From the AGU weekly highlights
Composite image. Data from MODIS. Credit: National Snow and Ice Data Center.
Key Points:
- EFA method is valuable in providing quantitative assessment of feedback
- Decrease in sea ice leads to increase in cloud
- Further decline in sea ice will likely result in cloudier Arctic
Arctic sea ice has been declining over the past several decades as global climate has warmed. In fact, sea ice has declined more quickly than many models predicted, indicating that climate models may not be correctly representing some processes controlling sea ice.
One source of uncertainty in models is feedback from cloud cover. Sea ice can affect cloud cover, as melting sea ice and increased evaporation from the ocean surface can lead to more cloud formation. In the Arctic, clouds have an overall warming effect on the surface, so greater cloudiness in this region could lead to even more sea-ice melt.
Liu et al. analyzed satellite observations of cloud cover and sea ice from 2000 to 2010 to evaluate feedbacks between sea ice and cloud cover. They find that a 1 percent decrease in sea ice concentration leads to a 0.36–0.47 percent increase in cloud cover, and that 22–34 percent of variance in cloud cover can be explained by changes in sea ice. So as sea ice declines, the researchers predict that the Arctic will become cloudier.
Geophysical Research Letters, doi:10.1029/2012GL051251, 2012 A cloudier Arctic expected with diminishing sea ice
- Yinghui Liu
- Cooperative Institute for Meteorological Satellite Studies, University of Wisconsin-Madison, Madison, Wisconsin, USA;
- Jeffrey R. Key
- Center for Satellite Applications and Research, NESDIS, NOAA, Madison, Wisconsin, USA;
- Zhengyu Liu
- Department of Atmospheric and Oceanic Sciences, University of Wisconsin-Madison, Madison, Wisconsin, USA, and Center for Climate Research, University of Wisconsin-Madison, Madison, Wisconsin, USA;
- Xuanji Wang
- Cooperative Institute for Meteorological Satellite Studies, University of Wisconsin-Madison, Madison, Wisconsin, USA;
- Stephen J. Vavrus
- Center for Climate Research, University of Wisconsin-Madison, Madison, Wisconsin, USA.
Ian H,
Let me add another “angle” to your point. Scattered clouds won’t block a high percentage of the radiative loss in the winter/night, but they reflect a larger percentage of the incoming sunlight because of the low angle. This difference could be huge if the clouds have significant height. Looking straight up through them, they’d be all gaps, but at a low angle, you couldn’t see through them at all.
These two effects could happen simultaneously. The sunlight from only slightly above the horizon can’t get through, while the sky straight up is almost clear.
That said, the next step is to look at the derivative of this phenomenon as a function of the marginal cloud density. As we go from no clouds to a few clouds, I’d expect the clouds to cool things. But as the density starts to get high, this effect diminishes.
Maybe the original article went into this, instead of just spouting general platitudes. I wonder.
Andres Valencia says:
March 29, 2012 at 6:52 pm
That’s according to HADCRUT3 that passed away without a successor on March 11, 2012.
I know what you mean. However it is back again now with the newer numbers and January’s anomaly of 0.218. February’s anomaly has been out for a couple of days now but has not been posted on their site yet so it cannot be used with woodfortrees. The February number is about 0.19 as can be inferred from
http://www.climate4you.com/GlobalTemperatures.htm#HadCRUT3%20TempDiagram
http://www.sciencedaily.com/releases/2001/06/010615071248.htm
Dr Essenhigh has already covered this.
JF
A couple of things.
Essenhigh’s hypothesis involves the proposition that moisture available for precipitation in the arctic comes from the arctic ocean. I wonder if that’s true?
A lot of the discussion on the GRL paper revolves around, or assumes, the sign of the effect of clouds on arctic temperatrures. There is some good stuff on the effect of angle if incicence on this balance but I’m wondering what the radiative temperature of an arctic icepack is?
Dave of Commonsense says:
March 29, 2012 at 5:44 pm
“These guys should be fired immediately for trying to pass this garbage off as science.
A quick check of current Arctic Ice Extent shows we are a mere 2.67% below Average compared to the 30 year average on this date. a tiny 0.381 below a nearly 13.8 Million seasonal high mark.”
It is well possible that they are right, and that the big decline in sea ice during 2007 was partially caused by this effect. Obviously we are already back on the way to more sea ice so something has overwhelmed that positive feedback.
A system with positive feedbacks develops a hysteresis, so that the opposing influence must first become strong enough to overwhelm that positive feedback to be able to effect a change. Of course, this leads, once the overwhelming happens, to a rapid state toggle. similar to the “ipping point” rethoric of the warmists but like flipping something on and off; not switching from warm to very warm.
In other words, I expect ongoing rapid cooling. 2007 was the flip.
Err 1958 USS Skate, did not seem foggy in the photos.
Clouds are insulators. They keep cold cold and hot hot in the regions below them, but if you are in them they are freezing cold.
The paper seems simplistic, but it does get me musing about clouds in the arctic.
Clouds require evaporation, and it seems little of the moisture can be “home grown,” because everything is frozen solid up there, right now. Even with the midnight sun just peeking over the horizon at the pole, temperatures remain down around thirty below. (See the DMI “mean temperature above 80 degrees” map on the WUWT “Sea Ice Reference Page.”) Temperatures will not poke slightly above freezing until after May 1, and will dip back below freezing as the sun sinks low around September 1. Therefore most of the year there are no puddles, and little evaporation.
Right now, even with the sun up, when a lead of open water forms it almost immediately skims over with ice. There is only a brief time when the water “smokes.”
Therefore most of the moisture in the clouds up there, during most of the year, is not “home grown,” but rather is “imported” from the south.
Therefore the amount of clouds seems to depend on whether you have a positive AO or a negative AO. In the first case the arctic vortex stays tight and cold air is held up in the arctic, and in the second case the jet stream loops south and arctic outbreaks charge far to the south, which allows a sort of back-slosh of warmer air to head north to replace the cold air. For example, this past winter, when the hounds of winter howled south over Europe, Asia and Alaska, warm air was sucked north over eastern Canada. It is only when this warm air heads north that you get much moisture for clouds, during the winter.
Oddly, when the warm air pokes up into the arctic, you are likely to get more ice, rather than less. The warm air feeds storms, and rather than an arctic calm you get howling winds. The wind shoves the ice about, piling up pressure ridges and opening wide leads which swiftly freeze over. Where calm allows the ice to act as insulation between the 28 degree F water and the minus-40 degree F air, wind exposes the water to the air, allowing more ice to form. Also more heat is released to make clouds, but also to vanish up into outer space.
As I began by saying, the subject is not simple. However it is fascinating, and fun to ponder upon.
For those whose minds are covered by a cloudy day, . . .
How does the title “Negative Feedback” coincide with the articles content of warmer arctics? Isn’t that positive feedback? More melt leads to more clouds leads to warmth and more melt?
Or is negative used in the form of “Unwanted?”
Be informed: More melt leads to more clouds leads to less warming and less melt.
It’s the albedo. Low-level clouds reflect away far more heat than they trap.
If they are right, we would see much more cloud in summer when the ice is melting than in winter.
Is there any evidence of this?
Wait a minute, right now global sea ice is only about 0.1 million square kilometers below normal (summing the northern and southern hemisphere anomalies), and this is, statistically, normal and above what we have seen in recent years. How can they claim that the decline in global sea ice is more rapid than predicted? Did the models predict it would be above normal??? That’s the only way I can see that the current conditions could possibly be “worse than we thought”.
Also, slightly off topic for this thread, but has anyone ever studied the influence of nearby volcanoes on the CO2 monitor at Mauna Loa that everyone cites as “THE global CO2 monitor”??
As far as I know, for most of the last 26 years, Kilauea has been erupting almost non-stop. Kilauea is pretty close to Mauna Loa, and I would think that a constantly erupting volcano in the vicinity of a CO2 monitor might skew the results higher for some reason….
When are people like “anon” going to have even the most basic understanding of nature?
Nature ABHORS positive feedback loops (think of your ears’ reaction to feedback from a microphone/amplifier, your ears don’t like that at all, now do they?). Positive feedback loops in nature would cause natural systems to spiral out of control, thus eventually causing the natural system in question to self-destruct. We have had over 4 billion years of climate change on Earth, and the system has yet to self-destruct, in spite of extreme changes in the system from time to time. Natural systems can be chaotic, and entropy will EVENTUALLY win, but natural systems also tend to be cyclical in nature due to the presence of natural dampeners (negative feedbacks) which keep the system in a rough balance.
Keep up the hoax.
Sea ice is as healthy as can be.
If memory serves, back in the 1970s, when the coming ice age was all the rage, one of the alleged causes would be the melting of the arctic ice. The hypothesis went something like this:
1) Melting iarctic ice exposed more Arctic Ocean surface water to evaportation
2) Evaporation of Arctic waters produced more clouds which drifted out over surrounding the land masses
3) These clouds produced snow in large quantities
4) This abundant snow would not have sufficient time or temperature to melt before the next winter/snow season arrived
5) Years of accumulating snow would produce glaciers and ice sheets reflecting sunlight/heat into space and–voila!–an Ice Age!
Perhaps Time magazine and Newsweek can recycle their old cover stories.
Frederick Michael says:
March 29, 2012 at 9:34 pm
That effect would also happen if cloud cover is complete, but the clouds themselves are thin.
When looking straight up, there is little water vapor to interfere with the radiation of heat. However because sunlight is coming in at a low angle, the visible light must pass through an effectively, much thicker cloud layer to reach the surface.
Let me add to that; FLIR (literally translated: “Forward Looking Infra-Red”, as opposed to the original/early belly-scanning downward-looking IR aircraft ‘cameras’) operating in the 8~12um range can see through light overcast … personal observation while aboard company’s Convair 580 flight test bed flying over US-75 in a cloud deck on an equipment checkout-run equipped with an IR pod (we were doing checkout of a nose-mounted Ku band ‘targeting’ RADAR) … looking out the windows at (where) the highway (should be) the traffic could not be seen, looking at the colorized FLIR imagery screen and viola! .. could see the traffic … what this confirms is that ‘light overcast’ is not 100% blocking of LWIR, a fair amount still transmits/transits through said lt ovrcst.
.
In the Arctic, clouds have an overall warming effect on the surface.
Might be, but how gut is the evidence for this? And is there a warming effect in summer as well, and how is the seasonal feedback of clouds in the Arctic? How is the seasonal distribution in cloud increase in Arctic?
DirkH says:
March 30, 2012 at 2:03 am
A quick check of current Arctic Ice Extent shows we are a mere 2.67% below Average compared to the 30 year average on this date. a tiny 0.381 below a nearly 13.8 Million seasonal high mark.”
==============================================
And the ratio continues to move closer to the mean.
Fresh numbers now are only 2.41% below Average.
I think we need color coding for the Earth’s clouds. I would suggest “red for clouds that warm” and “blue for clouds that cool”. I need a research grant on how to move the red clouds and/or the blue clouds to the appropriate areas. This would solve the global warming/cooling problem. If you don’t give me a grant, I will find a reason why the clouds are moving the wrong way; thereby, in 20 to 10,000 years will definitely cause weather issues. Of course my reason will be supported by data from 100,000 years ago to the present.
Give me a grant or I will promote industries that move the red/blue clouds in the “wrong directions.” Do what I say or a dire future will engulf the Earth in violent warming/cooling events; proving my hypothesis.
/sarc
Paul Homewood,
At Thule Airbase, fog only occurs in Summer when Northstar Bay is open water.
No. Clouds don’t warm or cool the Arctic in significant ways. Naturally occurring oscillations in oceanic current temperatures and the atmospheric Arctic Oscillation do. In the winter, a warmer cold is still freezing cold. So we can ignore that season. In every season, the warmed or colder current coming into the Arctic was prepped by ENSO factors elsewhere prior to its delivery of said water temperatures at the Arctic’s front and back door. And the melt season is highly correlated to the Arctic Oscillation conditions present at the time. Measuring clouds over the Arctic is like the proverbial search for the stink in a room occupied by an elephant.
It’s the elephant stupid.
In reply to DirkH and kbray, if you look at sea ice globally, for example on the WUWT sea ice reference page, the sum of the northern and southern hemisphere sea ice anomalies is now slightly positive, meaning that globally sea ice is basically right at normal (just a tick above, but statistically right at normal).
Am I the only one not impressed that only 22-34% of the variance in cloud cover is accounted for by changes in sea ice? Call me back when they get up to 85-95%.
Top Gears Jeremy Clarkson is the only man that could testify as to the Arctic ice conditions, after all he drove his Toyota Hilux to the North Pole and back
@Andreas V. re: March 29, 2012 at 6:42
When they talk about the decline in the Arctic Sea Ice, they could be referring to this graph
http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/seaice.anomaly.arctic.png
which indicates that in 1979 the ice level was averaging about .75M SQ K above the 1979-2008 mean and has declined (more rapidly from around 1996) to averaging 1M SQ K below the mean and hasn’t topped the mean line since 2003 (the last 10 years)