CP Climate of the Past CP 1814-9332 Copernicus GmbH Göttingen, Germany 10.5194/cp-5-1-2009 Western Europe is warming much faster than expected van Oldenborgh G. J. 1 Drijfhout S. 1 van Ulden A. 1 Haarsma R. 1 Sterl A. 1 Severijns C. 1 Hazeleger W. 1 Dijkstra H. 2 KNMI (Koninklijk Nederlands Meteorologisch Instituut), De Bilt, The Netherlands Institute for Marine and Atmospheric Research, Utrecht University, The Netherlands 21 01 2009 5 1 1 12 This is an open-access article ditributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. This article is available from http://www.clim-past.net/5/1/2009/cp-5-1-2009.html The full text article is available as a PDF file from http://www.clim-past.net/5/1/2009/cp-5-1-2009.pdf

The warming trend of the last decades is now so strong that it is discernible in local temperature observations. This opens the possibility to compare the trend to the warming predicted by comprehensive climate models (GCMs), which up to now could not be verified directly to observations on a local scale, because the signal-to-noise ratio was too low. The observed temperature trend in western Europe over the last decades appears much stronger than simulated by state-of-the-art GCMs. The difference is very unlikely due to random fluctuations, either in fast weather processes or in decadal climate fluctuations. In winter and spring, changes in atmospheric circulation are important; in spring and summer changes in soil moisture and cloud cover. A misrepresentation of the North Atlantic Current affects trends along the coast. Many of these processes ontinue to affect trends in projections for the 21st century. This implies that climate predictions for western Europe probably underestimate the effects of anthropogenic climate change.

 References Boe, J. and Terray, L.: Uncertainties in summer evapotranspiration changes over Europe and implications for regional climate change, Geophys. Res. Lett., 35, L05702, \doi10.1029/2007GL032417, 2008. Brandsma, T., Können, G P., and Wessels, H. R A.: Empirical estimation of the effect of urban heat advection on the temperature series of De Bilt (The Netherlands), Int. J. Climatol., 23, 829–845, \doi10.1002/joc.902, 2003. Brohan, P., Kennedy, J., Haris, I., Tett, S. F B., and Jones, P D.: Uncertainty estimates in regional and global observed temperature changes: a new dataset from 1850, J. Geophys. Res., 111, D12106, \doi10.1029/2005JD006548, 2006. Carton, J A., Giese, B S., and Grodsky, S A.: Sea level rise and the warming of the oceans in the SODA ocean reanalysis, J. Geophys. Res., 110, C09006, \doi10.1029/2004JC002817, 2005. Centraal Bureau voor Statistiek: StatLine, statline.cbs.nl, 2007. Christensen, J H. and Christensen, O B.: A summary of the PRUDENCE model projectionsof changes in European climate by the end of the century, Clim. Change, 81, 7–30, \doi10.1007/s10584-006-9210-7, 2007. Delworth, T L., Broccoli, A J., Rosati, A., Stouffer, R J., Balaji, V., Beesley, J A., Cooke, W F., Dixon, K W., Dunne, J., Dunne, K A., Durachta, J W., Findell, K L., Ginoux, P., Gnanadesikan, A., Gordon, C T., Griffies, S M., Gudgel, R., Harrison, M J., Held, I M., Hemler, R S., Horowitz, L W., Klein, S A., Knutson, T R., Kushner, P J., Langenhorst, A R., Lee, H C., Lin, S J., Lu, J., Malyshev, S L., Milly, P. C D., Ramaswamy, V., Russell, J., Schwarzkopf, M D., Shevliakova, E., Sirutis, J J., Spelman, M J., Stern, W F., Winton, M., Wittenberg, A T., Wyman, B., Zeng, F., and Zhang, R.: GFDL's CM2 global coupled climate models – Part 1: Formulation and simulation characteristics, J. Climate, 19, 643–674, \doi10.1175/JCLI3629.1, 2006. Drijfhout, S S. and Hazeleger, W.: Detecting Atlantic MOC changes in en ensemble of climate change simulations, J. Climate, 20, 1571–1582, \doi10.1175/JCLI4104.1, 2007. Frantzen, A J. and Raaff, W R.: De globale straling in het Rijnmondgebied (Global Radiation in the greater Rotterdam area), W. R., KNMI, De Bilt, Netherlands, 78–14, 1978. IPCC: Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC), edited by: Solomon, S., Qin, D., Manning, M., Chen, Z., Marquis, M., Averyt, K. B., Tignor, M., and Miller, H. L., Cambridge University Press, Cambridge, UK and New York, NY, USA, 2007. Johns, T., Durman, C., Banks, H., Roberts, M., McLaren, A., Ridley, J., Senior, C., Williams, K., Jones, A., Keen, A., Rickard, G., Cusack, S., Joshi, M., Ringer, M., Dong, B., Spencer, H., Hill, R., Gregory, J., Pardaens, A., Lowe, J., Bodas-Salcedo, A., Stark, S., and Searl, Y.: HadGEM1 – Model description and analysis of preliminary experiments for the IPCC Fourth Assessment Report, Tech. Rep 55, UK Met Office, Exeter, UK, 2004. Jungclaus, J H., Keenlyside, N., Botzet, M., Haak, H., Luo, J.-J., Latif, M., Marotzke, J., Mikolajewicz, U., and Roeckner, E.: Ocean circulation and tropical variability in the coupled model ECHAM5/MPI-OM, J. Climate, 19, 3952–3972, \doi10.1175/JCLI3827.1, 2006. K-1 model developers: K-1 coupled model (MIROC) description, Tech. Rep 1, Center for Climate System Research, University of Tokyo, www.ccsr.u-tokyo.ac.jp/kyosei/hasumi/MIROC/tech-repo.pdf, 2004. Kalnay, E., Kanamitsu, M., Kistler, R., Collins, W., Deaver, D., Gandin, L., Iredell, M., Saha, S., White, G., Woollen, J., Zhu, Y., Leetma, A., Reynolds, R., Chelliah, M., Ebisuzaki, W., Higgens, W., Janowiak, J., Mo, K C., Ropelewski, C., Wang, J., and Jenne, R.: The NCEP/NCAR 40-year reanalysis project, Bull. Amer. Met. Soc., 77, 437–471, \doi10.1175/1520-0477(1996)077<0437:TNYRP>2.0.CO;2, 1996. Kattenberg, A.: De toestand van het klimaat in Nederland 2008, KNMI, www.knmi.nl/toestandklimaat, 2008. Keenlyside, N S., Latif, M., Jungclaus, J., Kornblueh, L., and Roeckner, E.: Forecasting North Atlantic Sector Decadal Climate Variability, Nature, 453, 84–88, \doi10.1038/nature06921, 2008. Kim, S.-J., Flato, G M., de~Boer, G J., and McFarlane, N A.: A coupled climate model simulation of the Last Glacial Maximum, Part 1: transient multi-decadal response, Clim. Dynam., 19, 515–537, \doi10.1007/s00382-002-0243-y, 2002. Lenderink, G., van Ulden, A P., van~den Hurk, B., and Keller, F.: A study on combining global and regional climate model results for generating climate scenarios of temperature and precipitation for the Netherlands, Clim. Dynam., 29, 157–176, \doi10.1007/s00382-007-0227-z, 2007. Livezey, R E. and Chen, W Y.: Statistical Field Significance and its Determination by Monte Carlo Techniques, Mon. Weather Rev., 111, 46–59, \doi10.1175/1520-0493(1983)111<0046:SFSAID>2.0.CO;2, 1983. Lumpkin, R. and Speer, K.: Large-Scale Vertical and Horizontal Circulation in the North Atlantic Ocean, J. Phys. Oceanogr., 33, 1902–1920, \doi10.1175/1520-0485(2003)033<1902:LVAHCI>2.0.CO;2, 2003. Marsland, S J., Haak, H., Jungclaus, J H., Latif, M., and Röske, F.: The Max-Planck-Institute global ocean/sea ice model with orthogonal curvilinear coordinates, Ocean Modelling, 5, 91–127, \doi10.1016/S1463-5003(02)00015-X, 2003. Murphy, J M., Booth, B. B B., Collins, M., Harris, G R., Sexton, D., and Webb, M.: A methodology for probabilistic predictions of regional climate change from perturbed physics ensembles, Phil. Trans. R. Soc. A, 365, 1993–2028, \doi10.1098/rsta.2007.2077, 2007. Nakicenovic, N. et~al.: Special Report on Emissions Scenarios: A Special Report of Working Group III of the Intergovernmental Panel on Climate Change, Cambridge University Press, Cambridge, UK, www.grida.no/climate/ipcc/emission/, 2000. Norris, J R. and Wild, M.: Trends in aerosol radiative effects over Europe inferred from observed cloud cover, solar "dimming," and solar "brightening", J. Geophys. Res., 112, D08214, \doi10.1029/2006JD00779, 2007. Osborn, T J.: Simulating the winter North Atlantic Oscillation: the roles of internal variability and greenhouse gas forcing, Clim. Dyn., 22, 605–623, \doi10.1007/s00382-004-0405-1, 2004. Osborn, T J. and Jones, P D.: Air flow influences on local climate: observed United Kingdom climate variations, Atmos. Sci. Lett., 1, 62–74, \doi10.1006/asle.2000.0017, 2000. Rahmstorf, S., Cazenave, A., Church, J A., Hansen, J E., Keeling, R F., Parker, D E., and Somerville, R. C J.: Recent Climate Observations Compared to Projections, Science, 316, p 709, \doi10.1126/science.1136843, 2007. Rayner, N A., Brohan, P., Parker, D E., Folland, C K., Kennedy, J J., Vanicek, M., Ansell, T., and Tett, S. F B.: Improved analyses of changes and uncertainties in marine temperature measured in situ since the mid-nineteenth century: the HadSST2 dataset, J. Climate, 19, 446–469, \doi10.1175/JCLI3637.1, 2006. Reynolds, R W., Rayner, N A., Smith, T M., Stokes, D C., and Wang, W.: An Improved In Situ and Satellite SST Analysis for Climate, J. Climate, 15, 1609–1625, \doi10.1175/1520-0442(2002)015<1609:AIISAS>2.0.CO;2, 2002. Roeckner, E., Bäuml, G., Bonaventura, L., Brokopf, R., Esch, M., Giorgetta, M., Hagemann, S., Kirchner, I., Kornblueh, L., Manzini, E., Rhodin, A., Schlese, U., Schulzweida, U., and Tompkins, A.: The atmospheric general circulation model ECHAM 5. Part I: Model description, Tech. Rep. 349, Max-Planck-Institut für Meteorologie, Hamburg, Germany, edoc.mpg.de/175329, 2003. Scherrer, S C., Appenzeller, C., Liniger, M A., and Schär, C.: European temperature distribution changes in observations and climate change scenarios, Geophys. Res. Lett., 32, L19705, \doi10.1029/2005GL024108, 2005. Seneviratne, S I., Lüthi, D., Litschi, M., and Schär, C.: Land-atmosphere coupling and climate change in Europe, Nature, 443, 205–209, \doi10.1038/nature05095, 2006. Smith, D M., Cusack, S., Colman, A W., Folland, C K., Harris, G R., and Murphy, J M.: Improved Surface Temperature Prediction for the Coming Decade from a Global Climate Model, Science, 317, 796–799, \doi10.1126/science.1139540, 2007. Sterl, A., Severijns, C., Dijkstra, H., Hazeleger, W., van Oldenborgh, G J., van~den Broeke, M., Burgers, G., van den Hurk, B., van Leeuwen P J., and van Velthoven, P.: When can we expect extremely high surface temperatures?, Geophys. Res. Lett., 35, L14703, \doi1029/2008GL034071, 2008. Stern, D I.: Reversal of the trend in global anthropogenic sulfur emissions, Global Env. Change, 16, 207–220, \doi10.1016/j.gloenvcha.2006.01.001, 2006. Stott, P A.: Attribution of regional-scale temperature changes to anthropogenic and natural causes, Geophys. Res. Lett., 30, 1728, \doi10.1029/2003GL01732, 2003. Turnpenny, J R., Crossley, J F., Hulme, M., and Osborn, T J.: Air flow influences on local climate: comparison of a regional climate model with observations over the United Kingdom, Climate Res., 20, 189–202, \doi10.3354/cr020189, 2002. van~den Hurk, B. J. J M., Klein~Tank, A. M G., Lenderink, G., van Ulden, A P., van Oldenborgh, G J., Katsman, C A., van~den Brink, H W., Keller, F., Bessembinder, J. J F., Burgers, G., Komen, G J., Hazeleger, W., and Drijfhout, S S.: KNMI Climate Change Scenarios 2006 for the Netherlands, WR 2006-01, KNMI, www.knmi.nl/climatescenarios, 2006. van~den Hurk, B. J. J M., Klein~Tank, A. M G., Lenderink, G., van Ulden, A P., van Oldenborgh, G J., Katsman, C A., van~den Brink, H W., Keller, F., Bessembinder, J. J F., Burgers, G., Komen, G J., Hazeleger, W., and Drijfhout, S S.: New Climate Change Scenarios for the Netherlands, Water Sci. Technol., 56, 27–33, \doi10.2166/wst.2007.533, 2007. van Oldenborgh, G J. and van Ulden, A P.: On the relationship between global warming, local warming in the Netherlands and changes in circulation in the 20th century, Int. J. Climatol., 23, 1711–1724, \doi10.1002/joc.966, 2003. van Ulden, A P. and van Oldenborgh, G J.: Large-scale atmospheric circulation biases and changes in global climate model simulations and their importance for climate change in Central Europe, Atmos. Chem. Phys., 6, 863–881, 2006. van Ulden, A P., Lenderink, G., van~den Hurk, B., and Van~Meijgaard, E.: Circulation Statistics and Climate Change in Central Europe: PRUDENCE Simulations and Observations, Clim. Change, 81, 179–192, 2007. Vautard, R., Yiou, P., D'Andrea, F., de~Noblet, N., Viovy, N., Cassou, C., Polcher, J., Ciais, P., Kageyama, M., and Fan, Y.: Summertime European heat and drought waves induced by wintertime Mediterranean rainfall deficit, Geophys. Res. Lett., 34, L07711, \doi10.1029/2006GL028001, 2007. Wild, M., Gilgen, H., Roesch, A., Ohmura, A., Long, C N., Dutton, E G., Forgan, B., Kallis, A., Russak, V., and Tsvetkov, A.: From Dimming to Brightening: Decadal Changes in Solar Radiation at Earth's Surface, Science, 308, 847–850, \doi10.1126/science.1103215, 2005. Wild, M., Ohmura, A., and Makowski, K.: Impact of global dimming and brightening on global warming, Geophys. Res. Lett., 34, L04702, \doi10.1029/2006GL028031, 2007.