Tuesday
Aug212012
by 
Bishop Hill
Bishop Hill Cloudless days
Aug 21, 2012 Climate: Sceptics Climate: Surface Climate: solar Anthony reports an interesting new paper, which finds that cloud cover has decreased slightly over the last 40 years. It's not clear to me what impact this will have on AGW detection and attribution studies, but no doubt this will all come out in the wash.
Reader Comments (14)
Great
Perhaps the author will send some of this 'less cloudiness' to the UK for the rest of our 'summer'. That will make up for the poor overall weather we've had so far.
Hi
a couple of papers that "might" put recent changes into a longer term context:
Gagen, M., et al.. Cloud response to summer temperatures in Fennoscandia over the last thousand years. Geophys. Res. Lett. 38, L05701, 2011.
http://people.su.se/~hgrud/documents/Gagen%20et%20al%202011.pdf
Young G. H. F., McCarroll D., Loader N. J., Gagen M., Kirchhefer A. J., and Demmler J. C. (2012) Changes in atmospheric circulation and the Arctic Oscillation preserved within a millennial length reconstruction of summer cloud cover from northern Fennoscandia. Clim Dynam, doi:10.1007/s00382-011-1246-3.
sorry - could not find a PDF link
Rob
Thanks Rob
It would be nice to see something quantifiable regarding cloud cover over the equator/tropics; Trenberth could have more missing heat than he could shake a (hockey|) stick at!
Trenbeth's missing heat is 0.9 W/m^2. The imaginary extra warming they invent in the models by claiming black body IR emission at the Earth's surface is at least 90 times this, and is offset by equally imaginary extra cooling by clouds compared with reality.
I do hear that all those who believe in these models still believe in the tooth fairy......
Don't mock the tooth fairy. The evidence is overwhelming, for if the entity that leaves the sixpence under the pillow is NOT the tooth fairy, we have no explanation of what it is. Therefore we're right.
Yes, I know there is no sixpence now, and that the tooth fairy suffers from inflation just like the rest of us. It's a quid now, but it will still get you one and a half Mars bars.
The paper, unfortunately, quantifies the wrong clouds. The big elephant in the woodpile is the trend in oceanic stratocumulus. 23% of the world is covered with this cloud (that's 30% of the oceans) and it has an albedo of around 70. Any reduction in that cloud (if it were 4% then something would have to be counteracting the warming because that's a hell of an energy input) will heat the oceans. And, as we know, sea temps drive land temps. See:
A 2008 study – “Oceanic Influences on Recent Continental Warming”, by Compo, G.P., and P.D. Sardeshmukh, (Climate Diagnostics Center, Cooperative Institute for Research in Environmental Sciences, University of Colorado, and Physical Sciences Division, Earth System Research Laboratory, National Oceanic and Atmospheric Administration), Climate Dynamics, 2008)
[http://www.cdc.noaa.gov/people/gilbert.p.compo/CompoSardeshmukh2007a.pdf] states: “Evidence is presented that the recent worldwide land warming has occurred largely in response to a worldwide warming of the oceans rather than as a direct response to increasing greenhouse gases (GHGs) over land. Atmospheric model simulations of the last half-century with prescribed observed ocean temperature changes, but without prescribed GHG changes, account for most of the land warming. … Several recent studies suggest that the observed SST variability may be misrepresented in the coupled models used in preparing the IPCC's Fourth Assessment Report, with substantial errors on interannual and decadal scales. There is a hint of an underestimation of simulated decadal SST variability even in the published IPCC Report.”
I've got an essay out with my take on what's disrupting low level cloud formation: when it comes back I think I'll try to get it on WUWT.
JF
According to the paper the cloud decrease averaged over all continents was 1.56%. However within that figure, the type that decreased was low level nimbostratus, exactly the kind of cloud that would cause cooling. Cumulonimbus increased.
http://www.halesowenweather.co.uk/cet_sunshine.htm
"Note the trend which suggests that annual sunshine has increased from about 1400 hours in 1929 to about 1500 hours in 2009"
Julian: 40% of that low level cloud over the oceans has 25% greater optical depth than predicted**. It's clouds with bimodal droplet size distributions. The cause is a second optical effect seen often in the past but not considered by IPCC science. There is no net AIE to hide the imaginary CO2-AGW, the omn;ly lifeline left for Hansenkoism..
rhoda forgot to add that computer models all support the existence of the tooth fairy and the overwhelming consennsus of qualified scientific opinion cannot be denied.
"rhoda forgot to add that computer models all support the existence of the tooth fairy and the overwhelming consennsus of qualified scientific opinion cannot be denied." --diogenes
Not only that, but the Koch Brothers have funded the anti-tooth-fairy movement.
Low level cloud density is likely to be closely involved in climate shifting towards something cooler starting around 2014 I think. Henrik Svensmark has been doing what I think is very convincing research on how a weaker heliosphere allows cosmic rays to catalyze that increase in low level cloud solar reflectivity. Some put more emphasis on UV changes of course. Some just look at known cycles and try to predict from recurring patterns like a 200 year solar magnetic output cycle or the like. The Astrophysics scientist Dr. Abdussamatov is warning us of a coming "Little Ice Age" so I'm very interested in what we will see in low level cloud changes from about the year 2000 and on through 2014 which he tentatively figures as the onset of the climate change. Of course it looks like the sun is still jam packed with mystery so tripping over at least one great big black swan can be expected along the way. I suppose a blind spot will be involved like suddenly finding that a solar quiet can bring super volcanoes into a reawakening or the like. Maybe it won't be "Little" Ice Age, and will set in suddenly when a magnetic reversal happens creating the initial conditions in a year or less, for a glaciation cycle to start. Maybe it will all work together as one synergistic cold climate launching system. We live in interesting times. I find it quite exciting that we might witness the beginning of a glaciation cycle. I hope someone preserves the science insights that could come out of it.
Readera are invited to run the numbers comparing an albedo downshift from ~ .60 ( clouds ) to ~.20( ground under cloudless skies integrated over 1.56 % of continental area with the radiative sum of all urban heat island effects .