Cloud watchingRichard Treadgold | December 21, 2011
I am sent this snippet of correspondence that refers intriguingly to continuing research into the effect of clouds on the climate. No, I won’t say who’s speaking.
Your reference to clouds led me to the work of Prof Roger Davies, who holds the Buckley-Glavish chair in Climate Physics at Auckland U.
He is part of a global group triangulating cloud data from a dedicated satellite, and seems to be developing a view that clouds provide a natural thermostat function (which Richard Lindzen has previously speculated about).
This comes from a 2008 article “Watching the Clouds” in the science faculty magazine:
Over the past eight years of data, there has been little change in the clouds over much of the Earth. However two regions stand out as exceptions. Near the equator, where the high clouds that determine the greenhouse effect are especially numerous, the cloud cover has dropped in height, suggesting a lowering of their greenhouse effect, potentially to offset global warming.
In addition, the reflectivity of the Arctic has changed. In northern summer 2006, the reflectivity of the Arctic decreased significantly, due to less cloud cover and less ice in the area, both of which reflect sunlight. However, from the ground, only a moderate decrease in ice was seen compared to its normal summer melt. The following year, there was a significantly higher ice melt than predicted, despite the fact that satellite pictures were brighter than average, and much brighter than the previous summer, due to increased cloud.
But was the 2007 melt due to the darkness of 2006? Were the clouds of 2007 compensating for the low ice reflectivity to keep a balance? Right now, we don’t know enough to say.
Interesting, but Google shows up nothing recent. He generally seems to keep his head down.