<p><a href="https://docsbay.net/arid-lands-challenges-and-hopes" rel="nofollow noreferrer">ARID LANDS: CHALLENGES AND HOPES</a> <em>by</em> EARTH SYSTEM: HISTORY AND NATURAL VARIABILITY – Vol. III - <em>Arid Lands: Challenges and Hopes - Barakat H.N.</em> </p>

<blockquote>
  <p>Hyperarid zones cover 7.5% of Earth's land surface, arid zones cover
  12.1%, while semiarid zones are more extensive, occur in all continents, and cover 17.7% of Earth's land surface. The dry subhumid
  category covers 9.9% of Earth's land surface.</p>
</blockquote>

CC BY-SA 4.0
2019-05-07T09:02:09.387Z
2019-05-07T09:02:09.387Z
aaroncorcino
<p>It will depend on the exact definition of "arid" and the period of time. But using the widely used and accepted <a href="https://en.wikipedia.org/wiki/K%C3%B6ppen_climate_classification" rel="noreferrer">Köppen climate classification</a>, "arid" would correspond to the four climates in <a href="https://en.wikipedia.org/wiki/K%C3%B6ppen_climate_classification#Group_B:_Dry_(desert_and_semi-arid)_climates" rel="noreferrer">climatic group B</a>: "<strong>Dry (desert and semi-arid) climates</strong>". Using <a href="http://koeppen-geiger.vu-wien.ac.at/present.htm" rel="noreferrer">the most up-to-date present climate data (2006)</a> provided by the <a href="http://koeppen-geiger.vu-wien.ac.at/" rel="noreferrer">WORLD MAPS OF KÖPPEN-GEIGER CLIMATE CLASSIFICATION</a> at 0.5° of resolution, that looks like this (in an equal area projection):</p>

<p><a href="https://i.sstatic.net/sLj6J.png" rel="noreferrer"><img src="https://i.sstatic.net/sLj6J.png" alt="enter image description here"></a></p>

<p>We get that the four arid climates (group B), add up to $4.401 \times 
 10^7 {km}^2$ of a total of $1.527 \times 
 10^8 {km}^2$ inventoried in the dataset (A good match for the figure of of <a href="https://en.wikipedia.org/wiki/Earth" rel="noreferrer">global land area of $1.489 \times 10^8 km^2$ listed by wikipedia</a>), leading to a grand total of <strong>28.8% of Earth's land surface corresponding to arid climates</strong>.</p>

CC BY-SA 3.0
2018-03-22T19:12:57.057Z
I'd think perhaps that number is a bit high, owing to the coarse resolution.  E.g. the northeastern part of Africa has the non-arid Nile valley & delta, which is too small to show up on the map.
jamesqf
CC BY-SA 3.0
2018-03-22T19:28:33.377Z
@jamesqf I guess ~50 km resolution is more than enough to identify climates, anything smaller would be most likely a microclimate. And in any case. Why coarser resolution would bias to higher values for arid areas? Arguable, also small arid areas would be missing.
Camilo Rada
CC BY-SA 3.0
2018-03-23T17:54:51.637Z
I think it depends on exactly what the OP is asking for.  There are areas (I live in one) which are arid if considered from a climate perspective - that is, very little rainfall - but which have non-arid climate vegetation due to water from streams and/or aquifers.  Those zones are often long & narrow, like the Nile valley or the areas on the leeward sides of mountain ranges, so averaging over a coarse grid misses them.
jamesqf
CC BY-SA 3.0
2018-03-23T19:14:29.777Z
@jamesqf Well, that's what I meant by "It will depend on the exact definition of arid", I took common definition of arid as given by the Köppen classification, which doesn't consider vegetation type. Of course, with a different classification the answer would be different. But, as the OP didn't pointed any specifics I guessed he did not care on those subtleties. And instead of specifying a definition of arid he went on to accept the answer, so I guess it was OK. But you are right in the sense that the answer depends on the climate classification used (as I stated at the start of the answer).
Camilo Rada
CC BY-SA 3.0
2018-03-22T17:12:06.420Z
2018-03-22T17:53:45.977Z
2018-03-22T17:53:45.977Z
Camilo Rada
<p>Is there available information on how much of Earth surface is arid climate? </p>

CC BY-SA 3.0
2018-03-22T17:33:04.360Z
I'm glad you liked the answer. However, I wonder How the question you mention would be answering your question?
Camilo Rada
CC BY-SA 3.0
2018-03-22T17:38:01.870Z
May be I wronly assumed that by "dry land" he meant "arid" ? Did he just mean "land"?
Pablo
CC BY-SA 3.0
2018-03-22T17:46:13.920Z
I see. Yes, I think that question refers just to land, or in other words: Earth's surface not covered by water.
Camilo Rada
CC BY-SA 3.0
2018-03-22T17:49:39.927Z
It would be desirable if you edit your question accordingly, to do not mislead others that might end up here looking for the same answer.
Camilo Rada
<climate><geography><climatology><desert>
What percentage of Earth's surface is arid?
Pablo
# What percentage of Earth's surface is arid?

(Asked by: username_0 on 2018-03-22)

Is there available information on how much of Earth surface is arid climate?

**Tags:** climate, geography, climatology, desert

> **Comments:**
> **username_1**: I'm glad you liked the answer. However, I wonder How the question you mention would be answering your question?  
> **username_0**: May be I wronly assumed that by "dry land" he meant "arid" ? Did he just mean "land"?  
> **username_1**: I see. Yes, I think that question refers just to land, or in other words: Earth's surface not covered by water.  
> **username_1**: It would be desirable if you edit your question accordingly, to do not mislead others that might end up here looking for the same answer.  

---

## 2 answers

### Answer by username_1 on 2018-03-22. Score: 8 | Accepted answer

It will depend on the exact definition of "arid" and the period of time. But using the widely used and accepted [Köppen climate classification](https://en.wikipedia.org/wiki/K%C3%B6ppen_climate_classification), "arid" would correspond to the four climates in [climatic group B](https://en.wikipedia.org/wiki/K%C3%B6ppen_climate_classification#Group_B:_Dry_(desert_and_semi-arid)_climates): "**Dry (desert and semi-arid) climates**". Using [the most up-to-date present climate data (2006)](http://koeppen-geiger.vu-wien.ac.at/present.htm) provided by the [WORLD MAPS OF KÖPPEN-GEIGER CLIMATE CLASSIFICATION](http://koeppen-geiger.vu-wien.ac.at/) at 0.5° of resolution, that looks like this (in an equal area projection):

[![enter image description here](https://i.sstatic.net/sLj6J.png)](https://i.sstatic.net/sLj6J.png)

We get that the four arid climates (group B), add up to $4.401 \times
10^7 {km}^2$ of a total of $1.527 \times
10^8 {km}^2$ inventoried in the dataset (A good match for the figure of of [global land area of $1.489 \times 10^8 km^2$ listed by wikipedia](https://en.wikipedia.org/wiki/Earth)), leading to a grand total of **28.8% of Earth's land surface corresponding to arid climates**.

> **Comments:**
> **username_3**: I'd think perhaps that number is a bit high, owing to the coarse resolution.  E.g. the northeastern part of Africa has the non-arid Nile valley & delta, which is too small to show up on the map.  
> **username_1**: @username_3 I guess ~50 km resolution is more than enough to identify climates, anything smaller would be most likely a microclimate. And in any case. Why coarser resolution would bias to higher values for arid areas? Arguable, also small arid areas would be missing.  
> **username_3**: I think it depends on exactly what the OP is asking for.  There are areas (I live in one) which are arid if considered from a climate perspective - that is, very little rainfall - but which have non-arid climate vegetation due to water from streams and/or aquifers.  Those zones are often long & narrow, like the Nile valley or the areas on the leeward sides of mountain ranges, so averaging over a coarse grid misses them.  
> **username_1**: @username_3 Well, that's what I meant by "It will depend on the exact definition of arid", I took common definition of arid as given by the Köppen classification, which doesn't consider vegetation type. Of course, with a different classification the answer would be different. But, as the OP didn't pointed any specifics I guessed he did not care on those subtleties. And instead of specifying a definition of arid he went on to accept the answer, so I guess it was OK. But you are right in the sense that the answer depends on the climate classification used (as I stated at the start of the answer).  

---

### Answer by username_2 on 2019-05-07. Score: 3

[ARID LANDS: CHALLENGES AND HOPES](https://docsbay.net/arid-lands-challenges-and-hopes) *by* EARTH SYSTEM: HISTORY AND NATURAL VARIABILITY – Vol. III - *Arid Lands: Challenges and Hopes - Barakat H.N.*

> Hyperarid zones cover 7.5% of Earth's land surface, arid zones cover
> 12.1%, while semiarid zones are more extensive, occur in all continents, and cover 17.7% of Earth's land surface. The dry subhumid
> category covers 9.9% of Earth's land surface.


---

