NEW RESEARCH FROM Maynooth University has found that sea levels in Dublin Bay have risen at approximately double the global rate between 1997 and 2016. 

The research, led by the Hamilton Institute and ICARUS Climate Research Centre at the university, generated an updated sea level dataset for Dublin stretching from 1938 to 2016.

While the overall trend shows an estimated increase of around 1.1mm per year between 1953 and 2016, sea levels in Dublin Bay rose at a rate of 7mm per year from 1997 to 2016. 

“Fluctuations are identified with sea levels rising from 1982 to 1988, before falling from 1989 to 1996, and once again rising from 1997 to 2016 at a rate of 7mm per year,” said Amin Shoari Nejad, lead author of the research.

“This recent sea level rise is faster than expected at approximately double the rate of global sea level rise,” he said.

Dr Gerard McCarthy, of ICARUS Climate Research Centre and Department of Geography at Maynooth, said: “If you look at too short a timeframe, the fluctuations over decades could impact estimates of trends.

“But this research has taken a longer view and what we are most confident about from looking at the stretch of years is the overall rise.”

The researchers at Maynooth, in collaboration with colleagues at University College Cork (UCC) and Dublin City University (DCU), are continuing to explore the reasons behind the fluctuations.

To carry out their data checks, the researchers compared sea level records for Dublin Port and gauges at Arklow and Howth Harbour, as well as international datasets from the UK and France.

The Dublin Port record was calibrated by adjusting the ‘biased’ high water level measurements that affect the overall calculation of mean sea level. High waters were seen to be rising faster than nearby gauges so a model was built using the stable low water levels to compute mean sea level.

“To correct these mean sea level values, we use a novel Bayesian linear regression that includes the Mean Low Water values as a predictor in the model. We validate the re-created MSL dataset and show its consistency with other nearby tide gauge datasets,” said Shoari Nejad.

“Overall, sea level rise is in line with expected trends, but large multidecadal variability has led to higher rates of rise in recent years,” he added.