Coasts - Sea Level Change AGAIN

Question 1

What is isostatic change?

Answer 1

A change in sea level as a result of the changing level of the land.

Question 2

What is eustatic change?

Answer 2

A change in sea level caused when the amount of water in the oceans changes.

Question 3

Is isostatic change a local or global change?

Answer 3

Local

Question 4

Is eustatic change a local or global change?

Answer 4

Global

Question 5

When was the last glacial maximum?

Answer 5

18,000 years ago

Question 6

What was the sea level like at the last glacial maximum compared today?

Answer 6

On average 110m lower than today

Question 7

At the last glacial maximum, what joined the UK to mainland Europe and Scandinavia?

Answer 7

A large land bridge called Doggerland

Question 8

How quickly are current sea levels rising?

Answer 8

3.2mm per year

Question 9

What is the predicted rise in sea level by 2100?

Answer 9

4-6m

Question 10

What is currently the main cause of rising sea levels?

Answer 10

Thermal expansion

Question 11

Give 3 causes of isostatic change

Answer 11

• tectonic activity
• glaciation
• post-glacial readjustment

Question 12

Give an example of tectonic activity causing isostatic change

Answer 12

Tohoku earthquake, Japan, 2011. Some sections of the coastline dropped by 0.84m.

Question 13

How would glaciation cause isostatic subsidence?

Answer 13

The loading of a glacier or ice sheet’s weight onto the land causes the land surface to become pressed into the asthenosphere.

Question 14

What is isostatic subsidence?

Answer 14

The falling of a land mass relative to the sea.

Question 15

What is isostatic recovery?

Answer 15

The rising of a land mass relative to the sea.

Question 16

How does post-glacial readjustment cause isostatic change?

Answer 16

The melting of glaciers and ice sheets on land allows it to rise back up as the asthenosphere rebounds.

Question 17

Give an example of post-glacial readjustment causing isostatic change.

Answer 17

Currently causing sea levels to fall in Scotland. During the last ice age Scotland the part of the UK covered with the thickest ice which melted last. This is causing land in south east England to sink.

Question 18

Give three causes of eustatic change.

Answer 18

• thermal expansion of water
• changes in ice sheet extent
• tectonic activity

Question 19

How does thermal expansion cause eustatic change?

Answer 19

As water is heated it expands, increasing the volume of the water in the oceans. This causes sea level rise.

Question 20

How do changes in ice sheet extent cause eustatic change?

Answer 20

Ice forming on land means water is removed from other stores such as the ocean, lowering sea levels. When ice on land melts it is then available to be stored in the oceans, which would increase sea level.

Question 21

How does tectonic activity cause eustatic sea level rise?

Answer 21

New land formation under the ocean displaces water. This usually occurs at mid-ocean ridges.

Question 22

What is total sea level change?

Answer 22

The balance between isostatic and eustatic change.

Question 23

What is the total sea level change in Scotland?

Answer 23

Sea level is falling, as isostatic recovery is causing the land to rise at a higher rate than thermal expansion and melting ice sheets are causing the sea level to rise.