How does rising atmospheric CO2 affect marine organisms?

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Five Hundred Years of ENSO
Wang, S., Zhu, J., Cai, J. and Wen, X.  2004.  Reconstruction and analysis of time series of ENSO for the last 500 years.  Progress in Natural Science 14: 1074-1079.

What was done
Climate alarmists contend that ENSO events will become more frequent as temperatures around the globe continue to rise.  The authors decided to investigate this claim by evaluating all such events they could identify in existing records of the past 500 years to see if there had been any significant increase in their frequency of occurrence over the 20th century, during which period the earth recovered from the global chill of the Little Ice Age that had held sway over most of the planet throughout most of the prior four centuries.

What was learned
Although Wang et al. note that El Niņo frequency was a little higher in the 20th century, while that of La Niņa was somewhat higher during the Little Ice Age, they report that "ENSO frequency [was] relatively stationary during the last 500 years, including the Little Ice Age (1550-1850) and Modern Warming Period (the 20th century)."  They also cite Diaz and Pulwarty (1994) within this context, stating that the latter researchers found that "the frequency of ENSO during the Little Ice Age does not differ greatly from that found in the 20th century based on singular spectrum analysis and evolutive spectral analysis."

What it means
If there has been any change in ENSO frequency associated with the global warming of the 20th century, it has apparently been way too small to justify the world's climate alarmists in their contention that ENSO events become more frequent as the climate warms.

Diaz, H.F. and Pulwarty, R.S.  1994.  An analysis of the time scales of variability in centuries-long ENSO-sensitive records of the last 1000 years.  Climatic Change 26: 317-342.

Reviewed 30 March 2005