Posted on 10/14/2010 3:19:26 PM PDT by decimon
NEW YORK -- Water vapor and clouds are the major contributors to Earth's greenhouse effect, but a new atmosphere-ocean climate modeling study shows that the planet's temperature ultimately depends on the atmospheric level of carbon dioxide.
The study, conducted by Andrew Lacis and colleagues at NASA's Goddard Institute for Space Studies (GISS) in New York, examined the nature of Earth's greenhouse effect and clarified the role that greenhouse gases and clouds play in absorbing outgoing infrared radiation. Notably, the team identified non-condensing greenhouse gases -- such as carbon dioxide, methane, nitrous oxide, ozone, and chlorofluorocarbons -- as providing the core support for the terrestrial greenhouse effect.
Without non-condensing greenhouse gases, water vapor and clouds would be unable to provide the feedback mechanisms that amplify the greenhouse effect. The study's results will be published Friday, Oct. 15 in Science.
A companion study led by GISS co-author Gavin Schmidt that has been accepted for publication in the Journal of Geophysical Research shows that carbon dioxide accounts for about 20 percent of the greenhouse effect, water vapor and clouds together account for 75 percent, and minor gases and aerosols make up the remaining five percent. However, it is the 25 percent non-condensing greenhouse gas component, which includes carbon dioxide, that is the key factor in sustaining Earth's greenhouse effect. By this accounting, carbon dioxide is responsible for 80 percent of the radiative forcing that sustains the Earth's greenhouse effect.
The climate forcing experiment described in Science was simple in design and concept -- all of the non-condensing greenhouse gases and aerosols were zeroed out, and the global climate model was run forward in time to see what would happen to the greenhouse effect.
Without the sustaining support by the non-condensing greenhouse gases, Earth's greenhouse effect collapsed as water vapor quickly precipitated from the atmosphere, plunging the model Earth into an icebound state -- a clear demonstration that water vapor, although contributing 50 percent of the total greenhouse warming, acts as a feedback process, and as such, cannot by itself uphold the Earth's greenhouse effect.
"Our climate modeling simulation should be viewed as an experiment in atmospheric physics, illustrating a cause and effect problem which allowed us to gain a better understanding of the working mechanics of Earth's greenhouse effect, and enabled us to demonstrate the direct relationship that exists between rising atmospheric carbon dioxide and rising global temperature," Lacis said.
The study ties in to the geologic record in which carbon dioxide levels have oscillated between approximately 180 parts per million during ice ages, and about 280 parts per million during warmer interglacial periods. To provide perspective to the nearly 1 C (1.8 F) increase in global temperature over the past century, it is estimated that the global mean temperature difference between the extremes of the ice age and interglacial periods is only about 5 C (9 F).
"When carbon dioxide increases, more water vapor returns to the atmosphere. This is what helped to melt the glaciers that once covered New York City," said co-author David Rind, of NASA's Goddard Institute for Space Studies. "Today we are in uncharted territory as carbon dioxide approaches 390 parts per million in what has been referred to as the 'superinterglacial.'"
"The bottom line is that atmospheric carbon dioxide acts as a thermostat in regulating the temperature of Earth," Lacis said. "The Intergovernmental Panel on Climate Change has fully documented the fact that industrial activity is responsible for the rapidly increasing levels of atmospheric carbon dioxide and other greenhouse gases. It is not surprising then that global warming can be linked directly to the observed increase in atmospheric carbon dioxide and to human industrial activity in general."
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Written by: Kathryn Hansen NASA's Earth Science News Team
http://www.nasa.gov/topics/earth/features/co2-temperature.html
from: Science Daily
As the sun has matured over the past 4.5 billion years, it has become both brighter and hotter, increasing the amount of solar radiation received by Earth, along with surface temperatures. Earth has coped by reducing the amount of carbon dioxide in the atmosphere, thus reducing the warming effect. (Despite current concerns about rising carbon dioxide levels triggering detrimental climate change, the pressure of carbon dioxide in the atmosphere has dropped some 2,000-fold over the past 3.5 billion years; modern, man-made increases in atmospheric carbon dioxide offset a fraction of this overall decrease.)
I would also add to this that the hypothesis of CO2 forced warming has some major flaws that seem to flout the laws of thermodynamics. First, in order to increase the temperature, the Earth system energy must be somehow increasing over and above what it receives from the sun. Second, the "trapping" of infrared by CO2 is a transient event, on the order of nanoseconds, IIRC. That's just not enough to cause a long, slow increase in temperature--or even a short, rapid increase. Nor is the trapping directional--CO2 absorbs IR coming from any direction and re-emits it in all directions, making the net effect null anyway.
Wait just a darned minute here! I thought this “fact” was already settled science? Why then are we now hearing about a study that shows what was already known?
Note to all:
Earth once had an atmospheric CO2 level some 10 times present levels.
Temperatures were mild.
Where did all the CO2 go? Well, some of it became limestone. South Florida has about 14,000 feet of limerock beneath it.
Results of modelling?
Bah! Humbug!
ping GW
No Smoking Hot Spot (The Australian)
That article takes Greenhouse Theory at face value and by the criterion set up in the theory itself finds no evidence of warming on the basis of greenhouse effect.
The Hidden Flaw in Greenhouse Theory
Falsification Of The Atmospheric CO2 Greenhouse Effects Within The Frame Of Physics
Harvard astrophysicist dismisses AGW theory, challenges peers to 'take back climate science'
It Is Impossible For A 100 ppm Increase In Atmospheric CO2 Concentration To Cause Global Warming
Those four articles each show that Greenhouse Theory has no basis in reality due to a direct conflict with the known laws of physics. No wonder the smoking gun "hotspot" can't be found.
Claim That Sea Level Is Rising Is a Total Fraud
That article pretty much puts the kibosh on any serious trend of planetary warming from any cause. Think about it. If there is absolutely no sign at all of rising sea levels how could the planet be warming? Beyond the centuries long slow warming of the earth and rising of the seas of course. But that is only a few millimeters per century due to the inter-glacial period we are in.
Tha fits with the fact that co2 is heavier than air.
This is an unscientific pantload.
Water vapor is king - period. NOx would be next. Nitrogen makes up more of a percentage of the atmosphere than CO2.
Considering some of the modell ‘scientists’, perhaps the following might be more accurate: Bah! Humbuggery!
Nothing new — he’s a global warming demagogue, and has been for a long while. Thanks decimon.
In case I’ve misled, James Hansen is not mentioned in the article.
You are right. Meant eats C02. In their eyes
This is a screwup.
Him too.
Dear NASA, try reducing the water vapor amount by 30 % in your models. Keep the non-condensing gases at their same current levels. Then rerun your model. Guess what you idiots discovered ? Simply the amount of green house gas concentration loss (condensing or non-condensing) that will cause an ice age.
What gets me is CO2 is at a near record low. If CO2 drops down to 200 ppm plants stop growing and we die. Typically the earth CO2 level is around 3000 ppm.
We are in an ice age plants in the Ocean and land don't do very well in cold weather (less water and sun light.) they are nearly suffocating from the lack of CO2 right now. As they die CO2 drops.
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