Ken re "Nothing in this conversation has induced me to change this perspective"-- did you actually read my last message?
Haberl et al left out forest wastes and animal wastes and neglected the growth in such wastes that will occur with growth of population Growth of population will obviously stress available land so we have to prove Haberl et al wrong, which will not be difficult providing we begin to recognize, as per a recent Tom Friedman NYT editorial, that "we need an integrated solution to a whole array of integrated problems -- food security, poverty, biodiversity, ocean degradation, energy, climate change, etc." [paraphrased from memory]. That means -- rather than, as traditionally, exploiting it -- starting to invest in land, raising its productrivity (e.g., but not exclusively, with biochar -- putting up a few fences would help as Stephen has pointed out). Nature doesn't know how to build fences and is not efficient, human management can be, e.g. by cropping C4 plants rather than nature's dominant (since more resilient) C3 plants, roughly doubling photo-synthetic efficiency on the land selected for efficient management. So we need to reform the way we treat land and soil if we are to survive Friedman's integrated problems, but physical scientists tend to shy away from behavioural solutions -- is that your problem? Peter ----- Original Message ----- From: Ken Caldeira To: Stephen Salter Cc: Manu Sharma ; Peter Read ; [email protected] ; geoengineering ; [email protected] Sent: Monday, September 28, 2009 6:23 AM Subject: Re: Grass root answer to Ken's question Steven, What is the total area of the world that is susceptible to such processes? I think what the Royal Society report basically said is that in order of magnitudes, if we think 10 GtC/yr is the order of magnitude of the 100% solutions, biochar is not a 100% solution but could potentially be a 10% solution. I repeat my basic logic: Note that Haberl et al (2007) estimate that total global total food harvest is about 1.7 GtC / yr and global wood extraction is about 1 GtC / yr, so the 9.5 PgC / yr number cited by Lehmann et al (2006) represents carbon flows that are more than 5 times bigger than all the food harvesting in the world and more than 9 times bigger than all wood extraction in the world. These kinds of flows may be physically possible, but I remain skeptical regarding the practical feasibility of producing biochar at this scale. Nothing in this conversation has induced me to change this perspective. Best, Ken PS. Please not that I am not speaking for the Royal Society in making these comments. ___________________________________________________ Ken Caldeira Carnegie Institution Dept of Global Ecology 260 Panama Street, Stanford, CA 94305 USA [email protected]; [email protected] http://dge.stanford.edu/DGE/CIWDGE/labs/caldeiralab +1 650 704 7212; fax: +1 650 462 5968 On Sun, Sep 27, 2009 at 4:36 AM, Stephen Salter <[email protected]> wrote: Hi All [[snipped, PR]] --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "geoengineering" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/geoengineering?hl=en -~----------~----~----~----~------~----~------~--~---
