A dam right across the North Sea: A defense against climate change, but primarily a warning:
[Ed Note: English version of the story follows the Dutch version - Fnord666]
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. The costs, 250-500 billion euros, are "merely" 0.1% of the gross national product, annualy over 20 years, of all the countries that would be protected by such a dam. That's what Dr Sjoerd Groeskamp, oceanographer at the Royal Netherlands Institute for Sea Research, calculated together with his Swedish colleague Joakim Kjellson at GEOMAR in Kiel, Germany, published this month in the scientific journal the Bulletin of the American Meterological Society. 'Besides being a possible solution, the design of such an extreme dam is mainly a warning', says Groeskamp. 'It reveals the immensity of the problem hanging over our heads.'
[...] The authors acknowledge that the consequences of this dam for North Sea wildlife would be considerable. 'The tide would disappear in a large part of the North Sea, and with it the transport of silt and nutrients. The sea would eventually even become a freshwater lake. That will drastically change the ecosystem and therefore have an impact on the fishing industry as well', Groeskamp elaborates.
[...] Ultimately, the description of this extreme dam is more of a warning than a solution, Groeskamp states. 'The costs and the consequences of such a dam are huge indeed. However, we have calculated that the cost of doing nothing against sea level rise will ultimately be many times higher. This dam makes it almost tangible what the consequences of the sea level rise will be; a sea level rise of 10 metres by the year 2500 according to the bleakest scenarios. This dam is therefore mainly a call to do something about climate change now. If we do nothing, then this extreme dam might just be the only solution.'
Sjoerd Groeskamp, Joakim Kjellsson. NEED The Northern European Enclosure Dam for if climate change mitigation fails. Bulletin of the American Meteorological Society, 2020; DOI: 10.1175/BAMS-D-19-0145.1
(Score: 1, Insightful) by Anonymous Coward on Monday March 02 2020, @11:18PM (2 children)
Citation needed. The Baltic sea is not a lake, it is naturally open water, yet it is anoxic. Lake IJssel in The Netherlands is an articifically-created lake, yet it is not anoxic, and fishing thrives there. So do you have any sources to back up your claim that closing off a body of water inevitably makes it anoxic?
(Score: 4, Informative) by Joe Desertrat on Monday March 02 2020, @11:48PM
I don't claim that closing off a body of water inevitably makes it anoxic, at least in the sense of human lifespans. Lakes are temporary geological structures though, none of them will last forever.
Lake Ijsselmeer is a relatively small, shallow lake continually flushed by river water. That takes the place of the tidal action that a North Sea dam would bring to an end in the North Sea and allows for fish to still survive there. The North Sea might survive as a lake, at least in the geological short run, but the Baltic Sea would lose what little mixing it currently gets from the North Sea as a result of their tides.
Any dammed (whether naturally or unnaturally) body of water will pass through several stages in its geological lifespan, starting with being oligotrophic, but eventually siltation and pollution will bring it through the various stages of its life cycle until it is eutrophic and eventually hypereutrophic, with the final stages of being a swamp and then a meadow.
The other option is evaporation turning a closed body of water into a chemical lake and eventually a salt pan, much as the Dead Sea between Jordan and Israel, Death Valley in California and the Great Salt Lake in Utah (for a few examples) represent. A poster below mentions damming the Mediterranean at Gibraltar, geologists suggest it would become a salt desert in as few as 500-600 years. It has been in the past, which is why it is saltier than the Atlantic.
(Score: 1) by nitehawk214 on Tuesday March 03 2020, @04:29PM
If you build a damn from Scotland to Norway, the only way in or out would be through the channel. However, it is pretty deep, so I think it would work like lake Michigan and Huron or the Dardanelles; currents going both directions.
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