All About Sea Level Change

Question 1

When was the last glacial maximum?

Answer 1

20,000 years ago.

Question 2

What happened during the last glacial maximum?

Answer 2

Its estimated sea levels have risen by 125m.

Rapid increase was during inter glacial period with a 10m in just 500 years - 20mm per year during this period.

Question 3

What has happened over the last 3000 years?

Answer 3

Sea levels have been relatively stable.
Until mid 19th century when increase started again.
Rate increased from 6cm rise during 19th century to 19cm during 20th century.

Question 4

What is the current rate of sea level change?

Answer 4

3.2mm per year.

Question 5

What is the current sea level change mainly due to?

Answer 5

Thermal expansion of the ocean with significant contributions from glacial and ice field melt.

Question 6

Name 2 ways to why seal levels are rising?

Answer 6

Increases in the volume of the ocean.

Subsidence of the coast.

Question 7

Why is there an increase in the volume of the ocean?

Answer 7

Due to natural and current warming related to greenhouse gas emissions and human induced greenhouse gas.
Water currently stored as ice is released into oceans as it melts.
Also thermal expansion of oceans.

Question 8

Name 4 natural causes of coastal flooding?

Answer 8

Global warming.
Storm surges caused by hurricanes/tropical cyclones.
Storm surges caused by low pressure/high tides and high river discharge.
Tsunamis.

Question 9

Name 2 human causes of coastal flooding?

Answer 9

Global warming.

Coastal management.

Question 10

Name the future predictions of sea level rise.

Answer 10

Its uncertain.

between 0.3 - 0.5m increase by 2090.

Question 11

Name some ENVIRONMENTAL impacts of present and predicted sea level rise?
5

Answer 11

Coastal flooding.
Intrusion of salt water beneath the land.
Loss of productive coastal, delta, river flood plain agriculture.
Coastal habitats threatened.
Submergence of atolls and low lying areas.
Ecosystems can adjust.

Question 12

Where will coastal flooding take place?

ENVIRONMENTAL.

Answer 12

Low-lying areas meaning increased erosion.
eg Holderness.
When there’s spring tides and strong onshore winds.

Question 13

Where in Britain is there an increases risk of flooding?

ENVIRONMENTAL.

Answer 13

Southeast of Britain due to combined eustatic change and subsidence.

Question 14

What could an intrusion of salt water beneath the land do?

ENVIRONMENTAL.

Answer 14

Contaminate fresh water stores.

Question 15

What type of coastal habitats are threatened?

ENVIRONMENTAL.

Answer 15

Wetlands and salt marshes.

Question 16

Name a low lying place that may eventually become wiped out?

ENVIRONMENTAL.

Answer 16

Maldives.

Question 17

Name some SOCIAL impacts of present and predicted sea level rise?
5

Answer 17

Roads, rail and power stations under threat.
Greater migration away from coastal areas.
Impact of underground water sources.
Abstraction points moved.
Developments occurring on risk areas.

Question 18

Where would abstraction points have to be moved?

SOCIAL.

Answer 18

Moved upstream/inland to avoid salt water.

Question 19

Name ECONOMIC impacts of present and predicted sea level rise?
2.

Answer 19

Increase in costs for flooding protection measures and coastal migration for coastal cities.
Some developments insurance is expensive.

Question 20

What is the disadvantage of having some developments insurance being expensive?
ECONOMIC.

Answer 20

Dissuade people from moving into these areas and stops people moving out.

Question 21

What is a global impact of rising sea level?

Answer 21

Many of the world’s major urban areas are coastal, New York, London and Tokyo and 44% of the world’s population live within 100km of the coast.

Question 22

The economic, social, environmental and demographic impacts of higher sea levels will cause what?

Answer 22

Serious political implications for national governments, global organisations and international cooperation.

Question 23

Why will there be an increased amount of cliff erosion if sea levels rise?

Answer 23

As waves are attacking areas previously above high tide.