Carbon Cycle Uncertainty Increases Climate Change Risks and Mitigation Challenges

Paul A. T. Higgins AMS Policy Program, The American Meteorological Society, Washington, D.C.

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John Harte Environmental Science, Policy, and Management, University of California, Berkeley, Berkeley, California

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Abstract

Projections of greenhouse gas concentrations over the twenty-first century generally rely on two optimistic, but questionable, assumptions about the carbon cycle: 1) that elevated atmospheric CO2 concentrations will enhance terrestrial carbon storage and 2) that plant migration will be fast relative to climate changes. This paper demonstrates that carbon cycle uncertainty is considerably larger than currently recognized and that plausible carbon cycle responses could strongly amplify climate warming. This has important implications for societal decisions that relate to climate change risk management because it implies that a given level of human emissions could result in much larger climate changes than we now realize or that stabilizing atmospheric greenhouse gas concentrations at a “safe” level could require lower human emissions than currently understood. These results also suggest that terrestrial carbon cycle responses could be sufficiently strong to account for the changes in atmospheric carbon dioxide that occurred during transitions between ice age and interglacial periods.

Corresponding author address: Paul A. T. Higgins, AMS Policy Program, The American Meteorological Society, 1200 New York Avenue NW, Suite 450, Washington, DC 20005. E-mail: phiggins@ametsoc.edu

Abstract

Projections of greenhouse gas concentrations over the twenty-first century generally rely on two optimistic, but questionable, assumptions about the carbon cycle: 1) that elevated atmospheric CO2 concentrations will enhance terrestrial carbon storage and 2) that plant migration will be fast relative to climate changes. This paper demonstrates that carbon cycle uncertainty is considerably larger than currently recognized and that plausible carbon cycle responses could strongly amplify climate warming. This has important implications for societal decisions that relate to climate change risk management because it implies that a given level of human emissions could result in much larger climate changes than we now realize or that stabilizing atmospheric greenhouse gas concentrations at a “safe” level could require lower human emissions than currently understood. These results also suggest that terrestrial carbon cycle responses could be sufficiently strong to account for the changes in atmospheric carbon dioxide that occurred during transitions between ice age and interglacial periods.

Corresponding author address: Paul A. T. Higgins, AMS Policy Program, The American Meteorological Society, 1200 New York Avenue NW, Suite 450, Washington, DC 20005. E-mail: phiggins@ametsoc.edu
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  • Bird, M. I., J. Lloyd, and G. D. Farquhar, 1994: Terrestrial carbon storage at the LGM. Nature, 371, 566.

  • Clark, J. S., 1998: Why trees migrate so fast: Confronting theory with dispersal biology and the paleorecord. Amer. Nat., 152, 204224.

    • Search Google Scholar
    • Export Citation
  • Clark, J. S., M. Lewis, J. S. McLachlan, and J. HilleRisLambers, 2003: Estimating population spread: What can we forecast and how well? Ecology, 84, 19791988.

    • Search Google Scholar
    • Export Citation
  • Clarke, L., J. Edmonds, H. D. Jacoby, H. Pitcher, J. M. Reilly, and R. Richels, 2007: Scenarios of greenhouse gas emissions and atmospheric concentrations. U.S. Climate Change Science Program and the Subcommittee on Global Change Research Sub-Rep. 2.1A of Synthesis and Assessment Product 2.1, 154 pp.

  • Collatz, G. J., J. T. Ball, C. Grivet, and J. A. Berry, 1991: Physiological and environmental regulation of stomatal conductance, photosynthesis and transpiration: A model that includes a laminar boundary layer. Agric. For. Meteor., 53, 107136.

    • Search Google Scholar
    • Export Citation
  • Collatz, G. J., M. Ribas-Carbo, and J. A. Berry, 1992: Coupled photosynthesis-stomatal conductance model for leaves of C4 plants. Aust. J. Plant Physiol., 19, 519538.

    • Search Google Scholar
    • Export Citation
  • Cramer, W., and Coauthors, 2001: Global response of terrestrial ecosystem structure and function to CO2 and climate change: Results from six dynamic global vegetation models. Global Change Biol., 7, 357373.

    • Search Google Scholar
    • Export Citation
  • Crowley, T. J., 1995: Ice age terrestrial carbon changes revisited. Global Biogeochem. Cycles, 9, 377389.

  • Denman, K. L., and Coauthors, 2007: Couplings between changes in the climate system and biogeochemistry. Climate Change 2007: The Physical Science Basis, S. Solomon et al., Eds., Cambridge University Press, 499–587.

  • Dukes, J. S., and Coauthors, 2005: Responses of grassland production to single and multiple global environmental changes. PLoS Biol., 3, e319.

    • Search Google Scholar
    • Export Citation
  • Farquhar, G. D., S. von Caemmerer, and J. A. Berry, 1980: A biogeochemical model of photosynthetic CO2 assimilation in leaves of C3 species. Planta, 149, 7890.

    • Search Google Scholar
    • Export Citation
  • Foley, J. A., I. C. Prentice, N. Ramankutty, S. Levis, D. Pollard, S. Sitch, and A. Haxeltine, 1996: An integrated biosphere model of land surface processes, terrestrial carbon balance, and vegetation dynamics. Global Biogeochem. Cycles, 10, 603628.

    • Search Google Scholar
    • Export Citation
  • Friedlingstein, P., and Coauthors, 2006: Climate–carbon cycle feedback analysis: Results from the C4MIP model intercomparison. J. Climate, 19, 33373353.

    • Search Google Scholar
    • Export Citation
  • Global Soils Data Task Group, 2000: Global soil data products CD-ROM (IGBP-DIS). Oak Ridge National Laboratory Distributed Active Archive Center Global Soil Data Products, CD-ROM.

  • Higgins, P. A. T., 2009: Carbon cycle amplification: How optimistic assumptions cause persistent underestimates of potential climate damages and mitigation needs. Climatic Change, 95, 363368.

    • Search Google Scholar
    • Export Citation
  • Higgins, P. A. T., and S. H. Schneider, 2005: Potential biotic response and climate feedback to thermohaline circulation collapse in Central England. Global Change Biol., 11, 699709.

    • Search Google Scholar
    • Export Citation
  • Higgins, P. A. T., and J. Harte, 2006: Biophysical and biogeochemical responses to climate change depend on dispersal and migration. Bioscience, 56, 407417.

    • Search Google Scholar
    • Export Citation
  • Higgins, S. I., and D. M. Richardson, 1999: Predicting plant migration rates in a changing world: The role of long-distance dispersal. Amer. Nat., 153, 464475.

    • Search Google Scholar
    • Export Citation
  • Jansen, E. J., and Coauthors, 2007: Palaeoclimate. Climate Change 2007: The Physical Science Basis, S. Solomon et al., Eds., Cambridge University Press, 433–497.

  • Johns, T. C., and Coauthors, 2003: Anthropogenic climate change for 1860 to 2100 simulated with the HadCM3 model under updated emissions scenarios. Climate Dyn., 20, 583612.

    • Search Google Scholar
    • Export Citation
  • Körner, C., and Coauthors, 2005: Carbon flux and growth in mature deciduous forest trees exposed to elevated CO2. Science, 309, 13601362.

    • Search Google Scholar
    • Export Citation
  • Kucharik, C. J., and Coauthors, 2000: Testing the performance of a Dynamic Global Ecosystem Model: Water balance, carbon balance, and vegetation structure. Global Biogeochem. Cycles, 14, 795825.

    • Search Google Scholar
    • Export Citation
  • Leuenberger, M., U. Siegenthaler, and C. C. Langway, 1992: Carbon isotope composition of atmospheric CO2 during the last ice age from an Antarctic ice core. Nature, 357, 488490.

    • Search Google Scholar
    • Export Citation
  • Malcolm, J. R., A. Markham, R. P. Neilson, and M. Garaci, 2002: Estimated migration rates under scenarios of global climate change. J. Biogeogr., 29, 835849.

    • Search Google Scholar
    • Export Citation
  • Marland, G., T. A. Boden, and R. J. Andres, cited 2003: Global, regional, and national CO2 emissions. [Available online at http://cdiac.ornl.gov/trends/emis/overview.html.]

  • McGuire, A., and Coauthors, 2001: Carbon balance of the terrestrial biosphere in the twentieth century: Analyses of CO2, climate and land use effects with four process-based ecosystem models. Global Biogeochem. Cycles, 15, 183206.

    • Search Google Scholar
    • Export Citation
  • McLachlan, J. S., and J. S. Clark, 2004: Reconstructing historical ranges with fossil data at continental scales. For. Ecol. Manage., 197, 139147.

    • Search Google Scholar
    • Export Citation
  • Meehl, G. A., and Coauthors, 2007: Global climate projections. Climate Change 2007: The Physical Science Basis, S. Solomon et al., Eds., Cambridge University Press, 747–845.

  • Nakicenovic, N., and Coauthors, 2000: IPCC Special Report on Emissions Scenarios. Cambridge University Press, 599 pp.

  • New, M., M. Hulme, and P. Jones, 1999: Representing twentieth-century space—time climate variability. Part I: Development of a 1961–90 mean monthly terrestrial climatology. J. Climate, 12, 829856.

    • Search Google Scholar
    • Export Citation
  • Norby, R. J., and Coauthors, 2005: Forest response to elevated CO2 is conserved across a broad range of productivity. Proc. Natl. Acad. Sci. USA, 102, 18 05218 056.

    • Search Google Scholar
    • Export Citation
  • Norby, R. J., J. M. Warren, C. M. Iversen, B. E. Medlyn, and R. E. McMurtrie, 2010: CO2 enhancement of forest productivity constrained by limited nitrogen availability. Proc. Natl. Acad. Sci. USA, 107, 19 36819 373.

    • Search Google Scholar
    • Export Citation
  • Nowak, R. S., D. S. Ellsworth, and S. D. Smith, 2004: Functional responses of plants to elevated atmospheric CO2—Do photosynthetic and productivity data from FACE experiments support early predictions? New Phytol., 162, 253280.

    • Search Google Scholar
    • Export Citation
  • Petit, J. R., and Coauthors, 1999: Climate and atmospheric history of the past 420 000 years from the Vostok ice core, Antarctica. Nature, 399, 429436.

    • Search Google Scholar
    • Export Citation
  • Prentice, I. C., and Coauthors, 2001: The carbon cycle and atmospheric carbon dioxide. Climate Change 2001: The Scientific Basis, J. T. Houghton et al., Eds., Cambridge University Press, 183–237.

  • Randall, D. A., and Coauthors, 2007: Climate models and their evaluation. Climate Change 2007: The Physical Science Basis, S. Solomon et al., Eds., Cambridge University Press, 589–662.

  • Running, S. W., 2008: Ecosystem disturbance, carbon, and climate. Science, 321, 652653.

  • Shaw, M. R., E. S. Zavaleta, N. R. Chiariello, E. E. Cleland, H. A. Mooney, and C. B. Field, 2002: Grassland responses to global environmental changes suppressed by elevated CO2. Science, 298, 19871990.

    • Search Google Scholar
    • Export Citation
  • Solomon, A. M., and A. P. Kirilenko, 1997: Climate change and terrestrial biomass: What if trees do not migrate? Global Ecol. Biogeogr. Lett., 6, 139148.

    • Search Google Scholar
    • Export Citation
  • Tinner, W., and A. F. Lotter, 2001: Central European vegetation response to abrupt climate change at 8.2 ka. Geology, 29, 551554.

  • Zak, D., K. S. Pregitzer, M. E. Kubiske, and A. J. Burton, 2011: Forest productivity under elevated CO2 and O3: Positive feedbacks to soil N cycling sustain decade-long net primary productivity enhancement by CO2. Ecol. Lett., 14, 12201226.

    • Search Google Scholar
    • Export Citation
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