FloodsCoastal flooding in Ireland offers warning of things to come

Published 21 January 2014

Flooding in Ireland and the U.K. is typically associated with heavy rainfall, but the reason for more recent coastal flooding is different. Experts say that the increases in mean sea level suggests that mean sea-level rise rather than storminess is largely contributing to the dramatic increase in the frequency and scope of coastal flooding. Major cities like Cork, Dublin, and Galway will soon feel the impact of sea-level rise, and developers are discouraged from building within 100 meters of soft shoreline.

A study published six years ago by researchers at Met Éireann and UCD’s Meteorology and Climate Center showed that storm surges would increase in frequency along Ireland’s coast over the next few decades, and by 20 percent in the western coastal areas. The study also predicted a significant increase in the height of extreme surges along the west and east coast with most changes occurring in the winter as a result of changes in extreme wind speeds and mean sea-level pressure.

Both Ireland and Britain have experienced repeated and intense stormsy over a short period of time, storms that  experts attribute to changes in the Earth’s climate.

The Irish Times reports that some climatologists are convinced that the trend of declining Arctic sea ice may be contributing to changes in the North Atlantic Oscillation — the difference in sea level pressure between the Icelandic Low and the Azores High.  Strong westerly winds supported by oscillation between the two zones bring cool summers, mild winters, and frequent rain. Weaker westerlies bring more extreme temperatures in summer and winter, with heat waves, ice periods, and lower rainfall.

“Trends in extreme coastal high water across the globe reflect the increases in mean sea level, suggesting that mean sea-level rise rather than storminess is largely contributing to this increase,” according to the European Center for Climate Adaptation. “Under future scenarios of global warming, the current 100-year extreme water level is likely to occur every one to two years with the sea levels predicted for 2100,” based on a projected rise of 48 cm in sea levels by the end of year 2100.

Flooding in Ireland is typically associated with heavy rainfall, but coastal flooding events like the recent floods have more drastic effects, especially those that occur in combination with spring tides. Major cities like Cork, Dublin, and Galway will eventually feel the impact of sea-level rise. Developers are discouraged from building within 100 meters of soft shoreline. Sir David King, former chief scientific adviser to the British government, cited a report he published in 2004, predicting that storm surges would reach inland and affect cities resulting in billions of pounds a year in economic damage.