Hiding Rising Seas in Sunken Deserts

Dead Sea shoreline, 428 metres below sea level.

Dead Sea shoreline, 429 metres below sea level.

This weekend, a friend asked me if the rise in the oceans could be drained off into the world’s below-sea-level depressions. Could rising ocean waters be diverted to fill the Dead Sea and Death Valley Depressions, for example? It seems a creative solution. Instead of flooding the Maldives, Piazza San Marco, and south Florida, the expected ocean level rise could fill some of the Earth’s less inhabited wastelands instead.

At this moment, I don’t want to debate the idea of climate change and its impact on sea level. I think the evidence is substantial that Arctic ice and mountain glaciers are disappearing and the melt water is reaching the sea. But this may ultimately be a thousand-year-long melting blip before the return of another ice age. I don’t know. What I’d rather do today is simply try to put some numbers on the innocent question: Would it be practical to relieve coastal flooding by filling land-locked places that are below sea level?

Solving this question is relatively trivial and the answer may surprise you. Using Global Mapper, I loaded a digital elevation overlay, then contoured the outlines of many of the planet’s below-sea-level depressions. There are 49 countries containing land with elevations that are below sea level so there are a number of places to hide future flood waters. Some depressions are small and deep (including Turfan, China and Akdzhakaya, Turkmenistan) while others are broad and shallow. I measured these and the areas of subsea regions such as the Dead Sea and Afar depressions, the gigantic Qattar low elevation desert, Death Valley, Salton Trough, and others. Then I estimated the volume of water these basins could hold.

Areal extent of sub-sea-level Salton Depression, California.

Areal extent of sub-sea-level Salton Depression, California.

The Dead Sea coastline, as you undoubtedly know, is the lowest dry land on the planet – it is about 429 metres below sea level. The “sea” is within a 5,000 square kilometre depression, much of which is shallower than 300 metres. Nevertheless, the Dead Sea Depression, flooded with sea water, could hold 1,500 cubic kilometres of water. Filling the sink, however, would eliminate some rather nice olive groves and would submerge important historical sites – including Jericho, a town of 20,000 and perhaps the oldest community on Earth.

North Africa's Qattar Depression - a vast desert below sea level.

North Africa’s Qattar Depression – a vast desert below sea level.

Other desert depressions are less populated, so (other than some camel operators) who really cares if they get wet? In particular, there’s the vast north Africa Qattar Depression which covers about 25,000 square kilometres. If we include other low Saharan regions in Tunisia, Libya, and Algeria, we may find as much as 50,000 square kilometres of sand sit below sea level. One may argue that this territory is less attractive than the Dead Sea or Death Valley which we have also slated for drowning, but the enormous Sahara tracts are not deep. Much is barely a single meter below sea level. So, despite being vast in area, the volume of water potentially held is less than a fully inundated Dead Sea.

Continuing around the world, we may be able to siphon 7,500 cubic kilometres of water from the ocean, pumping the sea’s brine into the planet’s various depressions. That is a huge quantity of sea water and should take the pressure off the folks in Miami. But, unfortunately, it turns out to be a trivial drop in the proverbial bucket.

The Earth is a big place. The oceans cover 360 million square kilometres. A meter of sea level rise is a volume 50 times greater than all of the depressions that are below sea level  in the world. Climate scientists tell us that the ocean’s waters are presently rising at a rate of about 3 millimetres a year, or 3 centimetres a decade. In just ten years, all of those hypothetical sinks would be full and the waters will still be rising. Because the actual rate of melting is increasing through an amplifying feedback loop, we are told to expect about a meter of sea level increase in the next hundred years or so. It will likely take several centuries for all the world’s ice to melt. By then, the oceans will be 75 metres deeper than they are today.

The bottom line? Flooding Jericho will not save Miami’s Fontainebleau. Nor, if seas rise unabated, will we save Venice, New York, nor the homes of three billion of the planet’s seaside dwellers. Rather than attempting to hide the meltwater, it appears that we need to think of another plan to do something about the impending flood.

About Ron Miksha

Ron Miksha is a geophysicist who also does a bit of science writing and blogging. Ron has worked as a radio broadcaster, a beekeeper, and is based in Calgary, Alberta, Canada. He has written two books, dozens of magazine and journal articles, and complements his first book, Bad Beekeeping, with a popular blog at www.badbeekeeping.com. Ron wrote his most recent book, The Mountain Mystery, for everyone who has looked at a mountain and wondered what miracles of nature set it upon the landscape. For more about Ron, including some cool pictures taken when he was a teenager, please check Ron's site: miksha.com.
This entry was posted in Climate, Engineering, Environment, Oceans and tagged , , , . Bookmark the permalink.

16 Responses to Hiding Rising Seas in Sunken Deserts

  1. Pingback: Hiding Rising Seas in Sunken Deserts | Not So Solid Earth

  2. Reblogged this on Primate's Progress and commented:

    Would the depressions below sea level in 49 countries provide a way to accommodate rising sea levels? No.

    Human folly is the root source of our greatest problems (actually, that’s as true and useless as saying that oxygen is the root source of forest fires). Creationism, on which I’ve written so much, is one manifestation; global warming denial another, and much more serious in its probable effects.

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    • Miksha says:

      Thanks for your comment, Paul. The question itself was interesting to me because it showed how people often think about the Earth: Maybe we could just hide our problems in some sink hole somewhere. Alas, that seems to be a common attitude.

      Like

  3. Jorge Lahiff says:

    Filling desert basins with ocean water with the goal of lowering rising ocean levels and reversing global warming may work because the presence of these inland seas would help lower temperatures in some of the hottest places on earth. If lake Eyre in Australia were filled with ocean water from the Coral Sea, hydro electric power could be produced from the water’s journey into the lake and out to the South Sea, and Australia would have an inland sea larger than Germany. The Gobi desert and western China have about five huge depressions which could be filled with ocean water and connected to each other by canals streaching from China’s east coast to the Aral and Caspian Seas. The pressence of these seas would eliminate dust storms and lessen the severity of droughts in central Asia and in Northern China. Filling Africa’s Chad depression with water from the Atlantic would dramatically lower local temperatues, increase rainfall, and provide a huge fishery for local people. -These thoughts of mine are all dreams of coarse. But, some dreams become reality. If global warming is real, -if oceans are steadilly rising, we must attempt to reverse the proccess. To stand by and allow Holland, Bangladesh, London, Beijing, New York, Singapore, Lagos, and Rio to be flooded without attempting to do what I have proposed seems unwise. Filling the world’s desert basins with water may buy us the time we need to transition from coal and petrolium to cleaner and more sustainable energy sources (thorium reactors, algeatech, energy towers, tidal power, ect..).

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    • Miksha says:

      Thanks, Jorge – you have certainly given this idea a lot of thought! Thanks for the interesting points. My story, of course, was written in answer to a friend’s question and was not intended as a serious suggestion to slow the rising sea level. But your idea of flooding deserts to alter warming is intriguing.

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  4. Gavin says:

    For me the Aral sea is a great example, surely pumping sea water into that cannot do any damage, there is currently no water and once there is water then the fish arrive and that creates jobs and so on. They can divert all the fresh water they want but the sea itself would be fine if it only had salt water. I bet if you asked any Aral resident they would be happy to have any water!!

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    • Miksha says:

      I’m not a fan of geo-reconstruction, but you have a point. People wrecked the Aral and pumping in water would certainly reduce the nasty dust storms and lost fishing. I agree that the folks living nearby would probably prefer ocean water to no water in their own sea.

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  5. Drew says:

    another thing to consider is water diverted to deserts will drain back into the earth and evaporation will also cause levels to disapear over time, so maybe you could drain part of the ocean on regular basis

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    • Ron Miksha says:

      Thanks! Interesting comment. If the water actually drained into the Earth (refreshing aquifers) then some of the water would be taken out of circulation. However, the article tells us that filling the deserts and lowlands with water won’t take care of much of the problem: “A meter of sea level rise is a volume 50 times greater than all of the depressions that are below sea level in the world.” So even with regular draining into the subsurface (which won’t necessarily occur) only a tiny portion of sealevel rise is alleviated.

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  6. Los Vasquez says:

    There is really enough land ice to raise the ocean level 75 meters? That seems like a lot. We know that sea ice melt has no impact on water level. As for pumping, we can just dig trenches to the ocean from these locations. Then we could also harness the power of the tides coming in and out of these bodies.

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    • Ron Miksha says:

      Hello,
      According to earth scientists (and anyone with a calculator and a head for math), a rise of 70-80 metres of sealevel will result when all land ice has melted. Harnessing tidal power is still a promising source of energy, but it’s hardly necessary to wait until the oceans rise and trenches are dug to low-lying areas. Economics are largely in place today to make this energy viable.
      Ron

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  7. Anonymous says:

    You speak of flooding north Africa desert with extra water from melting ice. This desert doesn’t belong to your country and you don’t have the right to speak about it at all. you cause the climate change and you think you can decide to solve it like this. What will our people eat? You should know that our desert is being worked and can be used to produce more food to export towards land flooded countries. Why don’t you think to mobilize your country’s people to force your president to decide to reduce the co2 pollution.Think twice before deciding anything.

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    • Ron Miksha says:

      Thank you for your comment. I’m sorry that this blog post was offensive to you. You are completely right, no one has the right to flood another man’s country. I was not threatening Algeria, where you live. Perhaps you noticed that I start by mentioning the Dead Sea, Death Valley, and the Salton Sea? The latter two are in America (but I don’t live in the USA). My blog post responded to a question from a friend. He asked, “Why can’t we just flood the low areas on Earth to get rid of sealevel rise?” I explain, mathematically and geographically, why this is a bad idea. But no one is serious about it – it is a joke.

      I did not mention the geopolitical issues because the whole idea is nonsense. I ended the blog by writing “Rather than attempting to hide the meltwater, it appears that we need to think of another plan to do something about the impending flood.” I thought that made the story clear and the idea untenable.

      By the way, I do not have a president – my country has a prime minister and my country has enacted a carbon reduction program. Has yours?

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  8. Simon says:

    To ad to the benefits those big lakes wil cool down the earth a little by evaporation, it wil also reduce the salt level in the oceans if this continues for a long time in the past were there also salt lakes on the planet, it will increase rainfall, a thriving fish industry, salt mining, if the temperature drops a little and the humidety rises it will benefit the inviormend all around rainfall will increase, but also snowfall, trees have a beter chance to grow and will help cooling down the earth a little more, birds will come to the areas, crops wil be easier to grow, the economy will benefit, and the struggle to survive will decrease, if this will be done the poor will benefit, but are there people, ore country’s, willing to help those in need, i don’t think so all look to there own acaunt, and not to the children of the future, and maybe it is a litle drop butt every drop helps
    Simon

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    • Wizzy says:

      I agree there could be some benefits, but you underestimate the floodings’ drawbacks in fighting global waming: The most potent greenhouse gas is water vapor – much more so than CO2, water vapor feedback renders CO2 important in the first place -, so adding evaporation will add radiative heat. The desert has a high albedo, reflecting solar radiation, as opposed to water surfaces which feature an extremely low albedo, effectively absorbing solar heat. So just like the local climate would become less extreme, global temperature rise might most probably amplify by desert flooding measures.

      Liked by 1 person

      • Ron Miksha says:

        Thanks for your comments, but please realize that I am not endorsing this idea. Instead, I am showing how it’s a poor and unrealistic solution to global sea rise. I appreciate your remarks about the desert v water albedo effects as they offer further evidence of the failing of such a system. Of course this doesn’t change the answer to the original question: “Could rising sea water be sequestered in below-sealevel depressions?” The answer remains that the amount of water theoretically captured in such new basins would have an insignificant impact on the metres of ocean rise that’s likely coming.

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