[ad_1]
A study of trends in Dublin Bay over the past eight decades has shown that the sea-level is rising faster then expected – at about twice the rate of global sea level rise.
Leading scientists say that the recent trends in capital are higher than what climate change models predicted. MaynoothUniversity will conclude that local factors are contributing to the changes.
They warn that these must be identified to ensure Dublin is ready for the inevitable sea level rise due to global warming.
The Hamilton Institute and ICARUS Climate Research Centre recently created a revised sea level dataset of Dublin from 1938 to 2016. It confirms that the capital is following a similar trend as Cork.
The data show a trend that corresponds to an annual sea-level rise of 1.1 metres per year in Dublin between 1953 and 2016, according to their research published in Ocean ScienceThis week.
“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 7 millimetres per year. This recent sea level rise is faster than expected at approximately double the rate of global sea-level rise,” said Amin Shoari Nejad, lead author of the study – a PhD student at the Hamilton Institute.
“Overall sea level rise is in line with expected trends but large multidecadal variability has led to higher rates of rise in recent years.”
Researchers compared sea-level records. Dublin PortGet gauges at ArklowAnd HowthInternational datasets and harbours from the UK France.
“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,” said Dr Gerard McCarthy of ICARUS.
Flooding risk
MostWith 40% of the population living within 5km from the coast, Irish cities are coastal. Recent flooding highlights the need to understand how sea level is changing. IrelandCork, Galway, Dublin Limerick being most vulnerable.
According to the Maynooth team, future sea levels around the Irish coast will depend on a combination global and local factors. Global sea level rise is driven by climate change with up to 1m of sea level rise predicted by 2150, if greenhouse gas reductions fall short of targets – this is based on climate models applying the most-likely scenario based on current data.
Dr McCarthy said that sea-level rise in Cork and Dublin is higher than anticipated due to climate change. This indicates that there are local exacerbating factors.
Dublin record
Dublin’s sea level rise should be the easiest case, since it is the longest-recorded record of sea level in Ireland, he stated.
The Dublin record, however, had in recent years been viewed “a little dubiously” due to questions about data quality. In response, the Dublin record was calibrated using biased high-water measurements that affect average sea level calculations. This was done in light of improved gauges.
He stressed that although there are many indicators of rising sea levels, such as those in the Dublin climate action plan, they do not prove the cause. He said that one reason could be the compaction of sediments by reclaimed land at Dublin port.
Cork was also experiencing higher sea-level rise than expected in a previous report from 2021. This again highlights the need to identify the local factors that are causing it. This could be due to local subsidence in Cork harbour due to manmade or natural factors, or “a hangover from the last Ice Age”, Dr McCarthy said.
“Understanding this is key to adjust future climate projections of sea-level rise for use in local adaptation.”
Researchers at Maynooth continue to investigate the causes of these fluctuations with UCC and DCU colleagues.
Prof. Andrew ParnellHamilton Institute; Dr Brian KelleherDCU School of Chemical Sciences and Prof Robert DevoyUCC Department of Geography, Prof Peter ThorneAnd Alice GreenICARUS.
