As part of an ongoing study I have computed monthly deviations between CO2 level at each of the seven southern stations lying from 40 deg S to the Pole obtained from the NOAA record of monthly averages for ALL Southern Hemisphere stations and the NOAA (monthly) average global CO2 levels for the period 1982 through 2006.
I then computed the average annual deviations for all southern stations from the global annual mean CO2 levels. Note I used strictly ONLY complete year records for each station and dumped any year if it had missed a single month or more.
The outcomes are in the plot below. Error bars are ± one sigma as usual.

Please note the 2nd inflection around 1998 when global temperatures were last maximal – slight cooling or plateau since then.
Northern Hemisphere CO2 levels undoubtedly continued to climb monotonically on an annual scale over the period 1982 – 2006 and we can reasonably presume was accompanied by no significant attendant global warming since about 2000.
However, it appears that after a hiatus in the 1990s, Southern Ocean and Antarctic CO2 levels have continued to deviate increasingly, in the negative sense, in relation to the global CO2 average (dominated by data from Northern Hemisphere and Tropical Zone monitoring stations).
In my view, this southern offset from the global average CO2 level should be getting smaller, not larger, worldwide due to increasing global circulation to be in accord with present GCM theory.
Zones of blooming cyanobacteria directly back-scatter solar radiation due to calcite-producing coccolithophores, which are found everywhere but especially in subpolar regions (Coccolithus pelagicus), thereby decreasing ocean heat retention and cool the overall water column (Hansen et al. 1997; Hansen and Nazarenko, 2004).
By shading the deeper waters and trapping energy near the surface where it can escape to the atmosphere, it is suggested this cyanobacterial ‘canopy’ decreases heat input to the deep ocean.
Cyanobacteria also produce the sulfur compound dimethylsulfoniopropionate, which decomposes in sea water into dimethylsulfide, diffuses into the atmosphere, and is oxidized, leading to acidic aerosols that function as efficient cloud condensation nuclei. In areas where cloud condensation nuclei are scarce, this could increase planetary albedo by creating more and brighter clouds of greater longevity.
It is speculated that cyanobacteria in the Great Southern Ocean entered a phase of higher blooming rates in the early part of the millennium, thereby consuming CO2, increasing oceanic albedo and cloud cover (via dimethylsulfide emissions) and likely significantly cooling the southern hemisphere.
This ‘effect’ (if such is what it is) is found directly by deconvolution of the official NOAA CO2 data record, and doesn’t appear to have anything to do (that I can think of) with solar cycles etcetera.
Please note this information is preliminary and currently subject to discussion, checking and related computation by myself and several colleagues during preparation of a paper to be submitted most likely to Geophysical Research Letters. In the mean time, may I request that this new finding be fairly attributed to myself in this blog AND to Short et al. (in preparation) ‘Evidence for Increasing Negative Deviation of Southern Ocean and Antarctic Atmospheric Carbon Dioxide Levels from Global Average’ cited elsewhere.
References:
Hansen, J., Sato, M. & Ruedy, R. (1997) J. Geophys. Res. 102, 6831–6864.
Hansen, J. & Nazarenko, L. (2004) Proc. Natl. Acad. Sci. USA 101, 423–428.
Regards
Dr Steve Short
Director
Ecoengineers Pty Ltd
www.ecoengineers.com



Jennifer Marohasy BSc PhD has worked in industry and government. She is currently researching a novel technique for long-range weather forecasting funded by the B. Macfie Family Foundation.