It is a search for a mythical CO2 sink to explain an immeasurable CO2 lifetime to fit a hypothetical CO2 computer model that purports to show that an impossible amount of fossil fuel burning is heating the atmosphere.
It is all a fiction.

~ Geologist/Geochemist Dr. Tom V. Segalstad, 
a professor and head of the Geological Museum at the University of Oslo
and formerly an expert reviewer with the UN IPCC   [Senate Report]