How does rising atmospheric CO2 affect marine organisms?

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Internal Modes of Climate Variability
White, W.B., Cayan, D.R., Dettinger, M.D. and Auad, G.  2001.  Sources of global warming in upper ocean temperature during El Niño.  Journal of Geophysical Research 106: 4349-4367.

What was done
The authors examined fourteen different meteorological and oceanographic variables over the portion of the global ocean extending from 20°S to 60°N over the 41-year period from 1955 to 1995.  Although their primary objective was to better understand how global warming occurs during El Niño episodes, they also hoped to better understand how it might occur over longer time scales.

What was learned
It was determined, in the words of the authors, that "global average sea surface temperature from 40°S to 60°N fluctuates ± 0.3°C on interannual period scales, with global warming (cooling) during El Niño (La Niña)."  In addition, they found that "global warming and cooling during earth's internal mode of interannual climate variability arise from fluctuations in the global hydrological balance, not the global radiation balance," and that these fluctuations are the result of no known forcing of either anthropogenic or extraterrestrial origin.

What it means
The authors note that the indeterminate nature of their findings and conclusions "may come as a surprise to many readers," after which they go on to say that global warming and cooling on interdecadal and centennial time scales "can also occur in the absence of extraterrestrial and anthropogenic forcing."  Hence, it is not outside the realm of possibility that the global temperature history of the past century or so is largely independent of greenhouse gas forcing and is but a manifestation of random internal oscillations of earth's complex climate system.