3.2 Sea level rise

The average global sea level rise by 3,40 mm per year – and the rise accelerates

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The loss of ice in Greenland and the shrinking of glaciers in other parts of the Arctic currently contribute up to 40% of the average 3 mm global sea level rise per year. A number of studies suggest that Greenland could be a major contributor to a potential rise in sea levels of 0,5 to 1 meter by the end of the century. Taken by: Peter Prokosch

A significant sea level rise is one of the major anticipated consequences of climate change. There are  two main factors related to global warming: the added water from melting land ice and the expansion of sea water as it warms.

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The loss of ice in Greenland and the shrinking of glaciers in other parts of the Arctic currently contribute up to 40% of the average 3 mm global sea level rise per year. A number of studies suggest that Greenland could be a major contributor to a potential rise in sea levels of 0,5 to 1 meter by the end of the century.

Sea-level rise threatens cities around the world, and people need to grasp the potential dangers and costs. Hundreds of millions of peope live close to the oceans, and the majority of the world’s biggest cities are situated in vulnerable areas for salt water intrusion, wave erosion and inundations.

Sea level rise will vary around the world. Some land areas are rising, some sinking. Areas in the vicinity of large melting glaciers like Greenland. might experience a slightly sinking sea level due to gravitation differences. Other areas closer to the equator may experience particularly  rapid sea level rise.

Rising sea levels imperil lowlying areas like Bangladesh, Egypt, West-Africa, The South-East of the US coastal areas, parts of England and most big cities of the world. Low islands cannot expect to be inhabitable the second half of this century.

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This graphic explains the causes of sea level change according to the Intergovernmental Panel on Climate Change (IPCC). It explains the IPCC’s A1 scenario family, which consists of three scenarios on future use of fossil energy sources, including scenario A1F1, which involves the use of fossil-intensive energy sources. This resource also includes the graphic ‘Components of Mean Sea Level Rise for the Scenario A1F1’ which shows the projected sea level rise in metres by 2050 and by 2100 for Greenland, glaciers, expansion, the Antarctic, and the total sea level rise. Author: P. Rekacewicz,

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The Nile delta

The Nile Delta is one of the oldest intensely cultivated areas on earth. It is very heavily populated, with population densities up to 1600 inhabitants per square kilometer.

The low lying, fertile floodplains are surrounded by deserts. Only 2,5% of Egypt’s land area, the Nile delta and the Nile valley, is suitable for intensive agriculture.

Most of a 50 km wide land strip along the coast is less than 2 m above sea-level and is protected from flooding by a 1 to 10 km wide coastal sand belt only, shaped by discharge of the Rosetta and Damietta branches of the Nile.

Erosion of the protective sand belt is a serious problem and has accelerated since the construction of the Aswan dam.

Graphic: UNEP / GRID-Arendal

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