Coastal Flooding

Sea Level Rise

Sea levels with rise between 30 cm and 1metre by the year 2100.

Sea levels are rising today – The oceans are warming up and expanding, melting ice sheets are likely to speed this up.

There are many areas around the world at risk:

  • In Bangladesh, if sea levels rose by 1 metre, up to 15% of the country might be flooded
  • In the UK, London and Essex are at risk
  • Many small coral islands in the Pacific and Indian Oceans, like the Maldives and Tubalu, could disappear underwater


Tides are the regular rise and fall of the ocean due to the gravitational attraction of the moon and the sun on the Earth. As storms approach a coastline, the tide level is very important, as a high tide will likely result in a greater chance of coastal flooding.

There are generally three types of tides: diurnal – one high and low tide each day, semi-diurnal – two high and low tides each day, and mixed – two high and low tides each day of different heights. The different types of tides occur due to the arrangement of the land on earth, the shape of the local coastline, and the depth of the water near the coastline.

Storm Surge

Coastal Flooding, figure 1

What Creates a Storm Surge - BBC


There are several key challenges facing us in the future:

  • Scientists estimate that 1 in 50 year events could turn into 1 in 20 year events.
  • Beaches, spits, and rivers deltas may be eroded faster, and become submerged.
  • For coastal southern and eastern parts of the UK flooding is a major problem. Old sea defences would be useless – new ones would have to be built(£££££).
What is happening to sea levels, how might this affect humans?
Your answer should include: Rising / Flooding / Dangerous
How does a storm surge form?
Your answer should include: Tides / Winds
What are the likely problems associated with future flooding?
Your answer should include: Increase / Cost / Money / Old / Sea / Defences / Flooding