Coastal Flooding

A major concern in some coastal areas in the UK is the increased risk of erosion and flooding. Global warming heightens this risk in two ways:
1) An increase in sea level poses a threat of drowning coastal areas.
2) An increased frequency of damaging storms and storm surges that are capable of breaching coastal defenses.

The concern is important to the UK, as there are many human settlements on the coast. Over 5.3 million people in the UK live by the coast. The cost of defense will increase.
The coast has recreational value and increases tourism. It improves the economy; coastal tourism accounts for 21% of all domestic overnight holidays.
The UK is concerned about coastal flooding because it will put human settlements at risk and negatively impact the economy.

Sea levels are rising due to climate change, leading to thermal expansion as the seas warm up. Today's rising sea levels are a result of the warming seas.
For people who live on very low-lying land next to the sea, this could spell trouble; e.g., London and Essex are at risk.
When sea levels rise, it contributes to more coastal erosion—hydraulic action. Coastal erosion also leads to more mass movement (landslides) from storm damage.

Storms

A storm surge is a large-scale increase in the sea level due to a storm. Onshore gale-force winds drive water toward the coastline, while low air pressure allows the level of the sea to rise. Storm surges near the UK can raise the sea levels by 2m.
Climate change is expected to lead to an increase in storm surges and an increase in their magnitude. Every 1 million bars, the air pressure drops to a very low level. When low air pressure combines with a storm surge, a severe storm surge coincides with a high tide.
They are most serious when they are caused by very low-pressure weather systems such as cyclones and depressions.
Climate change has the potential to intensify and increase the frequency of depressions, which, when combined with storm surges, could have severe consequences.

MARINE EROSION & DEPOSITION

Climate change will lead to an increase in the frequency and magnitude of storm events. Combining these two factors will focus wave energy closer to the shore and soft rock, resulting in increased rates of coastal erosion in areas with clay soil cliffs. Scientists predict this: In 50 years, deltas will become faster and become submerged; beaches, spits, and river deltas will erode. In 20 years, by 2050, a major problem in coastal parts of the UK will be that major existing defences will be useless as sea levels rise to 50 cm with higher floods. Southern England and East Anglia, located near the sea, will face abandonment.

STORM XAVER - UK 2013

5-6 Dec 2013 - A deep depression moved southeast across the North Sea.
Scotland experienced extremely strong winds exceeding 200 km/h.
A storm surge affected much of Northern Europe, exacerbated as winds drove the surge into the funnel shape of the North Sea.
The storm surge in Eastern UK reached a height of 5.8m, making it the largest since 1953. Improved flood barriers and tidal walls prevented the surge from causing the same damage as in 1953, which killed 326 people.

IMPACTS

Environmental: The Environment Agency sent 140,000 warnings—extreme sand dune erosion in Hemsby, Norfolk—7 homes + lifeboat station fell into the sea. TEA claimed that 250 km of land defences, such as the Thames Barrier, protected 800,000 homes from the highest tides ever recorded.
Social: 18,000 homes + 1100 businesses were flooded (England + North Wales) In Eastern England, 1400 people underwent evacuation. (£ economic)
Economic: Total cost of flood damage: £1.7 billion. Death toll: 2.

The economic losses from flooding between November 19 and March 20 were £333m. It would've cost an additional £1 billion without coastal defences.
Frequent flooding can result in the loss of livelihoods and production.
Coastal defences receive the majority of investment funding.

Trigger mass migration in vulnerable, coastal areas—leading to a population decrease.
Human health issues escalate the likelihood of polluted drinking water and wastewater, as well as infrastructure failure. Exposure to pathogens and harmful chemicals is a risk that people face.

The loss of depositional features that support biodiversity is occurring.
Plant and animal habitats are deteriorating due to the loss of land near human settlements.
Contaminated water can pollute rivers and habitats.
Salt contamination of agricultural soil can negatively impact the crops.

HOLD THE LINE: Maintain the current positioning, the coastline. Hard-engineering methods have often been used, but soft-engineering methods are becoming popular.
ADVANCE THE LINE: Extend the coastline out to sea. Both hard and soft engineering methods have been used.
MANAGED REALIGNMENT: Allow the coastline to retreat in a managed way. Soft engineering methods are used.
DO NOTHING: Let nature take its course and allow any existing coastal defences to fail, so the sea can erode or develop the coastline.
a) Low cost + encourages beach development (tourism).
b) Have to be compensated for loss of land. People will have to sell marshes (important for the environment). Money to be used in higher-value land. It's sustainable as it preserves natural habitats. More conflict—loss of ecosystems.