This year's El Niño phenomenon is approaching record levels and could become the most intense ever recorded, threatening extreme weather worldwide and making 2027 the hottest year in history.
Combined with human-caused global warming, climate experts say the current episode offers a preview of average temperature levels expected by the late 2030s.
Sea surface temperatures in the Niño 3.4 reference zone of the equatorial Pacific Ocean are currently 2.6 degrees Celsius above the 30-year average, according to the Climate Brink tracking dashboard based on data from the National Oceanic and Atmospheric Administration.
Forecasts compiled by the dashboard indicate the phenomenon could peak at a 3.9 degrees Celsius anomaly in November. That figure significantly exceeds the 3.0 degrees Celsius anomaly recorded during the previous record year in 2015.
Because the global impacts of El Niño are primarily felt in the calendar year following its onset, scientists expect 2027 to set new heat records. Calculations by climatologists Zeke Hausfather and Andrew Dessler show the event will add an average of 0.3 degrees Celsius to global temperatures in 2027.
Forecasts and temperature projections
Andrew Dessler, a professor of atmospheric sciences at Texas A&M University, told AFP that the temporary surge serves as a preview of the future. He noted that a sustained long-term warming increase of that magnitude would otherwise not be expected until 2037, though he clarified that the primary heat concentration will remain in the equatorial Pacific.
Mike McPhaden, a senior researcher at the Pacific Marine Environmental Laboratory operated by the National Oceanic and Atmospheric Administration, offered similar projections. McPhaden told AFP that it is not inconceivable for global temperatures in 2027 to reach 1.7 degrees Celsius above pre-industrial averages.
The pre-industrial baseline represents global average temperatures before widespread fossil fuel combustion began during the 19th century. The National Oceanic and Atmospheric Administration, a United States federal agency based in Maryland, monitors ocean dynamics and climate trends across the globe.
Scientists measure El Niño using several distinct metrics. In February, the National Oceanic and Atmospheric Administration introduced a new system known as the Relative Oceanic El Niño Index, abbreviated as RONI.
The RONI metric compares sea surface temperature anomalies in the Niño 3.4 zone against the broader tropical ocean belt. Under this framework, the agency calculates a 69 percent probability that this year's event will be the strongest recorded since modern record-keeping began in 1950.
Atmospheric mechanism and weather impacts
El Niño is a naturally occurring climate pattern characterized by abnormal warming of surface waters in the central and eastern equatorial Pacific Ocean. Under normal conditions, easterly trade winds push warm ocean water toward the western Pacific, allowing cooler water to rise in the east.
When those trade winds weaken, warm water flows eastward across the Pacific surface. Emily Becker, a climatologist at the University of Miami in Florida, explained that when sea surface temperatures stay elevated for multiple months, storm activity increases over the region and triggers ripple effects throughout the entire global atmosphere.
As a result, some regions experience hotter and drier conditions while others face cooler and wetter weather. Michelle L'Heureux, an official at the Climate Prediction Center of the National Oceanic and Atmospheric Administration, told AFP that stronger El Niño events typically bring more severe consequences, though she emphasized that specific regional impacts are not guaranteed.
Climate change amplification
Climate scientists agree that greenhouse gas emissions amplify the impacts of El Niño. A warmer atmosphere retains more moisture, making rainfall events associated with the cycle heavier, while accelerating soil drying in regions subject to drought.
Although researchers continue to study whether climate change directly strengthens El Niño itself, emerging evidence points toward a structural connection. McPhaden noted that warmer tropical ocean waters increase the sensitivity of feeding winds, which can accelerate the development of the phenomenon through convection.
To evaluate long-term trends, McPhaden analyzed paleoclimate indicators from coral skeletons alongside 19th-century thermometer readings and modern computer simulations. His findings indicate that the overall intensity of El Niño episodes has increased by approximately 10 percent over the past century.
