Does the Last Glacial Maximum constrain climate sensitivity?
Article first published online: 19 SEP 2006
Copyright 2006 by the American Geophysical Union.
Geophysical Research Letters
Volume 33, Issue 18, September 2006
How to Cite
2006), Does the Last Glacial Maximum constrain climate sensitivity? Geophys. Res. Lett., 33, L18701, doi:10.1029/2006GL027137.(
- Issue published online: 19 SEP 2006
- Article first published online: 19 SEP 2006
- Manuscript Accepted: 10 AUG 2006
- Manuscript Revised: 30 JUN 2006
- Manuscript Received: 7 JUN 2006
 Four simulations with atmosphere-ocean climate models have been produced using identical Last Glacial Maximum ice sheets, topography and greenhouse gas concentrations. Compared to the pre-industrial, the diagnosed radiative feedback parameter ranges between −1.30 and −1.18 Wm−2K−1, the tropical ocean sea-surface temperature decreases between 1.7 and 2.7°C, and Antarctic surface air temperature decreases by 7 to 11°C. These values are all compatible with observational estimates, except for a tendency to underestimate the tropical ocean cooling. On the other hand, the same models have a climate sensitivity to CO2 concentration doubling ranging between 2.1 and 3.9 K. It is therefore inappropriate to simply scale an observational estimate of LGM temperature to predict climate sensitivity. This is mainly a consequence of the non-linear character of the cloud (mainly shortwave) feedback at low latitudes. Changes in albedo and cloud cover at mid and high latitudes are also important, but less so.