Posted on 11/05/2007 2:15:02 PM PST by blam
Cirrus Disappearance: Warming Might Thin Heat-trapping Clouds
ScienceDaily (Nov. 5, 2007) — The widely accepted (albeit unproven) theory that manmade global warming will accelerate itself by creating more heat-trapping clouds is challenged this month in new research from The University of Alabama in Huntsville.
Cirrus clouds. (Credit: NOAA Central Library, Photo by Albert E. Theberge Junior)
Instead of creating more clouds, individual tropical warming cycles that served as proxies for global warming saw a decrease in the coverage of heat-trapping cirrus clouds, says Dr. Roy Spencer, a principal research scientist in UAHuntsville's Earth System Science Center.
That was not what he expected to find.
"All leading climate models forecast that as the atmosphere warms there should be an increase in high altitude cirrus clouds, which would amplify any warming caused by manmade greenhouse gases," he said. "That amplification is a positive feedback. What we found in month-to-month fluctuations of the tropical climate system was a strongly negative feedback. As the tropical atmosphere warms, cirrus clouds decrease. That allows more infrared heat to escape from the atmosphere to outer space."
"While low clouds have a predominantly cooling effect due to their shading of sunlight, most cirrus clouds have a net warming effect on the Earth," Spencer said. With high altitude ice clouds their infrared heat trapping exceeds their solar shading effect.
In the tropics most cirrus-type clouds flow out of the upper reaches of thunderstorm clouds. As the Earth's surface warms - due to either manmade greenhouse gases or natural fluctuations in the climate system - more water evaporates from the surface. Since more evaporation leads to more precipitation, most climate researchers expected increased cirrus cloudiness to follow warming.
"To give an idea of how strong this enhanced cooling mechanism is, if it was operating on global warming, it would reduce estimates of future warming by over 75 percent," Spencer said. "The big question that no one can answer right now is whether this enhanced cooling mechanism applies to global warming."
The only way to see how these new findings impact global warming forecasts is to include them in computerized climate models.
"The role of clouds in global warming is widely agreed to be pretty uncertain," Spencer said. "Right now, all climate models predict that clouds will amplify warming. I'm betting that if the climate models' 'clouds' were made to behave the way we see these clouds behave in nature, it would substantially reduce the amount of climate change the models predict for the coming decades."
The UAHuntsville research team used 30- to 60-day tropical temperature fluctuations - known as "intraseasonal oscillations" - as proxies for global warming.
"Fifteen years ago, when we first started monitoring global temperatures with satellites, we noticed these big temperature fluctuations in the tropics," Spencer said. "What amounts to a decade of global warming routinely occurs in just a few weeks in the tropical atmosphere. Then, as if by flipping a switch, the rapid warming is replaced by strong cooling. It now looks like the change in cirrus cloud coverage is the major reason for this switch from warming to cooling."
The team analyzed six years of data from four instruments aboard three NASA and NOAA satellites. The researchers tracked precipitation amounts, air and sea surface temperatures, high and low altitude cloud cover, reflected sunlight, and infrared energy escaping out to space.
When they tracked the daily evolution of a composite of fifteen of the strongest intraseasonal oscillations they found that although rainfall and air temperatures would be rising, the amount of infrared energy being trapped by the cloudy areas would start to decrease rapidly as the air warmed. This unexpected behavior was traced to the decrease in cirrus cloud cover.
The new results raise questions about some current theories regarding precipitation, clouds and the efficiency with which weather systems convert water vapor into rainfall. These are significant issues in the global warming debate.
"Global warming theory says warming will generally be accompanied by more rainfall," Spencer said. "Everyone just assumed that more rainfall means more high altitude clouds. That would be your first guess and, since we didn't have any data to suggest otherwise ..."
There are significant gaps in the scientific understanding of precipitation systems and their interactions with the climate, he said. "At least 80 percent of the Earth's natural greenhouse effect is due to water vapor and clouds, and those are largely under the control of precipitation systems.
"Until we understand how precipitation systems change with warming, I don't believe we can know how much of our current warming is manmade. Without that knowledge, we can't predict future climate change with any degree of certainty."
Spencer and his colleagues expect these new findings to be controversial.
"I know some climate modelers will say that these results are interesting but that they probably don't apply to long-term global warming," he said. "But this represents a fundamental natural cooling process in the atmosphere. Let's see if climate models can get this part right before we rely on their long term projections."
The results of this research were published recently in the American Geophysical Union's "Geophysical Research Letters" on-line edition. The paper was co-authored by UAHuntsville's Dr. John R. Christy and Dr. W. Danny Braswell, and Dr. Justin Hnilo of Lawrence Livermore National Laboratory, Livermore, CA.
Adapted from materials provided by University Of Alabama In Huntsville.
For your ping list.
Could it be that the earth has mechanisms that maintain a relative temperature equilibrium? Even when the Krakatoa volcano exploded in the 19th century the earth was not cast into a permanent nuclear winter, though global temperatures drops were significant, it all worked out in about a year.
PING - Climate Science rebutting the fearmongering.
Looks like this data is supportive of Lindzen’s “Iris” theory, that cloud feedback would not be positive, but somewhat negative.
“To give an idea of how strong this enhanced cooling mechanism is, if it was operating on global warming, it would reduce estimates of future warming by over 75 percent,” Spencer said. “The big question that no one can answer right now is whether this enhanced cooling mechanism applies to global warming.”
“The role of clouds in global warming is widely agreed to be pretty uncertain,” Spencer said. “Right now, all climate models predict that clouds will amplify warming. I’m betting that if the climate models’ ‘clouds’ were made to behave the way we see these clouds behave in nature, it would substantially reduce the amount of climate change the models predict for the coming decade.”
“Could it be that the earth has mechanisms that maintain a relative temperature equilibrium? “
Any impulse or forcing moves us to a new equilibrium.
The AGW hypers are saying that new equilibrium could be as much as 3-5C for a doubling of CO2.
This data suggests that change would be about 1/4 the size.
I thought they already disappeared!.........
"Predict" in this context means "assume." IOW, the modelers appear to have assumed incorrectly on this factor.
Important New Paper On Cloud-Precipitation Interactions by Roy Spencer and colleagues
and before Roger Pielke Sr closed his great blog (and discussion forum) Roy Spencer also wrote these two articles:
Positive Feedback: Have We Been Fooling Ourselves? by Roy Spencer
Part 2: Feedbacks, the Infrared Iris, and the Role of Precipitation Processes by Roy Spencer
You know what? I think the science is far from settled.....and furthermore the changes are pointing away from Al Gore and the climate alarmists.
Both Sides, Now
lyrics / Joni Mitchell
Rows and floes of angel hair
And ice cream castles in the air
And feather canyons ev’rywhere
I’ve looked at clouds that way
But now they only block the sun
They rain and snow on ev’ryone
So many things I would have done
But clouds got in my way
I’ve looked at clouds from both sides now
From up and down, and still somehow
It’s cloud illusions I recall
I really don’t know clouds at all
Moons and Junes and Ferris wheels
The dizzy dancing way you feel
As ev’ry fairy tale comes real
I’ve looked at love that way
But now it’s just another show
You leave ‘em laughing when you go
And if you care, don’t let them know
Don’t give yourself away
I’ve looked at love from both sides now
From give and take, and still somehow
It’s love’s illusions I recall
I really don’t know love at all
Tears and fears and feeling proud
To say ‘I love you’ right out loud
Dreams and schemes and circus crowds
I’ve looked at life that way
But now old friends are acting strange
They shake their heads, they say I’ve changed
Well something’s lost, but something’s gained
In living ev’ry day
I’ve looked at life from both sides now
From win and lose and still somehow
It’s life’s illusions I recall
I really don’t know life at all
I’ve looked at life from both sides now
From up and down, and still somehow
It’s life’s illusions I recall
I really don’t know life at all
Oh! I have slipped the surly bonds of Earth
And danced the skies on laughter-silvered wings;
Sunward I’ve climbed, and joined the tumbling mirth
Of sun-split clouds, — and done a hundred things
You have not dreamed of — wheeled and soared and swung
High in the sunlit silence. Hov’ring there,
I’ve chased the shouting wind along, and flung
My eager craft through footless halls of air. . . .
Up, up the long, delirious burning blue
I’ve topped the wind-swept heights with easy grace
Where never lark, or ever eagle flew —
And, while with silent, lifting mind I’ve trod
The high untrespassed sanctity of space,
Put out my hand, and touched the face of God.
None too soon! Certainly the MOPAR factor has not been included in the Global Thermodynamic models. Perhaps, we have underestimated the Belvedere effect in the overall outlook on warming in northern Illinois. I believe it to be Cirrus and Hugh.
AGW™ ping
It was all those Dodge Dart slant sixes that did them in..............
MOre ‘outliers ‘ and ‘flat earthers’ who doubt Saint Al the Alknowing Goreacle. The debate is OVER!! When will these pesky scientists stop letting their ‘research’ get in the way of the global scientific consensus?
All leading climate models forecast that as the atmosphere warms there should be an increase in high altitude cirrus clouds, which would amplify any warming caused by manmade greenhouse gases," he said. "That amplification is a positive feedback. What we found in month-to-month fluctuations of the tropical climate system was a strongly negative feedback.
This just proves that man-made global warming is a fact.
Global warming is the greatest, most rock-solid theory in the history of science.
It doesn’t matter what the results are, even if the result is the exact opposite of the prediction, the result proves the theory. Seriously, no other theory in the history of science has every been able to do that.
If you're skeptical about the science that goes into that, your skepticism only proves the theory and makes you a lunatic at the same time.
God knew what He was doing. He promised us an Earth that would support us until such time as He sets things right and He keeps His promises.
LOL!
Just a hunch, but I don’t think Al Gore is going to like this article.
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