3.3.1
Sea Level Change
Sea Level Change
Sea Level Change
Factors combine to increase the risk of sea level change, which threatens the lives of people who live near coasts. There are three key factors that have contributed towards sea level change over different time periods, plus climate change.
Eustatic change
Eustatic change
- Eustatic change is the rising and falling of sea levels, influenced by ice ages.
- Water is stored in the form of ice when the world is experiencing an ice age, which causes the sea level to fall.
- As the world moves out of an ice age, the ice melts. This results in the sea level rising again.
Isostatic change
Isostatic change
- Isostatic change refers to the level of the land, which is also influenced by ice ages.
- During an ice age, the weight of the ice forces the land to sink.
- When the ice age has finished, the melting of the ice causes the land to rebound back up, like a spring.
Tectonic change
Tectonic change
- Tectonic change causes land to either rise or sink at the boundaries where tectonic plates meet.
- A sudden change in the movement of a plate can lead to a rise or fall in the seabed, causing a change in sea level.
- Earthquakes out at sea can trigger a tsunami, causing devastating effects for people living along coastlines.
Emergent vs Submergent Coastlines
Emergent vs Submergent Coastlines
Emergent and submergent coastlines cause the formation of different landforms.
Emergent coastlines
Emergent coastlines
- Emergent coastlines cause the formation of raised beaches and fossil cliffs caused by isostatic rebound.
- A raised beach and fossil cliff are formed when, following an ice age, the land rebounds. This causes the original height of land to increase.
- This leaves behind a beach and fossil cliff higher than their original position.
- E.g. in Fife, Scotland.
Submergent coastlines
Submergent coastlines
- Submergent coastlines cause the formation of rias, fjords and Dalmatian coasts.
- A ria is a flooded river valley formed when rising sea levels flood the valley, often creating an estuary.
- A fjord is an example of a flooded glaciated valley formed when a glacier erodes vertically, creating a u-shaped valley.
- E.g. Lysefjord in Norway.
- Dalmatian coasts are formed because of the arrangement of alternating rock types parallel to the coast.
Global Warming and Sea Level Change
Global Warming and Sea Level Change
The Intergovernmental Panel on Climate Change (IPCC) acknowledge that sea levels are rising from past and present data collected. The IPCC links this to global warming. Coastal flooding is a consequence of this.
Increased frequency of storms
Increased frequency of storms
- The strong winds caused by storms create high energy, destructive waves which have considerable erosional power.
- The increased energy of the sea will mean more material can be transported and for greater distances. This could leave some areas vulnerable to erosion if they are left without much protection.
- The frequency of storm surges will increase. When combined with sea level rise, these surges will reach further inland and cause more damage.
Rising sea levels
Rising sea levels
- Data from the IPCC indicates from 1901 to 2010, average sea levels have increased by 0.19m.
- Some of the contributing factors being linked to the melting of glaciers and ice sheets.
- E.g. the Greenland and Antarctic ice sheets have been decreasing rapidly.
- Higher sea levels could cause higher tides, and this would increase the frequency of coastal flooding.
- Higher tides could also remove more material from beaches, leaving cliffs less protected.
Global warming
Global warming
- Evidence from the IPCC indicates that the between 1983 and 2012, the Northern Hemisphere experienced the warmest 30-year period of the last 1,400 years.
- Changes in the world’s atmospheric temperatures are causing thermal expansion of the oceans, melting of glaciers and ice sheets.
- Global warming is largely because of anthropogenic greenhouse gas (GHG) emissions. The concentration of these gases has risen rapidly since industrialisation.
1Tectonic Processes & Hazards
1.1Tectonic Processes & Hazards
1.2Natural Disasters
1.3Natural Disaster Case Studies
1.4Trends & Patterns
2Option 2A: Glaciated Landscapes & Change
2.1Glaciated Landscapes Over Time
2.2Periglacial Landscapes
2.3Glacial Processes
2.4Glacial Landforms
3Option 2B: Coastal Landscapes & Change
3.1Coastal Landscapes
3.2Coastal Erosion & Deposition
3.3Coastal Risks
4Globalisation
4.1Globalisation
4.2Negatives of Globalisation
4.3Global Shift
4.5Culture
4.6Measuring Development
5Option 4A: Regenerating Places
5.1Types of Economies
5.2Function of Places
5.3Regeneration
5.4Regeneration Case Studies
6Option 4B: Diverse Places
6.1Population Structure
6.2Past & Present Connections
6.3Urban & Rural Spaces
6.4Diversity
6.5Urban & Rural Case Studies
6.6Case Study - Tower Hamlets
6.7Case Study - Sturton-le-Steeple
7The Water Cycle & Water Insecurity (A2 only)
7.1Hydrological Processes Global to Local
7.2Influences on the Water Cycle
7.3Water Insecurity
8The Carbon Cycle & Energy Security (A2 only)
8.1The Carbon Cycle
8.2Energy Consumption
8.3Alternative Energy
8.4Growing Demand for Resources
9Superpowers (A2 only)
9.1Superpowers
9.2Hard & Soft Power
9.2.1Hard & Soft Power
9.2.2Emerging Powers - China Rivalry
9.2.3Emerging Powers - Chinese Sources of Power
9.2.4Emerging Powers - Brazil
9.2.5Emerging Powers - Russia
9.2.6Emerging Powers - India
9.2.7Theories of Development
9.2.8Power Case Studies: Chinese One Belt One Road
9.2.9Power Case Studies: Pakistan Nuclear Arms
9.2.10Power Case Studies: OPEC
9.3IGOs, TNCs & Alliances
10Option 8A: Health & Human Rights (A2 only)
10.1Human Development
10.2Role of Governments & IGOs
10.3Human Rights
10.4Interventions
11Option 8B: Migration & Identity (A2 only)
11.1Globalisation & Migration
11.2Consequences of Migration
11.3Nation States
11.4Responses to Global Migration
Jump to other topics
1Tectonic Processes & Hazards
1.1Tectonic Processes & Hazards
1.2Natural Disasters
1.3Natural Disaster Case Studies
1.4Trends & Patterns
2Option 2A: Glaciated Landscapes & Change
2.1Glaciated Landscapes Over Time
2.2Periglacial Landscapes
2.3Glacial Processes
2.4Glacial Landforms
3Option 2B: Coastal Landscapes & Change
3.1Coastal Landscapes
3.2Coastal Erosion & Deposition
3.3Coastal Risks
4Globalisation
4.1Globalisation
4.2Negatives of Globalisation
4.3Global Shift
4.5Culture
4.6Measuring Development
5Option 4A: Regenerating Places
5.1Types of Economies
5.2Function of Places
5.3Regeneration
5.4Regeneration Case Studies
6Option 4B: Diverse Places
6.1Population Structure
6.2Past & Present Connections
6.3Urban & Rural Spaces
6.4Diversity
6.5Urban & Rural Case Studies
6.6Case Study - Tower Hamlets
6.7Case Study - Sturton-le-Steeple
7The Water Cycle & Water Insecurity (A2 only)
7.1Hydrological Processes Global to Local
7.2Influences on the Water Cycle
7.3Water Insecurity
8The Carbon Cycle & Energy Security (A2 only)
8.1The Carbon Cycle
8.2Energy Consumption
8.3Alternative Energy
8.4Growing Demand for Resources
9Superpowers (A2 only)
9.1Superpowers
9.2Hard & Soft Power
9.2.1Hard & Soft Power
9.2.2Emerging Powers - China Rivalry
9.2.3Emerging Powers - Chinese Sources of Power
9.2.4Emerging Powers - Brazil
9.2.5Emerging Powers - Russia
9.2.6Emerging Powers - India
9.2.7Theories of Development
9.2.8Power Case Studies: Chinese One Belt One Road
9.2.9Power Case Studies: Pakistan Nuclear Arms
9.2.10Power Case Studies: OPEC
9.3IGOs, TNCs & Alliances
10Option 8A: Health & Human Rights (A2 only)
10.1Human Development
10.2Role of Governments & IGOs
10.3Human Rights
10.4Interventions
11Option 8B: Migration & Identity (A2 only)
11.1Globalisation & Migration
11.2Consequences of Migration
11.3Nation States
11.4Responses to Global Migration
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