The potential impact of climatic change on landslides in Ireland

Abstract

The response of the Irish landscape to projected changes in climate is not well documented. Although general predictions of climate change for Ireland are well understood, aspects relevant to the impacts of climate change on specific hazards such as landslides have not been adequately discussed. This paper presents a position-based review of how climate change may influence landslide hazards in Ireland, drawing on existing datasets and published examples. Rather than present a new empirical dataset, the paper synthesises existing knowledge and proposes a research agenda for Ireland.

We first summarise the past and current and the modelled climate change under future climate change scenarios. We focus in particular on climate parameters commonly associated with slope instability, including rainfall intensity and duration, prolonged dry and rewetting cycles, storm tracks, wind, and wave action

To illustrate how projected climate changes may affect landslide activity in Ireland, we draw on data from the all-Ireland landslide inventory (Cullen and Bourke, 2024). While Cullen and Bourke (in review) present a national-scale analysis of this dataset, the current study adopts a case study approach to highlight specific examples that reveal both data limitations and research opportunities. The three case studies illustrate a range of antecedent and event meterological conditions. Our analysis of hourly rainfall preceding three landslides in 2020 shows that failures, particularly in peatlands, may occur under varying hydrometeorological conditions. In two cases, landslides followed intense rainfall after prolonged dry periods, while in another, failure occurred during an extended period of persistent wetness. This suggests that both short-duration rainfall extremes and antecedent moisture conditions play critical roles in landslide triggering, with the sequence of wet antecedent conditions followed by intense rainfall emerging as a particularly important pattern in the Irish context.

Based on this and broader evidence, we suggest that landslide frequency in Ireland is likely to increase under future climate conditions characterised by more intense rainfall and greater variability in wet and dry spells. While most well documented events to date involve peat failures, we note a significant data gap regarding coastal slope failures, where climate-driven changes in sea level and storm dynamics may have compounding effects. Addressing these gaps is essential for improving future landslide risk assessment and mitigation strategies.

We propose that future landslide research in Ireland prioritise several key areas. First, there is a need for detailed investigation into the role of rainfall intensity, duration, and temporal variability in triggering mass movements, particularly under changing climatic conditions. Second, long-term (multi-decadal) studies should be undertaken to capture the full range of slope responses to individual events and to sequences of storms, helping to distinguish between immediate triggers and cumulative preconditioning factors. Third, more frequent and systematic monitoring is needed, including annual topographic surveys and rapid post-event assessments, to document geomorphic change and improve hazard forecasting. Finally, dedicated research is required to understand the interaction between sea-level rise, storm surges, and wave impacts on coastal landslides, where both marine and terrestrial processes are important.