The Ever-Changing Coastline

Climate change is impacting every aspect of life on earth including our marine environment, infrastructure and industry. It is also affecting the way we enjoy surfing and other recreational activities.

Over time, the shape of our coastline has changed due to various factors including natural processes, human activity and the construction of flood defences.

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Natural processes

A natural process called longshore drift changes the shape of coastlines by removing materials that have eroded from the coast and beaches, before depositing them elsewhere. The process of erosion and accretion has increased due to climate change.

Particularly in recent years, significant changes in weather patterns are causing an increase in wet and stormy weather. This in turn is leading to higher sea levels.

Coastal erosion will continue to increase as bigger and more frequent storm surges continue, according to scientists. This will increase the risk of coastal flooding.

Human activity

The practice of reclaiming land from the sea has enabled development closer to the coast to satisfy the need for more coastal housing: a tract of lowland is reclaimed by constructing dykes parallel to the shoreline.

The area between the natural coastline and the dykes is drained off through tide gates. Water is discharged into the sea at low tide and the gates close automatically to prevent the seawater from re-entering at high tide. This is reshaping the natural coastline.

Flood defences

Sea walls and other flood defences put up to protect the reclaimed land are slowing coastal erosion and preventing natural processes from taking place.

With managed realignment schemes, the flood defences are set back further inland. This creates an inter-tidal habitat, including salt marshes and mudflats. The coastal marshes also help to protect against coastal flooding.

Sand dunes

Sand dunes are a natural sea defence, protecting against coastal flooding and erosion. However, they can be damaged by human activity and storms. When the sand dunes start to disappear, the sea can advance rapidly, reclaiming low-lying land.

Over many years, seaside towns have sprung up and have been developed on land that was once inter-tidal. Piers, seafront hotels, shops and roads have been built on the once inter-tidal land. Schemes have been designed to manage flood risks including beach nourishment, replacing materials previously lost to the sea and wind, and recharging the area with new materials.

How is this impacting marine and wildlife?

Britain's changing coastline is impacting our marine and wildlife in various ways. Research by the National Trust forecasts significant changes that will impact the wildlife along the 9,040 miles of British coastline.

The trust manages 707 miles of coastline in England, Northern Ireland and Wales. It has compiled a list of the marine and land species that will be impacted by climate change, with a forecast of "winners and losers" from research at all its sites UK-wide.

Creatures that are set to thrive due to a milder climate include basking sharks, the Glanville fritillary butterfly and the little egret. However, some species of tern, the Sandhill rustic moth and the grey seal are all at risk of losing their natural environment. The loss of any one species can upset nature's finely balanced ecosystem.

Conserving rock pools

Our coastal rock pools are tiny worlds of their own, containing diverse and complex ecosystems. The shallow pools are found in inter-tidal zones, meaning they are completely underwater at high tide. Rockpools are important to the coastline, acting to provide refuge and a nursery for a host of small species.

The planet's changing climate could put these unique ecosystems under threat. Only the toughest organisms can permanently survive in rock pools. They are often species with hard calcium carbonate shells.

Warming seawater due to climate change will increase the ocean's acidity. This is likely to weaken hard-shelled organisms. The warming ocean will also push species north in search of cooler water. Removing just one species from the rock pools formed on British coastlines can result in the collapse of an entire ecosystem.

Changes in plant life

Tiny and microscopic plants in our oceans absorb huge amounts of carbon dioxide and are credited with fixing almost 20% of global carbon. Many types of marine plant life are capable of absorbing carbon.

Seagrass accounts for 10% of the ocean's carbon storage capacity and scientists believe it can play a key role in slowing down climate change. It also provides a habitat for thousands of marine species such as turtles, seahorses and shellfish, while helping to sustain the biodiversity vital to our planet's future.

However, according to the United Nations' Environment Programme, seagrass is under threat. We have lost almost 30% of seagrass all over the earth as a result of human activities such as unregulated fishing, dredging and industrial run-off. The erosion of marine plants could contribute to an increase in harmful emissions.

Effects on coastal leisure activities

Climate change and rising seas will impact surfing in the not-too-distant future. In a coastal area where the seafloor is sandy and flat, the wave is likely to break further inshore. It will perhaps not break at all until the shore break. This will change the size and shape of the wave.

In coastal areas where the seafloor is rocky and uneven (a reef break), a higher sea level at the reef will leave a reduced area for the wave to break. This will increase the chances of the wave not breaking at all.

Studies carried out in the surfers' paradise of California indicate surf breaks are particularly vulnerable to sea-level rises. It is estimated a sea-level rise of only three feet will potentially drown out 80% of California's surfing spots.

Organisations such as the Surfrider Foundation and other outdoor recreation partners are working with local communities to help mitigate climate change. They plan to reduce the future impacts wherever possible.