Pacific El Niño Waters Reach Exceptional September High

Sea-surface temperatures in a key Pacific monitoring region reached an exceptional high in September as El Niño continued to intensify, with forecasts pointing to a peak in December. The reading has revived questions about whether the event could rank among the strongest on record, but climate scientists say historical comparisons are not yet settled. The Copernicus Climate Change Service reported a September temperature of 29.70°C in the Niño 3.4 region, above the peak readings it cited for the strong El Niño events of 1982-83, 1997-98 and 2015-16. The figure is a sea-surface temperature, not a measure of how far waters were above average. Copernicus director Carlo Buontempo said it was too early to determine whether the current event is the strongest ever observed. The service has adopted an index that accounts for long-term warming of tropical oceans; by that measure, the current event is not yet stronger than past events, though it remains very large. Other measurements also show unusual warmth. Australia’s Bureau of Meteorology said average weekly temperatures in the central Pacific had exceeded levels reached in December 2015.