Storm barrage essential in Cork city as sea levels rise
By the mid-80s, such doomsday scenarios were discounted by scientists such as Dr WF Budd who claimed temperature rises would be more subtle and such extremes unlikely.
A U-turn started by the 1990s, however, as predictions of sea levels rising by 1.5 metres began to trickle back into scientific journals. Then, two years ago, the Intergovernmental Panel of Climate Change predicted rises of up to .5 metre by 2100. Last month, that figure was thrown out by geophysicists at the University of Toronto who demonstrated that, should the West Antarctic Ice Sheet collapse and melt in a warming world — as many scientists are concerned it will — the coastlines of the US and of nations in the southern Indian Ocean will face the greatest threat. New York, Washington DC and parts of the Californian coast could face rising sea levels of up to six metres. It would be a global catastrophe especially as two thirds of the world’s population live within 37 miles of the coast.
Against this backdrop, Professor Robert Devoy of UCC’s Department of Geography and the Coastal and Marine Resources Centre is questioning the rationale behind pumping millions of euro into docklands developments.
“We have learnt a lot, but there is still a lot of arm-waving going on among scientists as to what is accurate. Our knowledge is still limited. People are uncertain of the best estimate. Are sea levels to rise by .5 metre, two metres or six metres? If we build in areas close to the sea, we will have to engineer for potential rising sea levels, an extraordinarily difficult thing to do. We can take a totally precautionary approach or do we design buildings to add on more later as sea levels rise? It’s all in the detail though and we need detail for planning. We don’t have that detail as there is a lot we don’t know. How much more will precautions cost?”
Prof Devoy isn’t scare-mongering. He’s urging caution. Cork City Council, on the other hand, says its dockland development proposals were drafted to take rising sea levels into account.
Up to 27% of the Netherlands is reclaimed land and with two-thirds of its land mass below sea level, it is a country that has engineered hugely for flooding — protected by 2,174 miles of primary flood defences, including dikes, pumping stations, dams and enormous “storm barriers” as well as 8,699 miles of secondary defences, such as canal dikes, basin dikes, holding ponds, and weirs. It is even considering giving back some of its hard-won “polders” to the sea by building huge flood plains that can absorb some of the increased flood waters they are expecting.
Prof Devoy points to the glaciers of Greenland where some glaciers are even now retreating fast. The melt out of Greenland would have a sharp impact on the sea levels of the south of Ireland, he says. Rising sea levels here would be compounded by “bigger magnitude storms” under global warming, as we lie in an easterly storm track of Atlantic storms with winds sweeping over Ireland and on to Scotland and Norway. If the glaciers melt, we’ll be facing more frequent and higher waves and more ferocious storms, he said.
“Dublin doesn’t have the same storm surge problem as Cork. Also remember Cork is built on wetlands and marshes. It can only take so much water, especially if we have more water in rivers. In general we need to be cautious about what coastline areas we release for development.”
Prof Devoy suggests that Cork City Council should again consider developing a storm barrage as opened on the River Thames in 1983. This would protect inland areas from surges at sea.
Halcro Consultants’ flood report for Cork city and county is to be published this year. It’s understood to paint a grim picture of flood risk in the city.
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