Eustatic change - global change in sea level. (affects the whole world) It is caused by thermal expansion and melting ice sheets.
Isostatic change - localised movement of land in response to loss or gain of weight (e.g. melting ice sheets leads to uplift).
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Flooding scenarios
A worst case scenario of a 15m rise in sea level by 2100 would put many of the world's greatest cities in danger including London, New York and Tokyo.
To reach this estimate the following calculations were made:
melting of W. Antarctic ice sheet = 15m rise
complete Greenland ice sheets melt - 7m rise
Collapse and melting of world's glacier systems - 2m rise
Thermal expansion of ocean - 1m rise
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Which areas are must vulnerable to rising sea leve
1.) Coastal areas - low lying e.g. Bangladesh
2.) Small islands e.g. Maldives (usually in the Pacific and Indian Oceans).
3.) River deltas e.g. Egypt - river Nile
4.) Areas buily on reclaimed land e.g. Dubai, Singapore
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Predicting future sea level change
Predicting eustatic sea-level rise is complex and uncertain because:
Unprecidented - hasn't happened before, difficult to estimate future greenhouse emissions and affects, don't know how the world's nations will respond - sustainable approach or not?
Difficult to measure
Positive feedback mechanism - don't know how to respond
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Carbon Dioxide Emissions
greatest emissions come from the MEDCs e.g. USA, UK, Germany, Japan - consumerism, wealth, electricity, heating, lighting
NICs/BRICs also have large contributions e.g. China, India - industrialisation, amazon - deforestation
LEDCs contribute virtually nothing - haven't undergone industrialisation, no wealth, not as much electricity etc
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Who are the IPCC
As the prediction of climate change in so uncertain, the IPCC envisage different possibilities for the future based on a range of emissions scenarios.
If we carry on:
High emissions scenario: rapid economic growth, increasing populations, reliance on fossil fuels, business as usual.
Sustainable approaches:
Low emissions scenario: Local solutions to sustainablity, slower rate of population increase, less rapid technological change
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Why is it so difficult to predict future gas emiss
1.) Unprecidented
2.) Posiive feedback mechanism
3.) Hard to predict the degree of international action that will be taken to reuce gas emissions
4.) Inertia in the system - even if GHG emissions stabilise, climate change will continue.
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Main effects as a result of increased temperatures
Mass migration from badly hit areas to relatively stable areas (e.g. from Africa to Europe)
Large scale conflicts over resources (food and water)
More hazardous world - increase in magnitude and frequency of floods, droughts, tropical storms
Collapse of the West Antarctic and Greenland ice sheets, causing a 15m sea level rise and threatening the lives of millions
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Socio economic effects of increased temperatures
Southeast England suffers permanent water shortages. Winters in London are up to 3 degrees warmer and summers 5 degrees hotter
Few Alpine ski runs have snow below 1,800m
Meltwater from retreating glaciers causes devastating floods in the Himalayas (ecological/environmental too)
The end of the Inuit hunting culture due to disappearing prey and habitat
An increase in insect-borne diseases, such as malaria, which claims, 1.3 million lives each year
Crop yields in Africa drop 105. Yields fall for the first time since the Agricultural Revolution in Europe, the USA and Russi
Three billion people have no ready supply of clean water, particularly in Asia
200 million more people at risk from hunger as drought increases in Africa and Asia
Half of Australia's Kakudo National Park Disasters (ecological/environmental too)
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Ecological/environmental effects of increased temp
53% of the Arctic tundra lost
Polar bears wiped out in the Arctic homeland
The ice sheet covering 80% of Greenland in irreversible retreat
Puffic colonies on the Scottish coast almost extinct
Up to 50% of wetlands on the Mediterranean and Baltic coasts disappear
97% of coral reefs killed
Half of Australia's Kakadu National Park disappears
80% of South Africa's unique collection of wild flowers disappears
Meltwater from retreating glaciers causes devastating floods in the Himalayas (socio economic too)
Half of Australia's Kakadu National Park disappears ( socio economic too)
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