THE intense El NiËœos of 1982 and 1997 resulted from a natural variability in global temperatures, rather than human influences.
Kim Cobb at the Scripps Institution of Oceanography in La Jolla, California, and colleagues analysed fossil corals from Palmyra Island (above), where the climate is dominated by El Niño, to construct a record of climatic changes in the Pacific Ocean stretching back over the past 1000 years.
The fossils revealed that dramatic El NiËœo activity was more frequent in the mid-17th century than today (Nature, vol 424, p 271). That makes it unlikely that global warming caused by…
