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Global sea level rise. Aim: To Investigate how sea level rise may have a disproportionately bigger effect on some countries using examples of Bangladesh and Pacific Islands. Flooding scenarios.
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Global sea level rise Aim: To Investigate how sea level rise may have a disproportionately bigger effect on some countries using examples of Bangladesh and Pacific Islands.
Flooding scenarios • A worst-case scenario of a 15m rise in sea level by 2100 would put many of the world’s great cities in danger including London, New York and Tokyo • To reach this estimate the following calculations were made • Melting of W.Antarctic ice sheet = 5 m rise • Complete Greenland ice sheets melt = 7 m rise • Collapse and melting of world’s glacier systems = 2 m rise • Thermal expansion of ocean = 1 m rise
Flooding vulnerability • Think back to disaster risk equation • Many of the people living on these islands are vulnerable and little capacity to cope • Islands are so small no where to flee • Prone to natural disasters • Rapidly growing populations • Vulnerability of groundwater contamination from sea water
Predicting future sea level change? • Predicting eustatic sea-level rise is complex! Reasons why include… • It is difficult to estimate future greenhouse emissions and effects • Difficult to predict how the world’s nations will respond in the future- ‘business as usual’ approach or sustainable approach to development? • Difficult to accurately predict thermal expansion and melting of ice sheets
Impacts – Eustatic rise in sea level More than 60% of the global population lives on or within 60km of the coast. Areas threatened by rising sea level
Sea level threats to Bangladesh Impacts - Bangladesh • Bangladesh is very densely populated. • Many fresh water fishing resources are under threat. • Fishing generates substantial income and any intrusion of salt water would disrupt the economy. • Storm surges are also a threat; cyclonic storms occur frequently and with devastating effects.
Over to you… • P43 – write down the definition of Thermohaline circulation and explain how oceans contribute to climate regulation. • P52 – how will Thermohaline Circulation be disrupted as a result of climate change? • Explain the difference between eustatic and isostatic sea level change. • Make notes on impact of rising sea levels in Bangladesh and the Pacific Islands – consider human and physical factors (mini case studies sheet). • Why is it difficult to make accurate predictions about the impacts of global warming?
Finally… • Look at course outline – impacts of GW. • Recap Arctic vs Africa – key case studies!