A catastrophic storm during high tide which will leave thousands of homes, businesses and landmark buildings in Dublin under water is inevitable over the coming decades, one of the country’s foremost climate change experts has warned.
Prof Peter Thorne said Ireland had been lucky to “dodge a bullet” until now during major storm events – because they have struck during low or neap tides – but it was only a matter of time until the elements combined for a devastating surge.
The Maynooth University academic, who was lead author on the fifth assessment report of the UN’s Intergovernmental Panel on Climate Change, and is aged 40, said he expected a major high tide flood event in his lifetime.
In the capital this would mean water from Dublin Bay surging into the Liffey while it was in full flow from the Wicklow mountains.
“The combination of water trying to escape and water being pushed up into the river means it will end up moving sideways,” he said.
Mr Thorne said the Liffey would “over-top into the surrounding areas” resulting in major flooding in the city centre, while areas like Clontarf and south Dublin would also be badly hit.
“There would be hundreds or thousands of properties basically – residential, commercial and government properties – that would be under water for a considerable length of time, with all the implications that that has.”
The cost of the clean-up, he predicted, would run into billions of euro.
Some of Dublin’s most iconic landmark buildings along the quays from Dublin Port to the Guinness brewery, including Custom House and the Four Courts, would be submerged, he told The Irish Times.
Very lucky
“In our lifetime the sea level rises are not going to accelerate much more than it is now – it will be going up a centimetre a year at most globally,” he said.
“But then you have the storm surges – and we have been lucky, frankly. We’ve been very lucky over recent decades that when those storm surges have hit they have been at low tide or neap tide.
“It is only a matter of time before one hits at high tide, or even worse, spring high tide. Then it will be very, very catastrophic.”
Predicting the timing is like “rolling the dice”.
“It could be decades, it could happen next week or it could not happen within our lifetime,” he said. “I would expect to see a major event in my lifetime. Somewhere in Ireland I would expect a major sea level combining with storm surge having a large-scale impact,” he said.
“It would take months to dry out the structure of properties flooded. Some may be so damaged they would end having to be destroyed and rebuilt. But mostly it would be matter for residents relocating for six to 12 months.”
He cautioned against people buying property less than 10 metres above current sea levels in the capital as well as other major urban centres built on the coast, including Cork, Galway and Waterford.
“If you are thinking of buying a property clearly don’t buy one near the sea level. If you have a property already that might be at risk, thinking of how to – at low cost – mitigate that risk . . . you can’t at this point, you are kind of in the lap of the gods.”
Low-lying areas
Mr Thorne said he “wouldn’t go anywhere near” many of the expensive coastal homes in low-lying areas of Dublin.
“If I was buying property today that I wanted to eventually leave to my children I would not be buying property probably within five to 10 metres of the sea level.”
Residents in Clontarf who successfully argued for the lowering of a recently built flood defence sea wall, at a cost of half a million euro to Dublin City Council, to restore their view were of a “King Canute mindset”, said Mr Thorne, who is also director of the Irish Climate Analysis and Research Units group. “For some reason these residents feel they can hold back the waters,” he said.
“At a national level we need to think about what areas we want to protect and to what level we want to protect them.
“Clontarf is a case in point where the government quite rightly wanted to protect the citizens, and the citizens unfortunately decided their view was more valuable than protecting their properties.”
Mr Thorne added: “I don’t think people see the risk very well. We are very poor as human beings at recognising and coping with risk. This is one example of that.”
Finite pot of money
Responding to the Government’s briefing last week updating the progress of its climate action plan, he said it faced “hard and difficult choices as to which properties and areas it decides to protect and which it doesn’t”.
“There is only a finite pot of money, and there is only a finite amount of properties that can be protected.”
The Government will have to decide this on a basis of where is strategically, economically and politically important to protect "and where to let go because you can't protect everything, you can't do everything".