As climate change accelerates, extreme weather events are becoming more frequent and severe around the world. At the same time, naturally occurring climate patterns can temporarily amplify these impacts, making some regions wetter, drier, hotter, or more prone to extreme weather. One of the most influential of these patterns is El Niño.
What is El Niño?
El Niño is a naturally occurring climate phenomenon characterised by warmer-than-average sea surface temperatures in the central and eastern tropical Pacific Ocean. The name, meaning "the Christ Child" in Spanish, was given by Peruvian fishermen because the warming typically reaches its peak around Christmas.
Scientists monitor sea surface temperatures across the Pacific Ocean to assess the strength of El Niño. When temperatures rise significantly above average, particularly by more than 2°C, it is classified as a very strong, or "super", El Niño event. As warmer ocean waters transfer heat into the atmosphere, global circulation patterns shift and influencing rainfall across different parts of the world.
Although scientists continue to monitor current developments, several months of observation are still required before determining whether an event will become one of the strongest on record. However, El Niño is about far more than global temperature records. Its impacts extend to agriculture, ecosystems, biodiversity, water resources, energy systems, and the livelihoods of millions of people.
Why does El Niño matter for cities?
While El Niño does not affect every region in the same way, its influence is felt most strongly across the tropics, where it can increase the likelihood of severe floods, prolonged droughts, heatwave and tropical storms. These climate hazards often have cascading effects on urban areas, disrupting infrastructure, water supplies and local economies.
Recent extreme weather events demonstrate the growing vulnerability of cities and communities worldwide. Japan experienced severe flooding and landslides following intense rainfall, while North America faced destructive wildfires in the west alongside deadly flash floods in the east. In China, Typhoon Bavi triggered widespread flooding, leaving homes, farmland and infrastructure heavily damaged.
As Lucas Snaije, Research Officer at IHS, explains, "the footprint of an El Niño travels far beyond its origins in the Pacific Ocean, impacting agriculture, energy supplies, trade, water resources, supply chains and livelihoods across entire regions." Cities often experience these shocks first-hand, compounding the already severe impacts of the climate crisis.
For urban planners, El Niño highlights the importance of preparing cities for climate uncertainty rather than a single hazard. Cities need resilient infrastructure capable of coping with both water scarcity and extreme rainfall, reliable energy systems that can withstand periods of high demand, and public spaces designed to reduce heat stress while protecting vulnerable communities.
"Cities will need to adopt more flexible and adaptive approaches to decision-making."
Lucas Snaije
Adaptive approaches for a changing climate
Nature-based solutions are increasingly recognised as an essential part of urban adaptation. Expanding urban forests, increasing tree canopy cover, restoring waterways, and integrating green and blue infrastructure can help reduce urban temperatures, improve stormwater management, and strengthen resilience without relying solely on energy-intensive technologies.
Importantly, El Niño should not be viewed in isolation. The increasing frequency and severity of extreme weather are primarily driven by human-induced climate change. El Niño can temporarily intensify these impacts, but it occurs against a backdrop of rising global temperatures caused largely by greenhouse gas emissions. Together, they reinforce the urgent need for cities to invest in climate adaptation while accelerating efforts to reduce emissions.
Urban interventions can simultaneously strengthen climate resilience and reduce emissions from improving building standards and expanding green infrastructure to decarbonising transport systems. Achieving these benefits will require stronger institutional capacity, better resourcing and more integrated planning, underpinned by a commitment to climate justice.” - Lucas highlights.
- Related content
- Related education
