4.5 Interaction of Human and Physical Processes Flashcards
Why is sea level rising?
Sea level is rising due to:
The ice on land is melting, an example of this would be Antartica, and this causes the water to fall into the sea and cause it to enlarge. The reason why ice, that is already in the sea, doesn’t contribute to sea level rise is because the ice is already in the sea so its volume is already contributing to the overall volume of the sea.
Thermal expansion is when water expands when it is heated up. This is because the particles gain more energy so they vibrate more and take up more room. Global warming means that the ambient temperature is higher so the water would expand more.
How bad will sea level get and give examples of it around the world?
A 1.5m rise in sea level (in Bangladesh) would cause:
17 million people (15%) would be affected.
16% of properties (22,000m^2) would be affected
A 1m rise in sea level (in the Maldives) would cause:
Most of the islands would be flooded even though the average height of the islands is 1.2m, that includes the few very mountainous islands that unbalance the average.
The main airport and capital would be flooded.
A 2m sea level rise (in the UK) would cause:
111,356 properties would be affected, that is only the South East.
Plains such as the Humber, Wash and Thames would all be greatly affected.
How will climate change affect erosion and deposition?
Climate change will mean that waves will be higher and therefore erode cliffs and soft rocks much quicker as more water is being thrown at the rocks. Buildings, railways and homes will become affected. Farmlands will become saline and unproductive.
Spits, bars and beaches will become less frequent as the wave power would be very powerful and it would erode the formations more. They would become less stable and be eroded away.
How does climate change affect the storm frequency, intensity and storm surges
Global warming causes more energy in the storms so they are more intense. Higher sea level also means that storm surges will become more frequent and be able to go over sea defences more easily.
How will storms and storm surges affect humans and environments?
Storms will cause a lot of damage to houses and therefore displace a lot of people. Habitats will be destroyed as the storm surges flood the habitats. Farmland will become saline and unproductive.
How do groynes and sea walls work?
Groynes
Groynes are wooden walls. They prevent longshore drift so they mean that the sediment builds up and then it means that the sediment absorbs the wave energy and means that erosion occurs less. However after the terminal groyne, lots of erosion occurs.
Sea walls
Sea walls actively stop the wave from eroding the face of the cliff. They absorb the wave energy. Recurved sea walls rebound the wave back out towards the sea and stops the wave from undercutting the sea wall.
How does beach replenishment and slope stabilisation work?
Beach replenishment
Beach replenishment is when sand is deposited. This sediment absorbs the wave energy and therefore stops the wave from eroding the cliff of the face.
Slope stabilisation
Slope stabilisation is when drains are placed inside a slope as water seeps into the sand yet stops at the clay. This means that the water is drained out and the slope is no longer at a danger of collapsing
Advantages and disadvantages of each management method?
Groynes
A: prevent LSD and reduces erosion. Cheap cost.
D: wood rot means that maintenance is required. Causes lots of erosion after the terminal groyne.
Sea wall
A: prevents waves from eroding the coast. Recurved sea walls are very effective and last a very long time
D: costs a LOT. Sea level rise causes it to become ineffective. Doesn’t look aesthetically pleasing.
Beach replenishment
A: uses a natural process and looks aesthetically pleasing. Cheap cost.
D: requires maintenance every year. Sand needs to be removed from one area for it to be deposited in another.
Differences between Hard and soft engineering and which is better?
Hard:
Uses large amounts of man-made material, such as concrete. They aim to stop natural processes-LSD, erosion. They typically involve large scale construction/disruption.
Soft:
Uses natural materials, such as sand. They aim to work with natural processes. They typically involve small scale construction, however they still need a bit of maintenance.
