All About Sea Level Change Flashcards
When was the last glacial maximum?
20,000 years ago.
What happened during the last glacial maximum?
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.
What has happened over the last 3000 years?
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.
What is the current rate of sea level change?
3.2mm per year.
What is the current sea level change mainly due to?
Thermal expansion of the ocean with significant contributions from glacial and ice field melt.
Name 2 ways to why seal levels are rising?
Increases in the volume of the ocean.
Subsidence of the coast.
Why is there an increase in the volume of the ocean?
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.
Name 4 natural causes of coastal flooding?
Global warming.
Storm surges caused by hurricanes/tropical cyclones.
Storm surges caused by low pressure/high tides and high river discharge.
Tsunamis.
Name 2 human causes of coastal flooding?
Global warming.
Coastal management.
Name the future predictions of sea level rise.
Its uncertain.
between 0.3 - 0.5m increase by 2090.
Name some ENVIRONMENTAL impacts of present and predicted sea level rise?
5
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.
Where will coastal flooding take place?
ENVIRONMENTAL.
Low-lying areas meaning increased erosion.
eg Holderness.
When there’s spring tides and strong onshore winds.
Where in Britain is there an increases risk of flooding?
ENVIRONMENTAL.
Southeast of Britain due to combined eustatic change and subsidence.
What could an intrusion of salt water beneath the land do?
ENVIRONMENTAL.
Contaminate fresh water stores.
What type of coastal habitats are threatened?
ENVIRONMENTAL.
Wetlands and salt marshes.
Name a low lying place that may eventually become wiped out?
ENVIRONMENTAL.
Maldives.
Name some SOCIAL impacts of present and predicted sea level rise?
5
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.
Where would abstraction points have to be moved?
SOCIAL.
Moved upstream/inland to avoid salt water.
Name ECONOMIC impacts of present and predicted sea level rise?
2.
Increase in costs for flooding protection measures and coastal migration for coastal cities.
Some developments insurance is expensive.
What is the disadvantage of having some developments insurance being expensive?
ECONOMIC.
Dissuade people from moving into these areas and stops people moving out.
What is a global impact of rising sea level?
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.
The economic, social, environmental and demographic impacts of higher sea levels will cause what?
Serious political implications for national governments, global organisations and international cooperation.
Why will there be an increased amount of cliff erosion if sea levels rise?
As waves are attacking areas previously above high tide.
