Rising sea levels mean ‘rare’ severe flooding will become the norm in Cork and Dublin

Rising sea levels in Ireland will lead to previously rare severe flooding becoming the norm unless reduced emissions come hand in hand with adaptation measures, scientists have said.

Data from Cork and Dublin show incontrovertible evidence that sea levels are rising around coastal areas, due to a combination of global warming of the oceans, as well as local factors.

New research led by the Hamilton Institute and Icarus Climate Research Center at Maynooth University, published in Ocean Scienceshow an estimated sea-level rise of 1.1mm per year in Dublin between 1953 and 2016.

However, a rise of 7mm per year between 1997 and 2016 is faster than expected, at approximately double the rate of global sea level rise, said lead author Amin Shoari Nejad of Maynooth University.

Icarus Maynooth associate professor and oceanographer Ger McCarthy said a recent study collaboration involving a range of institutions also shows significant sea-level rise in Cork in the past 180 years.

Minister Patrick O’Donavan, Cork City Council Chair Anne Doherty, and Lord Mayor of Cork City Joe Kavanagh speaking to business owners on Oliver Plunkett St following the floods in October 2020. Picture: Philip Williams

“We went back to the first survey of Ireland in 1842, in Passage West near Cork City, then went to the modern ones to see what had changed,” he said.

“In Cork, it has changed about 40cm. That is very large.

You’re talking about 15cm in Dublin, so 40cm in Cork is a massive amount. We expect Cork to be higher than Dublin anyway because of a kind of tilt on the country geologically, but even then, there were some extra local factors that we weren’t expecting to give a significant rise.”

While sea-level rises may not resonate with a lay person, the impacts of those numbers will, said Mr McCarthy.

“It may not seem like much to everyday life, but why does 40cm matter? Typically, a 20cm rise takes a flooding event that happens once in 50 years to become more regularly, to around once in every five years.

“That is massive change. It becomes an almost-once-in-a-lifetime event to something you are dealing with regularly.

I appreciate these numbers can sound small when your head isn’t stuck in them every day, but really, it is the difference in how regularly you get flooded.”

It is why reducing emissions in Ireland, as well as globally, is so important, and why it must be done now, according to the native Clonakilty.

Reducing emissions aggressively will buy more time for countries such as Ireland to adapt to the climate changes that are already irreversible, Mr McCarthy said.

A swollen south channel of the River Lee at Fr Mathew Quay, Trinity Bridge, Union Quay in December 2020. Picture: Larry Cummins
A swollen south channel of the River Lee at Fr Mathew Quay, Trinity Bridge, Union Quay in December 2020. Picture: Larry Cummins

“In Cork, for example, there was a good response after the devastating floods a decade ago,” he said.

“We saw this with Storm Barra in February this year, which had very high sea levels coming into Cork Harbour. However, the flooding was very modest in the city, because the likes of the ESB and others managed the water an awful lot better this time around.”

The two-pronged approach of mitigation and adaptation, as outlined by the UN-backed Intergovernmental Panel On Climate Change (IPCC) reports in recent months, are key for Ireland.

“Mitigation is cutting down greenhouse gases, while adaptation is about better management of flood risks in Cork City,” said Mr McCarthy.

You mitigate as much as possible, and you adapt appropriately to what is happening.”

Gamma Location Intelligence, which provides map and data analysis to insurance companies and local authorities, found in May 2020 that approximately 62,000 homes are at risk in the next 30 years.

In light of the recent IPCC findings of oceans rising due to human-induced global warming, Gamma said its estimates were likely to revise upwards.

Of the 62,000 homes found to be at risk in Gamma’s previous modelling, Dublin was predicted to be the worst affected.

It estimated that extreme coastal water levels would put some 23,435 properties — or 21,513 homes and 1,922 commercial properties — at risk. Cork would see just 1% of homes and businesses affected, but that still means 2,231 homes at risk, as well as 428 commercial properties.

Clare will see 7,376 homes and 1,320 businesses at risk, while Limerick will see 4,741 homes and 685, respectively — or more than 13% of homes in Clare, and almost 6% in Limerick.

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