Reference
Joos, F. and Bruno, M. 1998. Long-term variability of the terrestrial and oceanic carbon sinks and the budgets of the carbon isotopes 13C and 14C. Global Biogeochemical Cycles 12: 277-295.
What was done
The authors used ice core and direct observations of atmospheric CO2 and 13C to reconstruct the histories of terrestrial and oceanic uptake of anthropogenic carbon over the past two centuries.
What was learned
In the words of the authors, "the biosphere acted on average as a source [of CO2] during the last century and the first decades of this century .... Then, the biosphere turned into a sink." Various graphs they produce indicate that this great transformation, from significant carbon source to increasingly greater carbon sink, has been in progress for about the last hundred years.
What it means
In spite of all the news one hears about all the bad things that are supposedly happening to the biosphere as a consequence of the ongoing rise in the air's CO2 content, the real-world data upon which the calculations of this paper are based reveal that the biosphere has become ever more productive over the last hundred or so years. Hence, since the past century experienced an unprecedented rate of rise in atmospheric CO2 concentration - yet the biosphere grew ever larger and/or more productive over the same time period - we question the motives of those who call for reductions in CO2 emissions on the basis that more CO2 is bad for the biosphere. Clearly, anthropogenic CO2 emissions are not only not bad, they appear to be beneficial.
What's that you say? Something else must be compensating for the bad effects of CO2? Let's see. Could that something be ... global warming? No, that's supposed to be bad too. How about ... acid rain? No, that's supposed to be bad too. Wait. Could it be ... the ... burgeoning population of the planet? No, that's supposed to be bad too. Hmmm. You don't suppose we've been fed the wrong story all these years ... do you?
Reviewed 15 July 2000