Sensitivity of arctic summer sea ice coverage to global warming forcing: towards reducing uncertainty in arctic climate change projections

Article English OPEN
Zhang, Xiangdong (2010)

Substantial uncertainties have emerged in Arctic climate change projections by the fourth Intergovernmental Panel on Climate Change assessment report climate models. In particular, the models as a group considerably underestimate the recent accelerating sea ice reduction. To better understand the uncertainties, we evaluated sensitivities of summer sea ice coverage to global warming forcing in models and observations. The result suggests that the uncertainties result from the large range of sensitivities involved in the computation of sea ice mass balance by the climate models, specifically with the changes in sea ice area (SIA) ranging from 0.09 × 106 to −1.23 × 106 km2 in response to 1.0 K increase of air temperature. The sensitivities also vary largely across ensemble members in the same model, indicating impacts of initial condition on evolution of feedback strength with model integrations. Through observationally constraining, the selected model runs by the sensitivity analysis well captured the observed changes in SIA and surface air temperatures and greatly reduced their future projection uncertainties to a certain range from the currently announced one. The projected ice-free summer Arctic Ocean may occur as early as in the late 2030s using a criterion of 80% SIA loss and the Arctic regional mean surface air temperature will be likely increased by 8.5 ± 2.5 °C in winter and 3.7 ± 0.9 °C in summer by the end of this century.
  • References (17)
    17 references, page 1 of 2

    Alexander, M., Bhatt, U. S., Walsh, J. E., Timlin, M. S., Miller, J. S. and co-authors. 2004. The atmospheric response to realistic Arctic sea ice anomalies in an AGCM during winter. J. Clim. 17, 890-905.

    Bony, S. and Dufresne, J. L. 2005. Marine boundary layer clouds at the heart of tropical cloud feedback uncertainties in climate models. Geophys. Res. Lett. 32, L20806, doi:10.1029/2005GL023851.

    Colman, R. 2003. A comparison of climate feedbacks in general circulation models. Clim. Dyn. 20, 865-873.

    Comiso, J. C., Parkinson, C. L., Gersten, R. and Stock, L. 2008. Accelerated decline in the Arctic sea ice cover. Geophys. Res. Lett. 35, L01703, doi:10.1029/2007GL031972.

    Forster, P. M. D. and Gregory, J. M. 2006. The climate sensitivity and its components diagnosed from earth radiation. J. Clim. 19, 39-52.

    Gregory, J. M., Ingram, W. J., Palmer, M. A., Jones, G. S., Stott, P. A. and co-authors. 2004. A new method for diagnosing radiative forcing and climate sensitivity. Geophys. Res. Lett. 31, L03205, doi:10.1029/2003GL018747.

    Hansen, J., Sato, M. and Rueby, R. 1997. Radiative forcing and climate response. J. Geophys. Res. 104, 30997-31022.

    Hibler, W. D. 1979. A dynamic thermodynamic sea ice model. J. Phys. Oceanogr. 9, 815-846.

    Holland, M. M., Bitz, C. M. and Tremblay, B. 2006 Future abrupt reductions in the summer Arctic sea ice. Geophys. Res. Lett. 33, L23503, doi:10.1029/2006GL028024.

    Lindzen, R. S. and Choi, Y. S. 2009. On the determination of climate feedbacks from ERBE data. Geophys. Res. Lett. 36, L16705, doi:10.1029/2009GL039628.

  • Related Research Results (1)
    Arctic Sea Ice (2016)
  • Metrics
    No metrics available
Share - Bookmark