Climate Dynamics

, Volume 37, Issue 9, pp 1975–2003

Climate change under aggressive mitigation: the ENSEMBLES multi-model experiment

  • T. C. Johns
  • J.-F. Royer
  • I. Höschel
  • H. Huebener
  • E. Roeckner
  • E. Manzini
  • W. May
  • J.-L. Dufresne
  • O. H. Otterå
  • D. P. van Vuuren
  • D. Salas y Melia
  • M. A. Giorgetta
  • S. Denvil
  • S. Yang
  • P. G. Fogli
  • J. Körper
  • J. F. Tjiputra
  • E. Stehfest
  • C. D. Hewitt
Article

DOI: 10.1007/s00382-011-1005-5

Cite this article as:
Johns, T.C., Royer, J., Höschel, I. et al. Clim Dyn (2011) 37: 1975. doi:10.1007/s00382-011-1005-5

Abstract

We present results from multiple comprehensive models used to simulate an aggressive mitigation scenario based on detailed results of an Integrated Assessment Model. The experiment employs ten global climate and Earth System models (GCMs and ESMs) and pioneers elements of the long-term experimental design for the forthcoming 5th Intergovernmental Panel on Climate Change assessment. Atmospheric carbon-dioxide concentrations pathways rather than carbon emissions are specified in all models, including five ESMs that contain interactive carbon cycles. Specified forcings also include minor greenhouse gas concentration pathways, ozone concentration, aerosols (via concentrations or precursor emissions) and land use change (in five models). The new aggressive mitigation scenario (E1), constructed using an integrated assessment model (IMAGE 2.4) with reduced fossil fuel use for energy production aimed at stabilizing global warming below 2 K, is studied alongside the medium-high non-mitigation scenario SRES A1B. Resulting twenty-first century global mean warming and precipitation changes for A1B are broadly consistent with previous studies. In E1 twenty-first century global warming remains below 2 K in most models, but global mean precipitation changes are higher than in A1B up to 2065 and consistently higher per degree of warming. The spread in global temperature and precipitation responses is partly attributable to inter-model variations in aerosol loading and representations of aerosol-related radiative forcing effects. Our study illustrates that the benefits of mitigation will not be realised in temperature terms until several decades after emissions reductions begin, and may vary considerably between regions. A subset of the models containing integrated carbon cycles agree that land and ocean sinks remove roughly half of present day anthropogenic carbon emissions from the atmosphere, and that anthropogenic carbon emissions must decrease by at least 50% by 2050 relative to 1990, with further large reductions needed beyond that to achieve the E1 concentrations pathway. Negative allowable anthropogenic carbon emissions at and beyond 2100 cannot be ruled out for the E1 scenario. There is self-consistency between the multi-model ensemble of allowable anthropogenic carbon emissions and the E1 scenario emissions from IMAGE 2.4.

Keywords

ClimateClimate changeCarbon cycleProjectionsMitigationStabilizationAllowable emissionsEmissions reductionEarth system modelMulti-modelENSEMBLESCMIP5

Copyright information

© Springer-Verlag 2011

Authors and Affiliations

  • T. C. Johns
    • 1
  • J.-F. Royer
    • 2
  • I. Höschel
    • 3
  • H. Huebener
    • 4
  • E. Roeckner
    • 5
  • E. Manzini
    • 5
    • 6
    • 7
  • W. May
    • 8
  • J.-L. Dufresne
    • 9
  • O. H. Otterå
    • 10
    • 12
    • 11
  • D. P. van Vuuren
    • 14
    • 13
  • D. Salas y Melia
    • 2
  • M. A. Giorgetta
    • 5
  • S. Denvil
    • 15
  • S. Yang
    • 8
  • P. G. Fogli
    • 7
  • J. Körper
    • 3
  • J. F. Tjiputra
    • 12
    • 16
  • E. Stehfest
    • 14
  • C. D. Hewitt
    • 1
  1. 1.Hadley CentreMet OfficeExeterUK
  2. 2.Centre National de Recherches Météorologiques-Groupe d’Etude de l’Atmosphère Météorologique (CNRM-GAME Meteo-France CNRS)ToulouseFrance
  3. 3.Institute for MeteorologyFreie Universität BerlinBerlinGermany
  4. 4.Hessian Agency for the Environment and GeologyWiesbadenGermany
  5. 5.Max Planck Institute for MeteorologyHamburgGermany
  6. 6.Istituto Nazionale di Geofisica e VulcanologiaBolognaItaly
  7. 7.Centro Euro-Mediterraneo per i Cambiamenti Climatici (CMCC)BolognaItaly
  8. 8.Danish Climate CentreDanish Meteorological InstituteCopenhagenDenmark
  9. 9.UMR 8539 CNRS, ENS, UPMC, Ecole PolytechniqueLaboratoire de Météorologie Dynamique (LMD/IPSL)Paris Cedex 05France
  10. 10.Nansen Environmental and Remote Sensing CenterBergenNorway
  11. 11.Uni. Bjerknes CentreBergenNorway
  12. 12.Bjerknes Centre for Climate ResearchBergenNorway
  13. 13.Utrecht UniversityUtrechtThe Netherlands
  14. 14.Planbureau voor de Leefomgeving (PBL)BilthovenThe Netherlands
  15. 15.FR 636 CNRS, UVSQ, UPMCInstitut Pierre Simon Laplace (IPSL)Paris Cedex 05France
  16. 16.Department of GeophysicsUniversity of BergenBergenNorway