000117502 001__ 117502
000117502 005__ 20181203021107.0
000117502 0247_ $$2doi$$a10.1029/2000GB001298
000117502 037__ $$aARTICLE
000117502 245__ $$aCarbon balance of the terrestrial biosphere in the twentieth century: Analyses of CO2, climate and land use effects with four process-based ecosystem models
000117502 269__ $$a2001
000117502 260__ $$c2001
000117502 336__ $$aJournal Articles
000117502 500__ $$aReview
000117502 520__ $$aThe concurrent effects of increasing atmospheric CO2 concentration, climate variability, and cropland establishment and abandonment on terrestrial carbon storage between 1920 and 1992 were assessed using a standard simulation protocol with four process-based terrestrial biosphere models. Over the long-term (1920-1992), the simulations yielded a time history of terrestrial uptake that is consistent (within the uncertainty) with a long-term analysis based on ice core and atmospheric CO2 data. Up to 1958, three of four analyses indicated a net release of carbon from terrestrial ecosystems to the atmosphere caused by cropland establishment. After 1958, all analyses indicate a net uptake of carbon by terrestrial ecosystems, primarily because of the physiological effects of rapidly rising atmospheric CO2. During the 1980s the simulations indicate that terrestrial ecosystems stored between 0.3 and 1.5 Pg C yr(-1), which is within the uncertainty of analysis based on CO2 and O-2 budgets. Three of the four models indicated tin accordance with O-2 evidence) that the tropics were approximately neutral while a net sink existed in ecosystems north of the tropics. Although all of the models agree that the long-term effect of climate on carbon storage has been small relative to the effects of increasing atmospheric CO2 and land use, the models disagree as to whether climate variability and change in the twentieth century has promoted carbon storage or release. Simulated interannual variability from 1958 generally reproduced the El Nino/Southern Oscillation (ENSO)-scale variability in the atmospheric CO2 increase, but there were substantial differences in the magnitude of interannual variability simulated by the models. The analysis of the ability of the models to simulate the changing amplitude of the seasonal cycle of atmospheric CO2 suggested that the observed trend may be a consequence of CO2 effects, climate variability, land use changes, or a combination of these effects. The next steps for improving the process-based simulation of historical terrestrial carbon include (1) the transfer of insight gained from stand-level process studies to improve the sensitivity of simulated carbon storage responses to changes in CO2 and climate, (2) improvements in the data sets used to drive the models so that they incorporate the timing, extent, and types of major disturbances, (3) the enhancement of the models so that they consider major crop types and management schemes, (4) development of data sets that identify the spatial extent of major crop types and management schemes through time, and (5) the consideration of the effects of anthropogenic nitrogen deposition. The evaluation of the performance of the models in the context of a more complete consideration of the factors influencing historical terrestrial carbon dynamics is important for reducing uncertainties in representing the role of terrestrial ecosystems in future projections of the Earth system.
000117502 6531_ $$aNet primary production
000117502 6531_ $$aatmospheric co2
000117502 6531_ $$aseasonal cycle
000117502 6531_ $$ainterannual variation
000117502 6531_ $$aamazonian ecosystems
000117502 6531_ $$anitrogen deposition
000117502 6531_ $$aincreasing co2
000117502 6531_ $$aunited-states
000117502 6531_ $$aglobal-scale
000117502 6531_ $$ael-nino
000117502 700__ $$aMcGuire, A. D.
000117502 700__ $$aSitch, S.
000117502 700__ $$aClein, J. S.
000117502 700__ $$aDargaville, R.
000117502 700__ $$aEsser, G.
000117502 700__ $$aFoley, J.
000117502 700__ $$aHeimann, M.
000117502 700__ $$aJoos, F.
000117502 700__ $$0240033$$aKaplan, J.$$g176442
000117502 700__ $$aKicklighter, D. W.
000117502 700__ $$aMeier, R. A.
000117502 700__ $$aMelillo, J. M.
000117502 700__ $$aMoore, B.
000117502 700__ $$aPrentice, I. C.
000117502 700__ $$aRamankutty, N.
000117502 700__ $$aReichenau, T.
000117502 700__ $$aSchloss, A.
000117502 700__ $$aTian, H.
000117502 700__ $$aWilliams, L. J.
000117502 700__ $$aWittenberg, U.
000117502 773__ $$j15$$k1$$q183-206$$tGlobal Biogeochemical Cycles
000117502 909C0 $$0252129$$pECOS$$xU11021
000117502 909C0 $$0252021$$pARVE$$xU11903
000117502 909CO $$ooai:infoscience.tind.io:117502$$particle$$pENAC
000117502 937__ $$aECOS-ARTICLE-2008-099
000117502 973__ $$aOTHER$$rREVIEWED$$sPUBLISHED
000117502 980__ $$aARTICLE