Coastal questions and answers
The difference between demonstrating knowledge and applying knowledge
[Time for another Q and A post. This is to highlight the difference between AO1 (Demonstrating knowledge) and AO2 (Applying that knowledge) in the UK examination context. The geographical context is Coastal landscapes – an optional area of content, but a popular one.]
This post looks at two types of questions: a shorter tariff question which carries say 6-8 marks, and an essay question which carries between 16 and 20 marks.
A reminder: for A level Geography, there are two key Assessment Objectives (AOs):
AO1: demonstrate knowledge and understanding of places, environments, concepts, processes, interactions, and change, at a variety of scales.
AO2: apply knowledge and understanding in different contexts to interpret, analyse, and evaluate geographical information and issues.
So, as on previous occasions, here are two versions of each answer.
The first is unannotated.
The second is in two formats:
(a) AO1 in italics
(b) AO2 in bold.
[Remember my self-imposed limit of 600 words for the essay question.]
Assess the role of climate change on raised beaches.
A raised beach is a coastal landform that is found sitting above an active beach and coast. They are often 2 or 3 metres above current sea level and are flat platforms or benches in the landscape.
Sometimes they have a fossil/inactive cliff at the back. During the onset of glacial periods, such as the Devensian, sea levels fell as water was locked up in ice meaning the sea withdrew from active beaches, eventually stranding them above lowered sea levels. Sea levels fell 100–120m in the last glacial period, but during the last warm interglacial they may have been 5m higher than today. This would have drowned some beach benches, which would have been exposed as sea levels dropped during the last glacial.
Climate change drives sea-level change, which in turn creates raised beaches, especially during a eustatic drop in sea level. But, in many places, isostatic changes in land levels also play a role. In Scotland and Scandinavia most raised beaches have formed in the last few thousand years as land has rebounded upwards in response to the removal of the weight of ice sheets.
Climate change today is causing sea levels to rise due to land-based ice melt and thermal expansion. Sea levels could rise by 1–2m by 2200 at current rates. This could drown existing beaches and potentially reactivate ancient raised beaches in some places.
Assess the role of climate change on raised beaches.
A raised beach is a coastal landform that is found sitting above an active beach and coast. They are often 2 or 3 metres above current sea level and are flat platforms or benches in the landscape.
Sometimes they have a fossil/inactive cliff at the back. During the onset of glacial periods, such as the Devensian, sea levels fell as water was locked up in ice meaning the sea withdrew from active beaches, eventually stranding them above lowered sea levels. Sea levels fell 100–120m in the last glacial period, but during the last warm interglacial they may have been 5m higher than today. This would have drowned some beach benches, which would have been exposed as sea levels dropped during the last glacial.
Climate change drives sea-level change, which in turn creates raised beaches, especially during a eustatic drop in sea level. But, in many places, isostatic changes in land levels also play a role. In Scotland and Scandinavia most raised beaches have formed in the last few thousand years as land has rebounded upwards in response to the removal of the weight of ice sheets.
Climate change today is causing sea levels to rise due to land-based ice melt and thermal expansion. Sea levels could rise by 1–2m by 2200 at current rates. This could drown existing beaches and potentially reactivate ancient raised beaches in some places.
A raised beach (Devon, UK)
Evaluate the statement ‘The changes caused by human activity in coastal landscapes are always negative.’
People have interfered with coastal landscapes for centuries because coasts are important for trade and fishing so have been made into ports and locations for industry. More recently, they have been used for leisure and recreation, and often heavily urbanised. Coasts are a dynamic, changing physical system and people usually want to prevent change to allow continued use of the coast. This has led to inappropriate coastal management and negative impacts. However, more recently the environmental value of coasts has been recognised, and some activity has had more positive impacts.
Coastal management, especially ‘hold the line’ schemes using groynes and sea walls, are often viewed as positive interventions by communities vulnerable to coastal erosion. At Mapleton and Hornsea on Yorkshire’s Holderness coast, property and businesses have been protected by these schemes.
However, groynes interfere with the natural process of longshore drift, starving places downdrift of sediment and increasing erosion — for example, at Spurn Head. This shows that impacts can be both positive and negative in different places and depending on who is affected.
Humans have often failed to understand the complex systems at coasts. Both the Aswan Dam in Egypt and Akosombo Dam in Ghana had unforeseen consequences on coasts hundreds of kilometres away. By trapping sediment behind their dams, the coastal sediment cells were disrupted leading to increased erosion at Rossetta in Egypt and Lomé in Togo. This is actually similar to the impacts of groynes. Coasts operate as interconnected systems of sediment sources, transfers and sinks. Interfering with sources and transfers inevitably causes problems. However, today coasts are managed as integrated units called shoreline management plans and this greater understanding of physical systems has reduced negative impacts as coastal management is more holistic and sensitive to the environment.
In some cases, such as the Blackwater Estuary in Essex, damaging sea walls and flood embankments have actually been removed in the last 20 years allowing saltmarshes to be restored, increasing coastal ecosystems and the wildlife that depends on them. Although still rare, coastal sand dunes, estuaries, sea-grass beds and even coral reefs are being restored because humans have recognised their importance.
Having said that, many coastlines are now so densely urbanised and industrialised that pollution from sewage, farm runoff and industrial effluent has created low-oxygen dead zones just offshore where ecosystems are seriously damaged. The Gulf of Mexico, Baltic and Chesapeake Bay are examples. Dead zones are often made worse by dredging the seabed to make channels for ships, which releases toxic chemicals from sediments. These areas are large and very hard to reverse. As they are on the seabed they are ‘out of sight and out of mind’ but result from treating the ocean as a convenient pollution disposal zone.
Overall, there are more negatives than positive impacts, partly because until recently coastal processes were poorly understood and the ecosystem and the seabed were treated as potential pollution sinks. This is changing, slowly and only in some locations, due to restoration attempts and coastal defences that work with natural processes. However, the positive impacts are small scale and to some extent affect only small groups of people. (519 words)
Evaluate the statement ‘The changes caused by human activity in coastal landscapes are always negative.’
People have interfered with coastal landscapes for centuries because coasts are important for trade and fishing so have been made into ports and locations for industry. More recently, they have been used for leisure and recreation, and often heavily urbanised. Coasts are a dynamic, changing physical system and people usually want to prevent change to allow continued use of the coast. This has led to inappropriate coastal management and negative impacts. However, more recently the environmental value of coasts has been recognised, and some activity has had more positive impacts.
Coastal management, especially ‘hold the line’ schemes using groynes and sea walls, are often viewed as positive interventions by communities vulnerable to coastal erosion. At Mapleton and Hornsea on Yorkshire’s Holderness coast, property and businesses have been protected by these schemes.
However, groynes interfere with the natural process of longshore drift, starving places downdrift of sediment and increasing erosion — for example, at Spurn Head. This shows that impacts can be both positive and negative in different places and depending on who is affected.
Humans have often failed to understand the complex systems at coasts. Both the Aswan Dam in Egypt and Akosombo Dam in Ghana had unforeseen consequences on coasts hundreds of kilometres away. By trapping sediment behind their dams, the coastal sediment cells were disrupted leading to increased erosion at Rossetta in Egypt and Lomé in Togo. This is actually similar to the impacts of groynes. Coasts operate as interconnected systems of sediment sources, transfers and sinks. Interfering with sources and transfers inevitably causes problems. However, today coasts are managed as integrated units called shoreline management plans and this greater understanding of physical systems has reduced negative impacts as coastal management is more holistic and sensitive to the environment.
In some cases, such as the Blackwater Estuary in Essex, damaging sea walls and flood embankments have actually been removed in the last 20 years allowing saltmarshes to be restored, increasing coastal ecosystems and the wildlife that depends on them. Although still rare, coastal sand dunes, estuaries, sea-grass beds and even coral reefs are being restored because humans have recognised their importance.
Having said that, many coastlines are now so densely urbanised and industrialised that pollution from sewage, farm runoff and industrial effluent has created low-oxygen dead zones just offshore where ecosystems are seriously damaged. The Gulf of Mexico, Baltic and Chesapeake Bay are examples. Dead zones are often made worse by dredging the seabed to make channels for ships, which releases toxic chemicals from sediments. These areas are large and very hard to reverse. As they are on the seabed they are ‘out of sight and out of mind’ but result from treating the ocean as a convenient pollution disposal zone.
Overall, there are more negatives than positive impacts, partly because until recently coastal processes were poorly understood and the ecosystem and the seabed were treated as potential pollution sinks. This is changing, slowly and only in some locations, due to restoration attempts and coastal defences that work with natural processes. However, the positive impacts are small scale and to some extent affect only small groups of people. (519 words)