Reconciling estimates of the contemporary North American carbon balance among terrestrial biosphere models, atmospheric inversions and a new approach for estimating net ecosystem exchange from inventory-based data

Journal Article · Sun Jan 01 00:00:00 EST 2012 · Global Change Biology

DOI:https://doi.org/10.1111/j.1365-2486.2011.02627.x· OSTI ID:1036563

Hayes, Daniel J ^[1]; Turner, David P ^[2]; Stinson, Graham ^[3]; Mcguire, David ^[4]; Wei, Yaxing ^[1]; West, Tristram O. ^[5]; Heath, Linda S. ^[6]; De Jong, Bernardus ^[7]; McConkey, Brian G. ^[8]; Birdsey, Richard A. ^[9]; Kurz, Werner ^[10]; Jacobson, Andrew ^[11]; Huntzinger, Deborah ^[12]; Pan, Yude ^[9]; Post, Wilfred M ^[1]; Cook, Robert B ^[1]

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1. ORNL
2. Oregon State University, Corvallis
3. Pacific Forestry Centre, Canadian Forest Service
4. University of Alaska
5. Joint Global Change Research Institute, PNNL
6. USDA Forest Service
7. ECOSUR
8. Agriculture and Agri-Food Canada
9. U.S. Department of Agriculture Forest Service
10. Canadian Forest Service
11. NOAA ESRL and CIRES
12. University of Michigan

We develop an approach for estimating net ecosystem exchange (NEE) using inventory-based information over North America (NA) for a recent 7-year period (ca. 2000 2006). The approach notably retains information on the spatial distribution of NEE, or the vertical exchange between land and atmosphere of all non-fossil fuel sources and sinks of CO2, while accounting for lateral transfers of forest and crop products as well as their eventual emissions. The total NEE estimate of a 327 252 TgC yr1 sink for NA was driven primarily by CO2 uptake in the Forest Lands sector (248 TgC yr1), largely in the Northwest and Southeast regions of the US, and in the Crop Lands sector (297 TgC yr1), predominantly in the Midwest US states. These sinks are counteracted by the carbon source estimated for the Other Lands sector (+218 TgC yr1), where much of the forest and crop products are assumed to be returned to the atmosphere (through livestock and human consumption). The ecosystems of Mexico are estimated tobe a small net source (+18 TgC yr1) due to land use change between 1993 and 2002. We compare these inventorybased estimates with results from a suite of terrestrial biosphere and atmospheric inversion models, where the mean continental-scale NEE estimate for each ensemble is 511 TgC yr1 and 931 TgC yr1, respectively. In the modeling approaches, all sectors, including Other Lands, were generally estimated to be a carbon sink, driven in part by assumed CO2 fertilization and/or lack of consideration of carbon sources from disturbances and product emissions. Additional fluxes not measured by the inventories, although highly uncertain, could add an additional 239 TgC yr1 to the inventory-based NA sink estimate, thus suggesting some convergence with the modeling approaches.

• Research Organization: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE Office of Science (SC)
• DOE Contract Number: DE-AC05-00OR22725
• OSTI ID: 1036563
• Journal Information: Global Change Biology, Vol. 18, Issue 4; ISSN 1354-1013
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
BIOSPHERE
CARBON
CARBON SINKS
CARBON SOURCES
CONVERGENCE
CROPS
DISTURBANCES
DOMESTIC ANIMALS
ECOSYSTEMS
FERTILIZATION
FORESTS
INVENTORIES
LAND USE
SPATIAL DISTRIBUTION
TEMPERATURE INVERSIONS
agriculture
carbon cycle
climate change
CO2 emissions
CO2 sinks
forests
inventory
modeling
North America