Hi,
ENSO is a fact, dramatic 100% certain.
http://www.usda.gov/oce/waob/jawf/enso/ensodef.gif
http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_advisory/index.html
The questions is if the S&P 500 and others index reflect de ciclic diseases caused for him.
Salut