- 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).
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
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
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
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
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.
- Low emissions scenario: Local solutions to sustainablity, slower rate of population increase, less rapid technological change
Why is it so difficult to predict future gas emiss
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.
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
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)
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)