The linked reference, with an open access pdf, indicates that more work is need before models can provide reliable projections of the rate of Tibetan permafrost degradation:
Wang, W., Rinke, A., Moore, J. C., Cui, X., Ji, D., Li, Q., Zhang, N., Wang, C., Zhang, S., Lawrence, D. M., McGuire, A. D., Zhang, W., Delire, C., Koven, C., Saito, K., MacDougall, A., Burke, E., and Decharme, B.: Diagnostic and model dependent uncertainty of simulated Tibetan permafrost area, The Cryosphere Discuss., 9, 1769-1810, doi:10.5194/tcd-9-1769-2015, 2015.
http://www.the-cryosphere-discuss.net/9/1769/2015/tcd-9-1769-2015.html