<p><strong>No, this is not practicable.</strong></p>
<p>Imagine making another Lake Superior, the 3rd most voluminous lake on Earth, which <a href="https://en.wikipedia.org/wiki/Lake_Superior" rel="nofollow noreferrer">according to Wikipedia</a> holds 10% of the world's fresh surface water (excluding the ice in Antarctica). It has a volume of 12,100 km<sup>3</sup>, and would cover about one-fifth of California (at the same depth of about 150 m).</p>
<p>The ocean has an area of 361 million km<sup>2</sup>, so removing another Lake Superior's worth of water would reduce its depth <span class="math-container">$d$</span> by:</p>
<p><span class="math-container">$$\Delta d = \frac{12.1\times 10^3}{361 \times 10^6} = 33.5\times 10^{-6}\ \mathrm{km, or}\ 33.5\ \mathrm{mm} $$</span></p>
<p>... a bit over one inch. According to <a href="https://sealevelrise.org/states/california/" rel="nofollow noreferrer">sealevelrise.org</a>, this is about 10 years' worth of rise.</p>
<p>If you had 639 5400-horsepower Pentair Fairbanks Nijhuis pumps (the <a href="https://actionelectricmotorandpump.com/2019/01/fun-fact-whats-the-largest-pump-in-the-world/" rel="nofollow noreferrer">most powerful pump</a> in the world, built for keeping the Netherlands dry), you could pump at 38 million litres per second and keep up with sea-level change (not accounting for evaporation or rainfall). At 4000 kW per pump, I think this would require the combined output from the six or seven largest solar farms in California, or a bit more than the output of the <a href="https://en.wikipedia.org/wiki/Diablo_Canyon_Power_Plant" rel="nofollow noreferrer">Diablo Canyon nuclear power plant</a>.</p>
<p>Unfortunately, there are a lot of other factors controlling local sea-level; <a href="https://earthscience.stackexchange.com/a/5455/70">see this other answer for example</a>. Not to mention the issue of figuring out where this saline lake will go...</p>

CC BY-SA 4.0
2021-12-07T21:04:44.330Z
I've been trying to find how much water the Great Basin would hold. [During the Pleistocene era (3 million to 10,000 years ago), water was abundant as glaciers advanced and retreated in a climate that was an average 8°F cooler than today. Lakes filled many of the basins to a depth of up to 1,000 feet.](https://www.nps.gov/grba/learn/nature/groundwater.htm)
Keith McClary
CC BY-SA 4.0
2022-08-15T19:20:14.293Z
Please change your headline to **YES**. You've just calculated that it is possible! Just require a shift in utilization of resources, away from the military complex, livingry not weaponry!
Mars Robertson
CC BY-SA 4.0
2021-12-07T20:16:07.147Z
2022-08-18T17:39:52.597Z
2022-08-18T17:39:52.597Z
Matt Hall
<p>Taking water out of the sea does require energy to lift it even if it's destination will eventually be below sea level. The dam idea of retaining rain water would require energy and resources for the production of the dam and require the loss of usable land. That is not the best dam way to approach this solution.</p>
<p>Removing water up stream, from say the Mississippi or Rio Grande, could be diverted to a lower elevation area via a pipeline or canal system. This too would require energy and resources to build, but the fresh water could at least be sent to areas that are currently unusable arid areas. This would result in a greening effect without the risk of contaminating water tables below. Another benifit would be the ability to increase the amount available farm land without the need of taking water from an already depleted ground water source. Also replenishment of water tables would occur, and your end goal of reducing the amount of water entering the ocean would be accomplished.</p>

CC BY-SA 4.0
2021-05-07T16:08:06.737Z
Josh. Mankind has been damming rivers and moving water around since the dawn of civilization. But it's in no way a panacea. To meaningfully move water around requires massive infrastructure, massive amounts of energy and a willingness to disrupt the ecology and economy of the areas downstream of your diversion. Rivers like the Rio Grande are already overexploited.
Andy M
CC BY-SA 4.0
2021-05-07T13:09:49.487Z
2021-05-07T13:09:49.487Z
Josh
<p>Yes, it could reduce sea level rise, but it would be no good for irrigation. Many deserts, like the Aral Sea and Death Valley, are below sea level. This means you would not need to use energy to pump the water, but could use the siphon principle. Some people say that even if you filled all these low-lying deserts with sea water, it would not do much to lower sea level. However, it would have many other beneficial effects, especially in the Aral Sea. It would greatly improve marine transport, create new fisheries, prevent the present salt desert being blown onto agricultural land, and quite likely change the climate so there would be more precipitation.</p>

<p>Another way to reduce sea level, though it would be only by a tiny amount, would be to build more dams. Deprived of the held-back rain water, the sea level would reduce a little if enough rainwater was prevented from reaching the sea. The dams would produce carbon neutral power, create fisheries and be used for irrigation. On the other hand, if the proposed dams on the Nile are anything to go by, they also have the potential to start wars unless they are sited with great care and good international diplomacy and cooperation.</p>

CC BY-SA 4.0
2020-01-09T18:40:51.147Z
Black Sea to Caspian is not all that far.. Caspian to Aral is also not very far. A small amount of pumping would be needed to start it off, but not very much. The benefits would be huge.
Michael Walsby
CC BY-SA 4.0
2020-01-09T18:52:41.763Z
The Caspian is below well below sea level. It tickles me to see that you are desperately down-marking me every chance you get, yet my reputation keeps going up! Sorry about that - you should complain to the watchers.
Michael Walsby
CC BY-SA 4.0
2023-07-29T18:00:16.060Z
I upvoted this answer because it is useful considering the question of climate change.
Riad
CC BY-SA 4.0
2020-01-09T18:21:23.673Z
2020-01-09T18:21:23.673Z
Michael Walsby
<p>It is my genuine opinion that <strong>YES</strong></p>
<h3>How much exactly?</h3>
<p>See the example: <a href="https://en.wikipedia.org/wiki/Qattara_Depression_Project" rel="nofollow noreferrer">https://en.wikipedia.org/wiki/Qattara_Depression_Project</a></p>
<blockquote>
<p>The Qattara depression is a region that lies 60 m below sea level on average and is currently a vast, uninhabited desert. By connecting the region and the Mediterranean Sea with tunnels and/or canals, water could be let into the area. The inflowing water would then evaporate quickly because of the desert climate. This way a continuous flow of water could be created if inflow and evaporation were balanced out. With this continuously flowing water, hydroelectricity could be generated.</p>
</blockquote>
<p>According to <a href="https://gis.stackexchange.com/a/267199">this answer</a>: <code>3mm</code></p>
<p><em>(current annual sea rise is around <code>3-4mm</code> per year)</em></p>
<p><a href="https://i.sstatic.net/P7I15.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/P7I15.png" alt="enter image description here" /></a></p>
<p>According to my math: <code>3mm</code></p>
<pre><code>Volume of Ocean 1,350,000,000   cubic kilometer
Volume of Qattara   1213    cubic kilometers
        
The ratio   0.0000008985185185  
Average depth of Ocean  3700    meters

0.0000008985185185 * 3700m = 0.003324518519m
        
0.3324518519cm
3.324518519mm

Evaporation, changing water table, changing weather patterns not included .
Too many 2nd and 3rd order effects to reliably predict.

Calculation above: pure math based on the volume.
</code></pre>
<h3>Scientific papers about Quattara Depression Project</h3>
<ul>
<li>Linked from the Wikipedia notes - <a href="https://link.springer.com/chapter/10.1007/978-3-642-14779-1_23" rel="nofollow noreferrer">Mapping of the Qattara Depression, Egypt, using SRTM Elevation Data for Possible Hydropower and Climate Change Macro-Projects</a></li>
</ul>
<blockquote>
<p>The transformation of Qattara Depression into isolated anthropogenic inland sea could provide some ocean level adjustment, as well as generate energy, induce rainfall over some of the adjacent desert, reduce hottest desert daytime and nighttime air temperatures, and permit new local-use fisheries (aquaculture) as well as international tourism resorts.</p>
</blockquote>
<p><a href="https://i.sstatic.net/L5x8d.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/L5x8d.png" alt="enter image description here" /></a></p>
<ul>
<li><a href="https://energycentral.com/c/ec/qattara-depression-project-time-revisit" rel="nofollow noreferrer">https://energycentral.com/c/ec/qattara-depression-project-time-revisit</a> - very detailed proposal, including building it in stages, as the water flows into the depression it generates hydropower</li>
</ul>
<blockquote>
<p>Despite nearly a century of studies and proposals, and despite high interest on the part of Egyptian authorities, all plans for development of the depression have come to naught. In the end, they foundered on the analysis of costs vs. benefits and risks. A lot has changed, though, in the four decades since the last feasibility study was commissioned — and ultimately rejected — by the Egyptian government of Anwar Sadat. Perhaps it’s time to revisit?</p>
</blockquote>
<h3>Technical feasibility and roadmap</h3>
<p>This can be achieved with the technology that is available Today:</p>
<ul>
<li>developed in stages</li>
<li>generating hydropower in the process</li>
<li>pumping water uphill when excess energy</li>
</ul>
<p>TBD. TBC. This answer can be improved. Old papers didn't account for Elon Musk and Boring Company though when calculating the cost.</p>
<h3>Financing</h3>
<p>ROI of reducing sea levels might be better than relocating cities that go underwater, however it will require some transnational agreements <em>(country A has a sinking city, country B has a depression, financing coming from X)</em>.</p>
<h3>Availability of labour</h3>
<p>There is another large space project - <a href="https://www.youtube.com/watch?v=ibfEiWDAq28&amp;t=1236s" rel="nofollow noreferrer">The Grand Africa Green Up</a> - they mentioned availability of labour. Useful to know.</p>
<p><a href="https://i.sstatic.net/34EPD.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/34EPD.png" alt="enter image description here" /></a></p>
<h3>Ethical aspect of geoengineering</h3>
<p>We are already doing geoengineering with greenhouse gases in the atmosphere ‍♀️ to use some desert and create energy, create jobs, and reduce sea levels - benefits far outweigh any potential concerns.</p>
<h3>Note about glaciers and $$$</h3>
<p><a href="https://www.nature.com/articles/d41586-018-03036-4" rel="nofollow noreferrer">Geoengineer polar glaciers to slow sea-level rise</a></p>
<blockquote>
<p>If nothing is done, 0.5–5% of the world’s population will be flooded each year after 2100. For example, a 0.5-metre rise in Guangzhou, China, would displace more than 1 million people; a 2-metre rise would affect more than 2 million1. Without coastal protection, the global cost of damages could reach US$50 trillion a year. Sea walls and flood defences cost tens of billions of dollars a year to construct and maintain.</p>
</blockquote>
<h3>Related projects</h3>
<p>Not affiliated in any way, just being aware of their existence, in the theme of using desert (not just flooding):</p>
<ul>
<li><a href="http://carbon.ycombinator.com/desert-flooding/" rel="nofollow noreferrer">http://carbon.ycombinator.com/desert-flooding/</a> - it focuses on farming algae for CO2</li>
<li>company that does exactly that: <a href="https://www.brilliantplanet.com/" rel="nofollow noreferrer">https://www.brilliantplanet.com/</a></li>
<li><a href="https://en.wikipedia.org/wiki/Desertec" rel="nofollow noreferrer">https://en.wikipedia.org/wiki/Desertec</a></li>
<li><a href="https://en.wikipedia.org/wiki/Medgrid" rel="nofollow noreferrer">https://en.wikipedia.org/wiki/Medgrid</a></li>
<li><a href="https://xlinks.co/" rel="nofollow noreferrer">https://xlinks.co/</a> - solar farm on Sahara, cable to the UK</li>
<li><a href="https://suncable.energy/" rel="nofollow noreferrer">https://suncable.energy/</a> - solar farm in Australia, cable to Singapore</li>
</ul>
<hr />
<p><strong>EDIT / UPDATE:</strong> I've updated this answer a few times to reflect the feedback in the comments - thank you  If you can, if you feel like it - please reverse the downvotes so that this answer receives some attention and bubbles on top - math adds up and people are already actively working on it.</p>

CC BY-SA 4.0
2022-08-16T09:12:18.817Z
How much would this reduce sea level?  Or do you mean indirectly, by helping with low-carbon energy sources (which I don't think is what the question is after)?
gerrit
CC BY-SA 4.0
2022-08-17T10:31:07.750Z
Despite providing a detailed calculation on how much *(`3mm`, roughly the annual sea rise)* and even linking to another answer that comes to the same result this post is currently `-2`... Thank you for the comments so far, I was able to improve the answer.
Mars Robertson
CC BY-SA 4.0
2022-08-18T05:59:31.110Z
[Wikipedia](https://en.wikipedia.org/wiki/Sea_level_rise) suggests a 10.1 cm sea level rise since 1992 and "2–3 metres (6.6–9.8 ft) if global warming is limited to 1.5 °C", so if your math is right, it's a fairly insignificant drop in the bucket?  So your headline and excitement seem a bit out of place?
JeopardyTempest
CC BY-SA 4.0
2022-08-18T09:53:21.427Z
Matter of optics and presenting data. Option 1: `10.1 cm since 1992` Option 2: `3mm per year`. In this particular example - only 1 project in 1 area - not even pumping but letting it flow downhill to generate hydropower in the process. Then we can continue with the project and **FLOOD the DESERT** just like YC Combinator suggested in the *"Request for Startups - Desert Flooding"*
Mars Robertson
CC BY-SA 4.0
2022-08-18T21:12:24.740Z
Evaporation is a significant factor for any open-water body in a climate like the arid interior of California: "The open water
surface evaporation rate at the Salton Sea is estimated at approximately 69 inches per year and the
average annual crop reference evapotranspiration rate at Brawley is reported to be approximately
71 inches per year (California Irrigation Management Information System [CIMIS] 2012)." That is, water moved out of the ocean to an inland reservoir will evaporate, fall as rain somewhere else, and then make its way back to the ocean.
jeffronicus
CC BY-SA 4.0
2022-08-19T15:36:48.720Z
Yet the project costs money to build (and the unviable cost to transfer power from such remote areas has been looked at in other posts I believe).  Are there a very large number locations of similar feasibility?  Then the potentiality could be more closely scrutinized.  As is I can't see it being meaningful help based upon your numbers.
JeopardyTempest
CC BY-SA 4.0
2022-08-19T17:18:33.877Z
@JeopardyTempest "cost money" - https://en.wikipedia.org/wiki/Public_works - I would have thought we have a recession and there will be massive infrastructure projects to provide employment? But that's just me, I'm aware of what is going with the climate and I'm aware how others are unaware. That's fine.
Mars Robertson
CC BY-SA 4.0
2022-08-15T19:27:34.780Z
2022-11-06T18:16:14.667Z
2022-11-06T18:16:14.667Z
Mars Robertson
<p>I have been reading the discussion about pumping sea water into the desert for purposes of irrigation and changing the dry climate of that area, but what about to just purely offset the rising sea levels? Could pumping ocean water (with solar power) north of Malibu California into the dry areas help with coastline erosion and put water into the desert as a secondary but not primary benefit?
I am a completely non-scientific person who just happens to have an interest in coastal erosion so I welcome all your educated thoughts on this. Ideally it would be done in all the deserts globally to have a coordinated effort. Think of the infrastructure jobs in places like Africa. It would require a “world bank” initiative to create the funds to do this but as a global coordinated effort it may be required as part of planet rehabilitation. Yes I said “create” the funds, ie “print money” which would have a slightly inflationary effect on world economies but would mostly “inflate” depressed economies through wealth redistribution since these economies would likely be the major supply of labor. Like we see in Canada when the people from poor fishing towns went to work on the pipelines and brought cash back home. </p>

CC BY-SA 4.0
2020-01-09T17:39:10.087Z
There's a related question about pumping water into the desert here: https://earthscience.stackexchange.com/questions/7553/what-would-be-the-effect-of-bringing-seawater-pipes-to-the-sahara-desert
jeffronicus
CC BY-SA 4.0
2020-01-09T23:13:32.127Z
[Farmer John](https://gis.stackexchange.com/a/267199) calculates that the Qattara depression in Egypt would hold 3mm of sea level.
Keith McClary
CC BY-SA 4.0
2020-01-09T23:23:14.350Z
["Can Huge Man-Made Lakes Fix Our Rising Sea Levels?"](https://gawker.com/5977734/can-huge-man-made-lakes-fix-our-rising-sea-levels) says 3cm of sea level for all land which is below sea level and dry.
Keith McClary
CC BY-SA 4.0
2021-05-10T02:28:33.457Z
Water is heavy so the result is less change in sea level relative to land than you might expect.Some of it will flow back to oceans.The flow causes erosion which is contrary to what you want.Adding to the water table makes the sea level will rise.Because we have coercive governments wealth can be redistributed without possibly wasteful infrastructure building.Thus infrastructure should be considered separately from the need to redistribute.If the infrastructure is a net beneficial public good then it is a good idea.An impermeable barrier around a desert is costly.Will cost exceed benefit?
H2ONaCl
CC BY-SA 4.0
2021-07-08T19:42:47.693Z
Most of the water that do not flow to the oceans directly will evaporate and go to the oceans as rain. Some water may go in earth cavities (underground water). The existing underground water may become more salty.
Valentin Stoykov
CC BY-SA 4.0
2021-12-07T23:25:14.327Z
Evaporation rates in hot desert regions can be above 3m of water per year; I expect just keeping up with evaporation would keep a LOT of pumps busy. Much better to double down on emissions reductions to slow and stabilise sea level rise than attempt to deal with the consequences after.
Ken Fabian
CC BY-SA 4.0
2022-09-19T11:24:10.903Z
Scientists think that injecting aerosolos into the polar reagions would cost 11billion to reduce the temp by 2 degrees every year, that's about 2 dollarts per human.
bandybabboon
CC BY-SA 4.0
2023-01-14T16:40:15.723Z
Mitt Romney is *at least investigating the possibility* of refilling the Great Salt Lake with ocean water
InquilineKea
<climate-change><water><sea-level><geoengineering>
Could pumping ocean water into desert areas help reduce sea level rise?
Cheryl Bozynski
# Could pumping ocean water into desert areas help reduce sea level rise?

(Asked by: username_0 on 2020-01-09)

I have been reading the discussion about pumping sea water into the desert for purposes of irrigation and changing the dry climate of that area, but what about to just purely offset the rising sea levels? Could pumping ocean water (with solar power) north of Malibu California into the dry areas help with coastline erosion and put water into the desert as a secondary but not primary benefit?
I am a completely non-scientific person who just happens to have an interest in coastal erosion so I welcome all your educated thoughts on this. Ideally it would be done in all the deserts globally to have a coordinated effort. Think of the infrastructure jobs in places like Africa. It would require a “world bank” initiative to create the funds to do this but as a global coordinated effort it may be required as part of planet rehabilitation. Yes I said “create” the funds, ie “print money” which would have a slightly inflationary effect on world economies but would mostly “inflate” depressed economies through wealth redistribution since these economies would likely be the major supply of labor. Like we see in Canada when the people from poor fishing towns went to work on the pipelines and brought cash back home.

**Tags:** climate-change, water, sea-level, geoengineering

> **Comments:**
> **username_1**: There's a related question about pumping water into the desert here: https://earthscience.stackexchange.com/questions/7553/what-would-be-the-effect-of-bringing-seawater-pipes-to-the-sahara-desert  
> **username_2**: [Farmer John](https://gis.stackexchange.com/a/267199) calculates that the Qattara depression in Egypt would hold 3mm of sea level.  
> **username_2**: ["Can Huge Man-Made Lakes Fix Our Rising Sea Levels?"](https://gawker.com/5977734/can-huge-man-made-lakes-fix-our-rising-sea-levels) says 3cm of sea level for all land which is below sea level and dry.  
> **username_3**: Water is heavy so the result is less change in sea level relative to land than you might expect.Some of it will flow back to oceans.The flow causes erosion which is contrary to what you want.Adding to the water table makes the sea level will rise.Because we have coercive governments wealth can be redistributed without possibly wasteful infrastructure building.Thus infrastructure should be considered separately from the need to redistribute.If the infrastructure is a net beneficial public good then it is a good idea.An impermeable barrier around a desert is costly.Will cost exceed benefit?  
> **username_4**: Most of the water that do not flow to the oceans directly will evaporate and go to the oceans as rain. Some water may go in earth cavities (underground water). The existing underground water may become more salty.  
> **username_5**: Evaporation rates in hot desert regions can be above 3m of water per year; I expect just keeping up with evaporation would keep a LOT of pumps busy. Much better to double down on emissions reductions to slow and stabilise sea level rise than attempt to deal with the consequences after.  
> **username_6**: Scientists think that injecting aerosolos into the polar reagions would cost 11billion to reduce the temp by 2 degrees every year, that's about 2 dollarts per human.  
> **username_7**: Mitt Romney is *at least investigating the possibility* of refilling the Great Salt Lake with ocean water  

---

## 4 answers

### Answer by username_8 on 2021-12-07. Score: 2

**No, this is not practicable.**

Imagine making another Lake Superior, the 3rd most voluminous lake on Earth, which [according to Wikipedia](https://en.wikipedia.org/wiki/Lake_Superior) holds 10% of the world's fresh surface water (excluding the ice in Antarctica). It has a volume of 12,100 km3, and would cover about one-fifth of California (at the same depth of about 150 m).

The ocean has an area of 361 million km2, so removing another Lake Superior's worth of water would reduce its depth $d$ by:

$$\Delta d = \frac{12.1\times 10^3}{361 \times 10^6} = 33.5\times 10^{-6}\ \mathrm{km, or}\ 33.5\ \mathrm{mm} $$

... a bit over one inch. According to [sealevelrise.org](https://sealevelrise.org/states/california/), this is about 10 years' worth of rise.

If you had 639 5400-horsepower Pentair Fairbanks Nijhuis pumps (the [most powerful pump](https://actionelectricmotorandpump.com/2019/01/fun-fact-whats-the-largest-pump-in-the-world/) in the world, built for keeping the Netherlands dry), you could pump at 38 million litres per second and keep up with sea-level change (not accounting for evaporation or rainfall). At 4000 kW per pump, I think this would require the combined output from the six or seven largest solar farms in California, or a bit more than the output of the [Diablo Canyon nuclear power plant](https://en.wikipedia.org/wiki/Diablo_Canyon_Power_Plant).

Unfortunately, there are a lot of other factors controlling local sea-level; [see this other answer for example](https://earthscience.stackexchange.com/a/5455/70). Not to mention the issue of figuring out where this saline lake will go...

> **Comments:**
> **username_2**: I've been trying to find how much water the Great Basin would hold. [During the Pleistocene era (3 million to 10,000 years ago), water was abundant as glaciers advanced and retreated in a climate that was an average 8°F cooler than today. Lakes filled many of the basins to a depth of up to 1,000 feet.](https://www.nps.gov/grba/learn/nature/groundwater.htm)  
> **username_9**: Please change your headline to **YES**. You've just calculated that it is possible! Just require a shift in utilization of resources, away from the military complex, livingry not weaponry!  

---

### Answer by username_10 on 2021-05-07. Score: 0

Taking water out of the sea does require energy to lift it even if it's destination will eventually be below sea level. The dam idea of retaining rain water would require energy and resources for the production of the dam and require the loss of usable land. That is not the best dam way to approach this solution.

Removing water up stream, from say the Mississippi or Rio Grande, could be diverted to a lower elevation area via a pipeline or canal system. This too would require energy and resources to build, but the fresh water could at least be sent to areas that are currently unusable arid areas. This would result in a greening effect without the risk of contaminating water tables below. Another benifit would be the ability to increase the amount available farm land without the need of taking water from an already depleted ground water source. Also replenishment of water tables would occur, and your end goal of reducing the amount of water entering the ocean would be accomplished.

> **Comments:**
> **username_11**: username_10. Mankind has been damming rivers and moving water around since the dawn of civilization. But it's in no way a panacea. To meaningfully move water around requires massive infrastructure, massive amounts of energy and a willingness to disrupt the ecology and economy of the areas downstream of your diversion. Rivers like the Rio Grande are already overexploited.  

---

### Answer by username_12 on 2020-01-09. Score: -4

Yes, it could reduce sea level rise, but it would be no good for irrigation. Many deserts, like the Aral Sea and Death Valley, are below sea level. This means you would not need to use energy to pump the water, but could use the siphon principle. Some people say that even if you filled all these low-lying deserts with sea water, it would not do much to lower sea level. However, it would have many other beneficial effects, especially in the Aral Sea. It would greatly improve marine transport, create new fisheries, prevent the present salt desert being blown onto agricultural land, and quite likely change the climate so there would be more precipitation.

Another way to reduce sea level, though it would be only by a tiny amount, would be to build more dams. Deprived of the held-back rain water, the sea level would reduce a little if enough rainwater was prevented from reaching the sea. The dams would produce carbon neutral power, create fisheries and be used for irrigation. On the other hand, if the proposed dams on the Nile are anything to go by, they also have the potential to start wars unless they are sited with great care and good international diplomacy and cooperation.

> **Comments:**
> **username_12**: Black Sea to Caspian is not all that far.. Caspian to Aral is also not very far. A small amount of pumping would be needed to start it off, but not very much. The benefits would be huge.  
> **username_12**: The Caspian is below well below sea level. It tickles me to see that you are desperately down-marking me every chance you get, yet my reputation keeps going up! Sorry about that - you should complain to the watchers.  
> **username_13**: I upvoted this answer because it is useful considering the question of climate change.  

---

### Answer by username_9 on 2022-08-15. Score: -6

It is my genuine opinion that **YES**

### How much exactly?

See the example: <https://en.wikipedia.org/wiki/Qattara_Depression_Project>

> The Qattara depression is a region that lies 60 m below sea level on average and is currently a vast, uninhabited desert. By connecting the region and the Mediterranean Sea with tunnels and/or canals, water could be let into the area. The inflowing water would then evaporate quickly because of the desert climate. This way a continuous flow of water could be created if inflow and evaporation were balanced out. With this continuously flowing water, hydroelectricity could be generated.

According to [this answer](https://gis.stackexchange.com/a/267199): `3mm`

*(current annual sea rise is around `3-4mm` per year)*

[![enter image description here](https://i.sstatic.net/P7I15.png)](https://i.sstatic.net/P7I15.png)

According to my math: `3mm`

```
Volume of Ocean 1,350,000,000   cubic kilometer
Volume of Qattara   1213    cubic kilometers
        
The ratio   0.0000008985185185  
Average depth of Ocean  3700    meters

0.0000008985185185 * 3700m = 0.003324518519m
        
0.3324518519cm
3.324518519mm

Evaporation, changing water table, changing weather patterns not included .
Too many 2nd and 3rd order effects to reliably predict.

Calculation above: pure math based on the volume.

```

### Scientific papers about Quattara Depression Project

* Linked from the Wikipedia notes - [Mapping of the Qattara Depression, Egypt, using SRTM Elevation Data for Possible Hydropower and Climate Change Macro-Projects](https://link.springer.com/chapter/10.1007/978-3-642-14779-1_23)

> The transformation of Qattara Depression into isolated anthropogenic inland sea could provide some ocean level adjustment, as well as generate energy, induce rainfall over some of the adjacent desert, reduce hottest desert daytime and nighttime air temperatures, and permit new local-use fisheries (aquaculture) as well as international tourism resorts.

[![enter image description here](https://i.sstatic.net/L5x8d.png)](https://i.sstatic.net/L5x8d.png)

* <https://energycentral.com/c/ec/qattara-depression-project-time-revisit> - very detailed proposal, including building it in stages, as the water flows into the depression it generates hydropower

> Despite nearly a century of studies and proposals, and despite high interest on the part of Egyptian authorities, all plans for development of the depression have come to naught. In the end, they foundered on the analysis of costs vs. benefits and risks. A lot has changed, though, in the four decades since the last feasibility study was commissioned — and ultimately rejected — by the Egyptian government of Anwar Sadat. Perhaps it’s time to revisit?

### Technical feasibility and roadmap

This can be achieved with the technology that is available Today:

* developed in stages
* generating hydropower in the process
* pumping water uphill when excess energy

TBD. TBC. This answer can be improved. Old papers didn't account for Elon Musk and Boring Company though when calculating the cost.

### Financing

ROI of reducing sea levels might be better than relocating cities that go underwater, however it will require some transnational agreements *(country A has a sinking city, country B has a depression, financing coming from X)*.

### Availability of labour

There is another large space project - [The Grand Africa Green Up](https://www.youtube.com/watch?v=ibfEiWDAq28&t=1236s) - they mentioned availability of labour. Useful to know.

[![enter image description here](https://i.sstatic.net/34EPD.png)](https://i.sstatic.net/34EPD.png)

### Ethical aspect of geoengineering

We are already doing geoengineering with greenhouse gases in the atmosphere ‍♀️ to use some desert and create energy, create jobs, and reduce sea levels - benefits far outweigh any potential concerns.

### Note about glaciers and $$$

[Geoengineer polar glaciers to slow sea-level rise](https://www.nature.com/articles/d41586-018-03036-4)

> If nothing is done, 0.5–5% of the world’s population will be flooded each year after 2100. For example, a 0.5-metre rise in Guangzhou, China, would displace more than 1 million people; a 2-metre rise would affect more than 2 million1. Without coastal protection, the global cost of damages could reach US$50 trillion a year. Sea walls and flood defences cost tens of billions of dollars a year to construct and maintain.

### Related projects

Not affiliated in any way, just being aware of their existence, in the theme of using desert (not just flooding):

* <http://carbon.ycombinator.com/desert-flooding/> - it focuses on farming algae for CO2
* company that does exactly that: <https://www.brilliantplanet.com/>
* <https://en.wikipedia.org/wiki/Desertec>
* <https://en.wikipedia.org/wiki/Medgrid>
* <https://xlinks.co/> - solar farm on Sahara, cable to the UK
* <https://suncable.energy/> - solar farm in Australia, cable to Singapore

---

**EDIT / UPDATE:** I've updated this answer a few times to reflect the feedback in the comments - thank you If you can, if you feel like it - please reverse the downvotes so that this answer receives some attention and bubbles on top - math adds up and people are already actively working on it.

> **Comments:**
> **username_14**: How much would this reduce sea level?  Or do you mean indirectly, by helping with low-carbon energy sources (which I don't think is what the question is after)?  
> **username_9**: Despite providing a detailed calculation on how much *(`3mm`, roughly the annual sea rise)* and even linking to another answer that comes to the same result this post is currently `-2`... Thank you for the comments so far, I was able to improve the answer.  
> **username_15**: [Wikipedia](https://en.wikipedia.org/wiki/Sea_level_rise) suggests a 10.1 cm sea level rise since 1992 and "2–3 metres (6.6–9.8 ft) if global warming is limited to 1.5 °C", so if your math is right, it's a fairly insignificant drop in the bucket?  So your headline and excitement seem a bit out of place?  
> **username_9**: Matter of optics and presenting data. Option 1: `10.1 cm since 1992` Option 2: `3mm per year`. In this particular example - only 1 project in 1 area - not even pumping but letting it flow downhill to generate hydropower in the process. Then we can continue with the project and **FLOOD the DESERT** just like YC Combinator suggested in the *"Request for Startups - Desert Flooding"*  
> **username_1**: Evaporation is a significant factor for any open-water body in a climate like the arid interior of California: "The open water surface evaporation rate at the Salton Sea is estimated at approximately 69 inches per year and the average annual crop reference evapotranspiration rate at Brawley is reported to be approximately 71 inches per year (California Irrigation Management Information System [CIMIS] 2012)." That is, water moved out of the ocean to an inland reservoir will evaporate, fall as rain somewhere else, and then make its way back to the ocean.  
> **username_15**: Yet the project costs money to build (and the unviable cost to transfer power from such remote areas has been looked at in other posts I believe).  Are there a very large number locations of similar feasibility?  Then the potentiality could be more closely scrutinized.  As is I can't see it being meaningful help based upon your numbers.  
> **username_9**: @username_15 "cost money" - https://en.wikipedia.org/wiki/Public_works - I would have thought we have a recession and there will be massive infrastructure projects to provide employment? But that's just me, I'm aware of what is going with the climate and I'm aware how others are unaware. That's fine.  

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