molecules and less densely packed than solid matters molecules. Water also always flows to the lowest point which to me is the compounds most prevalent characteristic. In doing this it creates things we know called stalactites and stalacmites and underneath every inch of surface on this planet we have a thing called a water table, i think the answer to this quest  
> **username_0**: I am still just asking for a "blurry approximation"  - If all the Ice in Glaciers and Ice Caps were to melt - and none were to go into aquifirs and none were to evaporate -  What would be the approximate rise of sea-level? How High up would that water go? How much land area would be lost?  This is purely hypothetical.  Does anyone know the answer? Or are we only capable of explaning why this simple question will never be answered?   I hope  someone will quit making excuses and just give a simple answer.  
> **username_5**: I cant believe with all the clever people around no one can give the answer the gent is asking for - I too would like to see the figures of how much the depth or rise of water would be if all the ice melted. it should be a fairly easy calculation, but no one is willing to give an actual answer. the answer should be calculated by area covered by ice multiplied by the average heigh or thickness of ice above sea level spread out over the total area of the oceans just a ball park figure would be good enough - i cant find a reasonable answer to how much ice water would be added.  

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## 1 answers

### Answer by username_6 on 2019-03-13. Score: 7

As @username_1 commented, a precise calculation would need to incorporate a litospheric model to account for isostatic [post-glacial rebound](https://en.wikipedia.org/wiki/Post-glacial_rebound). But the "blurry approximation" you want, can be obtained based only on topographic data. This approximation would be reasonably accurate if the melting of the ice happens quickly.

For this, we need topographic data of the current surface, and of the bedrock topography. That's the bare ground below the ice. The only source of such data at a global scale (at least that I'm aware of) is [ETOPO1](https://www.ngdc.noaa.gov/mgg/global/global.html), at a resolution of 1 arc-minute (roughly 1.8 km).

A visualization of current surface data from ETOPO1, using an equal-area projection (Eckert IV) and setting the sea level at 0 m looks like this:

[![enter image description here](https://i.sstatic.net/nPFXt.png)](https://i.sstatic.net/nPFXt.png)

And if we measure sea and land areas, it says that **currently, a 70.97% of the global surface corresponds to oceans**, pretty consistent with the figure you have. Be aware that this simple approach does not consider lakes or rivers, only oceans. It would also misinterpret below sea level dry land as ocean. However, all those factors are arguably minor contributions at a global scale.

Now, if we use the bedrock version of ETOPO1, and set the sea level at [66.5 m, consistent with the best estimates of water stored in land ice](https://www.sciencedirect.com/science/article/pii/B9780444635242000051). The globe would look like this

[![enter image description here](https://i.sstatic.net/MSFPJ.png)](https://i.sstatic.net/MSFPJ.png)

In this case, **if all the ice melts, the fraction of the Earth's surface covered by water would be 75.18%**. Equivalent to an increase of 4.21% relative to the current value.


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