To put it another way, the post-ice age rise in CO2 is typically less than the current manmade rise. Yet the post-ice age temperature rise is of the order of 6C.

In relation to the biomass that counts (CO2-wise), from Wikipedia:

Global primary production can be estimated from satellite observations. Satellites scan the normalised difference vegetation index (NDVI) over terrestrial habitats, and scan sea-surface chlorophyll levels over oceans. This results in 56.4 billion tonnes C/yr (53.8%), for terrestrial primary production, and 48.5 billion tonnes C/yr (46.2%) for oceanic primary production.

Thus, the total photoautotrophic primary production for the Earth is about 104.9 billion tonnes C/yr. This translates to about 426 gC/m²/yr for land production (excluding areas with permanent ice cover), and 140 gC/m²/yr for the oceans.

However, there is a much more significant difference in standing stocks – while accounting for almost half of total annual production, living oceanic autotrophs account for only about 0.2% of the total biomass.

BTW, in an interesting aside, there is 5 times as much biomass of krill (which feed on oceanic autotrophs) on the planet as there is biomass of humans.

http://www.nature.com/nature/journal/v394/n6688/full/394055a0.html

In the mean time I’m going to do some crocheting and be patient as Nick advises.

I don’t recall any paper for global biomass balances between the land and oceans which shows an increase or altered balance in recent times due to ‘extra CO2′. The 50:50 or 53:47 ratios (land:ocean) have a fair bit of imprecision (prob. ~±5%) anyway. It is just not possible to be precise about such massive amounts!

Cyanobacterial primary productivity in the oceans is generally limited by nutrients – principally available nitrogen and dissolved iron. Water temperature (and hence concentration of dissolved CO2) is almost invariably not a limiting factor, except in the rarest circumstances.

Even if the oceans were a net CO2 emitter (I haven’t read the Frank paper) this would not alter the cyanobacterial primary productivity.

But I very much doubt that proposition!

While the remineralization depth can be shown to be quite significant in altering atmospheric CO2 (Kwon et al., September 2009), the magnitude of the sinking flux of organic carbon, most of which derives from CO2 ‘fixed’ by cyanobacteria is so overwhelming that it ensures that the oceans are always a net sink of CO2.

This is why we have massive amounts of oil, gas, Latrobe Valley brown coal (a marine sediment) etc., etc., deriving from the oceanic fixed carbon sinks. No one (not even God) thought to switch those processes off!