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I can see a new grand purpose to this plan. To protect the mediterranean coast from the RAISING sea caused by global warming. Rather than each town and country

I can see a new grand purpose to this plan. To protect the mediterranean coast from the RAISING sea caused by global warming. Rather than each town and country trying to protect itself. As we are finding out, power is getting cheaper and cheaper all the time, and North Africa is a great source of sun power. So the need to generate power is reduced. This would eliminate many of the objections to the plan.

BatFastard 9y ago
Would probably only need 1 dam at Gibraltar. I wonder if the Mediterranean has a net info or outflow of water?
- Shivetya 9y ago
  I was always under the impression that evaporation would have threatened its existence if not for the in flow from the Atlantic
  - twic 9y ago
    On average, the Mediterranean basin shows an excess of evaporation over freshwater inputs and a heat loss through air-sea interaction. It has an overall freshwater deficit, as the loss to the atmosphere by evaporation is larger than the gains by precipitation and runoff from the main rivers and input from the Black Sea. The total heat budget is negative, that is, the Mediterranean Sea loses more energy than it gains. These losses of freshwater and heat are compensated by the two-layer exchange at the Strait of Gibraltar comprising a relatively warm and fresh (15.4°C, 36.2 psu) upper water inflow and a relatively cooler and saltier (13°C, 38.4 psu) outflow to the Atlantic (Bryden et al. 1994; Tsimplis and Bryden 2000). On long timescales, the losses of freshwater and heat from the surface are compensated and the net salt flux is close to zero. https://link.springer.com/article/10.1007/s00382-011-1012-6 https://link.springer.com/article/10.1007/s00382-011-1012-6
- jcranmer 9y ago
  Net outflow, hence the Messinian Salinity Crises that happened whenever the outflow at Gibraltar was blocked.
  - BatFastard 9y ago
    After looking at the Messinian Salinity Crises it tells me that without water from the Atlantic the Mediterranean would dry up. Therefore there is a net inflow into the Mediterranean, right?
- pmontra 9y ago
  As others have pointed out the Mediterranean Sea loses water and needs an inflow to compensate. In the case of a dam at Gibraltar it should be easy to let some water in. I wonder if we are able to build such a gigantic dam even if we wanted to. We probably need another one at Suez. According to Google Maps the elevation of the channel is always less than 100 m, which is the worst case figure for sea rise if all the ice of the world melts. Water would come in from the Red Sea. Btw, not all terrains are suitable for building dams.
  - BatFastard 9y ago
    There are already locks on the Suez I believe. I would think that the Rock of Gibraltar would give the damn a decent base rock formation underneath, but you have a good point.
    - AnimalMuppet 9y ago
      No, the Suez Canal does not have locks.
    - pmontra 9y ago
      No locks. You can check at https://www.google.com/maps/@31.1497898,32.3699699,12z/data=!3m1!1e3 https://www.google.com/maps/@31.1497898,32.3699699,12z/data=... Furthermore all the area of the channel is low elevation. It will go under water when the sea level raises. Ships will just sail over it.
- detritus 9y ago
  Having spent much of my youth waking up and staring across the Straits every day, I question your use of 'only' in this thought. They may 'only' be 12 or so miles across, but the amount of concrete and fill that would be needed to dam the straits would dwarf anything even the Chinese could manage up with for another couple of hundred years, I imagine. This idea looks a lot more plausible on paper than it would in person.
djsumdog 9y ago
I really hope you're being sarcastic. Building dams are environmentally devastating. Dams created a multi-billion dollar fertilizer industry in Egypt where none existed before adding them to the Nile. They blocks sediment on rivers, inhibits salmon from returning to their spawning grounds (even with the help of fish ladders). Any type of geoengineering at this type of scale would have some very large unintended blowback.
- BatFastard 9y ago
  I am not. Lets look at the trade offs. Each city doing a huge construction project to protect them selves from raising sea levels, or one huge dam. What you say about all of those side effects are true. But what are the effects of not doing anything?
  - chr1 9y ago
    Indeed cities of mediterranean and baltic seas are luck to be able to escape raising sea levels by building on dam. But the sea level doesn't rise fast enough to motivate enough people to build a dam, so people will end up slowly leaving places that get inundated. But there is another way to prevent raising sea levels, which is moving that water into aquifers and lakes in places that are currently deserts. Huge deserts in Sahara Iran and Middle Asia can easily take the large chunk of water that is currently stored in polar caps. We just need to invest more in building large scale climate modifying structures, like solar towers, solar power plants, dams and canals.
    - sova 9y ago
      Hmmmm. Solar piping that gently draws water out over long distances?
    - BatFastard 9y ago
      Love the idea, but isn't it the same problem of boiling the frog?
  - philtar 9y ago

BatFastard 9y ago

Would probably only need 1 dam at Gibraltar. I wonder if the Mediterranean has a net info or outflow of water?

Shivetya 9y ago
I was always under the impression that evaporation would have threatened its existence if not for the in flow from the Atlantic
- twic 9y ago
  On average, the Mediterranean basin shows an excess of evaporation over freshwater inputs and a heat loss through air-sea interaction. It has an overall freshwater deficit, as the loss to the atmosphere by evaporation is larger than the gains by precipitation and runoff from the main rivers and input from the Black Sea. The total heat budget is negative, that is, the Mediterranean Sea loses more energy than it gains. These losses of freshwater and heat are compensated by the two-layer exchange at the Strait of Gibraltar comprising a relatively warm and fresh (15.4°C, 36.2 psu) upper water inflow and a relatively cooler and saltier (13°C, 38.4 psu) outflow to the Atlantic (Bryden et al. 1994; Tsimplis and Bryden 2000). On long timescales, the losses of freshwater and heat from the surface are compensated and the net salt flux is close to zero. https://link.springer.com/article/10.1007/s00382-011-1012-6 https://link.springer.com/article/10.1007/s00382-011-1012-6
jcranmer 9y ago
Net outflow, hence the Messinian Salinity Crises that happened whenever the outflow at Gibraltar was blocked.
- BatFastard 9y ago
  After looking at the Messinian Salinity Crises it tells me that without water from the Atlantic the Mediterranean would dry up. Therefore there is a net inflow into the Mediterranean, right?
pmontra 9y ago
As others have pointed out the Mediterranean Sea loses water and needs an inflow to compensate. In the case of a dam at Gibraltar it should be easy to let some water in. I wonder if we are able to build such a gigantic dam even if we wanted to. We probably need another one at Suez. According to Google Maps the elevation of the channel is always less than 100 m, which is the worst case figure for sea rise if all the ice of the world melts. Water would come in from the Red Sea. Btw, not all terrains are suitable for building dams.
- BatFastard 9y ago
  There are already locks on the Suez I believe. I would think that the Rock of Gibraltar would give the damn a decent base rock formation underneath, but you have a good point.
  - AnimalMuppet 9y ago
    No, the Suez Canal does not have locks.
  - pmontra 9y ago
    No locks. You can check at https://www.google.com/maps/@31.1497898,32.3699699,12z/data=!3m1!1e3 https://www.google.com/maps/@31.1497898,32.3699699,12z/data=... Furthermore all the area of the channel is low elevation. It will go under water when the sea level raises. Ships will just sail over it.
detritus 9y ago
Having spent much of my youth waking up and staring across the Straits every day, I question your use of 'only' in this thought. They may 'only' be 12 or so miles across, but the amount of concrete and fill that would be needed to dam the straits would dwarf anything even the Chinese could manage up with for another couple of hundred years, I imagine. This idea looks a lot more plausible on paper than it would in person.

djsumdog 9y ago

I really hope you're being sarcastic. Building dams are environmentally devastating. Dams created a multi-billion dollar fertilizer industry in Egypt where none existed before adding them to the Nile. They blocks sediment on rivers, inhibits salmon from returning to their spawning grounds (even with the help of fish ladders). Any type of geoengineering at this type of scale would have some very large unintended blowback.

BatFastard 9y ago
I am not. Lets look at the trade offs. Each city doing a huge construction project to protect them selves from raising sea levels, or one huge dam. What you say about all of those side effects are true. But what are the effects of not doing anything?
- chr1 9y ago
  Indeed cities of mediterranean and baltic seas are luck to be able to escape raising sea levels by building on dam. But the sea level doesn't rise fast enough to motivate enough people to build a dam, so people will end up slowly leaving places that get inundated. But there is another way to prevent raising sea levels, which is moving that water into aquifers and lakes in places that are currently deserts. Huge deserts in Sahara Iran and Middle Asia can easily take the large chunk of water that is currently stored in polar caps. We just need to invest more in building large scale climate modifying structures, like solar towers, solar power plants, dams and canals.
  - sova 9y ago
    Hmmmm. Solar piping that gently draws water out over long distances?
  - BatFastard 9y ago
    Love the idea, but isn't it the same problem of boiling the frog?
- philtar 9y ago