North Sea

Geography

Main article: Geography of the North Sea

|image-width=250 The North Sea is bounded by the Orkney Islands and east coast of Great Britain to the west{{cite encyclopedia and the northern and central European mainland to the east and south, including Norway, Denmark, Germany, the Netherlands, Belgium, and France.{{cite book |access-date=17 February 2020 |archive-date=17 April 2023 |archive-url=https://web.archive.org/web/20230417083622/https://books.google.com/books?id=GEpMAAAAMAAJ&pg=PA499 |url-status=live

The North Sea is more than 970 km long and 580 km wide, with an area of 750000 km2 and a volume of 54000 km3. Around the edges of the North Sea are sizeable islands and archipelagos, including Shetland, Orkney, and the Frisian Islands. The North Sea receives freshwater from a number of European continental watersheds, as well as the British Isles. A large part of the European drainage basin empties into the North Sea, including water from the Baltic Sea. The largest and most important rivers flowing into the North Sea are the Elbe and the Rhine – Meuse.{{cite book |access-date=2 October 2020 |archive-date=17 April 2023 |archive-url=https://web.archive.org/web/20230417083657/https://books.google.com/books?id=E7xLaYVGEF4C&q=%22North+Sea%22+watershed&pg=PA262 |url-status=live |access-date = 24 November 2008 |archive-url = https://web.archive.org/web/20081217143715/http://www.emecs.or.jp/guidebook/eng/pdf/05north.pdf |archive-date = 17 December 2008

Major features

For the most part, the sea lies on the European continental shelf with a mean depth of 90 m.{{cite book |access-date=26 December 2008 |archive-date=17 April 2023 |archive-url=https://web.archive.org/web/20230417083622/https://books.google.com/books?id=L7V-JtHroGkC&pg=PA100 |url-status=live

The Dogger Bank, a vast moraine, or accumulation of unconsolidated glacial debris, rises to a mere 15 to below the surface.{{cite book |url-access=registration |access-date = 20 July 2007 |archive-date = 11 July 2012 |archive-url = https://archive.today/20120711211708/http://mapserver.maptech.com/homepage/index.cfm?lat=54.74456315454079&lon=2.3527509224287115&scale=1500000&zoom=50&type=0&icon=0&width=498&height=498&searchscope=dom&CFID=1719760&CFTOKEN=33728793&scriptfile=http://mapserver.maptech.com/homepage/index.cfm&latlontype=DMS |access-date=17 February 2020 |archive-date=17 April 2023 |archive-url=https://web.archive.org/web/20230417083623/https://books.google.com/books?id=EMMBAAAAYAAJ&pg=PA420 |url-status=live |access-date=17 February 2020 |archive-date=17 April 2023 |archive-url=https://web.archive.org/web/20230417083623/https://books.google.com/books?id=cxsPAAAAYAAJ&pg=PA445 |url-status=live

Other areas which are less deep are Cleaver Bank, Fisher Bank and Noordhinder Bank.

Extent

The International Hydrographic Organization defines the limits of the North Sea as follows:

Hydrology

Temperature and salinity

The average temperature is 17 °C in the summer and 6 °C in the winter. The average temperatures have been trending higher since 1988, which has been attributed to climate change.{{cite web |access-date = 1 December 2008 |archive-date = 3 January 2009 |archive-url = https://web.archive.org/web/20090103150607/http://www.terradaily.com/reports/Global_Warming_Triggers_North_Sea_Temperature_Rise_999.html |url-status = live

The salinity averages between 34 and of water. The salinity has the highest variability where there is fresh water inflow, such as at the Rhine and Elbe estuaries, the Baltic Sea exit and along the coast of Norway.{{cite book |chapter-url=https://books.google.com/books?id=2NC3JmKI7mYC&pg=PA120 |access-date=3 December 2008 |archive-date=17 April 2023 |archive-url=https://web.archive.org/web/20230417083623/https://books.google.com/books?id=2NC3JmKI7mYC&pg=PA120 |url-status=live

Water circulation and tides

The main pattern to the flow of water in the North Sea is an anti-clockwise rotation along the edges.{{cite web |archive-url = https://web.archive.org/web/20061231073713/http://www.metoffice.gov.uk/education/secondary/students/flood.html |archive-date = 31 December 2006 |access-date = 2 November 2008}}

The North Sea is an arm of the Atlantic Ocean receiving the majority of ocean current from the northwest opening, and a lesser portion of warm current from the smaller opening at the English Channel. These tidal currents leave along the Norwegian coast.{{cite web |access-date = 9 January 2009 |archive-url = https://web.archive.org/web/20081209094254/http://www.safetyatsea.se/index.php?art=2041&group=400 |archive-date = 9 December 2008 |chapter-url=https://books.google.com/books?id=sGSMw7gCOLYC&pg=PA67 |access-date=3 December 2008 |archive-date=17 April 2023 |archive-url=https://web.archive.org/web/20230417083634/https://books.google.com/books?id=sGSMw7gCOLYC&pg=PA67 |url-status=live

The North Sea located on the continental shelf has different waves from those in deep ocean water. The wave speeds are diminished and the wave amplitudes are increased. In the North Sea there are two amphidromic systems and a third incomplete amphidromic system.{{cite book |access-date=4 December 2008 |archive-date=17 April 2023 |archive-url=https://web.archive.org/web/20230417083656/https://books.google.com/books?id=c3MOQKCru6sC&pg=PA328 |url-status=live |access-date=4 December 2008 |archive-date=17 April 2023 |archive-url=https://web.archive.org/web/20230417083702/https://books.google.com/books?id=STBKHpqMt6MC&pg=PA157 |url-status=live

The Kelvin tide of the Atlantic Ocean is a semidiurnal wave that travels northward. Some of the energy from this wave travels through the English Channel into the North Sea. The wave continues to travel northward in the Atlantic Ocean, and once past the northern tip of Great Britain, the Kelvin wave turns east and south and once again enters the North Sea.{{cite book |access-date=1 July 2020 |archive-date=17 April 2023 |archive-url=https://web.archive.org/web/20230417083624/https://books.google.com/books?id=Ysa4ymmEotYC&pg=PA93 |url-status=live

Coasts

Main article: Coastline of the North Sea

The eastern and western coasts of the North Sea are jagged, formed by glaciers during the ice ages. The coastlines along the southernmost part are covered with the remains of deposited glacial sediment. The Norwegian mountains plunge into the sea creating deep fjords and archipelagos. South of Stavanger, the coast softens, the islands become fewer. The eastern Scottish coast is similar, though less severe than Norway. From north east of England, the cliffs become lower and are composed of less resistant moraine, which erodes more easily, so that the coasts have more rounded contours. In the Netherlands, Belgium and in East Anglia the littoral is low and marshy. The east coast and south-east of the North Sea (Wadden Sea) have coastlines that are mainly sandy and straight owing to longshore drift, particularly along Belgium and Denmark.{{Cite book |access-date = 4 December 2007 |archive-url = https://web.archive.org/web/20070710023601/http://www.ospar.org/eng/doc/pdfs/R2C2.pdf |archive-date = 10 July 2007

Coastal management

The southern coastal areas were originally flood plains and swampy land. In areas especially vulnerable to storm surges, people settled behind elevated levees and on natural areas of high ground such as spits and geestland. As early as 500 BC, people were constructing artificial dwelling hills higher than the prevailing flood levels. It was only around the beginning of the High Middle Ages, in 1200 AD, that inhabitants began to connect single ring dikes into a dike line along the entire coast, thereby turning amphibious regions between the land and the sea into permanent solid ground.{{cite book |orig-date=2002 |access-date=4 December 2008 |archive-date=17 April 2023 |archive-url=https://web.archive.org/web/20230417083652/https://books.google.com/books?id=NACgnCN_jaEC&pg=PA308 |url-status=live

The modern form of the dikes supplemented by overflow and lateral diversion channels, began to appear in the 17th and 18th centuries, built in the Netherlands.{{cite web |access-date = 24 July 2007 |archive-date = 26 June 2007 |archive-url = https://web.archive.org/web/20070626085020/http://www.eh-resources.org/floods.html |url-status = live |access-date = 24 July 2007 |archive-url = https://web.archive.org/web/20070525134637/http://www.allwondersoftheworld.com/seven-modern-wonders/north-sea-protection-works.html |archive-date = 25 May 2007}} Currently, 27% of the Netherlands is below sea level protected by dikes, dunes, and beach flats.{{cite web |access-date = 19 July 2007 |archive-url = https://web.archive.org/web/20090201074700/http://geography.about.com/od/specificplacesofinterest/a/dykes.htm |archive-date = 1 February 2009

Coastal management today consists of several levels.{{cite web |archive-url = https://archive.today/20130102043157/http://www.basf.com/group/corporate/en/content/news-and-media-relations/science-around-us/imperiled-dikes/index |archive-date = 2 January 2013 |access-date = 16 January 2009 |access-date = 16 January 2009 |archive-url = https://web.archive.org/web/20090205005638/http://icce2008.hamburg.baw.de/downloads/intern/Paper/BookOfAbstracts/0863_Peters.pdf |archive-date = 5 February 2009 |access-date = 2 November 2008 |archive-url = https://web.archive.org/web/20081212154705/http://www.snh.org.uk/publications/on-line/heritagemanagement/erosion/appendix_1.2.shtml |archive-date = 12 December 2008

Storm tides

Main article: Storm tides of the North Sea

Storm surges threaten, in particular, the coasts of the Netherlands, Belgium, Germany, and Denmark and low-lying areas of eastern England particularly around The Wash and Fens. Storm surges are caused by changes in barometric pressure combined with strong wind created wave action.{{cite book |chapter-url=https://books.google.com/books?id=0I6BNSgx3_cC&pg=RA1-PA150 |access-date=15 December 2008 |archive-date=17 April 2023 |archive-url=https://web.archive.org/web/20230417083625/https://books.google.com/books?id=0I6BNSgx3_cC&pg=RA1-PA150 |url-status=live

The first recorded storm tide flood was the Julianenflut, on 17 February 1164. In its wake, the Jadebusen, (a bay on the coast of Germany), began to form. A storm tide in 1228 is recorded to have killed more than 100,000 people.{{cite web |access-date = 4 December 2008 |archive-url = https://web.archive.org/web/20081217143715/http://www.emetsoc.org/annual_meetings/documents/Morin_SilverMedalLecture_2008.pdf |archive-date = 17 December 2008 |access-date =4 December 2008 |archive-date =12 May 2011 |archive-url =https://web.archive.org/web/20110512012345/http://translate.google.ca/translate?hl=en&sl=de&u=http://www.g-o.de/dossier-detail-395-8.html&sa=X&oi=translate&resnum=5&ct=result&prev=/search%3Fq%3D1362%2BGroote%2BManndr%25C3%25A4nke%26hl%3Den%26client%3Dfirefox-a%26rls%3Dorg.mozilla:en-GB:official%26sa%3DG |url-status =live In the 20th century, the North Sea flood of 1953 flooded several nations' coasts and cost more than 2,000 lives.{{Cite book |archive-url = https://web.archive.org/web/20021126105045/http://www.naturegrid.org.uk/rivers/gt%20stour%20case%20study-pages/fld-cstl.html |archive-date = 26 November 2002 |access-date = 24 July 2007 315 citizens of Hamburg died in the North Sea flood of 1962.{{cite book |access-date=2 October 2020 |archive-date=17 April 2023 |archive-url=https://web.archive.org/web/20230417083632/https://books.google.com/books?id=m5IOAAAAQAAJ&q=North+Frisian+Flood+of+1981&pg=PA131 |url-status=live

Tsunamis

Though rare, the North Sea has been the site of a number of historically documented tsunamis. The Storegga Slides were a series of underwater landslides, in which a piece of the Norwegian continental shelf slid into the Norwegian Sea. The immense landslips occurred between 8150 BCE and 6000 BCE, and caused a tsunami up to 20 m high that swept through the North Sea, having the greatest effect on Scotland and the Faeroe Islands.{{cite news |access-date = 24 July 2007 |archive-date = 1 November 2007 |archive-url = https://web.archive.org/web/20071101180658/http://www.spiegel.de/international/0,1518,441819,00.html |url-status = live The Dover Straits earthquake of 1580 is among the first recorded earthquakes in the North Sea measuring between 5.6 and 5.9 on the Richter scale. This event caused extensive damage in Calais both through its tremors and possibly triggered a tsunami, though this has never been confirmed. The theory is a vast underwater landslide in the English Channel was triggered by the earthquake, which in turn caused a tsunami. The tsunami triggered by the 1755 Lisbon earthquake reached Holland, although the waves had lost their destructive power. The largest earthquake ever recorded in the United Kingdom was the 1931 Dogger Bank earthquake, which measured 6.1 on the Richter magnitude scale and caused a small tsunami that flooded parts of the British coast.{{Cite book |access-date = 2 November 2008 |archive-url = https://web.archive.org/web/20140425180447/http://www.naturalsciences.be/active/sciencenews/archive2005/tsunami |archive-date = 25 April 2014

In 1995, the 25.6 m tall Draupner wave occurred in the North Sea, becoming the first rogue wave to be observed using scientific instruments.

Geology

Main article: Geology of the North Sea, Geology of southern North Sea

Shallow epicontinental seas like the current North Sea have since long existed on the European continental shelf. The rifting that formed the northern part of the Atlantic Ocean during the Jurassic and Cretaceous periods, from about , caused tectonic uplift in the British Isles.{{cite journal Since then, a shallow sea has almost continuously existed between the uplands of the Fennoscandian Shield and the British Isles. This precursor of the current North Sea has grown and shrunk with the rise and fall of the eustatic sea level during geologic time. Sometimes it was connected with other shallow seas, such as the sea above the Paris Basin to the south-west, the Paratethys Sea to the south-east, or the Tethys Ocean to the south.{{cite web |access-date = 19 November 2008 |archive-date = 22 June 2015 |archive-url = https://web.archive.org/web/20150622010928/http://www.earthdynamics.org/torsvik/torsvik-papers/2002/2002-Torsvik-etal-BATLAS.pdf |url-status = live

During the Late Cretaceous, about , all of modern mainland Europe except for Scandinavia was a scattering of islands. By the Early Oligocene, , the emergence of Western and Central Europe had almost completely separated the North Sea from the Tethys Ocean, which gradually shrank to become the Mediterranean as Southern Europe and South West Asia became dry land.{{cite book |access-date = 1 July 2020 |archive-date = 17 April 2023 |archive-url = https://web.archive.org/web/20230417083625/https://books.google.com/books?id=ZSuuvlMuQaEC&pg=PA66 |url-status = live |access-date = 17 February 2020 |archive-date = 17 April 2023 |archive-url = https://web.archive.org/web/20230417083626/https://books.google.com/books?id=WX2iJQmKTvcC&pg=PA18 |url-status = live

In 2006 a bone fragment was found while drilling for oil in the North Sea. Analysis indicated that it was a Plateosaurus from 199 to 216 million years ago. This was the deepest dinosaur fossil ever found and the first find for Norway.

File:Doggerland.svg|Map showing hypothetical extent of Doggerland (), which provided a land bridge between Great Britain and continental Europe File:North Sea -.jpg|North Sea from De Koog, Texel island File:Mediterranean Rupelian.jpg|The North Sea between and , as Central Europe became dry land

Nature

Fish and shellfish

Copepods and other zooplankton are plentiful in the North Sea. These tiny organisms are crucial elements of the food chain supporting many species of fish. Over 230 species of fish live in the North Sea. Cod, haddock, whiting, saithe, plaice, sole, mackerel, herring, pouting, sprat, and sandeel are all very common and are fished commercially.{{cite web |access-date = 23 June 2013 |archive-date = 25 January 2012 |archive-url = https://web.archive.org/web/20120125104206/http://qsr2010.ospar.org/en/ch12_02.html |url-status = live

Crustaceans are also commonly found throughout the sea. Norway lobster, deep-water prawns, and brown shrimp are all commercially fished, but other species of lobster, shrimp, oyster, mussels and clams all live in the North Sea. Recently non-indigenous species have become established including the Pacific oyster and Atlantic jackknife clam.

Birds

The coasts of the North Sea are home to nature reserves including the Ythan Estuary, Fowlsheugh Nature Preserve, and Farne Islands in the UK and the Wadden Sea National Parks in Denmark, Germany and the Netherlands.{{cite web | access-date = 12 January 2009 | archive-url = https://web.archive.org/web/20090205005633/http://www.marbef.org/outreach/downloads/North%20sea%20pullout.pdf | archive-date = 5 February 2009

Marine mammals

The North Sea is also home to marine mammals. Common seals, grey seals, and harbour porpoises can be found along the coasts, at marine installations, and on islands. The very northern North Sea islands such as the Shetland Islands are occasionally home to a larger variety of pinnipeds including bearded, harp, hooded and ringed seals, and even walrus. North Sea cetaceans include various porpoise, dolphin and whale species.

Flora

Plant species in the North Sea include species of wrack, among them bladder wrack, knotted wrack, and serrated wrack. Algae, macroalgal, and kelp, such as oarweed and laminaria hyperboria, and species of maerl are found as well. Eelgrass, formerly common in the entirety of the Wadden Sea, was nearly wiped out in the 20th century by a disease.{{cite journal Similarly, sea grass used to coat huge tracts of ocean floor, but have been damaged by trawling and dredging have diminished its habitat and prevented its return. Invasive Japanese seaweed has spread along the shores of the sea, clogging harbours and inlets and has become a nuisance.{{cite book |access-date=1 July 2020 |archive-date=17 April 2023 |archive-url=https://web.archive.org/web/20230417083626/https://books.google.com/books?id=gHrXsKJ89rEC&pg=PA432 |url-status=live

Biodiversity and conservation

Due to the heavy human populations and high level of industrialization along its shores, the wildlife of the North Sea has suffered from pollution, overhunting, and overfishing. Flamingos and pelicans were once found along the southern shores of the North Sea, but became extinct over the second millennium.{{cite web |access-date = 24 November 2008 |archive-url = https://wayback.archive-it.org/all/20081217143715/http://www.fmap.ca/ramweb/media/biodiversity_loss/downloads/Examples_regional_extinctions.doc |archive-date = 17 December 2008 Grey whales also resided in the North Sea but were driven to extinction in the Atlantic in the 17th century{{cite web |access-date = 3 December 2008 |archive-url = https://web.archive.org/web/20090104224507/http://www.petermaas.nl/extinct/speciesinfo/atlanticgreywhale.htm |archive-date = 4 January 2009 |access-date = 3 December 2008 |archive-date = 17 April 2023 |archive-url = https://web.archive.org/web/20230417083626/https://www.theguardian.com/environment/2002/mar/21/fish.food |url-status = live |access-date = 3 December 2008 |archive-url = https://web.archive.org/web/20081217143716/http://www.cemagref.fr/english/seven/News/07/25ans/ETsturgeon.pdf |archive-date = 17 December 2008

Other factors like the introduction of non-indigenous species, industrial and agricultural pollution, trawling and dredging, human-induced eutrophication, construction on coastal breeding and feeding grounds, sand and gravel extraction, offshore construction, and heavy shipping traffic have also contributed to the decline. For example, a resident orca pod was lost in the 1960s, presumably due to the peak in PCB pollution in this time period.{{cite news |access-date=17 February 2019 |archive-date=20 February 2019 |archive-url=https://web.archive.org/web/20190220003210/https://www.theguardian.com/environment/2016/jan/14/uks-last-resident-killer-whales-doomed-to-extinction |url-status=live

The OSPAR commission manages the OSPAR convention to counteract the harmful effects of human activity on wildlife in the North Sea, preserve endangered species, and provide environmental protection. |access-date=30 November 2008 |archive-url=https://web.archive.org/web/20090108222855/http://europa.eu/scadplus/leg/en/lvb/l28061.htm |archive-date=8 January 2009 All North Sea border states are signatories of the MARPOL 73/78 Accords, which preserve the marine environment by preventing pollution from ships.{{cite journal | access-date = 12 January 2009 | archive-date = 10 May 2011 | archive-url = https://web.archive.org/web/20110510104253/http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=OJ:L:2000:332:0081:0089:EN:PDF | url-status = live |chapter-url = http://www.snh.org.uk/pdfs/strategy/CMNP/Case%20Study/Wadden%20Sea%20Region%20Final.pdf |access-date = 1 December 2008 |archive-url = https://web.archive.org/web/20081217143713/http://www.snh.org.uk/pdfs/strategy/CMNP/Case%20Study/Wadden%20Sea%20Region%20Final.pdf |archive-date = 17 December 2008

Names

The North Sea has had various names throughout history. One of the earliest recorded names was Septentrionalis Oceanus, or "Northern Ocean", which was cited by Pliny.{{cite book |chapter-url=https://books.google.com/books?id=DMPjAyyz1W4C&pg=PA119 |access-date=8 December 2008 |archive-date=17 April 2023 |archive-url=https://web.archive.org/web/20230417084127/https://books.google.com/books?id=DMPjAyyz1W4C&pg=PA119 |url-status=live |access-date=1 July 2020 |archive-date=17 April 2023 |archive-url=https://web.archive.org/web/20230417084127/https://books.google.com/books?id=npQ6Hd3G4kgC&pg=PA401 |url-status=live

File:Prima Europe tabula.jpg|A 1482 recreation of a map from Ptolemy's Geography showing the "Oceanus Germanicus" File:Solar eclipse 1715May03 Halley map.png|Edmond Halley's solar eclipse 1715 map showing The German Sea File:Geological map Britain William Smith 1815.jpg|William Smith's 1815 geological map of England and Wales showing The German Ocean

History

Main article: History of the North Sea

Early history

The North Sea has provided waterway access for commerce and conquest. Many areas have access to the North Sea because of its long coastline and the European rivers that empty it. There is little documentary evidence concerning the North Sea before the Roman conquest of Britain in 43 CE, however, archaeological evidence reveals the diffusion of cultures and technologies from across or along the North Sea to Great Britain and Scandinavia and reliance by some prehistoric cultures on fishing, whaling, and seaborne trade on the North Sea. The Romans established organised ports in Britain, which increased shipping and began sustained trade and many Scandinavian tribes participated in raids and wars against the Romans and Roman coinage and manufacturing were important trade goods. When the Romans abandoned Britain in 410, the Germanic Angles, Frisians, Saxons, and Jutes began the next great migration across the North Sea during the Migration Period. They made successive invasions of the island from what is now the Netherlands, Denmark, and Germany.{{cite book |access-date=1 July 2020 |archive-date=17 April 2023 |archive-url=https://web.archive.org/web/20230417084206/https://books.google.com/books?id=MThYNoTutLkC&pg=PA49 |url-status=live

The Viking Age began in 793 with the attack on Lindisfarne; for the next quarter-millennium, the Vikings ruled the North Sea. In their superior longships, they raided, traded, and established colonies and outposts along the coasts of the sea. From the Middle Ages through the 15th century, the northern European coastal ports exported domestic goods, dyes, linen, salt, metal goods and wine. The Scandinavian and Baltic areas shipped grain, fish, naval necessities, and timber. In turn, the North Sea countries imported high-grade cloths, spices, and fruits from the Mediterranean region. Commerce during this era was mainly conducted by maritime trade due to underdeveloped roadways.{{cite journal

In the 13th century the Hanseatic League, though centred on the Baltic Sea, started to control most of the trade through important members and outposts on the North Sea.{{cite book |access-date = 1 July 2020 |archive-date = 17 April 2023 |archive-url = https://web.archive.org/web/20230417084139/https://books.google.com/books?id=OzIRDbARyWIC&pg=PA128 |url-status = live |access-date = 1 July 2020 |archive-date = 17 April 2023 |archive-url = https://web.archive.org/web/20230417084129/https://books.google.com/books?id=8qvY8pxVxcwC&pg=PA305 |url-status = live |access-date=1 July 2020 |archive-date=17 April 2023 |archive-url=https://web.archive.org/web/20230417084139/https://books.google.com/books?id=2AAoAAAAYAAJ&pg=RA1-PA539 |url-status=live

Age of sail

The 17th century Dutch Golden Age saw Dutch maritime power at its zenith.{{cite book |access-date=1 July 2020 |archive-date=17 April 2023 |archive-url=https://web.archive.org/web/20230417084129/https://books.google.com/books?id=haiG4P79gysC&pg=PA7 |url-status=live |url-access=registration Important overseas colonies, a vast merchant marine, a large fishing fleet, powerful navy, and sophisticated financial markets made the Dutch the ascendant power in the North Sea, to be challenged by an ambitious England. This rivalry led to the first three Anglo-Dutch Wars between 1652 and 1673, which ended with Dutch victories. After the Glorious Revolution in 1688, the Dutch prince William ascended to the English throne. With unified leadership, commercial, military, and political power began to shift from Amsterdam to London.{{cite book |access-date=1 July 2020 |archive-date=17 April 2023 |archive-url=https://web.archive.org/web/20230417084129/https://books.google.com/books?id=5wlngm9J29kC&pg=PA134 |url-status=live The British did not face a challenge to their dominance of the North Sea until the 20th century.{{cite book |access-date=1 July 2020 |archive-date=17 April 2023 |archive-url=https://web.archive.org/web/20230417084141/https://books.google.com/books?id=TKXn0IQBKCcC&pg=PA183 |url-status=live

Modern era

Tensions in the North Sea were again heightened in 1904 by the Dogger Bank incident. During the Russo-Japanese War, several ships of the Russian Baltic Fleet, which was on its way to the Far East, mistook British fishing boats for Japanese ships and fired on them, and then upon each other, near the Dogger Bank, nearly causing Britain to enter the war on the side of Japan.

During the First World War, Great Britain's Grand Fleet and Germany's Kaiserliche Marine faced each other in the North Sea,{{cite book |access-date=1 July 2020 |archive-date=17 April 2023 |archive-url=https://web.archive.org/web/20230417084134/https://books.google.com/books?id=6hwb6ovvYCcC |url-status=live |orig-date=2005 |access-date=1 July 2020 |archive-date=17 April 2023 |archive-url=https://web.archive.org/web/20230417084141/https://books.google.com/books?id=B1cMtKQP3P8C&pg=RA2-PA836 |url-status=live |access-date=1 July 2020 |archive-date=17 April 2023 |archive-url=https://web.archive.org/web/20230417084132/https://books.google.com/books?id=4IcGeprPmDkC |url-status=live |access-date=1 July 2020 |archive-date=17 April 2023 |archive-url=https://web.archive.org/web/20230417084135/https://books.google.com/books?id=Ka-1eQRnXMUC |url-status=live World War I also brought the first extensive use of submarine warfare, and a number of submarine actions occurred in the North Sea.{{cite book |orig-date=2005 |access-date=2 October 2020 |archive-date=17 April 2023 |archive-url=https://web.archive.org/web/20230417084131/https://books.google.com/books?id=B1cMtKQP3P8C&q=World+War+I:+Encyclopedia |url-status=live

The Second World War also saw action in the North Sea, though it was restricted more to aircraft reconnaissance and action by fighter/bomber aircraft, submarines and smaller vessels such as minesweepers and torpedo boats.

After the war, hundreds of thousands of tons of chemical weapons were disposed of by being dumped in the North Sea.{{cite book |access-date=1 July 2020 |archive-date=17 April 2023 |archive-url=https://web.archive.org/web/20230417084132/https://books.google.com/books?id=TGJ5qp7QrgMC&pg=PA49 |url-status=live

After the war, the North Sea lost much of its military significance because it is bordered only by NATO member-states. However, it gained significant economic importance in the 1960s as the states around the North Sea began full-scale exploitation of its oil and gas resources.It was, incidentally, the home of several Pirate Radio stations from 1960 to 1990. {{cite book |orig-date=1976 |access-date=1 July 2020 |archive-date=17 April 2023 |archive-url=https://web.archive.org/web/20230417084137/https://books.google.com/books?id=9I8OAAAAQAAJ&pg=RA2-PA195 |url-status=live |access-date =11 November 2007 |archive-date =22 October 2007 |archive-url =https://web.archive.org/web/20071022043115/http://www.forthports.co.uk/ports/ |url-status =live

Economy

Political status

Countries that border the North Sea all claim the 12 nmi of territorial waters, within which they have exclusive fishing rights.{{Cite book | access-date = 12 January 2009 | archive-date = 5 February 2009 | archive-url = https://web.archive.org/web/20090205005632/http://www.fig.net/pub/figpub/pub36/chapters/chapter_5.pdf | url-status = live |access-date = 2 November 2008 |archive-date = 14 July 2013 |archive-url = https://web.archive.org/web/20130714182421/http://ec.europa.eu/fisheries/cfp/ |url-status = live

After the discovery of mineral resources in the North Sea during the early 1960s, the Convention on the Continental Shelf established country rights largely divided along the median line. The median line is defined as the line "every point of which is equidistant from the nearest points of the baselines from which the breadth of the territorial sea of each State is measured". The ocean floor border between Germany, the Netherlands, and Denmark was only reapportioned in 1969 after protracted negotiations and a judgment of the International Court of Justice.{{Cite book |access-date=24 July 2007 |archive-date=1 December 2008 |archive-url=https://web.archive.org/web/20081201013509/http://www.icj-cij.org/docket/index.php?p1=3&p2=3&k=cc&case=52&code=cs2&p3=4 |url-status=live

Oil and gas

As early as 1859, oil was discovered in onshore areas around the North Sea and natural gas as early as 1910. Onshore resources, for example the K12-B field in the Netherlands continue to be exploited today.

Offshore test drilling began in 1966 and then, in 1969, Phillips Petroleum Company discovered the Ekofisk oil field{{cite book |chapter-url=https://books.google.com/books?id=TW6yMgPdgbQC&pg=PP1 |access-date=8 December 2008 |archive-date=17 April 2023 |archive-url=https://web.archive.org/web/20230417084132/https://books.google.com/books?id=TW6yMgPdgbQC&pg=PP1 |url-status=live |chapter-url=https://books.google.com/books?id=jZIOAAAAQAAJ&pg=PA73 |access-date=1 July 2020 |archive-date=17 April 2023 |archive-url=https://web.archive.org/web/20230417084136/https://books.google.com/books?id=jZIOAAAAQAAJ&pg=PA73 |url-status=live |access-date = 15 January 2009 |archive-url = https://web.archive.org/web/20061007012331/http://www.total.no/en/About+TOTAL+NORGE/History/Fina/index.aspx |archive-date = 7 October 2006

The exploitation of the North Sea oil reserves began just before the 1973 oil crisis, and the climb of international oil prices made the large investments needed for extraction much more attractive.{{cite book |chapter-url=https://books.google.com/books?id=MfjDlUe8Kc0C&pg=PA102 The start in 1973 of the oil reserves by the UK allowed them to stop the declining position in international trade in 1974, and a huge increase after the discovery and exploitation of the huge oil field by Phillips group in 1977 as the Brae field.

Although the production costs are relatively high, the quality of the oil, the political stability of the region, and the proximity of important markets in western Europe have made the North Sea an important oil-producing region. The largest single humanitarian catastrophe in the North Sea oil industry was the destruction of the offshore oil platform Piper Alpha in 1988 in which 167 people lost their lives.

Besides the Ekofisk oil field, the Statfjord oil field is also notable as it was the cause of the first pipeline to span the Norwegian trench. The largest natural gas field in the North Sea, Troll gas field, lies in the Norwegian trench, dropping over 300 m, requiring the construction of the enormous Troll A platform to access it.

The price of Brent Crude, one of the first types of oil extracted from the North Sea is used today as a standard price for comparison for crude oil from the rest of the world. The North Sea contains western Europe's largest oil and natural gas reserves and is one of the world's key non-OPEC producing regions.{{cite web | access-date = 23 January 2008 | archive-date = 9 March 2009 | archive-url = https://web.archive.org/web/20090309153553/http://www.auburn.edu/~johnspm/gloss/absolute_advantage | url-status = live

In the UK sector of the North Sea, the oil industry invested £14.4 billion in 2013 and was on track to spend £13 billion in 2014. Industry body Oil & Gas UK put the decline down to rising costs, lower production, high tax rates, and less exploration.

In January 2018, The North Sea region contained 184 offshore rigs, which made it the region with the highest number of offshore rigs in the world at the time.

The British North Sea's oil and gas production, peaking in 2000, had declined by 2024, while offshore wind projects like Dogger Bank grew to support renewable energy goals, with windfall taxes funding the transition.

Fishing

Main article: Fishing in the North Sea

The North Sea is Europe's main fishery accounting for over 5% of international commercial fish caught. Fishing in the North Sea is concentrated in the southern part of the coastal waters. The main method of fishing is trawling.{{cite book |access-date=12 January 2009 |archive-date=17 April 2023 |archive-url=https://web.archive.org/web/20230417084702/https://books.google.com/books?id=mtucgF2qOrIC&pg=RA1-PA252 |url-status=live In 1995, the total volume of fish and shellfish caught in the North Sea was approximately 3.5 million tonnes.{{cite web |access-date = 29 November 2008 |archive-url = https://web.archive.org/web/20081202121543/http://www.mumm.ac.be/EN/NorthSea/fishing.php |archive-date = 2 December 2008 |access-date =9 December 2007 |archive-date =9 November 2008 |archive-url =https://web.archive.org/web/20081109062620/http://www.ens-newswire.com/ens/nov2008/2008-11-05-03.asp

In recent decades, overfishing has left many fisheries unproductive, disturbing marine food chain dynamics and costing jobs in the fishing industry. Herring, cod and plaice fisheries may soon face the same plight as mackerel fishing, which ceased in the 1970s due to overfishing.{{cite web |access-date = 2 November 2008 |archive-url = https://web.archive.org/web/20070704031349/http://archive.greenpeace.org/comms/cbio/crisis1.html |archive-date = 4 July 2007 The objective of the European Union Common Fisheries Policy is to minimize the environmental impact associated with resource use by reducing fish discards, increasing the productivity of fisheries, stabilising markets of fisheries and fish processing, and supplying fish at reasonable prices for the consumer.{{Cite book |access-date =19 July 2007 |archive-date =22 March 2008 |archive-url =https://web.archive.org/web/20080322120042/http://www.europarl.europa.eu/facts_2004/4_3_1_en.htm |url-status =live

Whaling

Whaling was an important economic activity from the 9th until the 13th century for Flemish whalers. The medieval Flemish, Basque and Norwegian whalers who were replaced in the 16th century by Dutch, English, Danes, and Germans, took massive numbers of whales and dolphins and nearly depleted the right whales. This activity likely led to the extinction of the Atlantic population of the once common grey whale. By 1902 the whaling had ended. After being absent for 300 years a single grey whale returned in 2010, it probably was the first of many more to find its way through the now ice-free Northwest Passage.

Mineral resources

In addition to oil, gas, and fish, the states along the North Sea also take millions of cubic metres per year of sand and gravel from the ocean floor. These are used for beach nourishment, land reclamation and construction. Rolled pieces of amber may be picked up on the east coast of England.{{cite book |access-date=12 January 2009 |archive-date=17 April 2023 |archive-url=https://web.archive.org/web/20230417084711/https://books.google.com/books?id=g6NVVpqhixIC&pg=PA153 |url-status=live

Renewable energy

Due to the strong prevailing winds, and shallow water, countries on the North Sea, particularly Germany and Denmark, have used the shore for wind power since the 1990s.{{cite book |access-date=12 January 2009 |archive-date=17 April 2023 |archive-url=https://web.archive.org/web/20230417084723/https://books.google.com/books?id=q9r6aYDLwkgC&pg=PA206 |url-status=live

The expansion of offshore wind farms has met with some resistance. Concerns have included shipping collisions{{cite web |access-date = 8 December 2008 |archive-date = 17 December 2008 |archive-url = https://web.archive.org/web/20081217143715/http://www.bmu.bund.de/files/pdfs/allgemein/application/pdf/new_research.pdf |access-date = 16 January 2009 |archive-url = https://web.archive.org/web/20090205005628/http://www.berr.gov.uk/files/file20258.pdf |archive-date = 5 February 2009 There are also concerns about reliability, and the rising costs of constructing and maintaining offshore wind farms.{{cite news |access-date =16 January 2009 |archive-date =1 December 2008 |archive-url =https://web.archive.org/web/20081201140506/http://news.bbc.co.uk/2/hi/business/7391056.stm |url-status =live

Energy production from tidal power is still in a pre-commercial stage. The European Marine Energy Centre has installed a wave testing system at Billia Croo on the Orkney mainland and a tidal power testing station on the nearby island of Eday. Since 2003, a prototype Wave Dragon energy converter has been in operation at Nissum Bredning fjord of northern Denmark.

Tourism

The beaches and coastal waters of the North Sea are destinations for tourists. The English, Belgian, Dutch, German and Danish coasts{{cite book |access-date=27 December 2008 |archive-date=17 April 2023 |archive-url=https://web.archive.org/web/20230417084645/https://books.google.com/books?id=21ikixG655wC&pg=PA139 |url-status=live |access-date=27 December 2008 |archive-date=17 April 2023 |archive-url=https://web.archive.org/web/20230417084645/https://books.google.com/books?id=mxq97WB2aVQC&pg=PA170 |url-status=live

The North Sea Trail is a long-distance trail linking seven countries around the North Sea.{{cite web |access-date = 2 January 2009 |archive-url = https://web.archive.org/web/20160101042324/http://www.northseatrail.org/ |archive-date = 1 January 2016 Windsurfing and sailing{{cite book |access-date=27 December 2008 |archive-date=17 April 2023 |archive-url=https://web.archive.org/web/20230417084645/https://books.google.com/books?id=vNnCnURw2O4C&pg=PA112 |url-status=live |url-access= registration |access-date=27 December 2008 recreational fishing and birdwatching are among other activities.

The climatic conditions on the North Sea coast have been claimed to be healthy. As early as the 19th century, travellers visited the North Sea coast for curative and restorative vacations. The sea air, temperature, wind, water, and sunshine are counted among the beneficial conditions that are said to activate the body's defences, improve circulation, strengthen the immune system, and have healing effects on the skin and the respiratory system.{{Cite book |access-date =2 November 2008 |archive-date =1 December 2008 |archive-url =https://web.archive.org/web/20081201021723/http://www.germany-tourism.de/ENG/destination_germany/master_tlkur-id1252.htm?cc_lang= |url-status =live

The Wadden Sea in Denmark, Germany and the Netherlands is an UNESCO World Heritage Site.

Marine traffic

The North Sea is important for marine transport and its shipping lanes are among the busiest in the world. Major ports are located along its coasts: Rotterdam, the busiest port in Europe and the fourth busiest port in the world by tonnage , Antwerp (was 16th) and Hamburg (was 27th), Bremen/Bremerhaven and Felixstowe, both in the top 30 busiest container seaports, as well as the Port of Bruges-Zeebrugge, Europe's leading ro-ro port.{{cite web |access-date = 28 December 2008 |archive-url = https://web.archive.org/web/20090725000609/http://www.marinetalk.com/articles-marine-companies/com/Port-Authority-Bruges-Zeebrugge-POR069.html |archive-date = 25 July 2009 |url-status = usurped

Fishing boats, service boats for offshore industries, sport and pleasure craft, and merchant ships to and from North Sea ports and Baltic ports must share routes on the North Sea. The Dover Strait alone sees more than 400 commercial vessels a day. Because of this volume, navigation in the North Sea can be difficult in high traffic zones, so ports have established elaborate vessel traffic services to monitor and direct ships into and out of port.{{cite book |access-date=12 January 2009 |archive-date=17 April 2023 |archive-url=https://web.archive.org/web/20230417084646/https://books.google.com/books?id=sGSMw7gCOLYC&pg=PA167 |url-status=live

The North Sea coasts are home to numerous canals and canal systems to facilitate traffic between and among rivers, artificial harbours, and the sea. The Kiel Canal, connecting the North Sea with the Baltic Sea, is the most heavily used artificial seaway in the world reporting an average of 89 ships per day not including sporting boats and other small watercraft in 2009. It saves an average of 250 nmi, instead of the voyage around the Jutland peninsula. The North Sea Canal connects Amsterdam with the North Sea.

Critical Maritime Infrastructure

The North Sea contains a dense concentration of critical maritime infrastructure (CMI). Including offshore and subsea assets that support energy supply, digital communications, and maritime transportation. In terms of research and policy, "critical" generally refers to infrastructure whose disruption could have significant societal and economic effects and therefor attracts heightened attention in risk management and protection planning Which maritime assets are treated as "critical" can vary across sectors and jurisdictions, as designation is partly are policy and administrative choice.

The discovery of the North Sea's physical characteristics has facilitated extensive offshore development. Compared with deep water oceans, the North Sea is relatively shallow, which supports large-scale offshore oil and gas activity. Recently there has also been the expansion of offshore wind and associated cable networks adding to the vastness of critical maritime infrastructure in the North Sea. Alongside fixed offshore installations, the North Sea seabed hosts networks of pipelines, electricity cables, and fiber-optic communications cables within in a maritime area with high levels of port activity and shipping traffic. One regional assessment estimates that the Nort Sea hosts around 71,000 km of active subsea cables (about 5% of the global network), in addition to extensive pipelines and other offshore systems.

Infrastructure

Critical maritime infrastructure in the North Sea includes offshore and subsea assets linked with energy production, transmission, and communications. These infrastructures are often interdependent as offshore production relies on export connections to shore, while maintenance and emergency response depend on ports, specialized vessels, and onshore support basses.

The infrastructure landscape has been described as changing alongside decarbonization and investment policies. Oil and gas activity continues in parts of the North Sea, while late-life operations and decommissioning increase the need for monitoring and seabed management over a longer period of time. At the same time, offshore windfarms have expanded, increasing the number of installations at sea and the complexity of subsea power connections. Additional decarbonization-related developments include producing hydrogen offshore and using depleted oil and gas fields to store CO2 underground. These activities can require new or upgraded infrastructure such as offshore facilities, pipelines, and monitoring systems, which could increase reliance on these assets.

Offshore oil and gas installations

Offshore oil and gas infrastructure are complex installation that is essential for economic production in the North Sea. These installations include fixed and floating platforms as well as processing facilities, drilling units and associated subsea systems. Some installations function as hubs that gather hydrocarbons from multiple fields via subsea connection before exports to shore, supported by logistic chains.

Subsea Pipelines

Subsea pipelines transport oil and gas from offshore fields to onshore terminals and processing plants, and can also connect offshore hubs and nearby fields. Pipeline systems typically include trunk lines and infield flowlines as well as supporting equipment such as valves and monitoring and control systems. Existing pipeline corridors may also be discussed in connection with infrastructure, including potential reuse or adaptation for new purposes.

Offshore wind farms

Offshore wind developments typically include turbine arrays, offshore substation, and export cables that transmit electricity to shore. As projects scale up, associated electrical infrastructure can become more complex, including multiple export connections, onshore reinforcements, and links that support cross-border electricity integration. Construction and maintenance depend on specialised vessels and ports. Operating wind farms requires continuous monitoring, scheduled servicing and repair capacity to manage downtime.

Vulnerabilities and protection

CMI protection is complicated by the distribution of assets across large sea areas and the location of many components on or beneath the seabed. Reviews of CMI protection discuss a wide spectrum of risks such as accidents and technical failures, criminal activity and deliberate interference. It is important to note that planning often spans multiple policy fields such as marine safety, maritime security, and cybersecurity. Persistent monitoring is difficult due to limited visibility below the surface and the scale and technical challenges of surveillance in the maritime domain.

Accidental damage is commonly discussed in relation to dense maritime use and seabed activity. Mapping of cables and pipelines can support safe navigation and reduce risk from anchoring and fishing, but subsea infrastructure mapping may be incomplete or imprecise and can be distributed across multiple databases with limited standardization. Environmental and operational conditions can affect integrity and repair capacity; climate-related factors such as increasing storm intensity are discussed as part of the wider risk environment for offshore assets.

Deliberate disruption is frequently discussed with references to subsea cables and pipelines. It is noted that underwater supply lines are difficult to protect effectively on the sea floor and identifies submarines data and power cables as particularly vulnerable. The same analysis shows that cable damage can be carried out "hidden in common marine traffic" and describes scenarios where relatively common maritime equipment can damage cables if their location is known.

Cybersecurity is also treated as part of CMI protection since offshore installations and electricity networks increasingly rely on digital control and monitoring systems. It is noted that vulnerabilities associated with the digitalisation of maritime energy infrastructure have been reported hacking incidents affecting European wind farms and industrial control environments. More general critical infrastructure protection is framed as risk management in terms of identifying threats and vulnerabilities while evaluating likelihood and consequences, particularly for networked infrastructures where disruption can have cascading effects.

Protection and resilience measures include surveillance and maritime domain awareness as well as redundancy and resilience panning, and improved repair and recovery capacity. Subsea monitoring is technically channeling and resources-intensive needing vast monitoring capabilities as well as coordination between public authorities and private operators. It is also important to integrate diverse policy fields and strengthening public-private coordination, alongside investment in repair capacity and protective measures for maritime space.

International law and jurisdiction are also relevant to CMI protection, as many assets are located beyond territorial waters. It is noted that unauthorised mapping of infrastructure in another states territorial waters is not compatible with innocent passage. While in EEZ, the law of the sea does not provide coastal states with clear authority to prevent foreign vessels from collecting intelligence on maritime infrastructure, creating legal constraints for some preventative measures.

Citations

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