Emulating coupled atmosphere-ocean and carbon cycle models with a simpler model, MAGICC6 Part and

. Current scientific knowledge on the future response of the climate system to human-induced perturbations is comprehensively captured by various model intercomparison efforts. In the preparation of the Fourth Assessment Report (AR4) of the Intergovernmental Panel on Climate Change (IPCC), intercomparisons were organized for atmosphere-ocean general circulation models (AOGCMs) and carbon cycle models, named “CMIP3” and “C 4 MIP”, respectively. Despite their tremendous value for the scientific community and policy makers alike, there are some dif-ficulties in interpreting the results. For example, radiative forcings were not standardized across the various AOGCM integrations and carbon cycle runs, and, in some models, key forcings were omitted. Furthermore, the AOGCM analysis of plausible emissions pathways was restricted to only three SRES scenarios. This study attempts to address these issues. We present an updated version of MAGICC, the simple carbon cycle-climate model used in past IPCC Assessment Reports with enhanced representation of time-varying climate sensitivities, carbon cycle feedbacks, aerosol forcings and ocean heat uptake characteristics. This new version, MAGICC6, is successfully calibrated against the higher complexity AOGCMs and carbon cycle models. Parameterizations of MAGICC6 are provided. The mean of the emulations presented here using MAGICC6 deviates from the mean AOGCM responses by only 2.2% on average for the SRES scenarios. This enhanced emulation skill in comparison to previous

[1]  T. Andrews,et al.  Changes in global‐mean precipitation in response to warming, greenhouse gas forcing and black carbon , 2011 .

[2]  M. Meinshausen,et al.  Emulating Atlantic overturning strength for low emission scenarios: consequences for sea-level rise along the North American east coast , 2010 .

[3]  J. Randerson,et al.  Carbon-nitrogen interactions regulate climate-carbon cycle feedbacks: results from an atmosphere-ocean general circulation model , 2009 .

[4]  J. Edmonds,et al.  Uncertainties in climate stabilization , 2009 .

[5]  Olivier Boucher,et al.  Carbon dioxide induced stomatal closure increases radiative forcing via a rapid reduction in low cloud , 2009 .

[6]  Reto Knutti,et al.  The equilibrium sensitivity of the Earth's temperature to radiation changes , 2008 .

[7]  Jonathan M. Gregory,et al.  Time Variation of Effective Climate Sensitivity in GCMs , 2008 .

[8]  Pierre Friedlingstein,et al.  A Review of Uncertainties in Global Temperature Projections over the Twenty-First Century , 2008 .

[9]  B. O’Neill,et al.  Learning about parameter and structural uncertainty in carbon cycle models , 2008 .

[10]  Piers M. Forster,et al.  CO2 forcing induces semi‐direct effects with consequences for climate feedback interpretations , 2008 .

[11]  M. Webb,et al.  Tropospheric Adjustment Induces a Cloud Component in CO2 Forcing , 2008 .

[12]  John M. Reilly,et al.  Human-induced climate change : an interdisciplinary assessment , 2007 .

[13]  Piers M. Forster,et al.  Climate Forcings and Climate Sensitivities Diagnosed from Coupled Climate Model Integrations , 2006 .

[14]  Y. Tsushima,et al.  Time evolutions of various radiative forcings for the past 150 years estimated by a general circulation model , 2006 .

[15]  K. Riahi,et al.  The role of non-CO2 greenhouse gases in climate change mitigation: Long-term scenarios for the 21st century , 2006 .

[16]  S. Raper,et al.  Simulated climate change during the last 1,000 years: comparing the ECHO-G general circulation model with the MAGICC simple climate model , 2006 .

[17]  R. Schnur,et al.  Climate-carbon cycle feedback analysis: Results from the C , 2006 .

[18]  J. Hansen,et al.  Efficacy of climate forcings , 2005 .

[19]  Keywan Riahi,et al.  Long-term scenarios for black and organic carbon emissions , 2005 .

[20]  Leonard A. Smith,et al.  Uncertainty in predictions of the climate response to rising levels of greenhouse gases , 2005, Nature.

[21]  M. Webb,et al.  Quantification of modelling uncertainties in a large ensemble of climate change simulations , 2004, Nature.

[22]  Michael E. Mann,et al.  On smoothing potentially non‐stationary climate time series , 2004 .

[23]  Jonathan M. Gregory,et al.  A new method for diagnosing radiative forcing and climate sensitivity , 2004 .

[24]  S. Raper.  Interpretation of Model Results that Show changes in the Effective climate Sensitivity with Time , 2004 .

[25]  R. Stouffer.  Time Scales of Climate Response , 2004 .

[26]  T. D. Mitchell,et al.  Pattern Scaling: An Examination of the Accuracy of the Technique for Describing Future Climates , 2003 .

[27]  R. Sausen,et al.  A comparison of climate response to different radiative forcings in three general circulation models: towards an improved metric of climate change , 2003 .

[28]  G. Boer,et al.  Climate sensitivity and response , 2003 .

[29]  J. Houghton,et al.  Climate change 2001 : the scientific basis , 2001 .

[30]  M. Collins,et al.  Projections of future climate change , 2002 .

[31]  Stephen Sitch,et al.  Global warming feedbacks on terrestrial carbon uptake under the Intergovernmental Panel on Climate Change (IPCC) Emission Scenarios , 2001 .

[32]  T. Wigley,et al.  Interpretation of High Projections for Global-Mean Warming , 2001, Science.

[33]  Jonathan M. Gregory,et al.  Use of an upwelling-diffusion energy balance climate model to simulate and diagnose A/OGCM results , 2001 .

[34]  Adam A. Scaife,et al.  Removal of chlorofluorocarbons by increased mass exchange between the stratosphere and troposphere in a changing climate , 2001, Nature.

[35]  K. Shine.  Radiative Forcing of Climate Change , 2000 .

[36]  John F. B. Mitchell,et al.  The time‐dependence of climate sensitivity , 2000 .

[37]  R. Garcia,et al.  Stratospheric ozone destruction: The importance of bromine relative to chlorine , 1999 .

[38]  M. Allen.  Do-it-yourself climate prediction , 1999, Nature.

[39]  George A. Isaac,et al.  Scale Effects on Averaging of Cloud Droplet and Aerosol Number Concentrations: Observations and Models , 1999 .

[40]  D. Schimel,et al.  Atmospheric Chemistry and Greenhouse Gases , 1999 .

[41]  G. Myhre,et al.  New estimates of radiative forcing due to well mixed greenhouse gases , 1998 .

[42]  John F. B. Mitchell,et al.  The second Hadley Centre coupled ocean-atmosphere GCM: model description, spinup and validation , 1997 .

[43]  Corinne Le Quéré,et al.  An efficient and accurate representation of complex oceanic and biospheric models of anthropogenic carbon uptake , 1996 .

[44]  U. Cubasch,et al.  Emulation of the results from a coupled general circulation model using a simple climate model , 1996 .

[45]  John F. B. Mitchell,et al.  Transient Response of the Hadley Centre Coupled Ocean-Atmosphere Model to Increasing Carbon Dioxide. Part II: Spatial and Temporal Structure of Response , 1995 .

[46]  J. Murphy,et al.  Transient response of the Hadley Centre coupled ocean-atmosphere model to increasing carbon-dioxide , 1995 .

[47]  K. Trenberth,et al.  The total mass of the atmosphere , 1994 .

[48]  L. Harvey.  Transient temperature and sea level response of a two-dimensional ocean-climate model to greenhouse gas increases , 1994 .

[49]  Taro Takahashi,et al.  Seasonal variation of CO2 and nutrients in the high-latitude surface oceans: A comparative study , 1993 .

[50]  Tom M. L. Wigley,et al.  Balancing the carbon budget. Implications for projections of future carbon dioxide concentration changes , 1993 .

[51]  R. Gifford.  Implications of CO2 Effects on Vegetation for the Global Carbon Budget , 1993 .

[52]  Robert Sausen,et al.  On the cold start problem in transient simulations with coupled atmosphere-ocean models , 1992 .

[53]  T. Wigley,et al.  Implications for climate and sea level of revised IPCC emissions scenarios , 1992, Nature.

[54]  J. Sarmiento,et al.  A perturbation simulation of CO2 uptake in an ocean general circulation model , 1992 .

[55]  Tom M. L. Wigley,et al.  A simple inverse carbon cycle model , 1991 .

[56]  T. Wigley,et al.  Could reducing fossil-fuel emissions cause global warming? , 1991, Nature.

[57]  Xingjian Jiang,et al.  Revised projection of future greenhouse warming , 1991, Nature.

[58]  M. Schlesinger,et al.  Simple Model Representation of Atmosphere-Ocean GCMs and Estimation of the Time Scale of C02-Induced Climate Change , 1990 .

[59]  Michael E. Schlesinger,et al.  Developing climate scenarios from equilibrium GCM results , 1990 .

[60]  B. Albrecht.  Aerosols, Cloud Microphysics, and Fractional Cloudiness , 1989, Science.

[61]  T. Wigley,et al.  Thermal expansion of sea water associated with global warming , 1987, Nature.

[62]  Boyd R. Strain,et al.  Direct effects of increasing carbon dioxide on vegetation , 1985 .

[63]  Stephen H. Schneider,et al.  Transient climate response to external forcing on 100–104 year time scales part 1: Experiments with globally averaged, coupled, atmosphere and ocean energy balance models , 1985 .

[64]  T. Wigley,et al.  Analytical solution for the effect of increasing CO2 on global mean temperature , 1985, Nature.

[65]  S. Twomey.  The Influence of Pollution on the Shortwave Albedo of Clouds , 1977 .

[66]  S. Manabe,et al.  Climate Calculations with a Combined Ocean-Atmosphere Model , 1969 .