Judith Curry is discussing a new paper by Stephens et al, published in Reviews of Geophysics. As one commenter below the thread put it, his "this is an important paper" alarm was triggered, and having read it myself I agree.
Here's the abstract:
The fraction of the incoming solar energy scattered by Earth back to space is referred to as the planetary albedo. This reflected energy is a fundamental component of the Earth’s energy balance, and the processes that govern its magnitude, distribution, and variability shape Earth’s climate and climate change. We review our understanding of Earth’s albedo as it has progressed to the current time and provide a global perspective of our understanding of the processes that define it. Joint analyses of surface solar flux data that are a complicated mix of measurements and model calculations with top-of-atmosphere (TOA) flux measurements from current orbiting satellites yield a number of surprising results including (i) the Northern and Southern Hemispheres (NH, SH) reflect the same amount of sunlight within ~ 0.2Wm2. This symmetry is achieved by increased reflection from SH clouds offsetting precisely the greater reflection from the NH land masses. (ii) The albedo of Earth appears to be highly buffered on hemispheric and global scales as highlighted by both the hemispheric symmetry and a remarkably small interannual variability of reflected solar flux (~0.2% of the annual mean flux). We show how clouds provide the necessary degrees of freedom to modulate the Earth’s albedo setting the hemispheric symmetry. We also show that current climate models lack this same degree of hemispheric symmetry and regulation by clouds. The relevance of this hemispheric symmetry to the heat transport across the equator is discussed.
The idea that the albedo is buffered in some way seems important to me and it goes without saying that the inability of climate models to reproduce the buffering represents a critical failing. Changes in albedo are supposed to be an important part of the enhanced greenhouse effect that is supposed to produce rapid warming but hasn't. To some extent therefore, it may be that albedo buffering is a factor in the models' ever-increasing divergence from reality.
Pielke Sr calls the paper a landmark. I don't think he's wrong.
The full paper is available here.