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.
Discover more from Watts Up With That?
Subscribe to get the latest posts sent to your email.
evanmjones:
You may be right that increased cloud cover cools the arctic surface making more ice, but that’s not what the blog said. If it were to make more ice, I would agree with you. Here is what the blog said:
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.
“So as sea ice declines, the researchers predict that the Arctic will become cloudier.”
Is this certain? Ice area has crossed the avg 1979 – 2008 line just the other day: Reference pages: Sea Ice; arctic Roos (Norwegian graph)
So decreasing sea ice leads to increased cloudiness, leads to higher albedo, leads to global cooling.
QED
George Tetley says:
“…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.”
Yes, and that was in 2007, when the Arctic “Death Spiral” was in full swing:
http://nsidc.org/news/press/2007_seaiceminimum/20071001_pressrelease.html
Actually, measurments by satellites in the Arctic show that a reduction of low cloud cover occured at tthe same time as the decrease in summer sea ice accelerated. Likely, this reduction in cloud cover is the main reason of the extra decrease in sea ice during the summer.
Louis Hooffstetter says:
March 30, 2012 at 12:23 pm
George Tetley says:
“…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.”
Yes, and that was in 2007, when the Arctic “Death Spiral” was in full swing:
Perhaps that’s why his vehicle fell through the ice and had to be towed out? He only made it to 78º36’N too, a good job he didn’t attempt 90ºN.
So what is the overall effect of clouds outside the Arctic?
PeterB in Indianapolis says:
March 30, 2012 at 9:39 am
==================================
kbray in california says:
March 30, 2012 at 8:16 am
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.
===============================================
And even more recent numbers show only 1.66% below Average.
This Arctic Sea Ice Area Mean indicator is 98.34% of Average mean.
(and it’s still cold up there.)
PeterB in Indianapolis says:
March 30, 2012 at 6:02 am
When are people like “anon” going to have even the most basic understanding of nature?
Nature ABHORS positive feedback loops
Can climate have a positive feedback mechanism?
This is one question that climate scientist have always avoided addressing. If there was a positive feedback mechanism no matter how tiny, then a higher level of CO2 in the past has to have resulted in temperatures rising to the high limit condition before falling again. Since we know this is not the case the dominant variables must have a negative feedback characteristic which either means CO2 is a trivial variable and irrelevant or that the models have been based on an abnormal period and are fundamentally unsound.
The have used hindcasting in deriving the models which is a no go for true professionals but having made that mistake they have not verified the resulting models at random intervals over all known period data. The matches outside the last fifty years are between poor an a disgrace.
I also fail to understand their obsession with linear trends when it is clear that almost all the major factors are cyclical and hence sinusoidal so the only meaningful analysts possible should be based on Fourier series.
Can anyone point me to any computer model that actually even attempts to model in detail the Co2 production and use in nature without which all the models are just garbage. There has first to be proof that CO2 cycle does not just stabilise at a variable level or cyclical pattern according to an unknown mechanism, even with a human input ten thousand times ours for the science to be even considered probably correct let alone proven.
Regular voyages were made through the NW Passage in 1906? No, ONE was *completed* in 1906. Roald Amundsen traversed the passage in a *three year* journey, finishing in 1906.
Since 2007 both the NE and NW passages have been open for extended periods and *now* regular voyages are made by ships, yachts, and all manner of vessels. Michael Smith has everything bass ackwards.
kbray in california says:
March 30, 2012 at 5:27 pm
You seem to be fixated on the current sea ice extent being close to normal, as if this portends a recovery.
This is not an indicator of what will happen at the low point in the summertime. If you look at the sea ice graph below, you cans see that the current extent is similar to 2010 at this time, but the 2010 minimum extent was 4th lowest in the summertime behind 2007, 2009 and 2011. Since there is very little multi year ice, a quick melt is likely based on recent data.
http://arctic-roos.org/observations/satellite-data/sea-ice/observation_images/ssmi1_ice_ext.png
PeterB in Indianapolis says:
March 30, 2012 at 6:02 am
“When are people like “anon” going to have even the most basic understanding of nature?
Nature ABHORS positive feedback loops
Can climate have a positive feedback mechanism?
This is one question that climate scientist have always avoided addressing. If there was a positive feedback mechanism no matter how tiny, then a higher level of CO2 in the past has to have resulted in temperatures rising to the high limit condition before falling again. Since we know this is not the case the dominant variables must have a negative feedback characteristic which either means CO2 is a trivial variable and irrelevant or that the models have been based on an abnormal period and are fundamentally unsound.”
This is wrong. A positive feedback mechanism multiplies the response resulting from the forcing factor by a constant factor, for a linear response. There is no extrinsic high limit condition involved. Your logic, facts, and definition of positive feedback are totally wrong.
Eric Adler says:
March 31, 2012 at 5:18 pm
I know Eric.
We will see where we are at the end of the season.
I anticipate an improvement in the minimums.
Time is all it takes.