Cool Years Are Now Warmer Than the Past’s Warm Years: Tracking ENSO and Polar Influence

Global temperatures are rising despite natural fluctuations from the El Niño-Southern Oscillation (ENSO) cycle. According to Our World Data statistics, in 2024, the world was approximately 1.5°C warmer than pre-industrial times. Long-term climate trends, measured over 20-to-30-year periods, confirm an overall warming of around 1.3°C. 

According to Copernicus ERA5 dataset, February 2025 marked the 19th month in a 20-month period where the global-average temperature exceeded 1.5°C above pre-industrial levels. Looking at the 12-month period from March 2024 to February 2025, the global average temperature was 1.59°C above the pre-industrial level and 0.71°C above the 1991-2020 average. These record-breaking temperatures highlight the intensifying nature of global warming. 

However, temperature increases have not followed a straight path. ENSO, a climate cycle driven by wind patterns and Pacific Ocean temperatures, causes short-term fluctuations. It consists of: 

• El Niño (Warm Phase): Leads to higher global temperatures. 

• La Niña (Cool Phase): Temporarily lowers global temperatures. 

• Neutral Phase: Neither extreme is dominant. 

ENSO phases shift every two to seven years, creating a zig-zag pattern in temperature records. Despite these fluctuations, today’s La Niña years are hotter than El Niño years of the past, highlighting the accelerating impact of human-induced warming. El Niño drives extreme weather, worsening heatwaves and droughts in Australia, Southeast Asia, and Africa while triggering heavy rain and flooding in the Americas. It also fuels stronger tropical storms and hurricanes, especially in the Pacific. These effects amplify climate change risks and disasters. 

While ENSO originates in the Pacific, polar changes, such as Arctic sea and land ice loss are intensifying its effects. Polar warming influences global weather patterns, disrupts ocean currents, and weakens the planet’s ability to regulate heat. This feedback loop exacerbates global warming, making even “cooler La Niña” years warmer than previous ” warm El Niño ” periods. 

The stark reality is that natural cooling phases no longer provide relief from global warming. The combined effects of ENSO and polar climate shifts demand urgent action to reduce emissions and strengthen climate resilience worldwide. 

Feature image: Global temperature anomalies by El Niño and La Niña conditions. Credit: Copernicus Climate Change Service information (2025); NOAA National Centers for Environmental Information (2025); Our World in Data. 

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