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Biogenic carbon fluxes from global agricultural production and consumption
Julie
Wolf, JGCRI, julie.wolf@pnnl.gov
(Presenter)
Quantification of biogenic carbon fluxes from agricultural lands is needed to generate comprehensive bottom-up estimates of net carbon exchange for global and regional carbon monitoring. We quantify global agricultural carbon fluxes associated with annual crop net primary production (NPP), harvested biomass, consumption of biomass by humans and livestock, and net carbon exchange (NCE), and distribute them to 0.05 degree resolution. In 2011, global crop NPP was 5.25 ± 0.46 Pg carbon, of which 2.05 ± 0.05 Pg carbon was harvested. In addition to primary crop harvests, 0.54 Pg carbon was collected from crop residues for livestock fodder. In 2011, total livestock feed intake was 2.42 ± 0.21 Pg carbon, of which 2.31 ± 0.21 Pg carbon was emitted as CO2 and 0.07 ± 0.01 Pg carbon was emitted as CH4. Livestock grazed an estimated 1.27 Pg carbon of forage in 2011, representing 52.4% of total livestock feed intake. Global human food intake was 0.57 ± 0.03 Pg carbon in 2011, with an additional 0.26 Pg carbon lost or wasted from the food supply chain. A completed global agricultural carbon budget for 2009 accounts for the ultimate use of 79.6% of the 2009 harvest, and indicates that 5.01 Pg carbon was taken up by crop plants, 2.56 Pg was decomposed on-field, and 2.45 Pg was harvested and emitted elsewhere. The spatial distribution of these fluxes may be used for carbon monitoring purposes, to understand uncertainty around agricultural flux estimates, and for use in Earth system models. Associated Project(s):
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