Past sea level has varied by somewhat more than a hundred metres. This is primarily due to the growth and decay of ice sheets (mostly in the northern hemisphere) with water evaporated from the sea. The Mediterranean Basin's gradual growth as the Neotethys basin, begun in the Jurassic, did not suddenly affect ocean levels. While the Mediterranean was forming during the past 100 million years, the average ocean level was generally 200 metres above current levels. However, the largest known example of marine flooding was when the Atlantic breached the Strait of Gibraltar at the end of the Messinian Salinity Crisis about 5.2
Sea level rise (8%). The sea level will not rise uniformly everywhere on Earth, and it will even drop in some locations. Local factors include tectonic effects and subsidence of the land, tides, currents and storms. The rising trend is expected to continue for centuries. Because of long response times of the climate system, it has been estimated that each Celsius degree of temperature rise would trigger a sea level rise of approximately over the next 2,000 years. Sea level rises can considerably influence human populations in coastal and island regions and natural environments like marine ecosystems. Widespread coastal flooding would be expected