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New Brighton February 1990.

Monitoring sea level rise
Will my house be under water in 50 years?

We are often asked whether it would be wise to buy a house by the sea in the UK in light of all the publicity about global warming and sea level rise.

The first thing to realise is that changes in sea level in the UK vary considerably around the local Mean Sea Level (MSL) due to our large tides and winter storm surges. When high tide and surge occur simultaneously, one obtains an extreme high water level which at certain times can be much higher than normal.

For example, the early 1990s witnessed a number of extremely high water levels as a consequence of the strong westerlies at the time which climatologists have related to the North Atlantic Oscillation. In addition to the combined MSL + tide + surge water level, one also has to consider wind waves which can be large during storms and which can lead to flooding by overtopping defences. Therefore, if one lives by the sea, it is clear that one has to be prepared for a wide range of sea level change, even in normal times.

The intergovernmental Panel on Climate Change (IPCC) Third Assessment Report (TAR) suggests that MSL may rise by approximately 50cm in the next 100 years, and that regional meteorology may also change, which would effect the magnitude and frequency of storm surges (the astronomical tides themselves would not be affected in any major way). These changes could add significantly to the possibility of flooding in certain areas.

However, it is important to realise that most MSL change will happen in the second half of the next 100 years, as climate change takes a hold, and in the next 50 years one might expect MSL change of order 10-20cm. This is an important factor for coastal engineers to consider, but in most cases will have little impact on individual house owners. You should enquire from your local authorities what their policy is for coastal protection in your area, taking into account consideration of the potential sea level changes in the future. If coastal protection is not adequate already, climate change may make the problem worse.

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