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PARSONS Martin

Martin Parsons has a PhD in Islam and Christian-Muslim Relations and has written a major academic book on this subject. 

One of the pitfalls politicians often fall into with natural disasters is knee-jerk reactions. On Monday, David Cameron successfully avoided that on a visit to parts of East Anglia hit by Thursday night’s storm surge. Speaking at Wells next the Sea in North Norfolk where the lifeboat station had taken a battering, as well as quayside businesses and properties being deluged, he praised the emergency services before declaring

 ‘I think you could always do more…there’s always more flood defences which could be put in place’

The Prime Minister is absolutely right, of course, and there is a need for a measured thought out response to last weeks’ floods in the coming months. It is easy to congratulate ourselves that no one lost their lives in a storm surge that was in places higher than that of 1953, when 307 people drowned. However, there are already warning signs that all future governments will need to take a long hard look at sea defences.

The first reason is very simple. In southern England, particularly, relative sea level is rising – i.e. the gap between the height of the land and sea is getting smaller. There are two basic reasons for this. The first, is the thermal expansion of sea water. Between 1900 and 2000, average temperatures rose by 0.6C and, since slightly warmer water takes up a slightly bigger volume, this causes a small amount of sea level rise.

The second reason is what geologists term isostatic readjustment. The last ice sheet came as far south as the North Norfolk coast: the land north of it was weighed down by the huge weight of ice and has, since the ice melted, been slowly springing back up: i.e, the land there is getting higher. However, this also means that the land to the south – i.e. East Anglia and Southern England – is now, in a compensatory fashion, being tilted downwards towards the sea. Recently published academic research suggests that this relative sea level rise on the Suffolk coast has been approximately 2.4 mm a year since the 1950s. In other words, relative sea level is now approximately 13-14cm higher than it was when the 1953 floods took place and is continuing to rise.

What this means is that the sea defences which, last week, prevented the sort of loss of life we saw in 1953 will need very significant investment in order to maintain their present level of protection. Storm surges are not particularly rare events. In East Anglia, we had a marginally lower one in November 2006, while I well remember seeing as a boy, in 1978, a huge coaster that had been dumped by a storm surge on the same quayside at Wells in North Norfolk that the Prime Minister visited on Monday.

Most British sea defences are built to withstand around a 1:100 year flood – in other words, a flood of the size that only occurs once every 100 years. Significantly, there do not appear to be any reports of serious flooding in the Netherlands during last week’s storm surge. However, after losing nearly 1800 people in the 1953 floods, they built their sea defences to withstand 1:4,000 and in some cases 1:10,000 year floods. By comparison, even the Thames barrier is only designed to withstand a 1;1000 year flood.

The 1953 storm surge has been widely viewed as a 1:50 year flood. However, as relative sea level rises, storm surges that occur more frequently have a similar potential impact in terms of flooding.  So we are likely to see similar storm surges to last week’s more frequently. This means that we need to plan ahead not only to maintain the existing sea defences, many of which were built by the Macmillan government following the 1953 floods and are now in need of repair, but also to plan for new higher ones, in East Anglia and Southern England, if we are to prevent the sort of tragic loss of life that, thankfully, we avoided last week.

7 comments for: Martin Parsons: After last week’s storms, government needs to take a long, hard look at our sea defences.

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