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Post by steve on Aug 4, 2009 13:29:21 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. Oh please stop being so precious
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Post by radiant on Aug 4, 2009 14:09:55 GMT
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. Oh please stop being so precious Sounds like a confirmation that my theory about what you believe has been proven to be correct? I have no way of knowing of course. ;D
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Post by socold on Aug 4, 2009 18:57:27 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. "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. The study does not show the conclusion you claim it does.
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Post by socold on Aug 4, 2009 19:27:53 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. I think he's talking about the climate system as a whole amplifying any warming irregardless of the specific feedbacks doing that. One piece of evidence from past climate he is probably thinking of is the ~6C variations in global temperature between glacial and interglacial periods. That's a lot of warming and the best explaination in my opinion is that an overall positive feedback in the climate system helped achieve it through amplification. Consider the convese case that the climate acts to dampen warming rather than amplify it so that you get just 0.1C warming per 1wm-2 forcing. If that were the case then the interglacial warmings of 6C would require a staggering 60wm-2 extra energy into the Earth system. That's equivalent to around a 20% increase in solar output. We are talking about a seemingly unfeasible amount of additional power required to warm the Earth up 6C if climate feedback is strongly negative. But if the theory behind the climate models is correct then climate sensitivity is higher at about 0.75C per 1wm-2, and therefore a 6C warming only requires about a 8wm-2 forcing, which is far more feasible.
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wylie
Level 3 Rank
Posts: 129
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Post by wylie on Aug 4, 2009 20:57:04 GMT
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. I think he's talking about the climate system as a whole amplifying any warming irregardless of the specific feedbacks doing that. One piece of evidence from past climate he is probably thinking of is the ~6C variations in global temperature between glacial and interglacial periods. That's a lot of warming and the best explaination in my opinion is that an overall positive feedback in the climate system helped achieve it through amplification. Consider the convese case that the climate acts to dampen warming rather than amplify it so that you get just 0.1C warming per 1wm-2 forcing. If that were the case then the interglacial warmings of 6C would require a staggering 60wm-2 extra energy into the Earth system. That's equivalent to around a 20% increase in solar output. We are talking about a seemingly unfeasible amount of additional power required to warm the Earth up 6C if climate feedback is strongly negative. But if the theory behind the climate models is correct then climate sensitivity is higher at about 0.75C per 1wm-2, and therefore a 6C warming only requires about a 8wm-2 forcing, which is far more feasible. Socold, As is usual, I like your posts even though I almost always disagree with you. When I don't like them, I don't say anything. However, in this post, I was wondering whether or not you felt that the sensitivity to any particular forcing should always be the same? For example, let say we consider the forcing of a cdrop in TSI and compare it to the "darkening of the sky" from a volcanic dust cloud? Are we at all certain that the atmosphere MUST respond the same to the two forcings even though they might have the same "theoretical forcing magnitude"? Isn't our understanding of the climate still so primitive that we cannot say with any certainty whether or not the climate sensitivity responds similarly to different forcings? (even of the same magnitude) On a related topic to the subject of this thread, I was wondering if you would be bold enough to state what set of real circumstances in the real climate would convince you that the AGW as theorized to be caused by CO2 is either not valid or not significant? How about 20 years of declining temperatures and declining ocean heat content in the face of monotonically increasing CO2? Clearly, the strong (and not so strong) arguments of the many voices on this thread arguing with you and trying to persuade you otherwise have not seemed to change your mind. What would?? None of the above statements questions are at all rhetorical or sarcastic. They are all honest attempts at communication. I hope that I have convinced you of this even-handedness in the past, but I wanted you to know for certain again. Ian
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Post by socold on Aug 4, 2009 21:17:32 GMT
As is usual, I like your posts even though I almost always disagree with you. When I don't like them, I don't say anything. However, in this post, I was wondering whether or not you felt that the sensitivity to any particular forcing should always be the same? It won't be exactly the same because as you mention different types of forcing produce different reactions. The concept is a simplification in order to make comparisons, but like most concepts it's rough around the edges. That would do it. They influence what I think, they make me doubt AGW more but on a scale my opinion is still on the side of it being likely, just not certain.
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Post by poitsplace on Aug 4, 2009 23:11:40 GMT
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. I think he's talking about the climate system as a whole amplifying any warming irregardless of the specific feedbacks doing that. One piece of evidence from past climate he is probably thinking of is the ~6C variations in global temperature between glacial and interglacial periods. That's a lot of warming and the best explaination in my opinion is that an overall positive feedback in the climate system helped achieve it through amplification. Consider the convese case that the climate acts to dampen warming rather than amplify it so that you get just 0.1C warming per 1wm-2 forcing. If that were the case then the interglacial warmings of 6C would require a staggering 60wm-2 extra energy into the Earth system. That's equivalent to around a 20% increase in solar output. We are talking about a seemingly unfeasible amount of additional power required to warm the Earth up 6C if climate feedback is strongly negative. But if the theory behind the climate models is correct then climate sensitivity is higher at about 0.75C per 1wm-2, and therefore a 6C warming only requires about a 8wm-2 forcing, which is far more feasible. It has been pointed out many times in the past, currently the climate operates between two quasistable nodes. The temperature range between those nodes actually has powerful feedback. During the plateaus of the glacial periods, however the cooling feedbacks become weak to negative. Likewise during the plateaus of the interglacials the feedbacks again become weak to negative. Probably the most powerful feedback causing this is ice albedo. Right now though, its highly likely that ice albedo has gone neutral. In the winter the ice prevents the escape of ocean heat. During the summer, already limited sunlight and a higher water albedo (because of the angles) reflect some sunlight but nothing like the amounts suggested by simple surface area. Both of these also stop a second, incredibly powerful, negative feedback...the water cycle. Because it sort of recycles its own energy, the energy driving (or at least bound up in) the water cycle is currently more powerful than any other feedback or even forcing. This is really the only explanation that makes any sense given the data. The earth simply refuses to go into full snowball or melt modes in its current configuration.
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Post by steve on Aug 5, 2009 8:17:43 GMT
I think he's talking about the climate system as a whole amplifying any warming irregardless of the specific feedbacks doing that. One piece of evidence from past climate he is probably thinking of is the ~6C variations in global temperature between glacial and interglacial periods. That's a lot of warming and the best explaination in my opinion is that an overall positive feedback in the climate system helped achieve it through amplification. Consider the convese case that the climate acts to dampen warming rather than amplify it so that you get just 0.1C warming per 1wm-2 forcing. If that were the case then the interglacial warmings of 6C would require a staggering 60wm-2 extra energy into the Earth system. That's equivalent to around a 20% increase in solar output. We are talking about a seemingly unfeasible amount of additional power required to warm the Earth up 6C if climate feedback is strongly negative. But if the theory behind the climate models is correct then climate sensitivity is higher at about 0.75C per 1wm-2, and therefore a 6C warming only requires about a 8wm-2 forcing, which is far more feasible. It has been pointed out many times in the past, currently the climate operates between two quasistable nodes. The temperature range between those nodes actually has powerful feedback. During the plateaus of the glacial periods, however the cooling feedbacks become weak to negative. Likewise during the plateaus of the interglacials the feedbacks again become weak to negative. Probably the most powerful feedback causing this is ice albedo. Right now though, its highly likely that ice albedo has gone neutral. In the winter the ice prevents the escape of ocean heat. During the summer, already limited sunlight and a higher water albedo (because of the angles) reflect some sunlight but nothing like the amounts suggested by simple surface area. Both of these also stop a second, incredibly powerful, negative feedback...the water cycle. Because it sort of recycles its own energy, the energy driving (or at least bound up in) the water cycle is currently more powerful than any other feedback or even forcing. This is really the only explanation that makes any sense given the data. The earth simply refuses to go into full snowball or melt modes in its current configuration. You make the earth sound like a software package! Version 9.2, branded as the "Holocene" has fewer crashes into ice age and less overheating due to better modulation of the water coolant systems. Possibly the continued existence of the arctic and antarctic ice is helped by the configuration of land. As I was stating, while albedo feedback *was* important in the ice age cycles, it *was not* sufficient to explain the extremities of the cycles. We know there is a "configuration of earth roughly similar to our own when temperatures were a degree or two higher than now (the Eemian) and when CO2 levels were lower than now. So it is not a given that the latest "earth release" has solved all the instability problems of previous releases.
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Post by radiant on Aug 5, 2009 8:47:08 GMT
It has been pointed out many times in the past, currently the climate operates between two quasistable nodes. The temperature range between those nodes actually has powerful feedback. During the plateaus of the glacial periods, however the cooling feedbacks become weak to negative. Likewise during the plateaus of the interglacials the feedbacks again become weak to negative. Probably the most powerful feedback causing this is ice albedo. Right now though, its highly likely that ice albedo has gone neutral. In the winter the ice prevents the escape of ocean heat. During the summer, already limited sunlight and a higher water albedo (because of the angles) reflect some sunlight but nothing like the amounts suggested by simple surface area. Both of these also stop a second, incredibly powerful, negative feedback...the water cycle. Because it sort of recycles its own energy, the energy driving (or at least bound up in) the water cycle is currently more powerful than any other feedback or even forcing. This is really the only explanation that makes any sense given the data. The earth simply refuses to go into full snowball or melt modes in its current configuration. You make the earth sound like a software package! Version 9.2, branded as the "Holocene" has fewer crashes into ice age and less overheating due to better modulation of the water coolant systems. Possibly the continued existence of the arctic and antarctic ice is helped by the configuration of land. As I was stating, while albedo feedback *was* important in the ice age cycles, it *was not* sufficient to explain the extremities of the cycles. We know there is a "configuration of earth roughly similar to our own when temperatures were a degree or two higher than now (the Eemian) and when CO2 levels were lower than now. So it is not a given that the latest "earth release" has solved all the instability problems of previous releases. The Bering strait is very shallow. If you look at the ice going thru the Nares strait you can easily see that it is being enlarged by that ice flow. Small configuration changes to the land could easily create warming. 30 years of Arctic ice data tells us next to nothing if it is true that in 1944 a small boat could travel from Halifax to Vancouver in one season via the northern most route of the North West passage when generally only the southern route is possible. However i note it is 19 degrees on Victoria island between the two routes in the last day so who knows what will happen But maybe we can conclude that the ice only melted in 1944 because of the man made warming created by the immense amount of stuff exploded in ww2!
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Post by sigurdur on Aug 5, 2009 11:47:16 GMT
Radiant: You have it in a nutshell. The norhtern route was sailed in 1944. Would that be possible this year?
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Post by steve on Aug 5, 2009 17:27:13 GMT
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Post by radiant on Aug 5, 2009 17:56:58 GMT
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Post by steve on Aug 6, 2009 6:25:00 GMT
Ice conditions vary from place to place. The point is that while the NW passage was passable in 1944, evidence suggests that in the same year the Beaufort and Chuckchi seas had significant amounts of ice in late September whereas for the past 12 years they look like they offer clear passage.
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Post by robertski on Aug 6, 2009 7:40:58 GMT
Ice conditions vary from place to place. The point is that while the NW passage was passable in 1944, evidence suggests that in the same year the Beaufort and Chuckchi seas had significant amounts of ice in late September whereas for the past 12 years they look like they offer clear passage. And of course in 1944 they had no help from Radar and satlites to help the crossing, with Modern shipping nowadays, you would expect it to make the crossing easier.
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Post by radiant on Aug 6, 2009 8:31:34 GMT
Ice conditions vary from place to place. The point is that while the NW passage was passable in 1944, evidence suggests that in the same year the Beaufort and Chuckchi seas had significant amounts of ice in late September whereas for the past 12 years they look like they offer clear passage. Fair enuf. I misunderstood what you were saying. Perhaps todays winds have more westerly component and 1944 had more easterly. Surface winds seem to play a big part in ice formation and removal to warmer water in these areas. Personally i am inclined to believe in a very chaotic system that cannot be modelled or predicted in short time spans of a few hundred years. You mentioned the ARGO ocean bouys in response to my observation about total heat content being relevant - a system only being built from 2000 and in place from 2007 which is regarded as a surface measurement dispite the significant depths used - presumably because the sea is so immensely deep. solarcycle24com.proboards.com/index.cgi?board=globalwarming&action=display&thread=659&page=20#26151I think we know very little so far. And i have myself got a bit angry that i seem to have been mislead by sensationalist reporting. For example a few days ago an article in the UK mail described an advancing Iceland glacier as evidence of global warming. Back in 2000 UK newspapers and CNN reported the same retreating glacier as evidence of global warming. Iceland tells us these glaciers have been advancing for the last 300 years! We are also told that media reporting that science believed in global cooling in the 1970's was inaccurate and that belief i recall was mainsteam when i was at college and yet i have film evidence of a climate scientist cringing with anger and embarassment at being caught by a book he wrote in the 1970s describing what amounted to the consensus of global cooling. www.greenenergyinvestors.com/index.php?s=&showtopic=7252&view=findpost&p=118831As ever science is about personalities and opinions. It is the way it always has been.
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