A point I had forgotten about the recent Canadell et al paper, which mt’s recent post reminds me of: as he quotes (scroll down to the update):
Ceci suggèrerait d’après eux que les feedbacks carbone/climat se produisent plus rapidement que notre compréhension des phénomènes gouvernant l’absorption des puits ne le laissait penser.
This is indeed what C et al say, and its one possible interpretation. Another, of course, is that since obs show the airbourne fraction going up, and the models say that they should be going down, then… the models are wrong.