Thanks for the post Andrew, Regrettably, I can not find an open copy of the work <http://science.sciencemag.org/lookup/doi/10.1126/science.aad4273> and thus I'm flying somewhat blind with the following question.
*Question Background Information:* >From the time of air/seaborne nuclear testing began the abnormal (human generated) carbon 14 count has had to be taken into account within any study which uses C14. The beginning of such C14 accounting corrections is known by a number of terms, inter alia, start of the '*Standard Reference Year*', the '*Index Year*', and '*Before Present <https://en.wikipedia.org/wiki/Before_Present> (BP)*'. Factoring in this aspect of the past (present?) anthropogenic manipulation of C14 would be critical for the above type of study. Even-though the study is focused upon soil, the airborne human-generated C14 does eventually becomes incorporated within the soil (and oceans). Further, the location of the 48 test sites, mentioned in the paper's abstract, and their particular spacial relationship to any known/direct fall-out patterns (if any), would be an extremely important data as such factors would/could significantly skew the data. *The Question:* To what extent was the post BP factor(s) taken into account within the study? To conclude, even if the post BP C14 factors are properly accounted for, this study is an alarm to all soil management concerns for the need for the widespread use of soil treatments , inter alia, biochar, olivine, and carbon rich (biochar) organic fertilizer. Michael On Thursday, September 22, 2016 at 4:58:32 PM UTC-7, Andrew Lockley wrote: > > Poster's note : appears to imply that rather more care needs to be taken > with soil, and that soil CDR will be significantly more challenging than is > sometimes argued. > > http://science.sciencemag.org/lookup/doi/10.1126/science.aad4273 > > Radiocarbon constraints imply reduced carbon uptake by soils during the > 21st century > > Yujie He1,*, Susan E. Trumbore2, Margaret S. Torn3,Jennifer W. > Harden4,5, Lydia J. S. Vaughn3, Steven D. Allison1,6, James T. Randerson1 > > Email: [email protected] <javascript:> > > Science 23 Sep 2016: > Vol. 353, Issue 6306, pp. 1419-1424 > DOI: 10.1126/science.aad4273 > > Abstract > > Soil is the largest terrestrial carbon reservoir and may influence the > sign and magnitude of carbon cycle–climate feedbacks. Many Earth system > models (ESMs) estimate a significant soil carbon sink by 2100, yet the > underlying carbon dynamics determining this response have not been > systematically tested against observations. We used14C data from 157 > globally distributed soil profiles sampled to 1-meter depth to show that > ESMs underestimated the mean age of soil carbon by a factor of more than > six (430 ± 50 years versus 3100 ± 1800 years). Consequently, ESMs > overestimated the carbon sequestration potential of soils by a factor of > nearly two (40 ± 27%). These inconsistencies suggest that ESMs must better > represent carbon stabilization processes and the turnover time of slow and > passive reservoirs when simulating future atmospheric carbon dioxide > dynamics > -- You received this message because you are subscribed to the Google Groups "geoengineering" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at https://groups.google.com/group/geoengineering. For more options, visit https://groups.google.com/d/optout.
