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Unlock This CourseOur coastlines are under threat like never before. Climate change is causing sea levels to rise, storms to become more intense and coastal flooding to happen more often. This creates huge challenges for the millions of people who live near the coast and the valuable land, buildings and ecosystems found there.
Coastal management is about finding ways to protect people and property from these threats whilst also preserving the natural environment. It's a balancing act that requires careful planning and different approaches depending on the local situation.
Key Definitions:
Global warming causes sea levels to rise in two main ways. First, as water heats up, it expands - this is called thermal expansion. Second, ice sheets and glaciers melt, adding more water to the oceans. Scientists predict sea levels could rise by 0.5-2 metres by 2100.
Coastal flooding happens when seawater overwhelms coastal defences and floods normally dry land. Several factors work together to create these dangerous conditions.
Storm surges are the biggest natural cause of coastal flooding. When powerful storms like hurricanes hit the coast, strong winds push huge amounts of water towards the shore. This creates a wall of water that can be several metres higher than normal sea levels.
Created by strong winds pushing water towards the coast. Can raise sea levels by 3-8 metres during major storms.
Spring tides occur twice monthly when the sun and moon align, creating the highest tides of the month.
Low atmospheric pressure allows sea levels to rise higher than normal - every 1mb drop raises sea level by 1cm.
Human activities have made coastal flooding worse in many areas. Building on floodplains, removing natural barriers like sand dunes and climate change from burning fossil fuels all increase flood risk.
Coastal development often involves draining wetlands and building sea walls that can actually make flooding worse by preventing natural water absorption and creating artificial barriers that water eventually overwhelms.
The Thames Barrier protects London from storm surges coming up the River Thames. Built in 1984, it has 10 moveable gates that can be raised during high tides and storms. The barrier was originally designed to be used 2-3 times per year, but climate change means it's now used 6-7 times annually. Engineers are already planning upgrades to cope with future sea level rise.
There are four main approaches to managing coastal flooding and erosion. Each has advantages and disadvantages and the best choice depends on local conditions, costs and priorities.
Build or maintain coastal defences to keep the sea out. This protects existing development but is expensive and may not work long-term as sea levels rise.
Allow the sea to flood some areas whilst protecting others. This can create natural flood defences but means some land and buildings are lost.
Hard engineering uses concrete, steel and rock to build artificial barriers against the sea. These solutions are expensive but provide strong protection for valuable areas.
Concrete barriers built along the coast. Very effective but expensive (£5,000-10,000 per metre) and can increase erosion elsewhere.
Large rocks placed along the coast to absorb wave energy. Cheaper than sea walls but less effective and can look unsightly.
Wooden or concrete barriers built perpendicular to the beach to trap sand. Help build up beaches but can cause erosion downdrift.
Soft engineering works with natural processes to provide coastal protection. These methods are often cheaper and more environmentally friendly than hard engineering.
Adding sand to beaches to make them higher and wider. Provides natural wave protection but sand needs regular replacement.
Planting vegetation to stabilise sand dunes. Creates natural barriers and wildlife habitats but takes time to establish.
Creating salt marshes and wetlands to absorb flood water. Provides natural flood storage and wildlife habitat.
In 2013, the Environment Agency created Britain's largest coastal realignment project at Medmerry. Instead of rebuilding expensive sea defences, they moved the sea wall 2km inland and created 183 hectares of salt marsh and mudflats. This £28 million project protects 348 homes from flooding whilst creating valuable wildlife habitat. The new wetlands can store 250 million litres of flood water during storms.
Managing coastlines in a changing climate presents many challenges. Sea level rise means existing defences may not be adequate in the future, whilst more intense storms create greater flood risks.
Coastal defences are extremely expensive to build and maintain. A typical sea wall costs £5,000-10,000 per metre, whilst major flood barriers like the Thames Barrier cost billions. With hundreds of kilometres of coastline to protect, the costs quickly become enormous.
There's also the challenge of deciding which areas to protect. Should money be spent protecting expensive city centres, or rural communities that might be cheaper to relocate? These decisions affect people's lives and livelihoods.
Hard engineering solutions can damage coastal ecosystems. Sea walls prevent natural coastal processes, whilst rock armour can destroy beach habitats. There's growing recognition that working with nature through soft engineering can be more sustainable.
Climate change also affects coastal ecosystems directly. Rising sea levels drown salt marshes, whilst changing temperatures affect marine life. Coastal management must consider these environmental impacts alongside human needs.
The village of Happisburgh shows the challenges of coastal management. Despite spending millions on sea defences, the soft clay cliffs continue to erode at 2-3 metres per year. Over 35 homes have been lost to the sea since 1990. The government now follows a policy of 'no active intervention', meaning no new defences will be built. Residents face the difficult choice of relocating or watching their homes disappear into the sea.
Future coastal management will need to adapt to accelerating climate change. This means planning for higher sea levels, more intense storms and changing rainfall patterns. The focus is shifting towards more flexible, sustainable approaches that work with natural processes rather than against them.
Integrated coastal zone management considers the whole coastal system, including rivers, beaches, cliffs and human activities. This holistic approach recognises that changes in one area affect the entire coastline.
Early warning systems and emergency planning are becoming increasingly important. Even with the best defences, some flooding will still occur, so communities need to be prepared to respond quickly and effectively.