Changing Coastal Environments » Hazards of Coastal Living

What you'll learn this session

Study time: 30 minutes

The main hazards associated with coastal living
How coastal erosion affects communities
The impacts of coastal flooding and storm surges
Case studies of significant coastal hazard events
How coastal communities can manage and adapt to these hazards

Hazards of Coastal Living

Coastal areas are among the most densely populated regions in the world, with approximately 40% of the global population living within 100km of the coast. While these areas offer economic opportunities and attractive living environments, they also expose residents to unique hazards that can threaten lives, property and infrastructure.

Key Definitions:

Coastal hazard: A natural process that threatens human life, property or infrastructure in coastal areas.
Coastal erosion: The wearing away of land by the action of waves, currents and tides.
Storm surge: An abnormal rise in sea level during a storm, measured as the height of water above the normal predicted tide.
Coastal flooding: The inundation of normally dry coastal land by seawater, often due to extreme weather events.

🌊 Coastal Erosion

Coastal erosion occurs when waves, currents and weather events wear away the land along the coastline. This process can be gradual or sudden, depending on the geology of the coast and the strength of the waves. Soft rock coastlines like those made of clay or sand erode much faster than hard rock coastlines like granite or basalt.

Key impacts include:

Loss of land and property
Damage to infrastructure like roads and utilities
Reduced property values
Forced relocation of communities

🌧 Coastal Flooding

Coastal flooding occurs when normally dry coastal land is submerged by seawater. This can happen due to storm surges, tsunamis, or high tides combined with sea-level rise. Climate change is increasing the frequency and severity of coastal flooding events worldwide.

Key impacts include:

Damage to buildings and infrastructure
Loss of life and injury
Contamination of freshwater supplies
Economic disruption to businesses and tourism

Major Coastal Hazards in Detail

🌀 Storm Surges and Tropical Cyclones

Storm surges are one of the most dangerous coastal hazards, particularly when they coincide with high tides. They are caused by strong winds pushing water toward the shore, creating a wall of water that can be several metres above normal tide levels.

Tropical cyclones (also known as hurricanes or typhoons) are particularly dangerous as they combine multiple hazards:

🌪 High Winds

Winds exceeding 119 km/h can damage buildings, uproot trees and create dangerous flying debris.

💧 Heavy Rainfall

Intense rainfall can cause flash flooding, landslides and overwhelm drainage systems.

🌊 Storm Surge

The wall of water pushed ashore can flood large areas and cause rapid, devastating damage.

🌋 Cliff Collapse and Landslides

Coastal cliffs are constantly being undermined by wave action at their base. Over time, this can lead to sudden and catastrophic cliff collapses or landslides. These events are particularly dangerous because:

They often occur with little warning
They can bury people on beaches below
They can destroy properties built near cliff edges
They may be triggered by heavy rainfall or seismic activity

In the UK, areas like Holderness in Yorkshire and parts of the south coast experience some of the highest erosion rates in Europe, with some locations losing several metres of land each year.

Case Study Focus: 2013 East Coast Storm Surge, UK

On 5-6 December 2013, the east coast of England experienced the most serious coastal flooding since 1953. A combination of high tides, low pressure and strong northerly winds created a storm surge that affected the coastline from Scotland to Kent.

Key impacts:

Over 1,400 homes were flooded
Thousands of people were evacuated
Sea defences in many areas were breached or damaged
The surge caused significant erosion along vulnerable coastlines
The town of Boston in Lincolnshire saw water levels 1.5m higher than normal high tides
Total damage was estimated at over £400 million

The event highlighted the vulnerability of the UK's east coast to storm surges and the ongoing challenge of protecting coastal communities in the face of climate change and rising sea levels.

Sea Level Rise: A Growing Threat

Global sea levels are rising due to climate change, primarily because of:

Thermal expansion of seawater as it warms
Melting of glaciers and ice sheets

The Intergovernmental Panel on Climate Change (IPCC) projects that global mean sea level could rise by 0.29-1.1m by 2100, depending on emissions scenarios. This poses significant long-term risks to coastal communities worldwide.

🔃 Slow-Onset Impacts

Sea level rise creates gradual but persistent changes:

Increased coastal erosion rates
Permanent inundation of low-lying areas
Saltwater intrusion into groundwater
Loss of coastal wetlands and habitats

⚠ Amplified Extreme Events

Higher sea levels make coastal hazards more dangerous:

Storm surges reach further inland
Flooding occurs more frequently
Wave energy impacts higher on shorelines
Existing coastal defences may be overwhelmed

Living with Coastal Hazards

Communities around the world have developed various approaches to managing coastal hazards:

🚧 Hard Engineering

Building physical structures to protect coastlines:

Sea walls
Groynes
Breakwaters
Flood barriers

🌱 Soft Engineering

Working with natural processes:

Beach nourishment
Dune regeneration
Managed retreat
Wetland restoration

📝 Planning Approaches

Reducing risk through management:

Building restrictions in hazard zones
Early warning systems
Insurance schemes
Community education

Case Study Focus: Happisburgh, Norfolk, UK

Happisburgh (pronounced "Haze-bruh") on Norfolk's east coast provides a stark example of the human impact of coastal erosion in the UK.

Key facts:

The coastline is made of soft glacial till (clay, sand and gravel) that erodes easily
Historical maps show the village has lost significant land since the 1600s
Erosion rates accelerated after old wooden defences failed in the 1990s
Over 35 homes have been lost to the sea since the 1990s
The local council adopted a policy of 'managed retreat' as defending the coastline was deemed too expensive
Residents received limited compensation for lost properties
Beach Road collapsed into the sea in 2013 and several homes had to be demolished

Happisburgh illustrates the difficult choices coastal communities face when defending against erosion is not economically viable. The emotional and financial toll on residents who lose their homes is substantial, raising questions about social justice in coastal management.

Future Challenges and Adaptation

As climate change progresses, coastal communities face growing challenges:

Increasing hazard frequency and severity - More intense storms and higher sea levels will make coastal hazards more dangerous
Economic pressures - The cost of protecting coastlines will increase, forcing difficult decisions about what areas to defend
Environmental changes - Coastal ecosystems that provide natural protection may be lost or altered
Social justice concerns - Vulnerable populations often have fewer resources to adapt or relocate

Successful adaptation will require:

Long-term planning that accounts for climate change projections
Community involvement in decision-making processes
Innovative approaches that combine engineering, natural solutions and planning
Fair mechanisms to support those most affected by coastal hazards

Understanding coastal hazards is essential for making informed decisions about coastal development, protection and adaptation. As global citizens, we must consider how our actions today will affect coastal communities for generations to come.

🧠 Test Your Knowledge!