NASA satellite observations have identified concerning patterns associated with the buildup of a potential Super El Niño, highlighting the impact of warming ocean waters on marine ecosystems and global temperatures.
During an El Niño event, sea surface temperatures in the equatorial Pacific Ocean rise significantly, contributing to warmer global temperatures. New analysis of two decades of satellite data reveals how these warming waters disrupt the marine food web by limiting nutrient availability for ocean organisms. This phenomenon, known as 'nutrient stress,' is particularly pronounced during El Niño years.
Normally, microscopic plant-like organisms called phytoplankton thrive on cold, nutrient-rich water that wells up from deeper ocean layers. However, rising ocean temperatures interfere with this process. "When the surface of the ocean warms, it generates this very stable situation where a layer of low-density water sits on top of higher-density cold water," explained Dr. Adam Martiny, an oceanographer at the University of California. This warm surface layer traps essential nutrients below, preventing them from reaching phytoplankton near the surface, which impedes their growth and reproduction.
Scientists utilized NASA's Aqua satellite, specifically the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor, to measure shifts in the ratio of carbon to chlorophyll in plankton. A decrease in chlorophyll relative to carbon indicates that plankton are under stress. This data was supplemented with genetic testing of phytoplankton samples, which revealed that the most severe nutrient stress occurs in subtropical gyres—vast, calm ocean areas where a warm surface layer forms.
In the South Pacific, a region already characterized by limited nutrients, a warm surface water layer contributed to shortages of nitrogen and iron, resulting in the most severe nutrient-related stress detected by the research team. The 2015-2016 El Niño event, one of the strongest on record, saw sea surface temperatures climb significantly, leading to suppressed ocean upwelling in the equatorial Pacific and a marked increase in nutrient stress.
These findings emerge as experts warn that the world is approaching a 'Super El Niño,' potentially the strongest ever recorded. Research from the European Centre for Medium-Range Weather Forecasts suggests sea temperatures could be well above average later this year. Simulations indicate that equatorial Pacific Ocean temperatures may rise by 3°C (5.4°F) above average by December, with some scenarios showing increases exceeding 4°C (7.2°F). "If this forecast came true, it would be the strongest El Niño on record," stated Dr. Theodore Keeping, an extreme weather expert from Imperial College London. Such an event is predicted to have a substantial influence on global weather patterns, altering storm tracks and exacerbating heatwaves and droughts. This Super El Niño is expected to drive global temperatures higher, potentially making 2026 the hottest year on record, surpassing the previous record set in 2024 when global warming exceeded 1.5°C above pre-industrial levels for the first time.
El Niño and La Niña are phases of the El Niño-Southern Oscillation (ENSO), a natural climate pattern that shifts between warm and cool phases every two to seven years. These shifts influence global temperature, winds, and precipitation patterns. During an El Niño phase, the warming of the central and eastern tropical Pacific Ocean leads to reduced rainfall in regions like Indonesia and increased rainfall over the tropical Pacific, while weakening the normal east-to-west equatorial winds.