The North Sea is a sea of the Atlantic Ocean between Great Britain, Norway, Denmark, Germany, the Netherlands, Belgium and France. An epeiric (or "shelf") sea on the European continental shelf, it connects to the ocean through the English Channel in the south and the Norwegian Sea in the north. It is more than 970 kilometres (600 mi) long and 580 kilometres (360 mi) wide, covering 570,000 square kilometres (220,000 sq mi).
It has long hosted key north European shipping lanes as well as provided a major fishery. The coast is a popular destination for recreation and tourism in bordering countries, and more recently the sea has developed into a rich source of energy resources, including fossil fuels, wind, and early efforts in wave power.
Historically, the North Sea has featured prominently in geopolitical and military affairs, particularly in Northern Europe. It was also important globally through the power northern Europeans projected worldwide during much of the Middle Ages and into the modern era. The North Sea was the centre of the Vikings' rise. Subsequently, the Hanseatic League, the Dutch Republic, and the British each sought to gain command of the North Sea and thus access to the world's markets and resources. As Germany's only outlet to the ocean, the North Sea continued to be strategically important through both World Wars.
The coast has diverse geology and geography. In the north, deep fjords and sheer cliffs mark much of its Norwegian and Scottish coastlines respectively, whereas in the south, the coast consists mainly of sandy beaches, estuaries of long rivers and wide mudflats. Due to the dense population, heavy industrialization, and intense use of the sea and the area surrounding it, there have been various environmental issues affecting the sea's ecosystems. Adverse environmental issues – commonly including overfishing, industrial and agricultural runoff, dredging, and dumping, among others – , have led to several efforts to prevent degradation and to safeguard the long-term economic benefits.
The North Sea is bounded by the Orkney Islands and east coast of Great Britain to the west[1] and the northern and central European mainland to the east and south, including Norway, Denmark, Germany, the Netherlands, Belgium, and France.[2] In the southwest, beyond the Straits of Dover, the North Sea becomes the English Channel connecting to the Atlantic Ocean.[1][2] In the east, it connects to the Baltic Sea via the Skagerrak and Kattegat,[2] narrow straits that separate Denmark from Norway and Sweden respectively.[1] In the north it is bordered by the Shetland Islands, and connects with the Norwegian Sea, which is a marginal sea in the Arctic Ocean.[1][3]
The North Sea is more than 970 kilometres (600 mi) long and 580 kilometres (360 mi) wide, with an area of 570,000 square kilometres (220,000 sq mi) and a volume of 54,000 cubic kilometres (13,000 cu mi).[4] Around the edges of the North Sea are sizeable islands and archipelagos, including Shetland, Orkney, and the Frisian Islands.[2] 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.[5] Around 185 million people live in the catchment area of the rivers discharging into the North Sea encompassing some highly industrialized areas.[6]