Many of you will remember our pioneering discussion of the Sheep-albedo hypothesis, where we suggested that increasing numbers of sheep would cause a cooling climate because of their impact on the ground reflectivity. Well, new observations have now added significantly more complexity to this seemingly understood situation. It has just been reported that as well as the original sheep-albedo effect, there is now evidence of a second sheep-albedo effect (smaller sheep as the world warms). That would be a amplifying effect in general, but the actual population of sheep concerned come in many colours, so the overall affect is uncertain. (There is even speculation about a third effect (the sheep lifetime albedo impact), which could go either way depending the Lamb Marketing Board advertising campaign).
Yet more evidence that the science is very woolly.
*Title taken from a comment from glen