@article{RobinsonCalovGanopolski2011,
  author    = {Robinson, Alexander and Calov, Reinhard and Ganopolski, Andrey},
  title     = {Greenland ice sheet model parameters constrained using simulations of the Eemian Interglacial},
  series = {Climate of the past : an interactive open access journal of the European Geosciences Union},
  volume    = {7},
  journal   = {Climate of the past : an interactive open access journal of the European Geosciences Union},
  number    = {2},
  publisher = {Copernicus},
  address   = {G{\"o}ttingen},
  issn      = {1814-9324},
  doi       = {10.5194/cp-7-381-2011},
  pages     = {381 -- 396},
  year      = {2011},
  abstract  = {Using a new approach to force an ice sheet model, we performed an ensemble of simulations of the Greenland Ice Sheet evolution during the last two glacial cycles, with emphasis on the Eemian Interglacial. This ensemble was generated by perturbing four key parameters in the coupled regional climate-ice sheet model and by introducing additional uncertainty in the prescribed "background" climate change. The sensitivity of the surface melt model to climate change was determined to be the dominant driver of ice sheet instability, as reflected by simulated ice sheet loss during the Eemian Interglacial period. To eliminate unrealistic parameter combinations, constraints from present-day and paleo information were applied. The constraints include (i) the diagnosed present-day surface mass balance partition between surface melting and ice discharge at the margin, (ii) the modeled present-day elevation at GRIP; and (iii) the modeled elevation reduction at GRIP during the Eemian. Using these three constraints, a total of 360 simulations with 90 different model realizations were filtered down to 46 simulations and 20 model realizations considered valid. The paleo constraint eliminated more sensitive melt parameter values, in agreement with the surface mass balance partition assumption. The constrained simulations resulted in a range of Eemian ice loss of 0.4-4.4m sea level equivalent, with a more likely range of about 3.7-4.4m sea level if the GRIP delta O-18 isotope record can be considered an accurate proxy for the precipitation-weighted annual mean temperatures.},
  language  = {en}
}
@article{LevermannBamberDrijfhoutetal.2012,
  author    = {Levermann, Anders and Bamber, Jonathan L. and Drijfhout, Sybren and Ganopolski, Andrey and Haeberli, Winfried and Harris, Neil R. P. and Huss, Matthias and Krueger, Kirstin and Lenton, Timothy M. and Lindsay, Ronald W. and Notz, Dirk and Wadhams, Peter and Weber, Susanne},
  title     = {Potential climatic transitions with profound impact on Europe Review of the current state of six 'tipping elements of the climate system'},
  series = {Climatic change : an interdisciplinary, intern. journal devoted to the description, causes and implications of climatic change},
  volume    = {110},
  journal   = {Climatic change : an interdisciplinary, intern. journal devoted to the description, causes and implications of climatic change},
  number    = {3-4},
  publisher = {Springer},
  address   = {Dordrecht},
  issn      = {0165-0009},
  doi       = {10.1007/s10584-011-0126-5},
  pages     = {845 -- 878},
  year      = {2012},
  abstract  = {We discuss potential transitions of six climatic subsystems with large-scale impact on Europe, sometimes denoted as tipping elements. These are the ice sheets on Greenland and West Antarctica, the Atlantic thermohaline circulation, Arctic sea ice, Alpine glaciers and northern hemisphere stratospheric ozone. Each system is represented by co-authors actively publishing in the corresponding field. For each subsystem we summarize the mechanism of a potential transition in a warmer climate along with its impact on Europe and assess the likelihood for such a transition based on published scientific literature. As a summary, the 'tipping' potential for each system is provided as a function of global mean temperature increase which required some subjective interpretation of scientific facts by the authors and should be considered as a snapshot of our current understanding.},
  language  = {en}
}