Climate feedbacks under a very broad range of forcing
Article first published online: 3 JAN 2009
Copyright 2009 by the American Geophysical Union.
Geophysical Research Letters
Volume 36, Issue 1, January 2009
How to Cite
2009), Climate feedbacks under a very broad range of forcing, Geophys. Res. Lett., 36, L01702, doi:10.1029/2008GL036268., and (
- Issue published online: 3 JAN 2009
- Article first published online: 3 JAN 2009
- Manuscript Accepted: 2 DEC 2008
- Manuscript Revised: 13 NOV 2008
- Manuscript Received: 7 OCT 2008
- climate feedbacks
 An atmospheric general circulation model, coupled to a mixed layer ocean, is subjected to a broad range of forcing away from the current climate between 1/16 to 32 times current CO2 in halving/doubling steps. As climate warms climate sensitivity weakens (although not monotonically), albedo feedback weakens (driving much of the sensitivity weakening), water vapour feedback strengthens (at a rate slightly larger than it would if relative humidity remained unchanged), and lapse rate feedback increases (negatively); this latter change essentially offsetting the water vapour increases. Longwave cloud feedbacks are relatively stable (moderate and positive) across the full range; shortwave cloud feedback remains relatively weak, apart from under the coldest climates. Cloud optical property related components (from total water content, water/ice fraction and cloud thickness) remain remarkably stable. Cloud ‘amount’ feedbacks show the greatest trends: weakening as temperatures increase. Although cloud feedbacks show an overall consistency of features in different latitudes, precise patterns of changes differ substantially for different baseline climates.