Thursday, October 06, 2011

Is the soil carbon machine pumping 50% more CO2?

Photosynthesis – the process that creates soil carbon – could be taking up almost 50% more CO2 than previously estimated, according to a report in Nature, the British scientific journal. An international team of scientists have reset the bar for CO2 draw down from 120 billion tonnes per year to between 150-175 billion tonne annually… between 25% and 45% increase. This would logically mean the world’s soils have even greater capacity to store carbon. But even though they have no evidence to support the contention, the researchers declare there is no increase in soil carbon sequestration. The report's lead researcher Lisa Welp, from the University of California's Scripps Institute of Oceanography, said: “The extra CO2 taken up as photosynthesis is most likely returned right back to the atmosphere via respiration.” The leader of the CSIRO Changing Atmosphere research group, Paul Fraser, said “it doesn't mean they hold more carbon, they (plants) probably respire faster.” “Probably?” “Most likely?” Is this based on evidence? “I'd love to be able to say it does mean that but we just don't know that, that's in the next few steps (of research),” said Dr Fraser. There are two possible reactions to the higher rates of photosynthesis. One is to dismiss the possibility that it means good news for those of us who believe soils have the capacity to be a secure bridge to a low carbon future. The other is to accept these findings as further proof that there is a new paradigm that suits the times. Opposition spokesman on climate action, Greg Hunt, is among the latter when he says: the scientific evidence has moved more strongly in favour of the enormous potential of land and agriculture-based emissions reductions.” Which do you choose: the past or the future?

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