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  • Print publication year: 2013
  • Online publication date: February 2013

2 - An Introduction to Carbon Cycle Science



The carbon (C) cycle is central to processes that provide food, fiber, and fuel for all of the Earth's inhabitants. From the air we breathe to the soils we farm and the food we eat, we are inescapably intertwined with the C cycle. Contributions of terrestrial ecosystems to the global C cycle are key, and the link to land change is important to understand. In this chapter, the mechanisms of the C cycle are described in Section 2 along with the historical and current trends of carbon dioxide (CO2) storage and fluxes, as well as how those fluxes interact with climate. Methods to measure and monitor the various components of the C cycle are discussed in Section 3. The chapter covers all aspects of the C cycle with an emphasis on terrestrial C and a review of how different land-cover types (e.g., forest, grasslands, and crops) affect the C cycle (Section 4). A review of how the C cycle connects to other biogeochemical cycles under the influence of land change is presented in Section 5. Despite a fairly comprehensive understanding of the global C cycle derived from the recent increase in C cycle research, current gaps exist in our knowledge related to the magnitude of the influence of land use on C, as discussed in Section 6. For a comprehensive review of the C cycle, the reader is referred to Field and Raupach (2004).

Role of the Carbon Cycle in Earth's Evolution

CO2 in the atmosphere is critical for life on Earth in two ways. First, CO2 is the second most abundant greenhouse gas (GHG) in the atmosphere after water vapor. Without GHGs, the mean temperature at the Earth's surface would be about 33ºC lower than it is today and would probably be unable to support life. Second, photosynthetic organisms use CO2 in the presence of light to produce organic matter that eventually becomes the basic food source for all microbes, animals, and humans.

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Archer, D., and Brovkin, V. 2008. The millennial atmospheric lifetime of anthropogenic CO2. Climatic Change, 90(3):283–297. .
Baldocchi, D.D., Falge, E., Gu, L., Olson, R., Hollinger, D.Y., Running, S.W.,…Wofsy, S.G. 2001. Fluxnet: A new tool to study the temporal and spatial variability of ecosystem-scale carbon dioxide, water vapor and energy flux densities. Bulletin of American Meteorologocal Society, 82:2415–2434.
Baldocchi, D.D., Valentini, R., Running, S.W., Oechel, W., and Dahlman, R. 1996. Strategies for monitoring and modeling CO2 and vapor fluxes over terrestrial ecosystems. Global Change Biology, 2(3):159–168.
Barlaz, M.A. 1998. Carbon storage during biodegradation of municipal solid waste compo-nents in laboratory-scale landfills. Global Biogeochemical Cycles, 12(2):373–380.
Berner, R., Lasaga, A.C., and Garrels, R.M. 1983. The carbo-silicate geochemical cycle and its effect on atmospheric carbon dioxide over the past 100 million years. American Journal of Science, 283:641–683.
Boden, T., Marland, G., and Andres, R.J. 2009. Global, regional, and national fossil-fuel CO emissions, Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge, Tenn., U.S.A. . .
Bolinder, M.A., Angers, D.A., and Dubuc, J.P. 1997. Estimating shoot to root ratios and annual carbon inputs in soils for cereal crops. Agriculture, Ecosystems and Environment, 63(1):61–66. .
Canadell, J.G., Le Quéré, C., Raupach, M.R., Field, C.B., Buitenhuis, E.T., Ciais, P.,…Marland, G. 2007. Contributions to accelerating atmospheric CO2 growth from economic activity, carbon intensity, and efficiency of natural sinks. Proceedings of the National Academy of Sciences, 104(47):18866–18870. .
Chapin, F.S, Mooney, H.A., Chapin, M.C., and Matson, P.A. 2002. Principles of terrestrial ecosystem ecology. New York: Springer.
Chapin, F.S, Woodwell, G., Randerson, J., Rastetter, E., Lovett, G., Baldocchi, D.,…Schulze, E.D. 2006. Reconciling carbon-cycle concepts, terminology, and methods. Ecosystems, 9(7):1041–1050. .
Churkina, G., 2008. Modeling the carbon cycle of urban systems. Ecological Modelling, 216(2):107–113. .
Churkina, G., Brovkin, V., Von Bloh, W., Trusilova, K., Jung, M., and Dentener, F.J. 2009. Synergy of rising nitrogen depositions and atmospheric CO2 on land carbon uptake offsets global warming. Global Biogeochemical Cycles, 23:GB4027.
Churkina, G., Brown, D., and Keoleian, G.A. 2010. Carbon stored in human settlements: The conterminous us. Global Change Biology, 16:135–143.
Churkina, G., and Running, S.W. 1998. Contrasting climatic controls on the estimated productivity of different biomes. Ecosystems, 1:206–215.
Churkina, G., Running, S.W., and Schloss, A. 1999. Comparing global models of terrestrial net primary productivity (NPP): The importance of water availability to primary productivity in global terrestrial models. Global Change Biology, 5(Suppl. 1):46–55.
Ciais, P., Borges, A.V., Abril, G., Meybeck, M., Folberth, G., Hauglustaine, D., and Janssens, I.A. 2008. The impact of lateral carbon fluxes on the European carbon balance. Biogeosciences, 5(5):1259–1271. .
Conant, R.T., and Paustian, K. 2002. Spatial variability of soil organic carbon in grasslands: Implications for detecting change at different scales. Environmental Pollution, 116(Suppl. 1):S127–S135
Conant, R.T., Paustian, K., and Elliott, E.T. 2001. Grassland management and conversion into grassland: Effects on soil carbon. Ecological Applications, 11(2):343–355. .
Conant, R.T., Smith, G.R., and Paustian, K. 2003. Spatial variability of soil carbon in forested and cultivated sites. Journal of Environmental Quality, 32(1):278–286. .
CSPO and CATF. 2009. Innovation policy for climate change. Washington, DC: CSPO. .
Currie, W.S., Yanai, R.D., Piatek, K.B., Prescott, C.E., and Goodale, C.L. 2003. Processes affecting carbon storage in the forest floor and in downed woody debris. In The potential of U.S. forest soils to sequester carbon and mitigate the greenhouse effect, ed. Kimble, J.M., Heath, L.S., Birdsey, R.A., et al. Boca Raton, FL: CRC Press, pp. 135–157.
Dentener, F.J., Drevet, J., Lamarque, J.-F., Bey, I., Eickhout, B., Fiore, A.M.,…Wild, O. 2006. Nitrogen and sulfur deposition on regional and global scales: A multimodel evaluation. Global Biogeochemical Cycles, 20:GB4003.
Doney, S.C., and Schimel, D.S. 2007. Carbon and climate system coupling on timescales from the Precambrian to the Anthropocene. Annual Review of Environment and Resources,32(1):31–66. .
Field, C.B., and Raupach, M.R. 2004. The global carbon cycle: Integrating humans, climate and the natural world. Washington, DC: Island Press.
Free, M., Bister, M., and Emanuel, K. 2004. Potential intensity of tropical cyclones: Comparison of results from radiosonde and reanalysis data. Journal of Climate, 17(8):1722–1727. .
Friedlingstein, P., Cox, P., Betts, R., Bopp, L., Von Bloh, W., Brovkin, V.,…Zeng, N. 2006. Climate-carbon cycle feedback analysis: Results from the C4MIP model intercomparison. Journal of Climate, 19:3337–3353.
Gaillardet, J., Dupré, B., Louvat, P., and Allègre, C.J. 1999. Global silicate weathering and CO2 consumption rates deduced from the chemistry of large rivers. Chemical Geology, 159(1–4):3–30. .
Gajda, J., and Miller, F.M. 2000. Concrete as a sink for atmospheric carbon dioxide: A literature review and estimation of CO2 absorption by portland cement concrete. Skokie, IL: Portland Cement Association.
Galloway, J.N., Dentener, F.J., Capone, D.G., et al. 2004. Nitrogen cycles: Past, present, and future. Biogeochemistry, 70(153–226):153–226.
Gilmanov, T.G., Aires, L., Barcza, Z., Baron, V.S., Belelli, L., Beringer, J.,…Zhou, G. 2010. Productivity, respiration, and light-response parameters of world grassland and agroecosystems derived from flux-tower measurements. Rangeland Ecology and Management, 63(1):16–39. .
Gregg, J.W., Jones, C.G., and Dawson, T.E. 2003. Urbanization effects on tree growth in the vicinity of New York City. Nature, 424:183–187. .
Horst, T.W., and Weil, J.C. 1994. How far is far enough? The fetch requirements for micrometeorological measurement of surface fluxes. Journal of Atmospheric and Oceanic Technology, 11:1018–1025.
Houghton, R.A. 2008. Carbon flux to the atmosphere from land-use changes: 1850–2005. Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge, Tennessee.
Hungate, B.A., Dukes, J.S., Shaw, M.R., Luo, Y., and Field, C.B. 2003. Nitrogen and climate change. Science, 302:1512–1513.
Huntington, T.G. 2006. Evidence for intensification of the global water cycle: Review and synthesis. Journal of Hydrology, 319(1–4):83–95. .
Hutyra, L.R., Yoon, B., and Alberti, M. 2011. Terrestrial carbon stocks across a gradient of urbanization: A study of the Seattle, WA region. Global Change Biology, 17(2):783–797. .
Jackson, R.B., Canadell, J., Ehleringer, J.R., Mooney, H.A., Sala, O.E., and Schulze, E.D. 1996. A global analysis of root distributions for terrestrial biomes. Oecologia, 108:389–411.
Jobbágy, E.G., and Jackson, R.B. 2000. The vertical distribution of soil organic carbon and its relation to climate and vegetation. Ecological Applications, 10(2):423–436. .
Jones, C., and Cox, P.M. 2005. On the significance of atmospheric CO2 growth rate anomalies in 2002–2003. Geophysical Research Letters, 32:L14816. .
Jung, M., Herold, M., Henkel, K., and Churkina, G. 2006. Exploiting synergies of land cover products for carbon cycle modelling. Remote Sensing of Environment, 101:534–553.
Keeling, C.D. 1958. The concentration and isotopic abundances of atmospheric carbon dioxide in rural areas. Geochimica et Cosmochimica Acta, 13:277–298.
Keeling, C.D., and Whorf, T.P. 2005. Atmospheric CO2 records from sites in the SIO air sampling network. Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge, Tennessee.
Kicklighter, D.W., Bondeau, A., Schloss, A.L., Kaduk, J., Mcguire, A.D., and participants of the Potsdam NPP Model Intercomparison. 1999. Comparing global models of terrestrial net primary productivity (NPP): Global pattern and differentiation by major biomes. Global Change Biology, 5(S1):16–24. .
Kjellsen, K.O., Guimaraes, M., and Nilsson, A. 2005. The CO2 balance of concrete in a life cycle perspective. Oslo: Nordic Innovation Centre.
Knorr, W. 2009. Is the airborne fraction of anthropogenic CO2 emissions increasing?Geophysical Research Letters,36:L21710.
Landsberg, J.J., and Gower, S.T. 1997. Applications of physiological ecology to forest management. San Diego, CA: Academic Press.
Larcher, W. 1995. Physiological plant ecology, 3d ed. Berlin: Springer-Verlag.
Larcher, W. 2002. Physiological plant ecology, 4th ed. Berlin: Springer-Verlag.
Lawrence, M.G., Butler, T.M., Steinkamp, J., Gurjar, B.R., and Lelieveld, J. 2007. Regional pollution potentials of megacities and other major population centers. Atmospheric Chemistry and Physics, 7:3969–3987.
Le Quéré, C., Raupach, M.R., Canadell, J.G., Marland, G., Bopp, L, Ciais, P.,…Woodward, F.I. 2009. Trends in the sources and sinks of carbon dioxide. Nature Geoscience, 2(12):831–836.
Luthi, D., Le Floch, M., Bereiter, B., Blunier, T., Barnola, J.-M., Siegenthaler, U.,…Stocker, T.F. 2008. High-resolution carbon dioxide concentration record 650,000–800,000 years before present. Nature, 453(7193):379–382. .
Luyssaert, S., Inglima, I., Jung, M., Richardson, A.D., Reichstein, M., Papale, D.,…Janssens, I.A. 2007. CO2 balance of boreal, temperate, and tropical forests derived from a global database. Global Change Biology, 13(12):2509–2537. .
Matter, J.M., and Kelemen, P.B. 2009. Permanent storage of carbon dioxide in geological reservoirs by mineral carbonation. Nature Geoscience, 2(12):837–841. .
Nowak, D.J., and Crane, D.E., 2002. Carbon storage and sequestration by urban trees in the USA. Environmental Pollution, 116, 381–389. .
Oelkers, E.H., Gislason, S.R., and Matter, J. 2008. Mineral carbonation of CO2. Elements, 4(5):333–337. .
Papale, D. 2009, presentation “Upscaling Strategy” at the Ameriflux Principal Investigators’ meeting, Washington, DC.
Pouyat, R.V., Yesilonis, I.D., and Nowak, D.J. 2006. Carbon storage by urban soils in the United States. Journal of Environmental Quality, 35(4):1566–1575. .
Prince, S.D., Haskett, J., Steininger, M., Strand, H., and Wright, R. 2001. Net primary production of U.S. Midwest croplands from agricultural harvest yield data. Ecological Applications, 11(4):1194–1205. .
Raupach, M.R., Canadell, J.G., and Le Quéré, C. 2008. Anthropogenic and biophysical contributions to increasing atmospheric CO2 growth rate and airborne fraction. Biogeosciences, 5(6):1601–1613. .
Raven, J.A., and Falkowski, P.G. 1999. Oceanic sinks for atmospheric CO2. Plant, Cell, and Environment, 22(6):741–755. .
Reeburgh, W.S. 1997. Figures summarizing the global cycles of biogeochemically important elements. Bulletin of the Ecological Society of America, 78(4):260–267. .
Robertson, G.P., Klingensmith, K.M., Klug, E.A., Paul, E.A., Crum, J.R., and Ellis, B.G. 1997. Soil resources, microbial activity, and primary production across an agricultural ecosystem. Ecological Applications, 7:158–170.
Rodhe, H., Dentener, F.J., and Schulz, M. 2002. The global distribution of acidifying wet deposition. Environmental Science and Technology, 36:4382–4388.
Schneider, A., Friedl, M.A., and Potere, D. 2009. A new map of global urban extent from MODIS satellite data. Environmental Research Letters, 4(4):044003. .
Schulze, E.D., Luyssaert, S., Ciais, P., Freibauer, A., Janssens, I.A., … Gasch, J.H. 2009. Importance of methane and nitrous oxide for Europe's terrestrial greenhouse-gas balance. Nature Geoscience, 2 (12), 842–850. .
Schumacher, B.A. 2002. Methods for determination of total organic carbon (TOC) in soils and sediments. Washington, DC: U.S. Environmental Protection Agency.
Solomon, S., Qin, D., Manning, M., Marquis, M., Averyt, K., Tignore, M.M.B.,…Chen, Z., eds. 2007. Climate change 2007: The physical science basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge: Cambridge University Press.
Staehelin, J., and Poberaj, C.S. 2007. Long-term tropospheric ozone trends: A critical review. In Climate variability and extremes during the past 100 years, ed. Brönnimann, S., Luterbacher, J., Ewen, T., et al. The Netherlands: Springer, pp. 271–282.
Sundquist, E.T., Burruss, R.C., Faulkner, S.P., Gleason, R.A., Harden, J.W., Kharaka, Y.K.,…Waldrop, M.P. 2008. Carbon sequestration to mitigate climate change. Fact Sheet 2008–3097, U.S. Geological Survey. .
Tarnocai, C., Canadell, J.G., Schuur, E.A.G., Kuhry, P., Mazhitova, G., and Zimov, S. 2009. Soil organic carbon pools in the northern circumpolar permafrost region. Global Biogeochemical Cycles, 23(2):GB2023. .
Trusilova, K., and Churkina, G. 2008. The response of the terrestrial biosphere to urbanization: Land cover conversion, climate, and urban pollution. Biogeosciences, 5(6):1505–1515. .
UN. 1997. Comprehensive assessment of the freshwater resources of the world. Geneva: United Nations.
van der Werf, G.R., Randerson, J.T., Giglio, L., Collatz, G.J., Mu, M., Kasibhatla, P.S.,…Van Leeuwen, T.T., 2010. Global fire emissions and the contribution of deforestation, savanna, forest, agricultural, and peat fires (1997–2009). Atmospheric Chemistry and Physics, 10(23):11707–11735. .
Van Oost, K., Quine, T.A., Govers, G., De Gryze, S., Six, J., Harden, J.W.,…Merckx, R. 2007. The impact of agricultural soil erosion on the global carbon cycle. Science, 318(5850):626–629. .
Vitousek, P., Hedin, L.O., Matson, P.A., Fownes, J.H., and Neff, J. 1998. Within-system element cycles, input-output budgets, and nutrient limitations. In Success, limitations, and frontiers in ecosystem science, ed. Pace, M. and Groffman, P.. New York: Springer-Verlag, pp. 432–451.
Vörösmarty, C.J., and Sahagian, D. 2000. Anthropogenic disturbance of the terrestrial water cycle. Bioscience, 50(9):753–765. .
Waring, R., and Running, S.W. 1998. Forest ecosystems: Analysis at multiple scales, 2d ed. New York: Academic Press.