The UN has warned that a new El Niño phase could emerge within weeks, potentially bringing the strongest warming event in decades to a planet already heating from human-driven climate change. El Niño, the natural weather pattern that warms ocean surface temperatures across the equatorial Pacific, typically occurs every few years and disrupts global rainfall and temperature patterns.
This next cycle threatens to accelerate global warming temporarily. The last major El Niño struck in 2015-2016, spiking global temperatures and triggering drought across Southeast Asia, East Africa, and parts of South America while causing flooding in other regions. Scientists predict the incoming event could rival or exceed that intensity.
The timing compounds existing climate pressures. Global temperatures have already climbed 1.1 degrees Celsius since pre-industrial times, driven by greenhouse gas emissions. An El Niño on top of that baseline warming could push several nations past critical heat thresholds, stressing water supplies, agriculture, and infrastructure. The 2015-2016 event contributed to record global temperatures that year and exacerbated food insecurity in vulnerable regions.
El Niño cycles are natural phenomena driven by ocean-atmosphere interactions, separate from long-term climate change but amplified by it. When El Niño emerges during a warming planet, the combined effect produces sharper temperature spikes than either would alone. This pattern has scientists monitoring atmospheric indicators closely for the official transition.
The warning arrives as governments prepare for climate negotiations and as extreme weather events already linked to warming intensify globally. A major El Niño could accelerate the timeline for reaching key temperature milestones that trigger irreversible climate tipping points, putting added pressure on nations to accelerate emissions reductions.