Sea level rise

Sea levels are rising at a significant rate because of global warming caused by carbon dioxide (and other gases) being released into the atmosphere in alarming quantities. Melting of glaciers, the heating and expansion of oceans and the melting of the Antarctic ice caps has meant in the past ten years some coastal areas have seen sea level rises of 30cm!

 

Some studies project sea levels to rise by 18-60cm by the 2050s and 24-108cm by the end decades of the next century. This rise will have drastic effects on coastlines. Submergence is an obvious effect but increased erosion and accretion rates are also consequences. Estuaries could migrate landwards at rates of around 10 m/year. Open-coast landforms could exhibit long-shore migration rates of 50 m/year. While ebb-tidal deltas may extend laterally along the shore at rates of 300 m/year!

 

Sea encroaching upon land and subsequent changes in habitat and will have dire consequences for coastal cities and communities. The majority of people that would be affected live in China (72 million) and Bangladesh (71 million). Between 0.3% (Venezuela) and 100% (Kiribati and the Marshall islands where two small islands that are part of the Pacific nation of Kiribati have already disappeared) of the population would be affected. However small island nations would also be greatly effected (see Kiribati above) as, unlike deltas and other coastal areas, small islands have no hinterland to move to in the case of coastal land loss. Small island nations contribute just 0.6 percent of the global greenhouse gas emissions yet will be the first to suffer the consequences of sea level rise due to global warming.

For most countries indirect factors are generally listed as the main difficulties associated with sea-level rise. These include erosion patterns and damage to coastal infrastructure, salinisation of wells, sub- optimal functioning of the sewerage systems of coastal cities with resulting health impacts, loss of littoral ecosystems and loss of biotic resources.