Scientists are closely monitoring the development of a potentially record-breaking El Nino event, which could trigger severe climate disruptions worldwide in the coming months. El Nino is a natural climate phenomenon characterised by the warming of surface ocean temperatures in the central and eastern equatorial Pacific, disrupting normal weather patterns.

Under typical conditions, trade winds push warm surface waters westward from South America toward Asia, allowing colder, nutrient-rich water to rise along the coasts—a process called upwelling. During El Nino, these trade winds weaken, allowing warm waters to drift eastward toward the Americas, which displaces the Pacific jet stream and weakens or halts upwelling. This affects marine ecosystems and food chains, with repercussions for fisheries and wildlife.

Weather impacts linked to El Nino vary by region. Northern parts of the United States and Canada often face hotter temperatures and drought, while the US Gulf Coast and Southeast experience wetter conditions and increased flood risk. The phenomenon also influences global weather patterns, leading to heavy rainfall in countries like Chile and drought in Indonesia. Scientists anticipate an active Pacific typhoon season, a milder Atlantic hurricane season, irregular South Asian monsoons, and drier conditions in Australia.

In the United Kingdom, El Nino effects tend to be milder but can produce pronounced temperature swings, with colder winters and hotter summers. Experts warn that the current heatwave in the UK may be an early indicator of more extreme temperature rises, potentially exceeding 40 degrees Celsius in upcoming years as global temperatures continue to climb.

The distinction between a standard and a “Super El Nino” is determined by ocean temperature anomalies. According to Mark Roulston, director of operations at Lancaster University’s Climate Risk and Uncertainty Collective Intelligence Aggregation Laboratory (Crucial), El Nino conditions are identified when sea surface temperatures exceed 0.5°C above the norm for that period, while a Super El Nino requires anomalies greater than 2°C. Recent ocean temperature increases suggest this year’s event may reach or surpass the super threshold.

Current forecasts indicate a high likelihood—over 85%—that El Nino conditions will persist during the upcoming Northern Hemisphere winter, with approximately a 45% chance they will be strong enough to qualify as a Super El Nino. The US National Oceanographic and Atmospheric Administration (NOAA) projects a 66% chance of El Nino developing by next month and reaching strong or very strong levels by winter. The European Centre for Medium Range Weather Forecasts (ECMWF) models support the possibility of ocean temperatures rising more than 2.5°C above average by autumn.

Some experts, including Professor Bill McGuire of University College London, predict this event could rival or exceed previous strong El Ninos, such as the 1997-98 and even the historically severe 1877-78 occurrence. This year’s potential anomaly could push global temperatures higher, possibly marking 2027 as the hottest year on record and surpassing the 1.5°C warming limit established by the Paris Agreement.

While some may welcome warmer weather, the broader consequences of a Super El Nino are often severe. Past events have led to widespread food insecurity due to droughts and floods, as well as an increased risk of wildfires and coral reef die-offs. The 1997-98 Super El Nino, for example, resulted in the loss of an estimated 16% of the world’s coral reefs.

Experts emphasize that this event should not be mistaken as evidence against ongoing global warming trends. Roulston pointed out that El Nino-related climate fluctuations represent natural variability layered on top of the broader warming trend, with vulnerable populations especially at risk from the associated disruptions to agriculture and ecosystems.