Dáil Éireann Debate, Tuesday - 2 December 2025
324. Deputy Malcolm Byrne asked the Minister for Housing, Local Government and Heritage his Department's current projections on potential slowing of the Atlantic meridional overturning circulation; Ireland's preparedness for any potential impacts; and if he will make a statement on the matter. [67473/25]
Amharc ar fhreagraThe main basis for projections of the Atlantic Meridional Overturning Circulation (AMOC) are the CMIP6 global climate simulations which were performed as part of the IPCC’s sixth assessment report published in 2021. Ireland's contribution to CMIP6 consisted of a set of EC-Earth simulations performed by the Irish Centre for High-End Computing with funding from Met Éireann, the Marine Institute and the EPA. The AMOC is projected to decline by 34% to 45% by the end of the century in the CMIP6 ensemble mean across a range of future scenarios and a full shutdown cannot be ruled out at this time. The potential impacts of a slowdown or even full shutdown of the AMOC on Ireland's climate are discussed in more detail below.
Met Éireann is funding and conducting research as part of the Enhanced North Atlantic Climate Simulation (ENACTS) project, collaborating with the Irish Centre for High-End Computing and engaging with international research partners. This project is exploring the use of enhanced resolution to improve the representation of narrow ocean currents as well as incorporating freshwater inputs from melting Greenland and Antarctic ice. The updated projections produced with these enhancements will allow for further refinement in our understanding of how the AMOC will respond in the coming decades.
In addition, Met Éireann is planning a collaboration with the UK Met Office which will also seek to improve the representation of the AMOC in climate models using cutting-edge research techniques developed at the UKMO. This project is scheduled to start in 2026 and will produce updated projections of the AMOC in the coming years.
While not directly responsible for Ireland’s preparedness for potential impacts of an AMOC slowdown or shutdown, Met Éireann is researching this topic with a view to informing policy and decision makers. The projected decline of the AMOC from CMIP6 will be captured in the next set of standardised projections for Ireland produced by the TRANSLATE project.
While there are currently no specific studies focused on how a slowdown or shutdown of the AMOC would impact Ireland’s climate directly, studies on the effects of a strong AMOC decline on Europe suggest that if the AMOC were to decline or collapse under current climate conditions Ireland could experience cooler winters, drier summers and increased storminess. It is important to note, however, that a full AMOC collapse would take 50-100 years to unfold, during which time temperatures are likely to continue to rise globally. As a result, the likely impact of a substantial weakening or collapse of the AMOC is reduced warming over Ireland as continued global warming offsets any local cooling.
Given the limited research on the potential effects of an AMOC shutdown on Ireland’s climate, Met Éireann has prioritised several key areas of focus:
• Developing scenarios for a significant decline in the AMOC and examining the related impacts on Ireland’s climate.
• Enhancing the accuracy of AMOC projections by refining climate models.
• Studying how mid-latitude cyclones respond to changes in the jet stream.
In conclusion, while the risk of an AMOC shutdown is low, it would be a low probability/high impact event. The impacts derived from a complete shutdown could have serious consequences on the planet and on Irish society, such as disruption to land and marine ecosystems and biodiversity, and socioeconomic pressures related to climate resilience and responses to hazardous weather.
