date:Aug 12, 2014
orbital geometry might have taken over then to cause the period of weak El Nios.
In previous studies, warm-water shells and evidence of flooding in Andean lakes had been interpreted as signs of a much weaker El Nio around 10,000 years ago.
The new data is more reliable, Mr Carr said, for three reasons: the Peruvian coast is strongly affected by El Nio; the shells record ocean temperature, which is the most important parameter for the El Nio cycles; and the ability to record seasonal changes,