The British Science Association predicted worsening climatic conditions in the coming years. At their Annual Conference in Newcastle in September 2013 it was described how 2000 kilometre long 200 kilometre wide “atmospheric rivers” high above the earth can dump as much rain as the amount of water that flows from the Amazon River.
Professor Peter Lynch, Professor of Meteorology at University College Dublin predicted that the same “basis physics” relating to the planet’s water cycle will also see Ireland suffer storms of greater intensity with sudden and increased rainfall. He said that the “atmospheric cycle of water is becoming more energetic” and that high temperatures mean more moisture and more energy to be released. Ireland lies under a region where these filaments pass over head so that we face this increased risk of flooding, he said. Global average temperatures rose by almost a degree over the past 100 years and higher temperature means more water can be carried by the atmosphere. This moisture falls as rain as the air moves northward and cools dictating heavy downpours.
Data from the U.K. and U.S. indicate that this is already happening and the chance of experiencing the worst storm seen in 50 years had increased by 12% for the U.K. as a whole but current climate models are poor at predicting these storms. Whilst storms during winter periods cover wide areas, summer storms are much more local, depending on when an atmospheric river dumps its water. Professor Fowler of Newcastle University said that “these extreme events seem to be increasing but the hope is we can bring together information from past storms plus the prediction models to prevent this type of thing in the future”. NUI Galway predict that Ireland will suffer more landslides based on the increased frequency of significant landslides in the U.K.
More landslides are being triggered by changing climatic conditions primarily due to heavy rainfall. These slides are caused when the top section of sloped ground becomes saturated and the weight of gravity causes the section to slide. In the last fourteen months a five fold increase in the number of landslides has been recorded in the U.K. (source British Geological Survey). In 2012, 176 landslides occurred in the U.K. in the first five months to May whereas the annual average is recorded as 50. 2012 was the second wettest in the U.K. records suggesting a clear correlation between rainfall amounts and landslides.
Dr. Kieran Hickey of NUI Galway School of Geology & Archaeology says that the position is no different in Ireland. He said the risk of landslides rose sharply in the 48 hours after heavy rainfall and in Ireland most slides involve saturated peat breaking away and some of these were triggered by building works.
These are described as “bog bursts” with two major ones occurring in 2003 in North Mayo and in Derybrien in Co. Galway. In Mayo it happened after a “100 year rainfall event” which followed an extended dry period. Alan FitzGerald, FCII., FCILA., FUEDI-ELAEX