Over 70,000 Irish addresses at risk of coastal flooding by 2050

More than 70,000 Irish addresses will be at heightened risk of coastal flooding by 2050 as a result of climate change, according to mapping and data analysis of vulnerable coastal locations. Properties in Dublin, Louth, Limerick, Clare and Galway are the most vulnerable.

Some 88 per cent of these addresses are residential, amounting to 62,000 homes, projections by Gamma Location Intelligence (GLI) show – it evaluates risk for local authorities and insurance companies using advanced modelling and mapping.

Its analysis published on Thursday indicates Dublin will be the most affected county in terms of the number of addresses expected to be impacted by extreme coastal water levels, with 23,435 properties at risk, it predicts. This translates as 21,513 residential addresses and 1,922 commercial properties.

These findings are based on a predicted global temperature increase of 2 degrees which climate scientists expect to happen in the next 30 years in some scenarios and take into account current carbon emissions.

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Storm surge

This temperature increase would cause sea levels to rise and bring about more extreme weather events, leading to higher and more frequent coastal flooding, notably due to storm surges resulting in one-off sea rises – climatologists have predicted Ireland is overdue a 3m storm surge.

In the capital, areas in Clontarf, Bull Island, Sutton, Portmarnock, Malahide, Donabate, Sandymount and Dublin port are at heightened risk of flooding by mid century, especially during more extreme weather events such as a storm surge.

These areas would be at risk of flooding, or be flooded during a single weather event, while coastal levels would decrease again, GLI said. Applying that scenario to Dublin during a storm, "Howth could potentially become temporarily isolated," it noted.

GLI finds Louth will be second most affected county, with 10,280 residential and 968 commercial properties predicted to be impacted, followed by Clare with 7,376 homes and 1,320 businesses at risk. Limerick (5,426 properties in total) and Galway (4,501) complete the top five areas expected to be most impacted by increased flood risk.

However, in terms of the proportion of addresses that are expected to be affected, Louth will be the worst with 19 per cent of its addresses due to be impacted. The next highest is Clare (13.3 per cent). In contrast, only 3.9 per cent of Dublin’s addresses will be at risk.

GLI mapped out the possible consequence of this temperature increase using a “digital terrain model” within a “Perilfinder software platform”. It assesses risk for properties including flooding and subsidence.

It is estimated the cost of climate disruption influenced by sea level rise on Irish property will be in the order of €2 billion in coming decades – the model does not take existing or planned sea wall defences into account.

Vulnerable

Simultaneous heavy rainfall and high river levels in addition to coastal flooding will cause even more properties to be impacted, GLI pointed out – Cork city is particularly vulnerable in that scenario.

Spatial data scientist with GLI Richard Cantwell said global warming was already having an impact on people's daily lives, but its effects would become "more tangible and extreme in the years to come, especially on properties near coastlines".

“With increasing global temperatures, sea levels are rising which means flooding will become more commonplace. This will have a major impact on many Irish counties, particularly along the coast, and a significant number of properties are set to be affected – unless CO2 emissions are reduced which will help to delay the process,” Mr Cantwell added.

This kind of data was vital as homeowners, local authorities and insurance companies start to plan for the future, he said. “Flood risk is one that will increase exponentially, so it’s vital that the necessary infrastructure is in place to cater for the changing Irish landscape.”