Edexcel B GCSE Geography > The UK’s Evolving Physical Landscape > Increasing risks from coastal flooding and the threats to people and the environment
Coastal flooding is becoming a more serious issue due to the interaction between climate change, marine erosion, and deposition. These processes are putting both people and the natural environment at growing risk, especially in low-lying coastal areas. Understanding the causes and consequences helps us better plan for the future.
Climate Change and Sea Level Rise
Global temperatures are rising due to human activity, especially the burning of fossil fuels.
Warmer temperatures are melting polar ice and causing thermal expansion of seawater.
As a result, global sea levels are rising — approximately 3.3mm per year according to NASA.
This rise increases the baseline level of the sea, meaning that even small storm surges can now flood land that previously remained dry.
Example: Low-lying coastal communities like Fairbourne in Wales and areas of East Anglia are facing long-term managed retreat due to sea level rise.
Increased Frequency and Intensity of Storms
Climate change has increased storm intensity due to more energy in the atmosphere and oceans.
Storms now bring stronger winds, higher waves, and heavier rainfall, all of which worsen coastal erosion and flood risk.
Storm surges — temporary, extreme rises in sea level — become more damaging when sea levels are already higher.
Example: The 2013 North Sea storm surge caused major flooding in Boston, Lincolnshire, and parts of the Norfolk coast.
Impact on Erosion and Deposition
Destructive waves, powered by storms, increase the rate of marine erosion, undercutting cliffs and washing away beaches.
Rising sea levels and wave energy can destroy depositional landforms like spits, dunes, and salt marshes, which act as natural flood barriers.
Eroded sediment is often lost offshore, meaning less material is deposited to build up beaches.
Example: At Holderness, increased erosion has led to rapid cliff retreat and the loss of farmland and homes.
Threats to People
Homes, businesses, and key infrastructure near the coast are more at risk.
Flooding can damage roads, railways, and utilities, making areas harder to access and more expensive to maintain.
Some communities may be forced to relocate permanently, known as climate migration.
Insurance premiums rise or become unavailable in high-risk flood zones.
Example: The Dawlish railway line in Devon was washed away by storm waves in 2014, cutting off the South West for weeks.
Threats to the Environment
Coastal flooding causes saltwater intrusion into freshwater ecosystems, damaging habitats for plants and animals.
Salt marshes, dunes, and wetlands may be eroded or submerged, removing important wildlife breeding grounds.
Increased flooding affects agricultural land, especially in estuaries and floodplains, reducing food production.
Example: In Norfolk’s The Broads, saltwater flooding threatens both biodiversity and farmland.
Why the Risk is Increasing
Rising sea levels make all types of flooding more likely.
Stronger storms increase the energy of waves and the frequency of storm surges.
Human development continues to place more people in vulnerable coastal areas.
Rock Type
Resistance
Permeability
Landscape Type
Location
Igneous
High
Impermeable
Upland, boggy
Dartmoor
Sedimentary
Variable
Chalk: permeable
Clay: impermeable
Lowland, varied
Southern UK
Metamorphic
Very high
Impermeable
Steep uplands
Snowdonia
Summary
Climate Change and Rising Sea Levels
Global warming causes ice to melt and oceans to expand, resulting in higher sea levels and increased flooding of coastal areas.
Increased Storm Frequency and Intensity
Warmer oceans result in stronger and more frequent storms. These bring higher waves and stronger winds, increasing coastal erosion and flood risk.
Threats to People
Coastal flooding poses a significant threat to homes, infrastructure, and livelihoods, particularly in low-lying coastal areas such as the east coast of England and Bangladesh.
Environmental Impacts
Flooding can damage ecosystems such as salt marshes, dunes, and wetlands, leading to loss of biodiversity and natural flood defences.
Human Responses
Communities respond with hard and soft engineering solutions, such as sea walls, groynes, and managed retreat, but these approaches are often expensive.
Future Risk Increases
With rising global temperatures and sea levels, the risk to coastal areas is expected to continue growing without effective mitigation and adaptation strategies.
