El Niño has "firmly established" itself and is intensifying into a "very strong event" with a near-certainty of wreaking havoc globally until at least February, according to warnings from the World Meteorological Organization (WMO).
Scientists anticipate the phenomenon will significantly impact global rainfall and temperatures, potentially triggering widespread floods, droughts, and extreme heat. "El Niño is being supersized before our eyes," stated UN Secretary-General António Guterres, adding that "the planet is in uncharted waters, and those waters are heating up."
Understanding El Niño
El Niño is part of the naturally occurring El Niño-Southern Oscillation (ENSO) cycle, which alternates between warm El Niño phases and cool La Niña phases roughly every two to seven years. During an El Niño phase, the trade winds that typically push warm water across the Pacific towards Australia weaken or reverse. This prevents cool water from surfacing off the west coast of South America, allowing warm water to accumulate and spread, thus raising global average temperatures and disrupting weather patterns.
Sea surface temperatures in the central and eastern tropical Pacific Ocean, the heart of El Niño's development, are already significantly above average and continuing to rise. In recent months, the developing El Niño has accelerated rapidly, with Pacific Ocean temperatures exceeding 2°C above normal in some areas. Some underwater regions have registered temperatures a remarkable 8°C above average.
For the period between September and November, the WMO forecasts above-normal temperatures across almost all land masses globally. El Niño typically begins developing between March and June, peaks between November and February, and its most pronounced effects on global temperatures can extend into the year following its peak.
Projected Impacts
WMO Secretary-General Celeste Saulo noted that El Niño "has the potential to deliver a massive blow to communities and economies across the world." She added, "We are already seeing disruption and devastation from droughts and floods and we expect these impacts to increase as El Niño intensifies."
In the United Kingdom, forecasters are bracing for a cold and stormy winter. Warm ocean temperatures in the Pacific are expected to send "waves" through the atmosphere, potentially shifting the jet stream off its usual course and directing storms toward the UK. While the exact timing of these storms remains uncertain, increased likelihood of severe weather is anticipated.
Historical Context and Intensity
A separate study analyzing coral from the Galapagos Islands suggests that El Niño events have intensified over the past four decades. Researchers found that current El Niño events are nearly 40% stronger than those occurring in the preceding thousand years. "We don't see a time in the past where El Niños have been as strong as today," said lead author Professor Julia Cole. "We show that the strength of El Niño changes in parallel with the warming of global temperature."