El Niño, a natural warming cycle in the Pacific Ocean, was officially declared by the U.S. National Oceanic and Atmospheric Administration (NOAA) in June. This phenomenon involves above-average sea surface temperatures in the central to eastern equatorial Pacific. Forecasters indicate a 63% probability that this El Niño will intensify to a "very strong" event by late fall and early winter, potentially ranking among the largest since 1950. A "very strong" El Niño is defined by sea surface temperatures exceeding 2.0 degrees Celsius above average in the monitored Pacific region.
Historically, strong El Niño events, such as those in 1982-83, 1997-98, and 2015-16, have led to significant global impacts. The 1997-98 event, for instance, raised the average global temperature by 1.5 degrees Celsius and resulted in an estimated $5.7 trillion in global economic losses due to extreme weather. The 1982-83 event cost the world approximately $4.1 billion. Scientists are observing that current sea surface temperatures in the central and tropical Pacific have already passed the 0.5 degrees Celsius above average threshold used to define an El Niño.
This El Niño is occurring against a backdrop of global warming caused by fossil fuel pollution, which means its impacts could be more dramatic even if it does not reach "super" status. Models from the U.S. and Europe suggest tropical Pacific temperatures could climb more than 3 degrees Celsius above average by the end of the year. A very strong El Niño typically increases global air temperatures by about 0.2 degrees Celsius by releasing stored heat from the ocean into the atmosphere, potentially making 2027 another record-hot year. The event's global impacts, including disruptions to weather, food supplies, and economies, are expected to extend well into 2027.
