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Post by steve on Aug 3, 2009 6:37:30 GMT
Over most of geological history, the evidence for a correlation between CO2 changes and temperature changes is quite good. The extremes of the ice age cycles cannot be explained by albedo changes alone. Why? If you claim multiple degrees effect for 4 watts of forcing at TOA how can you not allow 10 or 12 degrees for the some 100 watt difference you can get out of clouds? Calculations please! Misunderstanding here. Part of the "multiple degrees effect" for the 4 Watts of forcing is related to changes in clouds and water vapour. So the ice age cycles can be explained quite easily by a change in albedo due to more or less ice, increases and decreases in greenhouse gas forcing based on the levels of the gases as determined from the ice core, plus a sensitivity of at least 0.5C per watt of forcing. To get a 100W difference out of clouds you need them all to disappear. That's not likely to happen.
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Post by icefisher on Aug 3, 2009 13:39:41 GMT
Why? If you claim multiple degrees effect for 4 watts of forcing at TOA how can you not allow 10 or 12 degrees for the some 100 watt difference you can get out of clouds? Calculations please! Misunderstanding here. Part of the "multiple degrees effect" for the 4 Watts of forcing is related to changes in clouds and water vapour. So the ice age cycles can be explained quite easily by a change in albedo due to more or less ice, increases and decreases in greenhouse gas forcing based on the levels of the gases as determined from the ice core, plus a sensitivity of at least 0.5C per watt of forcing. To get a 100W difference out of clouds you need them all to disappear. That's not likely to happen. You are not thinking there Steve. I have read that cloud cover makes up to about 100 degree difference in solar irradiation hitting the planet. Since the planet is covered 65% by clouds on average, you would get no increase in some places and partial increase in others and the full increase in yet other places if all clouds disappeared. Likewise if the planet became covered by thick clouds you might be able to achieve a loss of solar irradiation to the surface of maybe 50 watts. Now I am just guessing here as I nor anybody else even has a cloud model that can tell us accurately what the wattage loss of cloud cover is on an average day today. We have satellites to tell us the albedo but all those ground and sea stations lack sensors telling us what irradiation is on average. The entire excuse for not modeling clouds is how hard it is to estimate what their variety of effects are on average, what causes them, and gee Steve. . . .lets just toss out the cloud model and assume zero for it all and inpute all that variability to minimum sensitivity levels. . . .gimme a break! Thats kind of like having a loose cannon on deck. . . .say an 8 pounder on the deck of an 8 foot dinghy. Bottom line Steve these modelers need to consider this or their models will be as seaworthy as that dinghy. What we are getting instead is political hype, demagoguery, and that little sensitivity figure where all uncertainty is alleged to reside. Your current reply attempts the same nonsense.
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Post by steve on Aug 3, 2009 14:05:27 GMT
Clouds don't change their nature to fit with your hopes.
In the past clouds and water vapour have (the evidence suggests) changed so as to add to causes of warming and cooling to make it even warmer or even cooler. The idea that they change randomly, and that they will go the other way now to cancel any warming is just an optimists fantasy.
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Post by nautonnier on Aug 3, 2009 18:00:03 GMT
Clouds don't change their nature to fit with your hopes. In the past clouds and water vapour have (the evidence suggests) changed so as to add to causes of warming and cooling to make it even warmer or even cooler. The idea that they change randomly, and that they will go the other way now to cancel any warming is just an optimists fantasy. I think that sticking with physics and the results of the ERBE project will do Steve. "In the near-equatorial convective Tropics over warm water, the net radiation at the top of these clouds varies from +123 to −16 W m−2, a range of more than 100 W m−2. The corresponding cloud net radiative forcings at the top of the atmosphere for these cloud types range from +20 to −119 W m−2. This great variation in net radiative effect arises mostly from the reflectivity of the clouds, which is primarily dependent on the water and/or ice content of the clouds."
"With these feedbacks incorporated, a simple model shows that the net radiation in convective regions approaches that in adjacent nonconvective regions almost independently of the mean cloud-top temperature assumed for the convective clouds. If the nonconvective regions with which the convection interacts have small cloud radiative forcing, then the cloud radiative forcing in the convective region must also be small. We have verified that the cloud radiative forcing in regions of suppressed convection in the deep Tropics is small even when the abundance of low clouds is substantial. These conclusions follow if the convective and nonconvective areas are nearly in equilibrium with each other. If the circulation is forced by significant ocean heat transport, as in the east Pacific, or by strong dynamical forcing associated with land–sea contrasts, as in the Bay of Bengal area, then the net cloud radiative forcing in the convective regions can be significantly negative (e.g., Fig. 1 ). The net radiative effect of tropical convective clouds is thus dependent on the nature of the large-scale circulation within which they are embedded, and may respond to circulation anomalies associated with El Niño, for example."Tropical Convection and the Energy Balance at the Top of the Atmosphere; Dennis L. Hartmann, Leslie A. Moy, and Qiang Fu; Journal of Climate Article: pp. 4495–4511 AMS Online So clouds are only weakly positive in areas where there are not significant drivers for convection and can be "significantly negative" in the convective regions to minus100Wm-2 ........... And may respond to circulation anomalies associated with El Niño, for example. What was it you said? "The idea that they change randomly, and that they will go the other way now to cancel any warming is just an optimists fantasy." Seems that you might just be wrong on that count Steve. I will be interested in the results when the models are corrected for the real observed results. This is not optimism or pessimism its called science.
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Post by stevenotsteve on Aug 3, 2009 18:39:59 GMT
I was on the beach yesterday. It was lovely and warm. Then a big CO2 cloud drifted over us. You could tell it was a CO2 cloud because it was black and carbon is black just like our pencils. The nasty CO2 cloud blocked out all of the Sun. We had to put our jumpers on. Mummy said, if we had waited, the cloud would have warmed us like toast but we had to go home for our dinner.
The end.
Hadley Centre for Climate Prediction and Research. Please distribute to all primary schools.
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Post by socold on Aug 3, 2009 20:29:41 GMT
Clouds don't change their nature to fit with your hopes. In the past clouds and water vapour have (the evidence suggests) changed so as to add to causes of warming and cooling to make it even warmer or even cooler. The idea that they change randomly, and that they will go the other way now to cancel any warming is just an optimists fantasy. I think that sticking with physics and the results of the ERBE project will do Steve. "In the near-equatorial convective Tropics over warm water, the net radiation at the top of these clouds varies from +123 to −16 W m−2, a range of more than 100 W m−2. The corresponding cloud net radiative forcings at the top of the atmosphere for these cloud types range from +20 to −119 W m−2. This great variation in net radiative effect arises mostly from the reflectivity of the clouds, which is primarily dependent on the water and/or ice content of the clouds."
"With these feedbacks incorporated, a simple model shows that the net radiation in convective regions approaches that in adjacent nonconvective regions almost independently of the mean cloud-top temperature assumed for the convective clouds. If the nonconvective regions with which the convection interacts have small cloud radiative forcing, then the cloud radiative forcing in the convective region must also be small. We have verified that the cloud radiative forcing in regions of suppressed convection in the deep Tropics is small even when the abundance of low clouds is substantial. These conclusions follow if the convective and nonconvective areas are nearly in equilibrium with each other. If the circulation is forced by significant ocean heat transport, as in the east Pacific, or by strong dynamical forcing associated with land–sea contrasts, as in the Bay of Bengal area, then the net cloud radiative forcing in the convective regions can be significantly negative (e.g., Fig. 1 ). The net radiative effect of tropical convective clouds is thus dependent on the nature of the large-scale circulation within which they are embedded, and may respond to circulation anomalies associated with El Niño, for example."Tropical Convection and the Energy Balance at the Top of the Atmosphere; Dennis L. Hartmann, Leslie A. Moy, and Qiang Fu; Journal of Climate Article: pp. 4495–4511 AMS Online So clouds are only weakly positive in areas where there are not significant drivers for convection and can be "significantly negative" in the convective regions to minus100Wm-2 ........... And may respond to circulation anomalies associated with El Niño, for example. What was it you said? "The idea that they change randomly, and that they will go the other way now to cancel any warming is just an optimists fantasy." Seems that you might just be wrong on that count Steve. I will be interested in the results when the models are corrected for the real observed results. This is not optimism or pessimism its called science. You are confusing local forcing with longterm forcing. If over 50 years for example there is on average less clouds causing -100W forcing for example, that will be additional energy in.
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Post by stevenotsteve on Aug 3, 2009 21:35:25 GMT
socold. If over 50 years for example there is on average less clouds causing -100W forcing for example, that will be additional energy in.
Just think about what you are saying socold. Clouds can cause 100W differential. Sun creates clouds but sun only creates 4w because we only include TSI in our flawed climate models. Lets just add in that extra 96W and forget about that silly CO2.
Whoops, sorry, I forgot about the black CO2 clouds that block out the sun.
You make me smile socold, you only see what you want to see but you really do believe it don't you,
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Post by nautonnier on Aug 3, 2009 22:30:25 GMT
I think that sticking with physics and the results of the ERBE project will do Steve. "In the near-equatorial convective Tropics over warm water, the net radiation at the top of these clouds varies from +123 to −16 W m−2, a range of more than 100 W m−2. The corresponding cloud net radiative forcings at the top of the atmosphere for these cloud types range from +20 to −119 W m−2. This great variation in net radiative effect arises mostly from the reflectivity of the clouds, which is primarily dependent on the water and/or ice content of the clouds."
"With these feedbacks incorporated, a simple model shows that the net radiation in convective regions approaches that in adjacent nonconvective regions almost independently of the mean cloud-top temperature assumed for the convective clouds. If the nonconvective regions with which the convection interacts have small cloud radiative forcing, then the cloud radiative forcing in the convective region must also be small. We have verified that the cloud radiative forcing in regions of suppressed convection in the deep Tropics is small even when the abundance of low clouds is substantial. These conclusions follow if the convective and nonconvective areas are nearly in equilibrium with each other. If the circulation is forced by significant ocean heat transport, as in the east Pacific, or by strong dynamical forcing associated with land–sea contrasts, as in the Bay of Bengal area, then the net cloud radiative forcing in the convective regions can be significantly negative (e.g., Fig. 1 ). The net radiative effect of tropical convective clouds is thus dependent on the nature of the large-scale circulation within which they are embedded, and may respond to circulation anomalies associated with El Niño, for example."Tropical Convection and the Energy Balance at the Top of the Atmosphere; Dennis L. Hartmann, Leslie A. Moy, and Qiang Fu; Journal of Climate Article: pp. 4495–4511 AMS Online So clouds are only weakly positive in areas where there are not significant drivers for convection and can be "significantly negative" in the convective regions to minus100Wm-2 ........... And may respond to circulation anomalies associated with El Niño, for example. What was it you said? "The idea that they change randomly, and that they will go the other way now to cancel any warming is just an optimists fantasy." Seems that you might just be wrong on that count Steve. I will be interested in the results when the models are corrected for the real observed results. This is not optimism or pessimism its called science. You are confusing local forcing with longterm forcing. If over 50 years for example there is on average less clouds causing -100W forcing for example, that will be additional energy in. "If over 50 years for example there is on average less clouds causing -100W forcing for example, that will be additional energy in."I do like your untestable hypotheses. I was not confusing things - Steve was claiming that clouds did not "change" to meet Icefisher's hopes. I pointed out that peer reviewed studies using ERBE showed that clouds actually DID change dependent on the surface temperature. So if it gets hotter the albedo effect will be (to use your metric) equivalent to a strong negative forcing. There is no time limit on these physical processes they will recur each time the surface is hot and humid. I know that you don't WANT to believe empirical studies and would rather believe models of unfalsifiable hypotheses, but the real observations are available now and appear to be unaware of your AGW script.
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Post by steve on Aug 4, 2009 7:48:28 GMT
Nautonnier, you're missing the point a bit. Evidence from past climates suggests that the climate response to warming or cooling is to enhance the warming or cooling.
Now if the LW and SW forcing of tropical clouds tend to balance out in the short term changes in weather, that is interesting. But it's also probably what they've always done even when the overall response of clouds, water vapour and maybe other things has been to enhance the effects of a warming or cooling influence.
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Post by nautonnier on Aug 4, 2009 8:30:12 GMT
Nautonnier, you're missing the point a bit. Evidence from past climates suggests that the climate response to warming or cooling is to enhance the warming or cooling. Now if the LW and SW forcing of tropical clouds tend to balance out in the short term changes in weather, that is interesting. But it's also probably what they've always done even when the overall response of clouds, water vapour and maybe other things has been to enhance the effects of a warming or cooling influence. "Evidence from past climates suggests that the climate response to warming or cooling is to enhance the warming or cooling. "You will have this evidence to cite? As the overall effect so far appears to have been toward negative feedback to higher surface temperatures - which is what the paper stated.
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Post by robertski on Aug 4, 2009 8:34:23 GMT
Nautonnier, you're missing the point a bit. Evidence from past climates suggests that the climate response to warming or cooling is to enhance the warming or cooling. Now if the LW and SW forcing of tropical clouds tend to balance out in the short term changes in weather, that is interesting. But it's also probably what they've always done even when the overall response of clouds, water vapour and maybe other things has been to enhance the effects of a warming or cooling influence. A simple question then, based on your statement. What caused did the last Ice Age End? What caused the LIA and why did it end? Your above statement appears flawed. Explain please.
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Post by radiant on Aug 4, 2009 10:46:17 GMT
Nautonnier, you're missing the point a bit. Evidence from past climates suggests that the climate response to warming or cooling is to enhance the warming or cooling. I think what you mean is that you believe C02 causes substantial warming therefore if the atmosphere warms and then releases C02 from the oceans it must result in more warming. It is an unproven theory which has the difficulty that when it is hottest and C02 is at the most there are times when it gets colder with no change in c02 for thousands of years. You are a believer. You have faith. Those who do not have faith are deniers in your eyes and mind. You may as well burn us at the stake for not being believers.
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Post by icefisher on Aug 4, 2009 12:57:20 GMT
Clouds don't change their nature to fit with your hopes. In the past clouds and water vapour have (the evidence suggests) changed so as to add to causes of warming and cooling to make it even warmer or even cooler. The idea that they change randomly, and that they will go the other way now to cancel any warming is just an optimists fantasy. LOL! I haven't suggested anywhere that clouds are going to change randomly to fulfill my hopes. But I am not so stupid as to build a model that pretends to know they are not going to change. this is the biggest driver in the climate and its stupid to build a model on a weaker source, exaggerate its share, and suggest no change with the more powerful source. You claim that "evidence suggests" they are going to change in some limited way without understanding what drives clouds. Thats complete garbage in, garbage out Steve. Thats like trying to drive a curvy highway with a blindfold on and provides a handy explanation of why the models are off the road already!! Its not me claiming random misfortune for having my car in the road drainage ditch. The answer of course is you haven't yet learned to drive.
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Post by icefisher on Aug 4, 2009 13:09:43 GMT
You are confusing local forcing with longterm forcing. If over 50 years for example there is on average less clouds causing -100W forcing for example, that will be additional energy in. Incorrect Socold. You are confusing "modeled" longterm forcing that does not include any local forcing anywhere with the real world that has local forcing everywhere.
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Post by steve on Aug 4, 2009 13:27:29 GMT
Nautonnier, you're missing the point a bit. Evidence from past climates suggests that the climate response to warming or cooling is to enhance the warming or cooling. Now if the LW and SW forcing of tropical clouds tend to balance out in the short term changes in weather, that is interesting. But it's also probably what they've always done even when the overall response of clouds, water vapour and maybe other things has been to enhance the effects of a warming or cooling influence. A simple question then, based on your statement. What caused did the last Ice Age End? What caused the LIA and why did it end? Your above statement appears flawed. Explain please. Well technically we're in an interglacial period within the current ice age But the simplified explanation would be that slight changes in the orbit started to cause the large ice cap to melt a bit. The reduction in size of the ice cap changed the albedo and allowed more sunlight to be absorbed. This caused further melting and further warming. The warming of the oceans slowly resulted in CO2 being released from the oceans causing further warming, further melting and more solar absorption etc. On top of this positive feedbacks in the atmospheric processes enhanced the warming. Positive feedbacks are required because the changes in solar absorption from albedo changes and the warming effect of more greenhouse gases is just not enough to explain the temperature difference between the peak of the ice age and now. When enough ice has melted the albedo effect of melting more ice stopped being important. And the oceans eventually reached an equilibrium. So eventually these causes of warming went away.
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