Ireland rugged western coastlines largely composed of hard limestone, are more resistant to pounding waves from the North Atlantic. Yet in regions of rapid retreat the combination of rising sea levels and wave action is eroding away glacial deposits left behind thousands of years ago.
“What you’re seeing, particularly where we have the most rapid retreat, is we’ve got a rising sea level, and we’ve got waves then eating away at material that was dumped there during the last glacial period,” explained Robin Edwards, assistant professor of geography at Trinity College Dublin, who studies physical indicators of sea level change. “We’ve been mapping Ireland for hundreds of years so it’s not a mystery where the stuff is or why it’s eroding away. The challenge is what you do with it.”
Researchers including Curt Kelley and Rich Jackson are now working in Ireland southeastern mountains to fill in crucial gaps in reconstructions of the British-Irish Ice Sheet (BIIS), using geochronological techniques that provide precise timelines of glacial retreat. Their efforts bring science closer to refining global sea level rise projections.
For decades, disagreements between field scientists and climate modelers limited progress. “The debate… often came down to the fact that they were trying to do the same thing, but from very different directions, and they weren’t ending up at the same place,” Edwards said. “The really interesting information for why they weren’t ending up at the same place was the thing that ultimately helped both get better.”
Jackson added that while current climate simulations are valuable, they face challenges projecting far into the future. “When we start projecting farther out to the year 2300, the uncertainty on these projections the error bars get larger and maybe less useful.”
To tighten those margins, Kelley and Jackson’s teams are collecting samples that will later be interpreted directly by geophysical modelers. Sarah Bradley, a research associate at the University of Sheffield who helped develop two BRITICE project models in 2004 and 2017 welcomed their work. “If you come along and allow someone to question your work in a very open, honest manner, that’s how science evolves,” she said.
The implications extend well beyond Ireland. Low-lying islands and coastal communities worldwide face the same escalating risks of erosion, flooding, and powerful storms. Reliable sea level data could help protect lives and infrastructure.
“Once the person makes a model of sea level change, then that’s valuable to policymakers, city planners, engineers, everybody from environmentalists to fishermen,” Kelley said. “So it’s a bit of a tertiary effect, but it’s science that has direct impact.”