SEA LEVEL CHANGE

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WHAT ARE THE IMPLICATIONS OF SEA LEVEL CHANGE?

This essay considers the rate of sea level rise and its possible impacts in Britain and other parts of the world, especially LEDC countried like Bangladesh and South American countries.

Essay by Seb Desando, year 12

Current sea level rise has occurred at a mean rate of 1.8 mm per year for the past century, and more recently at rates estimated near 2.8 to 3.1mm per year (1993-2003). Sea level rise is largely due to global warming which is estimated to increase sea level over the coming century and longer periods at an even higher rate.

Glaciers: If the world's mountain glaciers and icecaps melt, sea levels will rise by an estimated 0.5m. These are especially prominent in Greenland and Antarctica.
Thermal expansion: The expansion of warming oceans was the main factor contributing to sea level rise, in the 20th Century, and currently accounts for more than half of the observed rise in sea levels. All bodies expand when they are heated, and that is true for the water that covers 70 per cent of the planet. The oceans are expanding upwards.
Ice sheets: These vast reserves contain billions of tonnes of frozen water - if the largest of them (the East Antarctic ice sheet) melts, the global sea level will rise by an estimated 64m.
Three major causes of sea level rise.
Recent studies carried out by scientists in Greenland reveal that changes in the polar ice sheets could raise sea levels by a metre or more by 2100. This scenario would have severe implications as ten per cent of the world's population (about 600 million people) live in vulnerable areas. Another study carried out by Dr Paul Blanchon, a marine scientist of the National University of Mexico in Cancun has revealed that sea levels could rise by a "catastrophic" 10 feet by the end of the century. This would put millions of people at risk and submerge coastal cities such as London, New York, Tokyo and Calcutta.
Climate change experts in North and South America have conducted research that shows these land masses to be adversely affected by the implications of sea level rise. Parts of the Caribbean, Mexico and Ecuador are seen as most at risk. One of the main catalysts behind the new estimates is the melting of the polar ice sheets. "These new data on sea level rises are alarming, when combined with the exponential growth of urbanisation and tourism along the coast of the Gulf of Mexico and the Mexican Caribbean, it is extremely worrying " says Arnoldo Matus Kramer, a researcher on climate change adaptation at Oxford University. Ecuador's profitable fishing industry, which is to a certain extent the core of the economy, would also be threatened.

Bangladesh, one of the world’s poorest countries, is also one of the most prone to rapid sea level rise. The population is already severely affected by storm surges. It is situated in the low-lying Ganges River delta and is also one of the most densely populated countries on earth. The people who live on Char Bangla are among the most vulnerable anywhere to a rise in sea level and have built up platforms of mud for their straw huts to try to keep them out of the water. However, in the long term these flood defence methods will be breached and some estimate that at least a fifth of the country will be under water. Florida, the Maldives and the Netherlands also face catastrophic flooding prospects due to sea level rise.

Potential impact of sea level rise on Bangladesh

Although most scientists believe that Britain remains relatively well placed to combat sea-level rises, large areas of the Norfolk Broads and the Thames estuary are likely to disappear by 2100. In addition, cities including London, Hull and Portsmouth will need new flood defences. According to Professor Robert Nicholls, of Southampton University "The government has been fairly far-sighted over this issue, with projects such as Thames Estuary 2100 being set up to prepare flooding defence projects". A study conducted by the Environment Agency shows a general pattern of subsidence of 1-2mm a year in London. With waters rising in the region by about 1mm a year, the combined effect is a 2-3mm a year rise in sea level with respect to the land. This eustatic and isostatic change, which when coupled together can be termed as rejuvenation, could have drastic effects on London and its inhabitants. The region is home to 1.3 million people and has a property value worth more than £80bn. Some dips relate to water extraction by pumping stations but others relate to the seasons that alternately load and unload the ground, making the Earth's crust "breathe" up and down over a longer period.

Effect of several metres sea level rise in the UK

The effects of sea level rise not only affect human beings but also the wildlife that adorn our planet. The increasing global temperature may spell doom for the Sunderban tigers as a WWF study has cautioned that a rise of 28 centimetres in sea levels will engulf 96 per cent of their habitat. The findings although specific for Bangladesh, raise alarm for the tiger population in India where the Sunderbans have the same ecosystem.
There is no doubt about the extent of the problems that global warming entails and sea levels rise and its implications could have catastrophic effects in the near future.

iblography

Bibliography:
http://www.guardian.co.uk/environment/2009/mar/11/sea-level-rises-climate-change-copenhagen
http://en.wikipedia.org/wiki/Current_sea_level_rise
http://news.bbc.co.uk/1/hi/8387137.stm
http://www.deccanherald.com/content/48592/28cm-sea-level-rise-drown.html
http://www.telegraph.co.uk/earth/environment/climatechange/5159086/New-warning-over-catastrophic-sea-level-rise-scientists-claim.html
http://maps.grida.no/go/graphic/potential-impact-of-sea-level-rise-on-bangladesh
http://news.bbc.co.uk/1/hi/sci/tech/4056755.stm
http://www.guardian.co.uk/science/2009/mar/08/climate-change-flooding
http://news.bbc.co.uk/1/hi/sci/tech/6231334.stm

WEB LINKS

NERC publication: Diasappearing Coasts

Marine Climate Change Impacts Partnership. Coastal Erosion and Coastal Geomprphology: This is an excellent report. Even if you don't read anything else, go through it as the diagrams, photos and tables of information are excellent.