Permanent El Niño-Like Conditions During the Pliocene Warm Period

@article{Wara2005PermanentEN,
  title={Permanent El Niño-Like Conditions During the Pliocene Warm Period},
  author={Michael Wara and Ana Christina Ravelo and Margaret Lois Delaney},
  journal={Science},
  year={2005},
  volume={309},
  pages={758 - 761}
}
During the warm early Pliocene (∼4.5 to 3.0 million years ago), the most recent interval with a climate warmer than today, the eastern Pacific thermocline was deep and the average west-to-east sea surface temperature difference across the equatorial Pacific was only 1.5 ± 0.9°C, much like it is during a modern El Niño event. Thus, the modern strong sea surface temperature gradient across the equatorial Pacific is not a stable and permanent feature. Sustained El Niño-like conditions, including… 
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