I mean, this is not exactly at the scale of Atlantropa[1] but also not too far off. And analogously to the Atlantropa project, the potential side effects are not even closely understood (and the article leaves me with the taste they haven't even tried to). Cutting of the baltic sea from the north sea? Sounds irresponsible to me...
That idea is bonkers insane. I love it. Was/is it technically feasible? Evidently the link to the Black Sea is ~1km at the narrowest and Strait of Gibraltar is 13km. Which sounds like an enormous feat of engineering, but maybe within the realm of possibility.
Edit: evidently the Hoover Dam is 379 meters long.
Anyone can draw a line on a map with a sharpie. Is there any reason to believe this is a serious proposal with a realistic chance of being implemented?
It is a completely bonkers idea without any regard for local topography. First, the coastlines marked in red have been endangered by flooding for thousands of years, they have shifted with the storms over the eons, and in modern times, become fortified with an existing system of dams and additional protections such as river sluices, wave breakers and land-generating projects that extend the lands before the dams to protect the dams better.
The black line in Germany would cut off all of the shipping lanes and make gates and sluices necessary out there between the island chain. Where ground is totally unsuitable for that: The Wattenmeer is more of a tidal salt water swamp which goes out for tens of kilometers from the cost. Interrupted of course by deep cuts where the major rivers go out and shipping goes in. On the outer rim of the island chain, there is also a current along the coast that will make any major construction difficult, to say the least. Many islands struggle with that current reshaping them, for the most well-known example, see Sylt.
And before anyone says "well, they did it in the Netherlands", no, they didn't. The Ijsselmeer was a bay they cut off and drained, not an exposed coastline.
The realistic option (that is getting implemented over time) is just fortifying the existing dams. A few minor islands might cease to exist, but saving them won't be cost-effective.
The Danish and Swedish part is never gonna happen at least. Blocking off the Baltic sea doesn’t make any sense, and in Denmark we don’t need this for most of the stretch of the west coast of Jutland.
I guess blocking the sea access to Hamburg is also a no thanks for Germany.
Would it be technically legal? If the waters are under danish control, what could germany or the baltic countries do? Obviously, it won't actually ever happen, but waterway sovereignty is interesting
(A kind of similar situation is the nile dam in Ethiopia, with the fallout it led to with Egypt)
That would be a big "maybe" with at least as many interpretations as there are countries around the baltic sea. International law isn't as cut-and-dried as the usual laws within states that people are used to. Lots of international laws are more like traditions that got written down, where any major shift in circumstances (like a war, crisis, revolution, ...) will lead to a more convenient (for some) reinterpretation. Enforcement of international law usually happens through wars, so there is the additional complication of asking: "is it worth a war to uphold 'the law'". No real judicial and enforcement system exists, only certain kinds of arbitration courts. No international police to uphold anything. Only maybe the UN asking some states to send troops, if you really annoy the world and have no friends in the security council vetoing it.
The dam would have to be in German waters (German Bight, furthest point outwards is Heligoland) or far out in the North Sea (Edit: not in international waters, we're all close here, there aren't any between the continent and the UK). Denmark could in theory cut off the Baltic countries, but for international shipping, they'll often take the Kiel canal that cuts through Northern Germany between the Baltic Sea and the Elbe river (close to the mouth where it flows into the North Sea) because they're often delivering to Germany or transfer the load in Germany or the Netherlands to bigger ships that'll take it where ever it needs to go (and the canal route is considerably shorter).
The Dutch have various plans how to fight the sea in the next 300 years. One of them calls for dams around the big cities and letting everything else flood, moving 2 million people [1]. Compared to that is this project (well, the Dutch part at least) relatively trivial - dredge some sand from here and put it over there as dunes. The coast from Zeeland to Den Helder is not terribly ecologically interesting nor big in fishing so in that sense it's much easier than the Deltaworks.
The father of Deltaworks said “Eens zullen we ons land met een zucht van verlichting aan de golven prijsgeven.” "One day with a sigh of relief we will give up this country to the waves." Drastic solutions are required after sea level rise of 2m. So, maybe not this century but certainly the next one.
It's not an officially sanctioned plan but the people behind it are serious enough. Basically, these are a few independent engineers pitching a solution to planning commissions. The proposed solution is being considered along with (presumably) a lot of other options and probably at this point not much more than a report and some pretty graphics. But that doesn't mean it's a bad plan of course.
As sea levels rise, plans like this will get a lot more attention. These people are talking about dealing with five to ten meters of sea level increases. That's going to cause a lot of challenges that will require some serious engineering. And and it's unlikely that a country like the Netherlands is going to patiently await rising sea levels and do nothing about it. That's just not how things work over there and there's too much history of dealing successfully with similar challenges in the past.
My home country has of course a bit of a track record when it comes to building effective sea defenses. The Delta works are pretty awesome and cost many billions. The trigger point for deciding on building all that was some severe flooding in the 1950s. Thousands died, and the sea pushed deep into the country. Basically, engineers went to work and started coming up with plans to prevent that from happening again. Implementing this took decades. The work was only completed in the nineties.
The end result is a system of of dikes, sluices, and other defenses that seem very effective so far. And a lot of know how for building stuff like this. Which is why e.g. Dubai has some nice new valuable offshore real estate in the form of a few nice new islands. Skills like that are going to be in demand a lot in the next decades as different countries figure out that they can either accept losing major chunks of their coastal real estate or try doing something about it. And that is going to unlock a lot of financing.
So, yes, plans like this sound like the right level of ambition at least. Too early to tell if this specific one will win. But something will happen.
I am on one of the islands behind the proposed dike. As a German it is hard to imagine that something like this can be done. However, the Dutch are really serious about such things. Here is an English article:
https://www.delta.tudelft.nl/article/do-we-need-second-coast...
No, as far as I can quickly find this proposal is propagated by a single (electrical) engineer, and does not have backing from any NGO's, governments or political parties.
More water in seas does not mean that sea level will rise evenly everywhere. I've heard that the relocation of water masses will in fact make sea level lower somewhere. Also landmasses will rise and sink.
Are there any serious calculations of the details?
> A 475-km-long dam between the north of Scotland and the west of Norway and another one of 160 km between the west point of France and the southwest of England could protect more than 25 million Europeans against the consequences of an expected sea level rise of several metres over the next few centuries
“Ah, sure fuck Ireland (and the west coast of the UK) anyway”
This. Inflows of saline water from the North Sea are important for the ecology of the Baltic Sea. The sea is naturally low in salinity due to its shallowness and the relatively large influx of fresh water from rivers. More saline water only gets into the sea via the straits from the Atlantic.
Apparently, the pulses that bring in saline water (along with more oxygen-rich water) into the Baltic Sea have been getting less frequent in recent decades. They still happen, though.
It seems outlandish that anybody would write about such an idea (or the damming of the Baltic Sea part of it) without even mentioning that. It sounds like a crazy engineering idea with no real regard for side effects.
[1] https://en.wikipedia.org/wiki/Atlantropa