Indirect radiative forcing of climate change through ozone effects on the land-carbon sink

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Abstract

The evolution of the Earth’s climate over the twenty-first century depends on the rate at which anthropogenic carbon dioxide emissions are removed from the atmosphere by the ocean and land carbon cycles1. Coupled climate–carbon cycle models suggest that global warming will act to limit the land-carbon sink2, but these first generation models neglected the impacts of changing atmospheric chemistry. Emissions associated with fossil fuel and biomass burning have acted to approximately double the global mean tropospheric ozone concentration3, and further increases are expected over the twenty-first century4. Tropospheric ozone is known to damage plants, reducing plant primary productivity and crop yields5, yet increasing atmospheric carbon dioxide concentrations are thought to stimulate plant primary productivity6. Increased carbon dioxide and ozone levels can both lead to stomatal closure, which reduces the uptake of either gas, and in turn limits the damaging effect of ozone and the carbon dioxide fertilization of photosynthesis6. Here we estimate the impact of projected changes in ozone levels on the land-carbon sink, using a global land carbon cycle model modified to include the effect of ozone deposition on photosynthesis and to account for interactions between ozone and carbon dioxide through stomatal closure7. For a range of sensitivity parameters based on manipulative field experiments, we find a significant suppression of the global land-carbon sink as increases in ozone concentrations affect plant productivity. In consequence, more carbon dioxide accumulates in the atmosphere. We suggest that the resulting indirect radiative forcing by ozone effects on plants could contribute more to global warming than the direct radiative forcing due to tropospheric ozone increases.

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Figure 1: Temporal changes of modelled ozone concentrations and gross primary productivity.
Figure 2: Temporal changes in land carbon storage and radiative forcing due to ozone.

References

  1. 1

    Cox, P. M., Betts, R. A., Jones, C. D., Spall, S. A. & Totterdell, I. J. Acceleration of global warming due to carbon-cycle feedbacks in a coupled climate model. Nature 408, 184–187 (2000)

  2. 2

    Friedlingstein, P. et al. Climate-carbon cycle feedback analysis: results from the C4MIP model intercomparison. J. Clim. 19, 3337–3353 (2006)

  3. 3

    Gauss, M. et al. Radiative forcing since preindustrial times due to ozone change in the troposphere and the lower stratosphere. Atmos. Chem. Phys. 6, 575–599 (2006)

  4. 4

    Gauss, M. et al. Radiative forcing in the 21st century due to ozone changes in the troposphere and the lower stratosphere. J. Geophys. Res. 108 4292 doi: 10.1029/2002JD002624 (2003)

  5. 5

    Ashmore, M. R. Assessing the future global impacts of ozone on vegetation. Plant Cell Environ. 28, 949–964 (2005)

  6. 6

    Karnosky, D. F. et al. Tropospheric O3 modulates responses of temperate hardwood forests to elevated CO2: a synthesis of molecular to ecosystem results from the Aspen FACE project. Funct. Ecol. 17, 289–304 (2003)

  7. 7

    Gedney, N. et al. Detection of a direct carbon dioxide effect in continental river runoff records. Nature 439, 835–838 (2006)

  8. 8

    Forster, P. et al. in Climate Change 2007: The Physical Science Basis (eds Solomon, S. et al.) 129–234 (Cambridge Univ. Press, Cambridge, UK, 2007)

  9. 9

    Wang, X. & Mauzerall, D. L. Characterizing distributions of surface ozone and its impact on grain production in China, Japan and South Korea: 1900 and 2020. Atmos. Environ. 38, 4383–4402 (2004)

  10. 10

    Prather, M. et al. in Climate Change 2001: The Scientific Basis (eds Houghton, J. T. et al.) 239–287 (Cambridge Univ. Press, Cambridge, UK, 2001)

  11. 11

    Felzer, B. S. et al. Future effects of ozone on carbon sequestration and climate change policy using a global biogeochemical model. Clim. Change 73 345–373 doi: 10.1007/s10584-005-6776-4 (2005)

  12. 12

    Field, C., Jackson, R. & Mooney, H. Stomatal responses to increased CO2: implications from the plant to the global-scale. Plant Cell Environ. 18, 1214–1255 (1995)

  13. 13

    Karnosky, D. F. et al. Scaling ozone responses of forest trees to the ecosystem level in a changing climate. Plant Cell Environ. 28, 965–981 (2005)

  14. 14

    Volk M. et al. Grassland yield declined by a quarter in 5 years of free-air ozone fumigation. Glob. Change Biol. 12 74–83 doi: 10.1111/j.1365-2486.2005.01083.x (2006)

  15. 15

    Percy, K. E. et al. New exposure-based metric approach for evaluating O3 risk to North American aspen forests. Environ. Pollut. 147, 554–566 (2007)

  16. 16

    Pleijel, H. et al. Relationships between ozone exposure and yield loss in European wheat and potato — a comparison of concentration- and flux-based exposure indices. Atmos. Environ. 38, 2259–2269 (2004)

  17. 17

    Essery, R. L. H., Best, M. J., Betts, R. A., Cox, P. M. & Taylor, C. M. Explicit representation of sub-grid heterogeneity in a GCM land-surface scheme. J. Hydrometeorol. 4, 530–543 (2001)

  18. 18

    Cox, P. M. et al. The impact of new GCM land-surface physics on the GCM simulation of climate and climate sensitivity. Clim. Dyn. 15, 183–203 (1999)

  19. 19

    Sanderson, M. G., Jones, C. D., Collins, W. J., Johnson, C. E. & Derwent, R. G. Effect of climate change on isoprene emissions and surface ozone levels. Geophys. Res. Lett. 30 1936 doi: 10.1029/2003GL017642 (2003)

  20. 20

    Karlsson, P. E. et al. New critical levels for ozone effects on young trees based on AOT40 and simulated cumulative leaf uptake of ozone. Atmos. Environ. 38, 2283–2294 (2004)

  21. 21

    New, M., Hulme, M. & Jones, P. Representing twentieth-century space-time climate variability. Part II. Development of 1901–96 monthly grids of terrestrial surface climate. J. Clim. 13, 2217–2238 (2000)

  22. 22

    Denman, K. L. et al. in Climate Change 2007: The Physical Science Basis (eds Solomon, S. et al.) 499–587 (Cambridge Univ. Press, Cambridge, UK, 2007)

  23. 23

    Imhoff, M. L. et al. Global patterns in human consumption of net primary production. Nature 429, 870–873 (2004)

  24. 24

    Schröter, D. et al. Ecosystem service supply and vulnerability to global change in Europe. Science 310 1333–1337 doi: 10.1126/science.1115233 (2005)

  25. 25

    Nussbaum, S. & Fuhrer, J. Difference in ozone uptake in grassland species between open-top chambers and ambient air. Environ. Pollut. 109, 463–471 (2000)

  26. 26

    Sabine, C. L. et al. The oceanic sink for anthropogenic CO2 . Science 305, 367–371 (2004)

  27. 27

    Berntsen, T. K., Myhre, G., Stordal, F. & Isaksen, I. S. A. Time evolution of tropospheric ozone and its radiative forcing. J. Geophys. Res. 105, 8915–8930 (2000)

  28. 28

    Ramaswamy, V. et al. in Climate Change 2001: The Scientific Basis (eds Houghton, J. T. et al.) 350–416 (Cambridge Univ. Press, Cambridge, UK, 2001)

  29. 29

    Dentener, F. D. et al. The global atmospheric environment for the next generation. Environ. Sci. Technol. 40, 3586–3594 (2005)

  30. 30

    van der Werf, G. R., Randerson, J. T., Collatz, G. J. & Giglio, L. Carbon emissions from fires in tropical and subtropical ecosystems. Glob. Change Biol. 9, 547–562 (2003)

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Acknowledgements

We thank N. Gedney for technical support, and M. Sanderson for information on the STOCHEM fields used in this study; we acknowledge discussions with the aforementioned and with M. Ashmore, R. Betts, D. Hemming, O. Boucher and L. Mercado. We also thank A. Everitt for computer support. S.S. was supported by the UK Department for Environment, Food and Rural Affairs (DEFRA) Climate Prediction Programme. W.J.C. was supported by the MoD, and by DEFRA Air and Environment Quality Division, and C.H. by the UK Natural Environment Research Council.

Author Contributions P.M.C. developed the modification to MOSES to include ozone effects on photosynthesis and stomatal conductance; W.J.C. provided the projections of future changes in tropospheric ozone; C.H. developed the IMOGEN software that enabled the global simulations to be carried out; and S.S. calibrated the ozone effects model against data from manipulative field experiments, and carried out and analysed the global simulations. All four authors were involved in the drafting of the paper, although SS took the lead role.

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Correspondence to S. Sitch.

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Supplementary Information

This file contains Supplementary Notes, Supplementary Figures S1-S4 with Legends, Supplementary Tables S1-S3 and additional references. (PDF 1055 kb)

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Sitch, S., Cox, P., Collins, W. et al. Indirect radiative forcing of climate change through ozone effects on the land-carbon sink. Nature 448, 791–794 (2007) doi:10.1038/nature06059

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