Forecasters at Met Éireann were briefed on the “profound impacts” from the possible collapse of an ocean current system that keeps Ireland’s weather relatively mild.
International climate scientists have raised the alarm over the cooling of what is known as the Atlantic Meridional Overturning Circulation (AMOC), the shutdown of which would be a potentially irreversible tipping point in the climate crisis.
Met Éireann forecasters were given guidance notes on how best to communicate the risks for Ireland and how the AMOC was at its weakest in over a millennium.
An advisory said: “It is projected to decline by a further 30 to 40 percent by 2100.”
Forecasters were told that a large cold pool of water, sometimes referred to as the ‘cold blob’, had been observed in North Atlantic waters in recent decades as part of the system weakening.
The guidance note said: “The northern part of the North Atlantic where the cold pool has been observed is the only global region which has cooled as the rest of the world has warmed due to climate change.
“Further weakening of the AMOC is expected to lead to a continuation of the cold pool in the North Atlantic, with the possibility of further cooling.”
It said that while warming caused by climate change was predicted to continue in Ireland, the influence of the cold pool could mean this was less than what would be seen in continental Europe.
The advisory said that while complete shutdown of the AMOC was still thought unlikely, it could not be “definitively ruled out”.
The note explained that if collapse did happen, the impact on Ireland would be “profound” with far more severe winters, warmer summers, and a possible increase in storminess.
It also said weakening of the AMOC was likely to result in further sea level rises around the country, in addition to what is already expected from climate change.