Erin, Green Gem of the Silver Sea
All aboard the RV Joyce for an expedition around Ireland's ocean territory
Hi everyone, it’s been a while…
Shortly after my last post, in August of 2022, I moved to Ireland to get a masters degree in literature (a strange sentence to find in an ocean science newsletter!). Instead of writing for In Circulation, I spent each week reading up on the country’s history and enjoying Irish novels, poems, and plays. Many of Ireland’s writers, from Lady Morgan and W.B. Yeats to Elizabeth Bowen and James Joyce, have written about the island’s environment, usually associating its natural beauty with mystical elements of Celtic culture like fairies as well as the true spirit of the Irish people. A river runs through each of the country’s major cities (the Liffey in Dublin, Garvoge in Sligo, Corrib in Galway, Lee in Cork, Shannon in Limerick), all but one of which lies on the coast. With such strong ties between land and sea, one would assume that the Emerald Isle is a hotspot for marine science.
Yet Ireland has not asserted themselves on the world stage as advocates against sea level rise in the way that other island nations such as the Maldives or Fiji have (the former’s President once held a cabinet meeting under water and the latter’s most famous citizen is Peter Thomson, the UN Ambassador for Climate Change). The Irish government has persistently ignored the ocean, at least legislatively: they did not formally approve any marine policy until two years ago, or 98 years after achieving independence. And this law was only passed after the EU mandated that its member nations include their ocean territory in the fight against climate change. This despite the fact that Ireland has jurisdiction over 220 million acres of open water — more than 10x the size of their land area!
But before we can understand why people living in an island in the Atlantic have not viewed the ocean as their top priority, we must first explore the marine surroundings of this “Green Gem of the Silver Sea,” as Joyce famously wrote.
So, where is Ireland?
Most of us would answer this question using an atlas, which tells us that the 21-million-acre island lies off the west coast of Britain. Some may even note its position as the second westernmost nation in Europe (behind Iceland of course). However, we marine science enthusiasts are more concerned with its location relative to the ocean’s gyres.
As we can see, Ireland sits just off the top of the North Atlantic gyre, which means that it receives an influx of cool, nutrient-rich water from the Arctic via the East Greenland current. It also sits at the very end of the Gulf Stream, meaning the land receives moisture from the tropics and gets the last little bit of equatorial heat before it peters out.
And as we can see from the plate tectonics map below, Ireland is the westernmost country that sits fully on the Eurasian plate (Iceland is bisected by the Mid Atlantic Ridge, and the Azores are actually at the junction of three tectonic plates!). The Eurasian plate is expanding away from the North American and African plates, meaning that the more oceanic crust is being created, so Ireland’s marine territory is verrrrrrry slowly, but surely, expanding.
Why are Ireland’s marine environments important?
As we can see from the Real Map above, Ireland has a HUGE continental shelf that extends roughly 370km (230 miles) to the south and west. This area of ocean contains two banks, or undersea plateaus: the Celtic and the Porcupine. There is also the Rockhall Bank to the far northwest, near the edge of Ireland’s ocean borders. At their shallowest points, these banks are 100-200m below sea level. Since sunlight reaches the top 200 meters of the ocean, these waters are a unique combination of warm and nutritious: warm because of the shallow depth, and nutritious because of the nutrient-dense waters flowing down from the Arctic.
As a result, fishing in Irish waters is plentiful: according to the 2020 and 2021 reports by Ireland’s Seafood Development Agency, their fishing industry was worth around €1.3 billion, with mackerel, whiting, crab, and lobster as the most abundant species on average. But since Ireland is part of the EU, other nations can fish in Irish waters, and EU officials estimate that the total value of Irish fisheries is closer to €5 billion! Nearly all of the catch are found on the Porcupine, Rockhall, and Celtic Banks, with the later containing the largest number of individual fishing grounds (see graphic below).
There is also a large amount of biodiversity in Irish waters that scientists are only recently discovering. Ireland started mapping its ocean territory in 1999; a decade later, researchers from National University of Ireland at Galway found a forest of 40 coral reefs on the Porcupine Bank! The lead scientist told the Irish Examiner that “these are by far the most pristine, thriving and hence spectacular examples of cold-water coral reefs that I’ve encountered in almost 10 years of study in Irish waters.” Despite being found slightly deeper than the ideal for most corals (around 70m below the surface, whereas the Porcupine reefs sit 100m below surface), these formations stood tall at two meters — a rare sight as most cold-water corals don’t grow above 0.5 meters. As discussed in a previous newsletter, coral reefs provide habitats for fish, algae, and other marine life, so it is important to protect these unique environments, often called the ‘rainforests of the ocean.’ Indeed, scientists at University College Cork are currently monitoring conditions in the area by tracking pollutants, food supply, undersea currents, ocean acidity and temperature.
Climate vs. Weather
You’ve probably heard it rains all the time here — indeed, frequent precipitation is a symptom of Ireland’s Temperate Oceanic climate (remember the difference between weather and climate). Most of northwestern Europe also has this climate, which is characterized by frequent precipitation, an absence of severe weather, and temperatures ranging from -3 to 22°C (26-72°F).
My own experience with Irish weather included a warm fall in 2022 followed by the rare occurrence of snow a few months later. Accumulation was less than 1” in Dublin, and while it melted pretty quickly, the air remained intensely cold and foggy. There were a few freezing January mornings, which faded into a mild spring and cool, stormy summer. I remember watching the heavy rain and intense winds from inside libraries and study rooms while writing my dissertation (rendering it a ~wet and Wilde~ summer for me). According to Met Eireann, Ireland’s weather service, 2023 had the wettest March & July on record, as well as the warmest June & May. Storms Antoni and Betty caused extreme flooding, but these were soon forgotten as the city sweltered under a week-long heatwave at the beginning of September. The air in the city center vibrated with the heat, which topped out at 21.2°C (70°F) in central Dublin— coupled with extremely high humidity of course. The rest of autumn alternated between warmth and rain (courtesy of Storms Babet and Debi), and a cold snap ushered in the start of the December.
Ultimately, how will climate change affect Ireland and its waters?
As mentioned above, Ireland is known for having predictable, uneventful weather, but because of the recent extreme heat and rainstorms, people are beginning to notice a change. 2023 was Ireland’s (and the world’s) warmest year on record: Met Eireann reports that the average air temperature on the isle was 11.2°C, which is 1.65°C above 20th century averages and 0.35°C warmer than 2022, the previous warmest year on record. In fact, this is the first time in Irish history that the average annual temp has risen above 11°C…! The number and intensity of storms, including eleven named ones, also increased, leading to one of the wettest years on record. Ireland’s weather service attributes these anomalies to abnormally high sea surface temperatures (SSTs), which also caused a marine heatwave in the Celtic Sea. Met Eireann’s official statement warns of “further warming in the future” and explains that increasingly severer storms put the Irish coast at risk for “‘compound events’ involving heavy rainfall and high tides combined.”
So, a warmer ocean leads to worsening weather. But where is all the nutrient-rich water coming down from the Arctic? Isn’t it supposed to blend with the Gulf Stream and mitigate the temperature (among other benefits)? Actually, recent scientific studies have discovered changes in ocean circulation that cannot be attributed to natural climatological variations. This means that the location of ocean gyres is shifting, essentially bringing different kinds of water to places where they shouldn’t be. In a 2020 paper, Yang et. al. found a “consistent poleward shift” of the North Atlantic gyre. Although the observed changes to date are small, their models (based on a steady increase of CO2 over 150 years) show that the Gulf Stream, which carries tropical waters to the northern Atlantic, has “experienced an overall northward displacement” in recent decades. The gyre, therefore, is moving tropical heat farther north, which not only creates moister air (leading to more rainfall) but also effectively blocks any cool Arctic water from flowing down into Ireland’s ocean territory. This could cause, among other things, fish stocks to move northward in search of both food and relief from water that will be too hot for them to survive in, thereby expanding what Yang et. al. calls “the ocean desert.”
Interestingly, fishing is less integral to Irish culture than in other coastal areas in Europe like Scandinavia. I was told a story about how, during the Great Famine of 1845-1851, some residents of Achill Island (a remote place off Ireland’s west coast) tried to take up fishing. Despite their proximity to the sea, these people had little knowledge of how to catch fish. After the potato crop failed year after year, the men decided to build a small boat and set out with makeshift rods to catch food for their families. Unfortunately, this boat capsized and every single one of them drowned; those remaining starved or left their village behind, which to this day remains abandoned. (Side note: Achill was the main filming location for The Banshees of Inisherin, chosen in large part because the landscapes had “a lot of tragedy behind them.”)
That being said, it is important to note the lack of consensus within the scientific community about what specifically will change about ocean circulation, let alone what changes will mean. Last year, Ireland’s Marine Institute published their annual Ocean Ecosystem and Status Report (OESR), which discusses the implications of a weakening Gulf Stream (this would cause Ireland and most of Northern Europe to undergo intense periods of extreme cold and receive less rainfall). The Institute recommends that policymakers “enhance coordinated observations of ocean circulation and heat content in Irish waters to understand whether recent cooling trends are part of an anthropogenically-forced, long-term decline in the AMOC or are associated with natural variability.” Furthermore, the OESR documents how sea levels are rising in Dublin and Cork at twice the global average, threatening the 40% of Ireland’s population that live within 5 km (3mi) of the coast. SSTs have also risen by as much as 0.5°C per decade over the past hundred years. And the pH of Irish waters — particularly near the Rockhall fishing grounds — is decreasing by roughly 0.02 per decade at both the surface and depths; this ocean acidification could threaten the cold-water coral reefs mentioned above as well as the abundant shellfish populations that Irish fisheries depend on.
Despite the urgent and well-documented threat of climate change, the government did not seriously take charge of their marine resources until after Brexit made it politically necessary. Ireland’s National Marine Planning Framework was not finalized until 2021, five years after the UK, Ireland’s closest neighbor and former ruler, voted to leave the EU (and seven years after the EU mandated that all coastal member nations create national plans for managing the ocean). Indeed, country’s relationship with its seas is tarnished by the legacies of British colonialism, but we’ll leave that for next week’s newsletter.
Main sources:
The Marine Institute's Real Map of Ireland
The Marine Institute's 2023 Ocean Status Report
Met Eireann rainfall information