The Irish Climate Analysis and Research UnitS (ICARUS) anticipate major changes to Irish rivers due to climate change, which may have more than just environmental costs.
As people look to the rising sea and soaring temperatures, the potential consequences of anthropogenic climate change for rivers in Ireland are constantly ignored. Yet, the negative impacts are already being felt across the island.
Using earth systems models and hydrological models, a 2022 study by ICARUS found that an increase in winter mean flows and a reduction in summer mean flows in Irish rivers are to be expected. These changes are in line with global projections, with this potentially contributing to the decrease in water quality as outlined by the European Union’s Water Framework Directive (WFD). The WFD aims to improve the conditions of rivers across Europe, although climate change presents new challenges for its implementation in Ireland.
The anticipated changes to seasonal mean flows of rivers also increase the risk of pollution for many agricultural river catchments, as ICARUS’s 2021 study suggests. The studied catchments displayed increased levels of pollutants such as nitrates and phosphorus. While agriculture and industrial activities are better known sources of these pollutants, they are also linked to the occurrence of extreme weather events. These agricultural pollutants have devastating effects on wildlife, with fish deaths and algal blooms being a potential outcome of this.
Due to the impact of climate change on air temperature and precipitation, the occurrence of extreme weather events in Ireland is an area of concern regarding run-off, with agriculture coming to the forefront of this discussion as Ireland attempts to meet its 2027 goal as outlined in the WFD. The risk of pollution in agricultural catchments is further exacerbated by the estimate that surface runoff is expected to increase by 6% on a global scale, according to a 2024 study published in the Journal of Hydrology and Earth System Sciences. The mitigation of this pollution requires catchment-specific approaches, as climate-driven changes presented differently in each catchment.
Increased flood risk is another potential cost of climate change for Irish rivers. In a recent study conducted by ICARUS Climate Research Centre, it was found that climate change may have caused the 2023 major flooding of Midleton, Co. Cork. This flood saw Midelton’s Main Street flood in just eight minutes, resulting in an estimated €200 million in damages. This flooding came during an anomaly in precipitation during Storm Babet, with over 100 mm of rainfall spanning across just 36 hours.
The need for climate adaptation strategies has been encouraged by ICARUS, with new evidence suggesting the flooding event in Midleton could become up to twice as likely to occur in the future as well as being 13% more intense under current climate projections. The River Dodder also presents a flood risk to urban areas in Dublin, with a study led by the University College Dublin Spatial Dynamics team finding a 16% increase in flood frequency in the catchment within the next 100-years. These events may have the potential to endanger human life, as seen in the major flood of Valencia, Spain in October of 2024. This flooding event, which has also been suggested to have been exacerbated by climate change, saw the loss of over 220 lives and over €2.6 billion in damages.
Based upon this evidence and expert opinion, intervention is needed to prevent further environmental and economic impacts, as well as prevent the potential loss of human life. While hard engineering strategies such as weirs and walls have been preferred by the Irish government in the past, the WFD promotes the use of sustainable approaches to the restoration of Irish rivers and climate change adaptation strategies. Additionally, the government has been encouraged to engage with farmers as stakeholders, given the high risk of pollution in agricultural catchments, which could devastate Irish wildlife.