[In Depth] Corals tie stronger El Niños to climate change
A detailed, long-term ocean temperature record derived from corals on Christmas Island in Kiribati and other islands in the tropical Pacific shows that the extreme warmth of recent El Niño events reflects not just the natural ocean-atmosphere cycle but a new factor: global warming caused by human activity. Over the last 7000 years, El Niños, which warm the eastern Pacific, waxed and waned. Then, during the 20th century, their intensity began to climb. The trend is likely to continue, boding ever-more-destructive El Niños in the future. The finding helps settle a long-standing debate about the role of global warming in these events, which had been hard to resolve because records are short and spotty in the remote parts of the Pacific where El Niño hits hardest. Author: Christopher Pala