<p><img src="https://i.sstatic.net/I06TG.png" alt="enter image description here">  </p>

<p>(Fig. 2.4 of <a href="https://books.google.com/books?id=vqgfH9DXXNAC&amp;printsec=frontcover&amp;dq=Deep-Sea%20Biology:%20A%20Natural%20History%20of%20Organisms%20at%20the%20Deep-Sea%20Floor&amp;hl=en&amp;sa=X&amp;ved=0ahUKEwix-sPbjYDaAhWCZd8KHQ1xDsEQ6AEIJzAA#v=onepage&amp;q=Deep-Sea%20Biology%3A%20A%20Natural%20History%20of%20Organisms%20at%20the%20Deep-Sea%20Floor&amp;f=false" rel="nofollow noreferrer">Deep-Sea Biology: A Natural History of Organisms at the Deep-Sea Floor</a>)</p>

<p>8.3% of the Earth's surface is above 1 kilometer.</p>

<p>This corresponds to about 29% of the land area.</p>

<p>So 71% of the land area is below 1 km.</p>

CC BY-SA 3.0
2014-12-11T15:31:43.580Z
It would be great if you could give a reference for these charts.
mwengler
CC BY-SA 3.0
2014-06-30T13:58:40.300Z
2018-03-22T14:11:47.430Z
2018-03-22T14:11:47.430Z
DavePhD
<p>For question 1), the exact number will vary depending on the elevation model you use for the calculation. High resolution elevation models are available for land, but for sea the resolution is much lower. The best global elevation model covering both land and seafloor is arguable <a href="https://www.ngdc.noaa.gov/mgg/global/global.html" rel="nofollow noreferrer">ETOPO1</a>, with a resolution of about 2 km. And if we mask all areas outside of the range -200 to 800 m it turns into this</p>

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

<p>And you can see that most tropical forest and large areas of boreal forest are included, so I wouldn't be surprised if 99% of living <strong>land</strong> species are within those ranges.</p>

<p>Now, the total area within those limits tuns out to be $1.286 \times 10^8 {km}^2$ of a total of $5.095 \times 10^8 {km}^2$ (A good match for the figure of <a href="https://en.wikipedia.org/wiki/Earth" rel="nofollow noreferrer">$5.101 \times 10^8 {km}^2$ listed by wikipedia</a>). <strong>Giving a total of 25.2% of Earth's surface</strong>.</p>

<p>From that total, a 5.3% is contributed by the terrain between -200 m and sea level ($0.270 \times 10^8 {km}^2$).</p>

<p>Note that so far we have NOT made any distinction between water covered and dry surface. Now, that distinction seem weird to me, as it rules out massive areas of shallow seas full of life. The <a href="https://www.sciencedirect.com/science/article/pii/S0960982212011529" rel="nofollow noreferrer">oceans are know to contain 15% of the known species</a>, therefore, ruling them out immediately render the "99% claim" invalid. Instead, that distinction seem to be there to include the minuscule amount of dry land between 0 and -200 m, that in turn is in general very dry (otherwise they would become lakes) something that doesn't makes any sense to me. If the sentence you heard really refers to "dry land", I would think <strong>it must then refer to land species only</strong>. Anyway, it is not difficult to properly answer question 1  by quantify the relevance of those below-sea-level dry areas. That can be accomplished using the <a href="http://glcf.umd.edu/data/watermask/" rel="nofollow noreferrer">MODIS global water mask</a>, a very useful dataset at 250m resolution that allows to distinguish between dry land and water covered areas. It looks like this:</p>

<p><a href="https://i.sstatic.net/IfCf6.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/IfCf6.png" alt="enter image description here"></a></p>

<p>(It doesn't cover Antarctica, but that continent doesn't contain any below sea level interior lands as seen in the first figure, so it doesn't really matter)</p>

<p>Using the two datasets, I've calculated that the surface of dry land between 0 and -200 m of elevation correspond to $0.0065 \times 10^8 {km}^2$ (a 0.1% of Earth's surface).</p>

<p>Taking that into account, <strong>the percentage of dry land between -200 and 800 m is a 69.1% of Earth's dry surface</strong>, or a 20.1% of the total Earth's surface.</p>

<hr>

<p>For question 2, I think your proposed interpretation is valid, and reasonable. But also other interpretations (like the total biomass mentioned in the comments) are valid. Nevertheless, as mentioned above it must refer to that "99% of <strong>land</strong> species live in <strong>dry land</strong> between -200 and 800 m" or that "99% of <strong>all</strong> species live between -200 and 800 m". Otherwise the claim is incompatible with the above mentioned fact that 15% of species live on the oceans.</p>

<p>A second caviat is that a large amount of species are yet to be discovered, perhaps <a href="https://news.nationalgeographic.com/news/2011/08/110824-earths-species-8-7-million-biology-planet-animals-science/" rel="nofollow noreferrer">up to the 86% of them</a>, and those will arguably be found preferentially in the less explored areas of the oceans.</p>

<p>I haven't seen quantitative biodiversity maps considering estimated for all known species. You will be able to validate that claim if you consider one special well studied group, like vertebrates or vascular plants. Tor those two groups, comparing the following two figures with the top one makes the "99% claim" perhaps reasonable, but an overwhelming majority of species don't belong to those groups, and I don't know if the biodiversity distribution would be similar.</p>

<p><a href="https://i.sstatic.net/bRlGj.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/bRlGj.png" alt="enter image description here"></a>
(vertebrates biodiversity map from <a href="https://www.savingspecies.org/stunning-new-biodiversity-maps-show-where-to-prioritize-conservation/" rel="nofollow noreferrer">savingspecies.org</a>)</p>

<p><a href="https://i.sstatic.net/zfxZD.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/zfxZD.jpg" alt="enter image description here"></a>
(vascular plants biodiversity map from <a href="http://www1.biologie.uni-hamburg.de/b-online/e56/56b.htm" rel="nofollow noreferrer">Hamburg University</a>)</p>

<p>If an actual number wants to be calculated based on actual data, the <a href="http://biodiversitymapping.org/wordpress/index.php/download/" rel="nofollow noreferrer">GIS  datasets</a> at <a href="http://biodiversitymapping.org/wordpress/index.php/home/" rel="nofollow noreferrer">biodiversitymapping.org</a> are a great resource.</p>

<p>Perhaps one argument in favour of the biomass interpretation of the claim, is that it would be a much easier and better constraint calculation.</p>

CC BY-SA 3.0
2018-03-22T20:46:04.733Z
2018-03-22T21:11:07.777Z
2018-03-22T21:11:07.777Z
Camilo Rada
<p>Being this my first questions on this .SE I hope that the topic is appropriate.</p>

<p>I've been told that 99% of the living species on earth live in between -200m and 800m above sea level, this made me just wonder how much of earth surface lies in this elevation span, but I couldn't find the answer googling. </p>

<p>1) Does anybody have a source to check what percentage of dry land has sea level elevation lower than 1 km (or 800m, or in between -200m and 800m...)?</p>

<p>2) How should I interpret the information given to me about the number of living species? I would just say for the 99% of the living species the intersection between the "natural habitat" and the altitude "-200m - 800m" is non empty, is it correct? Is there a source where I can check this information?</p>

<p>Thanks in advance!!</p>

CC BY-SA 3.0
2014-06-25T00:25:17.987Z
It would be nice to see a citation. However, that figure is plausible because it captures essentially all of the productive part of the oceans and well over half of the Earth's land area.
David Hammen
CC BY-SA 3.0
2014-06-25T00:42:18.907Z
Saying with precision where 99% of the species live is a bit dubious given that "some 86% of existing species on Earth and 91% of species in the ocean still await description." Reference: [Mora, Camilo, Derek P. Tittensor, Sina Adl, Alastair GB Simpson, and Boris Worm. "How many species are there on Earth and in the ocean?." PLoS biology 9, no. 8 (2011): e1001127](http://www.plosbiology.org/article/info%3Adoi%2F10.1371%2Fjournal.pbio.1001127).
David Hammen
CC BY-SA 3.0
2014-06-25T03:24:25.020Z
xAnswering question 1 is an easy exercise using [NOAAs ETOPO dataset](http://www.ngdc.noaa.gov/mgg/global/global.html) along with a land-water mask (to tell apart ocean from land below sea level).
gerrit
CC BY-SA 3.0
2014-06-25T06:43:09.363Z
Thank you all for the useful comments! In specific, regarding question 1) I'll have to give it a try, but it's probably going to take some time. And about question 2) I'm unfortunately unable to provide any written source, since I heard the information in a seminar. But am I wrong in thinking that if we consider it as a sum of biomass then the lack of description of species is irrelevant? At least one could try to check the information by this point of view, or is it completely non-sense? (My field of specialization is unluckily quite far from biology.)
Giovanni De Gaetano
CC BY-SA 3.0
2014-06-25T13:29:15.167Z
The statement is quite plausible. The title of your question, "Percentage of dry land surface with sea level elevation lower than 1 km" suggests you have a land-based bias. You are ignoring the 71% of the Earth's surface that is covered by water. While the oceans are deep, almost all oceanic life lies within the first 200 meters. Light doesn't penetrate beyond 150 meters or so.
David Hammen
<geography>
Percentage of dry land surface with sea level elevation lower than 1 km
Giovanni De Gaetano
# Percentage of dry land surface with sea level elevation lower than 1 km

(Asked by: username_0 on 2014-06-24)

Being this my first questions on this .SE I hope that the topic is appropriate.

I've been told that 99% of the living species on earth live in between -200m and 800m above sea level, this made me just wonder how much of earth surface lies in this elevation span, but I couldn't find the answer googling.

1) Does anybody have a source to check what percentage of dry land has sea level elevation lower than 1 km (or 800m, or in between -200m and 800m...)?

2) How should I interpret the information given to me about the number of living species? I would just say for the 99% of the living species the intersection between the "natural habitat" and the altitude "-200m - 800m" is non empty, is it correct? Is there a source where I can check this information?

Thanks in advance!!

**Tags:** geography

> **Comments:**
> **username_1**: It would be nice to see a citation. However, that figure is plausible because it captures essentially all of the productive part of the oceans and well over half of the Earth's land area.  
> **username_1**: Saying with precision where 99% of the species live is a bit dubious given that "some 86% of existing species on Earth and 91% of species in the ocean still await description." Reference: [Mora, username_5, Derek P. Tittensor, Sina Adl, Alastair GB Simpson, and Boris Worm. "How many species are there on Earth and in the ocean?." PLoS biology 9, no. 8 (2011): e1001127](http://www.plosbiology.org/article/info%3Adoi%2F10.1371%2Fjournal.pbio.1001127).  
> **username_2**: xAnswering question 1 is an easy exercise using [NOAAs ETOPO dataset](http://www.ngdc.noaa.gov/mgg/global/global.html) along with a land-water mask (to tell apart ocean from land below sea level).  
> **username_0**: Thank you all for the useful comments! In specific, regarding question 1) I'll have to give it a try, but it's probably going to take some time. And about question 2) I'm unfortunately unable to provide any written source, since I heard the information in a seminar. But am I wrong in thinking that if we consider it as a sum of biomass then the lack of description of species is irrelevant? At least one could try to check the information by this point of view, or is it completely non-sense? (My field of specialization is unluckily quite far from biology.)  
> **username_1**: The statement is quite plausible. The title of your question, "Percentage of dry land surface with sea level elevation lower than 1 km" suggests you have a land-based bias. You are ignoring the 71% of the Earth's surface that is covered by water. While the oceans are deep, almost all oceanic life lies within the first 200 meters. Light doesn't penetrate beyond 150 meters or so.  

---

## 2 answers

### Answer by username_3 on 2014-06-30. Score: 11

![enter image description here](https://i.sstatic.net/I06TG.png)

(Fig. 2.4 of [Deep-Sea Biology: A Natural History of Organisms at the Deep-Sea Floor](https://books.google.com/books?id=vqgfH9DXXNAC&printsec=frontcover&dq=Deep-Sea%20Biology:%20A%20Natural%20History%20of%20Organisms%20at%20the%20Deep-Sea%20Floor&hl=en&sa=X&ved=0ahUKEwix-sPbjYDaAhWCZd8KHQ1xDsEQ6AEIJzAA#v=onepage&q=Deep-Sea%20Biology%3A%20A%20Natural%20History%20of%20Organisms%20at%20the%20Deep-Sea%20Floor&f=false))

8.3% of the Earth's surface is above 1 kilometer.

This corresponds to about 29% of the land area.

So 71% of the land area is below 1 km.

> **Comments:**
> **username_4**: It would be great if you could give a reference for these charts.  

---

### Answer by username_5 on 2018-03-22. Score: 2

For question 1), the exact number will vary depending on the elevation model you use for the calculation. High resolution elevation models are available for land, but for sea the resolution is much lower. The best global elevation model covering both land and seafloor is arguable [ETOPO1](https://www.ngdc.noaa.gov/mgg/global/global.html), with a resolution of about 2 km. And if we mask all areas outside of the range -200 to 800 m it turns into this

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

And you can see that most tropical forest and large areas of boreal forest are included, so I wouldn't be surprised if 99% of living **land** species are within those ranges.

Now, the total area within those limits tuns out to be $1.286 \times 10^8 {km}^2$ of a total of $5.095 \times 10^8 {km}^2$ (A good match for the figure of [$5.101 \times 10^8 {km}^2$ listed by wikipedia](https://en.wikipedia.org/wiki/Earth)). **Giving a total of 25.2% of Earth's surface**.

From that total, a 5.3% is contributed by the terrain between -200 m and sea level ($0.270 \times 10^8 {km}^2$).

Note that so far we have NOT made any distinction between water covered and dry surface. Now, that distinction seem weird to me, as it rules out massive areas of shallow seas full of life. The [oceans are know to contain 15% of the known species](https://www.sciencedirect.com/science/article/pii/S0960982212011529), therefore, ruling them out immediately render the "99% claim" invalid. Instead, that distinction seem to be there to include the minuscule amount of dry land between 0 and -200 m, that in turn is in general very dry (otherwise they would become lakes) something that doesn't makes any sense to me. If the sentence you heard really refers to "dry land", I would think **it must then refer to land species only**. Anyway, it is not difficult to properly answer question 1 by quantify the relevance of those below-sea-level dry areas. That can be accomplished using the [MODIS global water mask](http://glcf.umd.edu/data/watermask/), a very useful dataset at 250m resolution that allows to distinguish between dry land and water covered areas. It looks like this:

[![enter image description here](https://i.sstatic.net/IfCf6.png)](https://i.sstatic.net/IfCf6.png)

(It doesn't cover Antarctica, but that continent doesn't contain any below sea level interior lands as seen in the first figure, so it doesn't really matter)

Using the two datasets, I've calculated that the surface of dry land between 0 and -200 m of elevation correspond to $0.0065 \times 10^8 {km}^2$ (a 0.1% of Earth's surface).

Taking that into account, **the percentage of dry land between -200 and 800 m is a 69.1% of Earth's dry surface**, or a 20.1% of the total Earth's surface.

---

For question 2, I think your proposed interpretation is valid, and reasonable. But also other interpretations (like the total biomass mentioned in the comments) are valid. Nevertheless, as mentioned above it must refer to that "99% of **land** species live in **dry land** between -200 and 800 m" or that "99% of **all** species live between -200 and 800 m". Otherwise the claim is incompatible with the above mentioned fact that 15% of species live on the oceans.

A second caviat is that a large amount of species are yet to be discovered, perhaps [up to the 86% of them](https://news.nationalgeographic.com/news/2011/08/110824-earths-species-8-7-million-biology-planet-animals-science/), and those will arguably be found preferentially in the less explored areas of the oceans.

I haven't seen quantitative biodiversity maps considering estimated for all known species. You will be able to validate that claim if you consider one special well studied group, like vertebrates or vascular plants. Tor those two groups, comparing the following two figures with the top one makes the "99% claim" perhaps reasonable, but an overwhelming majority of species don't belong to those groups, and I don't know if the biodiversity distribution would be similar.

[![enter image description here](https://i.sstatic.net/bRlGj.png)](https://i.sstatic.net/bRlGj.png)
(vertebrates biodiversity map from [savingspecies.org](https://www.savingspecies.org/stunning-new-biodiversity-maps-show-where-to-prioritize-conservation/))

[![enter image description here](https://i.sstatic.net/zfxZD.jpg)](https://i.sstatic.net/zfxZD.jpg)
(vascular plants biodiversity map from [Hamburg University](http://www1.biologie.uni-hamburg.de/b-online/e56/56b.htm))

If an actual number wants to be calculated based on actual data, the [GIS datasets](http://biodiversitymapping.org/wordpress/index.php/download/) at [biodiversitymapping.org](http://biodiversitymapping.org/wordpress/index.php/home/) are a great resource.

Perhaps one argument in favour of the biomass interpretation of the claim, is that it would be a much easier and better constraint calculation.


---

