title: Global carbon sinks and their variability inferred from atmospheric O2 and delta13C.
abstract: Recent time-series measurements of atmospheric O2 show that the land biosphere and world oceans annually sequestered 1.4 +/- 0.8 and 2.0 +/- 0.6 gigatons of carbon, respectively, between mid-1991 and mid-1997. The rapid storage of carbon by the land biosphere from 1991 to 1997 contrasts with the 1980s, when the land biosphere was approximately neutral. Comparison with measurements of delta13CO2 implies an isotopic flux of 89 +/- 21 gigatons of carbon per mil per year, in agreement with model- and inventory-based estimates of this flux. Both the delta13C and the O2 data show significant interannual variability in carbon storage over the period of record. The general agreement of the independent estimates from O2 and delta13C is a robust signal of variable carbon uptake by both the land biosphere and the oceans.
authors.affiliation: Department of Geoscience, Guyot Hall, Princeton University, Princeton, NJ 08544 USA.
authors.forename: M
authors.initials: M
authors.lastname: Battle
authors.forename: M L
authors.initials: ML
authors.lastname: Bender
authors.forename: P P
authors.initials: PP
authors.lastname: Tans
authors.forename: J W
authors.initials: JW
authors.lastname: White
authors.forename: J T
authors.initials: JT
authors.lastname: Ellis
authors.forename: T
authors.initials: T
authors.lastname: Conway
authors.forename: R J
authors.initials: RJ
authors.lastname: Francey
mesh_terms: D001272:Atmosphere; D002244:Carbon / Q000032:analysis* / Q000378:metabolism*; D002245:Carbon Dioxide / Q000032:analysis / Q000378:metabolism; D002247:Carbon Isotopes; D017753:Ecosystem; D009584:Nitrogen / Q000032:analysis; D009792:Oceans and Seas; D010100:Oxygen / Q000032:analysis*; D010101:Oxygen Consumption; D010788:Photosynthesis
chemical_list: D002247:Carbon Isotopes; D002245:Carbon Dioxide; D002244:Carbon; D009584:Nitrogen; D010100:Oxygen