May 2011

Journal

Can we reconcile atmospheric estimates of the Northern terrestrial carbon sink with land-based accounting?

By:
Ciais, Philippe; Luyssaert, Sebastiaan; Chevallier, Fredric; Poussi, Zegbeu; Peylin, Philippe; Breon, Francois-Marie; Canadell, J.G.; Shvidenko, Anatoly; Jonas, Matthias; King, Anthony W; Schulze, E.-D.; Roedenbeck, Christian; Piao, Shilong; Peters, Wouter
Journal Name:
Current Opinion in Environmental Sustainability
Page Number:
225-230
Volume:
2
Issue Number:
4
Publication Date:
May 2011
View DOI Listing:
https://doi.org/10.1016/j.cosust.2010.06.008

Abstract

We estimatethenorthernhemisphere(NH)terrestrialcarbon sink bycomparingfourrecentatmosphericinversionswith land-based Caccountingdataforsixlargenorthernregions. The meanNHterrestrialCO2 sink fromtheinversionmodelsis 1.7 PgCyear1 over theperiod2000–2004. Theuncertaintyof this estimateisbasedonthetypicalindividual(1-sigma) precision ofoneinversion(0.9PgCyear1) andisconsistent with themin–max rangeofthefourinversionmeanestimates (0.8 PgCyear1). Inversionsagreewithintheiruncertaintyfor the distributionoftheNHsinkofCO2 in longitude,withRussia being thelargestsink.Theland-basedaccountingestimateof NH carbonsinkis1.7PgCyear1 for thesumofthesixregions studied. The1-sigmauncertaintyoftheland-basedestimate (0.3 PgCyear1) issmallerthanthatofatmosphericinversions, but noindependentland-basedfluxestimateisavailableto derive a‘betweenaccountingmodel’uncertainty. Encouragingly, thetop-downatmosphericandthebottom-up land-based methodsconvergetoconsistentmeanestimates within theirrespectiveerrors,increasingtheconfidenceinthe overall budget.Theseresultsalsoconfirmthecontinuedcritical role ofNHterrestrialecosystemsinslowingdownthe atmospheric accumulationofanthropogenicCO2