Is the weather running AMOC in Ireland
Will Ireland be transformed into Iceland?
AMOC refers to the Atlantic Meridional Overturning Circulation, which is a large system of ocean currents where warm shallow water is moved north from the topics and then returned south by colder, deeper ocean currents. Such movement of the ocean currents provides a more mild climate for Ireland than in equivalent territories at the same latitude which are not affected by AMOC. The Gulf Stream is part of the AMOC. To the extent the AMOC is disrupted or lessened, the weather in Ireland may turn into that of Iceland.
At a recent gathering to celebrate the 50th anniversary of the International Energy Agency Mary Robinson spoke of how the celebration was well deserved, but that “Actually, we’re not in as good a place as we need to be at all.”
In outlining many of the “very bad things [that]may happen” because of climate breakdown, she includes the disappearing coral reefs, and the disappearance of arctic ice and the permafrost. She adds , “And now we have something new that I don’t recall them mentioning, which is the changes to the Gulf Stream,’ referring to the increasing risk from the weakening of the AMOC. She notes in her as usual direct and most engaging manner: “For Ireland, that really would not be funny.”
Not funny indeed.
If the AMOC is disrupted or weakened, sea levels in the Atlantic will rise by a meter, flooding many coastal cities, and wet and dry seasons in the Amazon could reverse. Temperatures across the globe would be transformed, with Europe becoming colder with less rainfall. And the changes could be affected by a slow decline but then lead to a sudden collapse over fewer than 100 years.
Ireland is located at the same latitude as parts of Canada and Siberia and yet its climate is much warmer. That’s in part because of the AMOC. If the AMOC does weaken, even disappear, Ireland’s weather would be more artic than tropical. Good bye to palm and cabbage palm trees in southwestern Ireland.
But how likely is that the AMOC will weaken or disappear, and if it does what will Ireland’s weather be like?
When we first came across the AMOC several decades ago, there seemed to be a consensus among scientists, including in IPCC reports, that the weakening, and especially collapse of the AMOC, was a theoretical possibility but unlikely, maybe highly unlikely, in the 21st century.
Even the sixth IPCC report (2015-23) continued to suggest, with “medium confidence,” that the AMOC would not collapse before the end of the century
That position is shifting.
“A 2019 article from the UK Met Office found that while a total AMOC shutdown this century is very unlikely, it does remain a possibility.” Borlace, Just Have a think, climate solutions.
Recent research indicates that Greenland’s glaciers and Arctic ice sheets are melting faster than expected, poring freshwater into the sea and promoting decline in the AMOC. Since 1950 there has been a 15% decline in the AMOC, which is now at its weakest state in more than a millennium.
Other research suggests that the tipping point for any decline or collapse will be reached between 2025 and 2095.
Others estimate a collapse of the AMOC to occur around mid-century under the current scenario of future emissions.
And if the collapse occurs, it will be quick.
If there is further weakening or a collapse of AMOC, what will it look like in Ireland? One view is reflected in the 2004 hit movie ‘The Day After Tomorrow,” which used the AMOC for the plot line. See, Borlace. The movie wildly exaggerated the effects so it is not worth relying on. Alternatively we can look at the existing weather conditions in comparable cities at the same latitude and estimate the climate.
What we need is a thorough, detailed assessment of the range of conditions that Ireland could face as a result of the weakening or collapse of the AMOC. Such a picture would differ from a view of Ireland with no changes in the AMOC. That’s not a simple proposition, but at least it might suggest some scope of the changes. For a simplistic example, a harsh cooling or freezing of the climate will demand extensive heating infrastructure while heating of the climate without any further weakening of the AMOC will demand extensive air conditioning.
Sources:
Daniel Murray, “Mary Robinson on Eamon Ryan’s international appeal and how to appease Irish farmers,” Business Post Ireland (16 Feb 2024). bit.ly/3UMXFvw
Just have a think – climate solutions, with Dave Borlace, on “Abrupt global ocean circulations collapse. Time to start prepping?” (11 Dec 2022) www.youtube.com/watch?v=j2ETr6X1lOk
Sam Starkey, “An ocean current keeps Ireland warm. What could happen if it collapses?” Green News (11 August 2021). bit.ly/3wCd1sH
Kevin O’Sullivan, “Collapse of Atlantic ocean current could turn Ireland’s climate into Iceland’s: potential changes to system known as Amoc would transform Ireland’s benign climate, Fianna Fáil senator warns,” The Irish Times (16 Feb 2024).
Doyle Rice, “Melting ice could create chaos in US weather and quickly overwhelm oceans, studies warn,” USA Today (9 Feb 2024). bit.ly/49vcyHp
Peter Ditlevsen and Susanne Ditlevsen, “Warning of a forthcoming collapse of the Atlantic meridional overturning circulation,” Nature Communications (25 July 2023). bit.ly/49ibjLj
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