Clim. Past Discuss., 9, 5785-5836, 2013
© Author(s) 2013. This work is distributed
under the Creative Commons Attribution 3.0 License.
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This discussion paper has been under review for the journal Climate of the Past (CP). Please refer to the corresponding final paper in CP.
Regional climate model simulations for Europe at 6 k and 0.2 k yr BP: sensitivity to changes in anthropogenic deforestation
G. Strandberg1,2, E. Kjellström1,2, A. Poska3,5, S. Wagner4, M.-J. Gaillard5, A.-K. Trondman5, A. Mauri6, H. J. B. Birks7,8,9, A. E. Bjune10, B. A. S. Davis6, R. Fyfe11, T. Giesecke12, L. Kalnina13, M. Kangur14, J. O. Kaplan6, W. O. van der Knaap15, U. Kokfelt3,5,16, P. Kuneš17, M. Latałowa18, L. Marquer5, F. Mazier3,19, A. B. Nielsen5,20, B. Smith3, H. Seppä21, and S. Sugita14
1Swedish Meteorological and Hydrological Institute, Norrköping, Sweden
2Department of Meteorology, Stockholm University, Stockholm, Sweden
3Department of Earth and Ecosystem Science, Lund University, Lund, Sweden
4Helmholtz-Zentrum Geesthacht, Geesthacht, Germany
5Department of Biology and Environmental Science, Linnaeus University, Kalmar, Sweden
6ARVE, École polytechnique fédérale de Lausanne, EPFL, Lausanne, Switzerland
7Department of Biology and Bjerknes Centre for Climate Research University of Bergen, Bergen, Norway
8Environmental Change Research Centre, University College London, London, UK
9School of Geography and the Environment, University of Oxford, Oxford, UK
10Uni Climate, Uni Research AS and Bjerknes Centre for Climate Research, Bergen, Norway
11School of Geography, Earth and Environmental Sciences, University of Plymouth, Plymouth, UK
12Department of Palynology and Climate Dynamics, Albrecht-von-Haller-Institute for Plant Sciences, University of Göttingen, Göttingen, Germany
13Faculty of Geography and Earth Sciences, University of Latvia, Riga, Latvia
14Institue of Ecology, Tallin University, Tallin, Estonia
15Institute of Plant Sciences and Oeschger Centre for Climate Change Research, University of Bern, Bern, Switzerland
16Center for Permafrost, Department of Geosciences and Natural Resource Management, University of Copenhagen, Copenhagen, Denmark
17Department of Botany, Faculty of Science, Charles University in Prague, Praha, Czech Republic
18Laboratory of Palaeoecology and Archaeobotany, Department of Plant Ecology, University of Gdañsk, Gdañsk, Poland
19GEODE, UMR5602, University of Toulouse, Toulouse, France
20Department of Geology, Lund University, Lund, Sweden
21Department of Geosciences and Geography, University of Helsinki, Helsinki, Finland

Abstract. This study aims to evaluate the direct effects of anthropogenic deforestation on simulated climate at two contrasting periods in the Holocene, ~6 k BP and ~0.2 k BP in Europe. We apply RCA3, a regional climate model with 50 km spatial resolution, for both time periods, considering three alternative descriptions of the past vegetation: (i) potential natural vegetation (V) simulated by the dynamic vegetation model LPJ-GUESS, (ii) potential vegetation with anthropogenic land cover (deforestation) as simulated by the HYDE model (V + H), and (iii) potential vegetation with anthropogenic land cover as simulated by the KK model (V + K). The KK model estimates are closer to a set of pollen-based reconstructions of vegetation cover than the HYDE model estimates. The climate-model results show that the simulated effects of deforestation depend on both local/regional climate and vegetation characteristics. At ~6 k BP the extent of simulated deforestation in Europe is generally small, but there are areas where deforestation is large enough to produce significant differences in summer temperatures of 0.5–1 °C. At ~0.2 k BP, simulated deforestation is much more extensive than previously assumed, in particular according to the KK model. This leads to significant temperature differences in large parts of Europe in both winter and summer. In winter, deforestation leads to lower temperatures because of the differences in albedo between forested and unforested areas, particularly in the snow-covered regions. In summer, deforestation leads to higher temperatures in central and eastern Europe since evapotranspiration from unforested areas is lower than from forests. Summer evaporation is already limited in the southernmost parts of Europe under potential vegetation conditions and, therefore, cannot become much lower. Accordingly, the albedo effect dominates also in summer, which implies that deforestation causes a decrease in temperatures. Differences in summer temperature due to deforestation range from −1 °C in south-western Europe to +1 °C in eastern Europe. The choice of anthropogenic land cover estimate has a significant influence on the simulated climate, but uncertainties in palaeoclimate proxy data for the two time periods do not allow for a thorough comparison with climate model results.

Citation: Strandberg, G., Kjellström, E., Poska, A., Wagner, S., Gaillard, M.-J., Trondman, A.-K., Mauri, A., Birks, H. J. B., Bjune, A. E., Davis, B. A. S., Fyfe, R., Giesecke, T., Kalnina, L., Kangur, M., Kaplan, J. O., van der Knaap, W. O., Kokfelt, U., Kuneš, P., Latałowa, M., Marquer, L., Mazier, F., Nielsen, A. B., Smith, B., Seppä, H., and Sugita, S.: Regional climate model simulations for Europe at 6 k and 0.2 k yr BP: sensitivity to changes in anthropogenic deforestation, Clim. Past Discuss., 9, 5785-5836, doi:10.5194/cpd-9-5785-2013, 2013.
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