New Method Relates Greenland Ice Sheet Changes to Sea Level Rise

Summary

Climate models are not yet able to include full ice sheet models of the Greenland and Antarctic ice sheets and dynamically simulate how ice sheet changes influence sea level. While these coupled ice sheet climate models are under development, simpler schemes relating melt rates to sea level have been developed. Early schemes failed to accurately capture the complications of accounting for both mass increase due to snow fall and mass loss due to snow melt. These have recently been found to depend on ice sheet elevation and ice sheet region. In the first of a pair of new studies developed jointly by several groups, including two U.S. Department of Energy-funded ice sheet groups, a new method was established that uses a detailed regional model of the Greenland ice sheet to include effects of elevation and region. In a second study, the team used the new scheme in five ice sheet models and forced them with climate warming conditions taken from two different climate models. The multimodel approach and multiforcing approach improve the ability to assess sea level rise uncertainty. Including the elevation effects in the model increases the estimated sea level rise by a small but significant amount (5% enhancement of melt by 2100 and 10% by 2200 for a climate warming scenario). By 2100, the choice of driving climate model conditions dominates the uncertainty, but by 2200 the uncertainty in the ice sheet model and the elevation scheme are larger. This study provides important results to guide the ongoing development of full, dynamic coupled ice sheet models.

References

Edwards, T. L., X. Fettweis, O. Gagliardini, F. Gillet-Chaulet, H. Goelzer, M. J. Hoffman, P. Huybrechts, A. J. Payne, M. Perego, S. F. Price, A. Quiquet, and C. Ritz. 2014a. “Probabilistic Parameterisation of the Surface Mass Balance—Elevation Feedback in Regional Climate Model Simulations of the Greenland Ice Sheet,” The Cryosphere 8, 181-94. DOI: 10.5194/tc-8-181-2014.

Edwards, T. L., X. Fettweis, O. Gagliardini, F. Gillet-Chaulet, H. Goelzer, M. J. Hoffman, P. Huybrechts, A. J. Payne, M. Perego, S. F. Price, A. Quiquet, and C. Ritz. 2014b. “Effect of Uncertainty in Surface Mass Balance—Elevation Feedback on Projections of the Future sea Level Contribution of the Greenland Ice Sheet,” The Cryosphere 8, 195-208. DOI: 10.5194/tc-8-195-2014.