Coastal Opportunities & Hazards (Cambridge (CIE) IGCSE Geography)

Coastal Opportunities

• There are many opportunities that the coast can bring:

• Development including:

  • Homes

  • Shops

  • Hotels

  • Roads

  • Schools

  • Restaurants etc. 

• Nature reserves

• Swimming and sports

• Industry

• Fishing and aquaculture

• Tourism

• Agriculture

• Ports and harbours

Coastal Hazards

• Coastal hazards can be either natural or human-induced

• Natural hazards include storms, flooding and tsunamis

• Human actions create consequences and impacts

Urbanisation and transport

• Consequences 

  • Changing how land is used (for ports, harbours, and airports); traffic on roads, trains, and the air; and taking water from the ground.

  • Getting rid of pollution and waste 

• Impacts

  • Damage to the environment and loss of species, visual and water pollution, saltwater ingress, health risks, and introduction of invasive species

Agriculture

• Consequences 

  • Reclaiming land, overuse of fertilisers and pesticides, animal numbers, water abstraction

• Impacts

  • Loss of ecosystems and species, coastal squeeze, water pollution, eutrophication and river channelisation

Fisheries and aquaculture

• Consequences 

  • Ports and harbours construction, fish processing, fishing tackle, fish farm waste, shrimp farming

• Impacts

  • Overfishing, knock-on effects on other species, water and beach pollution, invasive alien species, habitat damage and changes in marine communities

Industry

• Consequences 

  • Land use changes, power stations, of natural resource extraction, waste processing, cooling water; windmills; river dams, weirs and barriers; tidal barrages

• Impacts

  • Loss of habitats and species diversity; water pollution; eutrophication; heat and visual pollution; decreased input of fresh water and sediment to coastal zones; coastal erosion

Tourism and recreation

• Consequences 

  • Development and land use changes, such as: golf courses; road, rail and air congestion; ports, harbours and marinas; water abstraction; wastewater and waste disposal; boat tours and water activities (snorkelling, skiing, surfing, etc.)

• Impacts

  • Loss of habitats and species diversity; disturbance of habitats, migration patterns, and landforms; visual pollution; lowering of water table; saltwater ingress in aquifers; water pollution; eutrophication; human health risks

Natural coastal hazards

• Coastal hazards arise from several factors:

  • Storm surges are extremely low-pressure storms (like tropical storms), which cause a rapid rise in sea level

  • Storm tides occur when there is a combination of high tide and low-pressure storm

  • Tsunamis are large sea waves due to underwater earthquakes. The closer to the coast, the bigger the impact

  • King tides

  • Sea level rise due to global warming

  • High river discharge after a storm: when combined with a spring tide, water in the estuary cannot discharge into the sea, causing a backflow of water and flooding

• Any number of these hazards can bring coastal flooding 

• Although MEDCs have the largest costs, emerging countries experience the greatest effects

Tropical storms

• Hurricanes, typhoons and cyclones are all types of tropical storms; the only difference is where they form

  • Hurricanes form in the tropical North Atlantic Ocean and Northeast Pacific

  • Typhoons form in the Northwest Pacific Ocean

  • Cyclones form in the South Pacific and Indian Ocean

• In the northern hemisphere, they form between May and November

• Between October and May in the southern hemisphere

• A tropical storm can destroy coastal areas and kill people and the effects are worse in LEDCs due to a lack of economic funds

• Other impacts are:

  • Destruction of buildings and infrastructure

  • Heavy rainfall and storm surges

  • Loss of ecosystems, trees, land, crops and animals

  • Ships are wrecked at sea and sunk

  • Power and communications are lost

  • Costs can run into the millions, and the effects are greatest in heavily populated areas

• Managing tropical storms is difficult but some of the ways to reduce the risks are:

  • Sea walls and artificial levees to prevent flooding

  • Evacuation plans for the population

  • Satellite tracking and early warning systems

  • Build homes and buildings to withstand strong winds 

  • Raise homes above storm surge levels and have strong shutters on windows

  • Emergency supplies and shelters

  • Have storm insurance

Changing sea levels

• Rising sea levels produce submergent coastlines, with rias and fjords

• Falling sea levels produce emergent coastlines with relic features such as raised beaches, cliffs with caves, arches, etc.

• Sea levels have risen and fallen many times in the past

• During the last Ice Age, sea levels fell as the water was locked up in glaciers and ice sheets, rising again as the ice melted

• Sea levels are linked to global warming and will have a significant effect on many low-lying coasts and islands

• Rising sea levels put many Pacific Ocean islands, including Kiribati and Tuvalu, in danger of total submersion

• This issue is made worse as many of the world's densely populated areas are located on coastal lowlands

• New York and Miami in the US are major cities vulnerable to sea-level rise as the cities are built at sea level

Influence of geology

• Geology shapes the coastline over time, place and space

• Sands and clays, which are softer rocks, will easily erode by destructive waves to create low, flat landscapes like bays and beaches

• Coastlines of more resistant, harder rock will take longer to erode and produce rugged landscapes such as headlands

• The differences between hard and soft rocks will also impact the shape and characteristics of cliffs

Shape of cliff

• Hard rock cliffs are high and steep

• Soft rock cliffs are generally lower and less steep

Cliff face

• Hard rock cliff faces are bare and rugged

• Soft rock cliff faces are smoother with evidence of slumping

Foot of cliff

• Boulders and rocks are found along hard rock cliff bases

• The base of soft rock cliffs have few rocks and some sand and mud

Erosion 

• Coastal erosion is global, but geology has the greatest impact locally

• Limestone, sandstone, and boulder clay beaches erode faster than granite coastlines

• Waves and longshore drift remove sand from beaches and expose cliff bases to high-energy destructive processes 

• Using groynes to limit longshore drift depletes material elsewhere and creates shallow beaches, which increases coastal erosion

• Coastal erosion is a threat to many islands, endangering residents and visitors

• Tourist and coastal developments accelerate erosion and damage mangroves, coral reefs, sand dunes, and salt marshes