Connemara is slipping into the sea

New evidence uncovered by an international geologist shows that Connemara is slowly drowning at sea.

Because while rising sea levels are a factor globally, what is technically known as an isostatic rebound means that Ireland’s crust is tilting – so that, while the counties in north and east are rising up, southern counties including Galway are going down.

Welsh-based geologist Jonathon Wilkins came up with his findings by investigating the South Connemara coastline during two fortnightly stints while on holidays here.

He was travelling along a road in Máinis near Carna when his curiosity was aroused.

“I realised something strange was happening in the landscape. Close to the laboratory of NUI Galway’s Ryan Institute the tide was flooding sinuous channels in a peat bog, not a saltmarsh as I had first supposed, and peat bogs don’t accumulate in salt water,” he recalled.

On closer inspection, he found there were numerous tree stumps with radiating root plates.

The stumps are buried beneath peat, up to two metres in one location.

“The level of the stumps is below the highest tide level, and it has to be assumed that they didn’t grow with their roots in the sea,” he writes in an article published in the online magazine Earth Science Ireland.

“So here is very powerful evidence that sea level, to my surprise, is rising in this area, and demonstrably over quite a short time scale.”

The crust beneath southern Ireland is being levered downwards by a stronger “isostatic rebound”, which is where land mass that was depressed by the huge weight of ice sheets during the last glacial period rises.

This means counties to the north and east are going up – while the southern counties including Galway are going down.

And because so much of South Connemara’s landscape is made up of peat, when the sea encroaches onto land, it takes the peat away, leaving just rocks behind, which will go on to become solitary rocky islands.

“Erratic boulders are everywhere on the South Connemara shore, but I had not expected that they were mostly surrounded by a blanket bog until it was claimed by the sea, and that the strange, watery landscape is indeed being shaped by a slow drowning,” writes the geologist.

The article was raised at a meeting of Galway City Council by Sinn Féin Councillor Cathal Ó Conchuir, who said it merited further academic investigation.

See full story in this week’s Connacht Tribune.