Coastal Environmental Change (Edexcel IGCSE Geography)
Revision Note
Written by: Jacque Cartwright
Reviewed by: Bridgette Barrett
Influence of Geology
Geology shapes the coastline over time, place and space
A coastline made up of softer rocks such as sands and clays will be easily eroded by destructive waves to form low, flat landscapes such as bays and beaches
Coastlines of more resistant, harder rock will take longer to erode and produce rugged landscapes such as headlands
The differences between hard and soft rocks will also impact the shape and characteristics of cliffs
| Hard Rock | Soft Rock |
---|---|---|
Shape of cliff | High and steep | Generally lower and less steep |
Cliff face | Bare rock and rugged | Smoother; evidence of slumping |
Foot of cliff | Boulders and rocks | Few rocks; some sand and mud |
Geology, therefore, shapes the coastline vertically through the height and profile of a cliff and horizontally with bays and headlands
Influence of Vegetation
The longer a coastal landform has existed, the more likely it will be colonised by vegetation
Over time, vegetation will 'fix' a feature (e.g. a sand dune)
Vegetation adaptation is important in order to survive coastal conditions
Vegetation has to cope with high levels of salt in both air and soil
The largest influence of vegetation is to assist in protecting and preserving coastal landforms such as sand dunes, salt marshes and mangroves
Influence of Sea-level Changes & People
Rising sea levels produce submergent coastlines, with rias and fjords
Falling sea levels produce emergent coastlines, with relic features such as raised beaches, cliffs with caves, arches etc.
Sea levels have risen and fallen many times in the past
During the last Ice Age, sea levels fell as the water was locked up in glaciers and ice sheets, rising again as the ice melted
Sea levels are linked to global warming and will have a significant effect on many low-lying coasts and islands
Many Pacific Ocean islands, such as Kiribati and Tuvalu are at risk of being completely submerged by rising sea levels
This issue is made worse as many of the world's densely populated areas are located on coastal lowlands
New York and Miami in the US are major cities vulnerable to sea-level rise as the cities are built at sea level
Influence of People
Human Activity
Human activities, either intentionally or not, transform the features and landscape of a coastline:
Settlement - coasts have always been a place of attraction and residence for people
Economic Development - exploitation through fishing, farming, trade, tourism and energy production
Coastal Management - controlling the coastline to protect human interests
Through any or all of the above, the natural landscapes and features of the coast can be changed, thereby changing the coastline over time, space and place
Worked Example
Study Figure 2a in the Resource Booklet. Suggest two ways changes in sea level have created coastal landforms
(4 Marks)
This question tells you to use the figure to show how changes in sea level have created coastal landforms
You must identify features and then develop your answer to suggest how it was formed due to changes in sea levels
If you do not refer to the figure, you will not gain full marks
Answer:
From the figure we can see where the sea level has decreased (1). This has created an emergent coastline (1) with a relic cliff and raised beach (1). Over time, the raised beach has become vegetated, supporting the observation of changing sea levels (1)
Wave action (1) from previous sea levels has eroded the relic cliff to expose a wave cut-notch (1), showing that sea levels used to be higher than the present (1). This has led to the relic cliff and sea caves further back than the current cliff face in the figure (1)
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