What History Teaches Us About a Super El Niño

Some lessons from Ireland in the nineteenth century

The world is forecast to experience a very strong El Niño Southern Oscillation (ENSO) in 2026. It is emerging faster than predicted, evident in marine heatwaves in the pacific ocean with implications for marine ecosystems. This week The Economist suggested that the coming El Niño “could be the strongest ever recorded.” The headline is deliberately hyperbolic (after all, it ignores the mega El Niño thought to have accompanied the end-Permian mass extinction), but it raises an interesting question. If we are about to experience one of the strongest El Niño events in modern history, what should we expect? The best answer comes not from meteorology alone, but also economics and history.

Recent news coverage of the coming ‘super’ El Nino has made brief comparisons to the 1877 El Niño (New York Times 6 May and 21 May; Washington Post, 12 May), which we want to explore more here. Historians have long recognised the 1877–78 El Niño as one of the great global climate shocks of the nineteenth century, with catastrophic consequences, particularly in Asia and Africa. What is less known is that Ireland was also part of this story. The climatic shock helped create the conditions for the Irish Land War (1877-1882), a transformative period and one of the largest episodes of mass political mobilisation in the history of Ireland and the United Kingdom. Ireland teetered on the brink of mass revolution. A recent Guardian op-ed on the 2026-27 El Niño highlighted civil unrest as one possible outcome. Irish history provides insights into this historical relationship.

Source: Washington Post, 12 May

Impact on weather patterns

ENSO is one of the most important sources of naturally occurring global climate variability, generating large-scale anomalies in temperature and precipitation (McPhaden et al. 2006). It oscillates between a warm phase (El Niño) and a cool phase (La Niña), drawing analogies with a swing. Climate change may be amplifying these oscillations, although the extent remains uncertain, with the two phases oscillating. A recent review showed that ENSO sea surface temperatures increased after 1960, likely linked to climate change.

Figure 1 Ensemble Oceanic Nino Index

Source: Ensemble Oceanic Nino Index

ENSO’s impact on weather patterns varies across the globe. Some regions can expect much higher temperatures while the northern hemisphere can expect colder winters (as the BBC predicts for the UK in 2026). The La Niña phase can lead to cooler temperatures, while the El Niño to warming effects. The ENSO helps explain why temperatures soared in 2023 and 2024 (El Niño effect) and fell in 2025 (La Niña).

In their classic paper William Quinn, Victor Neal, and Santiago Antúnez de Mayolo (1987) reconstructed more than 450 years of ENSO history from ship logs, colonial records, weather observations, and historical accounts. They identified at least 47 strong or very strong ENSO events between 1525 and 1983, demonstrating that it is a recurrent feature of the climate system rather than a modern phenomenon. The chronology also suggests that ENSO activity varies over time, with periods of more frequent and intense events interspersed with quieter intervals, highlighting the importance of long-term climatic fluctuations in shaping regional weather. ENSO’s impacts, as Sun et al. (2024) show, also depend on wider environmental contexts.

Figure 2 ENSO events, 1500s-2020s

What are the economic consequences of ENSO events?

Climate variability is increasingly recognised as a major driver of population health, influencing food security, infectious disease dynamics, and economic stability across multiple spatial scales (Romanello et al. 2023; Romanello et al. 2025). A growing body of research demonstrates that ENSO has persistent and far-reaching effects on both economic and health outcomes. ENSO events have been shown to affect agricultural productivity and nutritional outcomes (Iizumi et al. 2014; Anttila-Hughes et al. 2021), alter disease environments (Mokhtar et al. 2024), and generate long-term impacts on economic growth (Callahan & Mankin 2023; Liu et al. 2023). Recent work reiterates the view that ENSO-related shocks can have enduring impacts on mortality and life expectancy (Xu et al. 2026). Strong ENSO episodes can generate synchronised disruptions across multiple regions, producing droughts, floods, and temperature extremes that affect food systems and disease environments.

The 1877-78 ENSO provides a key historical case. This event contributed to widespread drought and famine across Asia, Africa, and the Americas, with severe mortality impacts in India and China (Aceituno et al. 2009; Singh et al. 2018; Davis 2017; Ó Gráda 2009). However, climatic shocks alone do not determine outcomes, their impacts depend on how they propagate through local conditions.

The Global El Niño Behind Ireland’s “Forgotten Famine”

The Irish Land War is typically associated with the Land League movement, eviction protests, anti-landlordism, land reform and political change. A less familiar aspect is the environmental shock that helped trigger the crisis. Our recent research situates the severe distress in late-1870s Ireland in a global context, linked to one of the most powerful ENSO events of the nineteenth century. The El Niño of 1877–78 disrupted weather systems across the globe. Historians and climate scientists now associate it with devastating famines stretching from India and China to Brazil and parts of Africa. Across these regions, abnormal weather patterns damaged crops and pushed already vulnerable populations into crisis. In India, the traditional Monsoon cycle was disrupted leading to droughts and harvest shortfalls.

Figure 3 Monthly average temperatures in Ireland 1877-80, and mean temperatures in Ireland for 1990-2020 and 1871-76

Figure 3 Monthly average precipitation in Ireland 1877-80, and mean precipitation in Ireland for 1990-2020 and 1871-76

Ireland’s experience was different, avoiding the severity of mass famine and drought, nonetheless the impact of the same ENSO phenomenon was substantial. Rather than drought, the late 1870s brought unusually cold and wet conditions. The years 1877 to 1879 were marked by poor weather, failed harvests, and growing food insecurity. Wet summers also meant less turf was harvested as fuel when people faced into unusually cold winters. At the same time, Irish agriculture was being squeezed by falling agricultural prices as cheap imports from North and South America entered European markets.

This combination proved disastrous. Rural households faced declining incomes just as harvests deteriorated. From 1879 contemporary observers increasingly described conditions in western Ireland as a famine, with disease spreading, while relief efforts were critical in avoiding higher deaths. Contemporary attention focused on the western seaboard, but this obscured a parallel crisis in Ireland’s towns and cities, where excess mortality was often even higher.

The same El Niño that contributed to famine elsewhere in the world also helped create the conditions of Ireland’s Land War. The social and economic crisis brought rising evictions, which intensified longstanding tensions in Irish society between tenants and landlords, triggering social unrest. 1879 saw the formation of the Irish Land League, a mass movement for land redistribution that mobilised large swathes of the population, and saw some success in land reform legislation in 1881. This began a process of change to land ownership that fundamentally altered the dynamics of politics and society on the island.

We argue that these environmental dimensions of the Land War have been overlooked. Analysis of excess mortality suggests that the crisis of 1878–80 was far more severe than historians have generally assumed. Seen from this perspective, the Land War was not simply a political conflict over land, it was also the Irish response to a worldwide climate shock whose effects were felt across several continents.

Figure 5 Age standardised excess mortality, 1879

Conclusion

The late 1870s remind us that global climate events can have profoundly local consequences. The lesson of 1877–78 is that climate shocks become crises when they interact with local economic fragility, disease environments and political tensions. That is as true in the twenty-first century as it was in the nineteenth. One of the strongest ENSOs on record helped turn economic hardship in Ireland into a public-health crisis and provided the backdrop to one of the most transformative periods in modern Irish history.