Explanation:

Scientists have proposed the construction of a Northern European Enclosure Dam (NEED) enclosing all of the North Sea as an extraordinary measure to protect Northern European countries from rising seas as a result of climate change. The Northern European Enclosure Dam (NEED) is a proposed solution to the problem of rising ocean levels in Northern Europe. It would be a megaproject, involving the construction of two massive dams of a combined length of 637 km enclosing all of the North Sea:

• one between France and England, and
• another between Scotland and Norway.

The concept was conceived by the oceanographers Sjoerd Groeskamp and Joakim Kjellsson. According to them, separating the North and Baltic Seas from the Atlantic Ocean may be the “most viable option” to protect Northern Europe against unstoppable sea level rise (SLR). The scheme's authors describe it as "more of a warning than a solution". As of 2020, the scheme is largely a thought experiment intended to demonstrate the extreme cost of engineered solutions to the effects of climate change.