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Flashcards in 2B.7 Deck (26)
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1

What is isostatic change?

When land is changing relative to the sea locally which is due to isostatic rebound

- ice leaving ground

2

What is eustatic change?

When the sea changes relative to the land (global) due to melting ice from the poles

- more water in oceans

3

How do tectonic affect sea level?

Land can be pushed up by plates in a series of earthquakes which an displace the sea-bed leading to post glacial rebound

Eg Iceland = Surtsey has risen due to volcanic activity

4

How does accretion affect sea levels?

The deposition of sediment in rivers, estuaries or deltas can weigh down the crust and also cause sinking (subsidence)

Eg Thames estuary

5

What are submerging coastlines produced by?

Eustatic sea level change

6

What are emergent coastlines produced by?

Isostatic readjustment / rebound

7

Who monitors climate change?

The IPCC intergovernmental panel on climate change
—> show that it fluctuated in 1850s

8

What are predictions of sea level change?

Lowest = 28-61 cm rise
High = 52-98 cm rise

9

What contributes to sea level change?

Thermal expansion
Melting of glaciers - 27% so far,
Sea level rising 3mm a year which is seasonal (winter = cumulative budget) summer = melts
Melting of ice sheets eg 10% in Antarctic, 15% in Greenland

10

Why is there debate about sea level rise?

Unclear about how much thermal expansion
Unclear at speed of melting

11

What areas in the world are at most risk?

Maldives
Bangladesh
Netherlands
New York
Southampton
Mumbai

12

What are causes of coastal retreat?

Human causes
Sub-aerial processes
Wind direction
Tides
Weather systems

13

How do human causes impact recession rates?

- Alters Natural processes
- defences reduce sediment
- offshore dredging eg Hallsands and Admiralty
- chooses SMP on CBA

14

How do sub-aerial processes cause retreat?

Weakens rocks
Mass movements
—> moves sediment away
—> influenced by season changes

15

How do winds add to coastal retreat?

Dominant winds give off energy to waves which fluctuated adding to the dynamic coastal area ie foreshore.
Coasts experience mass erosion during winds

16

How do tides increase recession?

High tides = waves reach back shore and eroded
- destructive waves cause maximum erosion

17

How do weather systems lead to increased recession?

Low pressure = rising air = strong winds causing storm surges
In winter there are stronger depressions and larger more destructive waves
Higher temperature = more erosion = energy levels

18

What is a transboundary river?

River that traverses across two or more countries eg the Nile delta main river.

19

What are facts about the river Nile?

More salt in delta due to sea level rise = flocculation
2million hectares of land lost
6million people displaced
30% of Alexandrian population displaced
240km of Nile delta is Eastern Mediterranean
Will destroy tourism defences agriculture and settlements
95% of Egypt live near delta

20

What is coastal squeeze?

Population forcing areas to develop near coasts or rivers. eg Mediterranean.

21

What is a raised beach?

Former beach now above the high tide line which contain several layers eg Forthy, Clyde and Tay in eastern Scotland.

22

What is a fossil/relict cliff?

Near vertical slope initially formed by Marin erosion but now inland eg Vik in South Iceland.
These may still have coastal features eg Stack or cove.

23

What is a ria?

A flooded river valley

24

What is a fjord?

Flooded glaciated valley?

25

What is an example of a fjord?

In Norway, NZ, Canada.

26

What is an example of a ria?

In Devon, SW England