Skip to main content
Log in

Climate Change in Northern Africa: The Past is Not the Future

  • Published:
Climatic Change Aims and scope Submit manuscript

Abstract

By using a climate system model of intermediate complexity, we have simulated long-term natural climate changes occurring over the last 9000 years. The paleo-simulations in which the model is driven by orbital forcing only, i.e., by changes in insolation caused by changes in the Earth's orbit, are compared with sensitivity simulations in which various scenarios of increasing atmospheric CO2 concentration are prescribed. Focussing on climate and vegetation change in northern Africa, we recapture the strong greening of the Sahara in the early and mid-Holocene (some 9000–6000 years ago), and we show that some expansion of grasslandinto the Sahara is theoretically possible, if the atmospheric CO2 concentration increases well above pre-industrial values and if vegetation growth is not disturbed. Depending on the rate of CO2 increase, vegetation migration into the Sahara can be rapid, up to 1/10th of the Saharan area per decade, but could not exceed a coverage of 45%. In ourmodel, vegetation expansion into today's Sahara is triggered by an increase in summer precipitation which is amplified by a positive feedback between vegetation and precipitation. This is valid for simulations with orbital forcing and greenhouse-gas forcing. However, we argue that the mid-Holocene climate optimum some 9000 to 6000 years ago with its marked reduction of deserts in northern Africa is not a direct analogue for future greenhouse-gas induced climate change, as previously hypothesized. Not only does the global pattern of climate change differ between the mid-Holocene model experiments and the greenhouse-gas sensitivity experiments, but the relative role of mechanisms which lead to a reduction of the Sahara also changes. Moreover, the amplitude of simulated vegetation cover changes in northern Africa is less than is estimated for mid-Holocene climate.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Similar content being viewed by others

References

  • Anhuf, D., Frankenberg, P., and Lauer, W.: 1999, ‘Die postglaziale Warmphase vor 8000 Jahren’, Geologische Rundschau 51, 454–461.

    Google Scholar 

  • Berger, A.: 1978, ‘Long–Term Variations of Daily Insolation and Quaternary Climatic Change’, J. Atmos. Sci. 35, 2362–2367.

    Google Scholar 

  • Berger, A. and Loutre, M. F.: 1997, ‘Long–Term Variations in Insolation and their Effects on Climate, the LLN Experiments’, Surveys in Geophysics 18, 147–161.

    Google Scholar 

  • Betts, R. A., Cox, P. M., Lee, S. E., and Woodward, F. I.: 1997, ‘Contrasting Physiological and Structural Vegetation Feedbacks in Climate Change Simulations’, Nature 387, 796–799.

    Google Scholar 

  • Braconnot, P., Joussaume, S., Marti, O., and deNoblet–Ducoudre, N.: 1999, ‘Synergistic Feedbacks from Ocean and Vegetation on the African Monsoon Response to Mid–Holocene Insolation’, Geophys. Res. Lett. 26(16), 2481–2484.

    Google Scholar 

  • Broström, A., Coe, M., Harrison, S. P., Gallimore, R., Kutzbach, J. E., Foley, J. A., Prentice, I. C., and Behling, P.: 1998, ‘Land Surface Feedbacks and Paleomonsoons in Northern Africa’, Geophys. Res. Lett. 2519, 3615–3618.

    Google Scholar 

  • Brovkin, V., Bendtsen, J., Claussen, M., Ganopolski, A., Kubatzki, C., Petoukhov, V., and Andreev, A.: 2002, ‘Carbon Cycle, Vegetation and Climate Dynamics in the Holocene: Experiments with the CLIMBER–2 Model’, Global Biogeochem. Cycles, accepted.

  • Brovkin, V., Claussen, M., Petoukhov, V., and Ganopolski, A.: 1998, ‘On the Stability of the Atmosphere–Vegetation System in the Sahara/Sahel Region’, J. Geophys. Res. 103(D24), 31613–31624.

    Google Scholar 

  • Charney, J. G.: 1975, ‘Dynamics of Deserts and Droughts in the Sahel’, Quart. J. Roy. Meteorol. Soc. 101, 193–202.

    Google Scholar 

  • Claussen, M.: 1997, ‘Modelling Biogeophysical Feedback in the African and Indian Monsoon Region’, Clim. Dyn. 13, 247–257.

    Google Scholar 

  • Claussen, M.: 2001, ‘Biogeophysical Feedbacks and the Dynamics of Climate’, in Schulze, E. D., Harrison, S. P., Heimann, M., Holland, E. A., Lloyd, J., Prentice, I. C., and Schimel, D. (eds.), Global Biogeochemical Cycles in the Climate System, Academic Press, San Diego, pp. 61–71.

    Google Scholar 

  • Claussen, M., Brovkin, V., Ganopolski, A., Kubatzki, C., and Petoukhov, V.: 1998, ‘Modelling Global Terrestrial Vegetation — Climate Interaction’, Phil. Trans. Roy. Soc. London B 353, 53–63.

    Google Scholar 

  • Claussen, M. and Gayler, V.: 1997, ‘The Greening of Sahara during the Mid–Holocene: Results of an Interactive Atmosphere — Biome Model’, Global Ecol. Biogeog. Lett. 6, 369–377.

    Google Scholar 

  • Claussen, M., Kubatzki, C., Brovkin, V., Ganopolski, A., Hoelzmann, P., and Pachur, H. J.: 1999, ‘Simulation of an Abrupt Change in Saharan Vegetation at the End of the Mid–Holocene’, Geophys. Res. Lett. 24(14), 2037–2040.

    Google Scholar 

  • Colman, R. A., Power, S. B., MacAvaney, B. J., and Dahni, R. R.: 1995, ‘A Non–Flux–Corrected Transient CO2 Experiment using the BMRC Coupled Atmosphere/Ocean GCM.’, Geophys. Res. Lett. 22, 3047–3050.

    Google Scholar 

  • Cramer, W., Bondeau, A., Woodward, F. I., Prentice, I. C., Betts, R. A., Brovkin, V., Cox, P. M., Fisher, V., Foley, J. A., Friend, A. D., Kucharik, C., Lomas, M. R., Ramankutty, N., Sitch, S., Smith, B., White, A., and Young–Molling, C.: 2001, ‘Global Response of Terrestrial Ecosystem Structure and Function to CO2 and Climate Change: Results from Six Dynamic Global Vegetation Models’, Global Change Biology 7, 357–373.

    Google Scholar 

  • Cubasch, U., Meehl, G. A., Boer, G. J., Stouffer, R. J., Dix, M., Noda, A., Senior, C. A., Raper, S., and Yap, K. S.: 2001, ‘Projections of Future Climate Change’, in Houghton, J. T., Ding, Y., Griggs, D. J., Noguer, M., van der Linden, P., Dai, X., Maskell, K., and Johnson, C. I. (eds.), Climate Change 2001: The Scientific Basis. Contribution of Working Group I to the Third Assessment Report of the Intergovernmental Panel on Climate Change, Cambridge University Press, Cambridge, U.K. and New York, U.S.A., 881 pp.

    Google Scholar 

  • Doherty, R., Kutzbach, J., Foley, J., and Pollard, D.: 2000, ‘Fully Coupled Climate/Dynamical Vegetation Model Simulations over Northern Africa during the Mid–Holocene’, Clim. Dyn. 16, 561–573.

    Google Scholar 

  • Eltahir, E. A. B.: 1996, ‘Role of Vegetation in Sustaining Large–Scale Atmospheric Circulation in the Tropics’, J. Geophys. Res. 101(D2), 4255–4268.

    Google Scholar 

  • Eltahir, E. A. B. and Gong, C.: 1995, ‘Dynamics of Wet and Dry Years in West Africa’, J. Climate 9(5), 1030–1042.

    Google Scholar 

  • Frenzel, B., Pesci, M., and Velichko, A. A. (eds.): 1992, Atlas of Paleoclimates and Paleoenvironments of the Northern Hemisphere: Late Pleistocene–Holocene, Geographical Research Institute, Budapest, 153 pp.

    Google Scholar 

  • Ganopolski, A., Kubatzki, C., Claussen, M., Brovkin, V., and Petoukhov, V.: 1998a, ‘The Influence of Vegetation–Atmosphere–Ocean Interaction on Climate during the Mid–Holocene’, Science 280, 1916–1919.

    Google Scholar 

  • Ganopolski, A., Petoukhov, V., Rahmstorf, S., Brovkin, V., Claussen, M., Eliseev, A., and Kubatzki, C.: 2001, ‘CLIMBER–2: A Climate System Model of Intermediate Complexity. Part II: Validation and Sensitivity Tests’, Clim. Dyn. 17, 735–751.

    Google Scholar 

  • Ganopolski, A., Rahmstorf, S., Petoukhov, V., and Claussen, M.: 1998b, ‘Simulation of Modern and Glacial Climates with a Coupled Global Model of Intermediate Complexity’, Nature 391, 351–356.

    Google Scholar 

  • Harrison, S. P., Jolly, D., Laarif, F., Abe–Ouchi, A., Dong, B., Herterich, K., Hewitt, C., Joussaume, S., Kutzbach, J. E., Mitchell, J., de Noblet, N., and Valdes, P.: 1998, ‘Intercomparison of Simulated Global Vegetation Distributions in Response to 6kyr BP Orbital Forcing’, J. Climate 11, 2721–2742.

    Google Scholar 

  • Hoelzmann, P., Jolly, D., Harrison, S. P., Laarif, F., Bonnefille, R., and Pachur, H.–J.: 1998, ‘Mid–Holocene Land–Surface Conditions in Northern Africa and the Arabian Peninsula: A Data Set for the Analysis of Biogeophysical Feedbacks in the Climate System’, Global Biogeochem. Cycles 12, 35–51.

    Google Scholar 

  • Jolly, D., Harrison, S. P., Damnati, B., and Bonnefille, R.: 1998, ‘Simulated Climate and Biomes of Africa during the Late Quarternary: Comparison with Pollen and Lake Status Data’, Quat. Sci. Rev. 17(6–7), 629–657.

    Google Scholar 

  • Joussaume, S., Taylor, K. E., Braconnot, P., Mitchell, J. F. B., Kutzbach, J.E., Harrison, S. P., Prentice, I. C., Broccoli, A. J., Abe–Ouchi, A., Bartlein, P. J., Bonfiels, C., Dong., B., Guiot, J., Herterich, K., Hewit, C.D., Jolly, D., Kim, J.W., Kislov, A., Kitoh, A., Loutre, M. F., Masson, V., McAvaney, B., McFarlane, N., de Noblet, N., Peltier, W. R., Peterschmitt, J.Y., Pollard, D., Rind, D., Royer, J. F., Schlesinger, M. E., Syktus, J., Thompson, S., Valdes, P., Vettoretti, G., Webb, R. S., and Wyputta, U.: 1999, ‘Monsoon Changes for 6000 Years Ago: Results of 18 Simulatins from the Paleoclimate Modeling Intercomparison Project (PMIP)’, Geophys. Res. Lett. 26 (7), 859–862.

    Google Scholar 

  • Keeling, C. D.: 2000, ‘Atmospheric CO2 Concentrations — Mauna Loa Observatory, Hawaii, 1958–1999’, Report NDP–001, CDIAC, ORNL, Oak Ridge, U.S.A.

    Google Scholar 

  • Kubatzki, C.: 2000, Wechselwirkung zwischen Klima und Landoberfläche im Holozän. Dissertation, Fachbereich Geowissenschaften, Freie Universität Berlin, 182 S.

  • Kubatzki, C., Montoya, M., Rahmstorf, S., Ganopolski, A., and Claussen, M.: 2000, ‘Comparison of a Coupled Global Model of Intermediate Complexity and an AOGCM for the Last Interglacial’, Clim. Dyn. 16, 799–814.

    Google Scholar 

  • Kutzbach, J. E., Bonan, G., Foley, J., and Harrison, S. P.: 1996, ‘Vegetation and Soil Feedbacks on the Response of the African Monsoon to Orbital Forcing in the Early to Middle Holocene’, Nature 384, 623–626.

    Google Scholar 

  • Kutzbach, J. E. and Guetter, P. J.: 1986, ‘The Influence of Changing Orbital Parameters and Surface Boundary Conditions on Climate Simulations for the Past 18,000 Years’, J. Atmos. Sci. 43, 1726–1759.

    Google Scholar 

  • Kutzbach, H. E., Harrison, S. P., and Coe, M. T.: 2001, ‘Land–Ocean–Atmosphere Interactions and Monsoon Climate Change: A Paleoperspective’, in Schulze, E. D., Harrison, S. P., Heimann, M., Holland, E. A., Lloyd, J., Prentice, I. C., and Schimel, D. (eds.), Global Biogeochemical Cycles in the Climate System, Academic Press, San Diego, pp. 73–86.

    Google Scholar 

  • Maslin, M., Sarnthein, M., and Knaak, J.–J.: 1996, ‘Subtropical Eastern Atlantic Climate during the Eemian’, Naturwissenschaften 83, 122–126.

    Google Scholar 

  • deMenocal, P. B, Ortiz, J., Guilderson, T., Adkins, J., Sarnthein, M., Baker, L., and Yarusinski, M.: 2000, ‘Abrupt Onset and Termination of the African Humid Period: Rapid Climate Response to Gradual Insolation Forcing’, Quat. Sci. Rev 19, 347–361.

    Google Scholar 

  • Neftel, A., Moor, E., Oeschger, H., Stauffer, B., Friedli, H., Lütscher, H., and Siegenthaler, U.: 1990, ‘Atmospheric Carbon Dioxide Concentration–Historical Record, Siple Station, in: Trends 90: A Compendium of Data on Global Change’, Rep. 36, CDIAC, ORNL, Oak Ridge, U.S.A.

    Google Scholar 

  • Petit–Maire, N.: 1990, ‘Will Greenhouse Green the Sahara?’, Episodes 13 (2), 103–107.

    Google Scholar 

  • Petoukhov, V., Ganopolski, A., Brovkin, V., Claussen, M., Eliseev, A., Kubatzki, C., and Rahmstorf, S.: 2000, ‘CLIMBER–2: A Climate System Model of Intermediate Complexity. Part I: Model Description and Performance for Present Climate’, Clim. Dyn. 161, 1–17.

    Google Scholar 

  • Prentice, I. C., Jolly, D., and BIOME 6000 members: 2000, ‘Mid–Holocene and Glacial–Maximum Vegetation Geography of the Northern Continents and Africa’, J. Biogeography 27, 507–519.

    Google Scholar 

  • Sarnthein, M.: 1978, ‘Sand Deserts during Glacial Maximum and Climatic Optimum’, Nature 272, 43–46.

    Google Scholar 

  • Sarnthein, M., Tetzlaff, G., Koopmann, B., Wolter, K., and Pflaumann, U.: 1981, ‘Glacial and InterglacialWind Regimes over the Eastern Subtropical Atlantic and North–West Africa’, Nature 293, 193–196.

    Google Scholar 

  • Spitaler, R.: 1921, Das Klima des Eiszeitalters, Selbstverlag, Prag, 138 pp.

  • Stocker, T. F., Wright, D. G., and Mysak, L. A.: 1992, ‘A Zonally Averaged, Coupled Ocean–Atmosphere Model for Paleoclimate Studies’, J. Climate 5, 773–797.

    Google Scholar 

  • Texier, D., deNoblet, N., Harrison, S. P., Haxeltine, A., Jolly, D., Joussaume, S., Laarif, F., Prentice, I. C., and Tarasov, P.: 1997, ‘Quantifying the Role of Biosphere–Atmosphere Feed–Backs in Climate Change: Coupled Model Simulations for 6000 Years BP and Comparison with Paleodata for Northern Eurasia and Northern Africa’, Clim. Dyn. 13, 865–882.

    Google Scholar 

  • Xue, Y. and Shukla, J.: 1993, ‘The Influence of Land Surface Properties on Sahel Climate. Part I: Desertification’, J. Climate 6, 2232–2245.

    Google Scholar 

  • Wang, G. and Eltahir, E. A. B.: 2000a, ‘Biosphere–Atmosphere Interactions over West Africa. Part I. Development and Validation of a Coupled Dynamic Model’, Quart. J. Roy. Meteorol. Soc. 126, 1239–1260.

    Google Scholar 

  • Wang, G. and Eltahir, E. A. B.: 2000b, ‘Biosphere–Atmosphere Interactions over West Africa. 2. Multiple Equilibira’, Quart. J. Roy. Meteorol. Soc. 126, 1261–1280.

    Google Scholar 

  • Wang, G. and Eltahir, E. A. B.: 2000c, ‘Role of Vegetation Dynamics in Enhancing the Low–Frequency Variability of Sahel Rainfall’, Water Resour. Res. 36(4), 1013–1021.

    Google Scholar 

  • Yu, G. and Harrison, S. P.: 1996, ‘An Evaluation of the Simulated Water Balance of Eurasia and Northern Africa at 6000 y BP using Lake Status Data’, Clim. Dyn. 12, 723–735.

    Google Scholar 

  • Zeng, N. and Neelin, J. D.: 2000, ‘The Role of Vegetation–Climate Interaction and Interannual Variability in Shaping the African Savanna’, J. Climate 13, 2665–2670

    Google Scholar 

  • Zeng, N., Neelin, J. D., Lau, K.–M., and Tucker, C. J.: 1999, ‘Enhancement of Interdecadal Climate Variability in the Sahel by Vegetation Interaction’, Science 286, 1537–1540.

    Google Scholar 

  • Zheng, X. and Eltahir, E. A. B.: 1998, ‘The Role of Vegetation in the Dynamics of West African Monsoons’, J. Climate 11, 2078–2096.

    Google Scholar 

Download references

Author information

Authors and Affiliations

Authors

Rights and permissions

Reprints and permissions

About this article

Cite this article

Claussen, M., Brovkin, V., Ganopolski, A. et al. Climate Change in Northern Africa: The Past is Not the Future. Climatic Change 57, 99–118 (2003). https://doi.org/10.1023/A:1022115604225

Download citation

  • Issue Date:

  • DOI: https://doi.org/10.1023/A:1022115604225

Keywords

Navigation