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Post by steve on Jan 5, 2010 10:06:16 GMT
Nautonnier, The temptation to build a strawman when there is so much straw around is too strong. You "was only pointing out" what is clearly there in the description of radiative forcing. The concept of radiative forcing is an aid to comparing agents. The impact is assessed in a separate set of experiments. Why is that so hard to understand? And we seem to have gone back around the loop with Magellan's comment. So I'm still waiting for a reason as to why use of a slightly crap analogy matters. Should we stop buying electrical goods till we all understand the details of how a transistor works? "The concept of radiative forcing is an aid to comparing agents. The impact is assessed in a separate set of experiments. Why is that so hard to understand?"I fully understand what it is - I don't believe many of the 'users' of the radiative forcing coefficients understand though. They use the radiative forcing in watts per square metre *** from the slab 'green house' atmosphere as if it WAS the way the atmosphere works - plugging those values into the various radiation formulae as if they were universal constants even though you will agree they are 'just comparative constructs in an unreal hypothetical atmosphere'. No they don't. There are a number of levels to the discussion. Off top of head: 1a) What is the radiative forcing of each agent? This is derived from the radiation calculations. 1b) What is the equilibrium sensitivity of the atmosphere (How much would it eventually warm per unit of radiative forcing)? This is estimated from a number of sources. In particular on how the climate has reacted in the past. 2a) What is the so-called "global warming potential" of an agent? This tries to take into account the fact that, for example, while methane is a stronger "greenhouse gas", it tends to be removed from the atmosphere on timescales of a decade or so, so emission of a tonne of methane won't warm the atmosphere for as long, and therefore as much as a tonne of CO2. 2b) How will emissions change over time? 3) How does the climate react to impacts (big volcanoes, El Niños etc.) 4) On what timescales will the warming occur? This can be estimated with models that are based on the points 1-3 above. 5) What will the other feedbacks be (eg. drying out Amazon, melting sea ice, releasing methane from permafrosts). These are researched with more detailed models that take some assumptions from point 4. Each person takes what they need from this. If you are planning big infrastructure changes over 20-30 years, then you are interested in 4. If you are debating which gases you want to try and restrict, you look at 1 and 2. If you are a government who is arguably supposed to look after the long term health of your country, you look at 4 and 5. But if you want to undermine the debate, you pick on one aspect and pretend that noone ever thinks of all the others, and they've probably got that aspect a bit wrong anyway.
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Post by icefisher on Jan 5, 2010 10:34:17 GMT
No they don't. There are a number of levels to the discussion. Off top of head: 1a) What is the radiative forcing of each agent? This is derived from the radiation calculations. 1b) What is the equilibrium sensitivity of the atmosphere (How much would it eventually warm per unit of radiative forcing)? This is estimated from a number of sources. In particular on how the climate has reacted in the past. 2a) What is the so-called "global warming potential" of an agent? This tries to take into account the fact that, for example, while methane is a stronger "greenhouse gas", it tends to be removed from the atmosphere on timescales of a decade or so, so emission of a tonne of methane won't warm the atmosphere for as long, and therefore as much as a tonne of CO2. 2b) How will emissions change over time? 3) How does the climate react to impacts (big volcanoes, El Niños etc.) 4) On what timescales will the warming occur? This can be estimated with models that are based on the points 1-3 above. 5) What will the other feedbacks be (eg. drying out Amazon, melting sea ice, releasing methane from permafrosts). These are researched with more detailed models that take some assumptions from point 4. Each person takes what they need from this. And team member Dr Kevin Trenberth pointed out that it was a travesty that they could not explain the above in the context of the real world. Its not a matter of undermining the debate its a matter that the debate has not found answers to the above. Its obvious here is an interesting article of just how far off this system of predicting climate is: icecap.us/images/uploads/A_CHILLY_DECEMBER_AT_THE_700_MB_LEVEL.pdfAnd of course the rediscovery of the hockey stick
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Post by steve on Jan 5, 2010 12:10:21 GMT
I don't think I've ever seen a more irrelevant post.
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Post by sigurdur on Jan 5, 2010 12:18:48 GMT
I don't think I've ever seen a more irrelevant post. Yes and no Steve. We all know that the NH is experiencing rapid cooling. What started in North America last spring/summer seems to have spread around the world. The only hot spot left is a small part of the Southern Hemisphere and that is shrinking as well. It would seem that the 1st decade of the 21st century is going to go out with a breath of cold air. Everything is pointing in that direction as it will be very difficult to overcome the cold temps of the 1st 2-3 months.
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Post by steve on Jan 5, 2010 12:32:23 GMT
And north Africa, the Middle East, Northern canada and Alaska, the former soviet states to the south of Russia, Greenland, Indonesia and the Phillipines.
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Post by sigurdur on Jan 5, 2010 12:54:56 GMT
And north Africa, the Middle East, Northern canada and Alaska, the former soviet states to the south of Russia, Greenland, Indonesia and the Phillipines. I don't know about North Africa/ME. But I do know that Northern Canada and Alaska are certainly not hot. I am sure the folks in Yellowknife would welcome some of that heat tho.
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Post by hunter on Jan 5, 2010 13:20:28 GMT
One of the tricks the AGW community uses is to pretend that .Xo changes in temperature is evidence of dangerous anything. Another is the confusion of weather and climate. The examples of the former- we are dealing with daily. The examples of the latter we see every time an AGW promoter claims that a particular weather event is 'consistent with AGW'. Yet when skeptics properly point out that a weather event is not consistent with AGW, we are entertained with true believers asserting that 'weather is not climate'. Climate manifests as weather. There is no such thing as climate apart from weather. Claiming, as the Manniacs did last year, that Antarctica was 'heating up' based on a small region's warming that occurred decades ago, when in fact it is not, is a great example of hte former. Steve's dismissal of the Coal Creek data is a great example of the latter. Some of the ways AGW theory is falsified is by use of unreliable data. Another is its non-falsifiable nature. Another is the confusion of CO2 physics with the theory of AGW. AGW is not about CO2. It is about dramatic positive feedbacks. Another falsification of AGW theory is failed predictions.
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Post by nautonnier on Jan 5, 2010 13:42:59 GMT
"The concept of radiative forcing is an aid to comparing agents. The impact is assessed in a separate set of experiments. Why is that so hard to understand?"I fully understand what it is - I don't believe many of the 'users' of the radiative forcing coefficients understand though. They use the radiative forcing in watts per square metre *** from the slab 'green house' atmosphere as if it WAS the way the atmosphere works - plugging those values into the various radiation formulae as if they were universal constants even though you will agree they are 'just comparative constructs in an unreal hypothetical atmosphere'. No they don't. There are a number of levels to the discussion. Off top of head: 1a) What is the radiative forcing of each agent? This is derived from the radiation calculations. 1b) What is the equilibrium sensitivity of the atmosphere (How much would it eventually warm per unit of radiative forcing)? This is estimated from a number of sources. In particular on how the climate has reacted in the past. 2a) What is the so-called "global warming potential" of an agent? This tries to take into account the fact that, for example, while methane is a stronger "greenhouse gas", it tends to be removed from the atmosphere on timescales of a decade or so, so emission of a tonne of methane won't warm the atmosphere for as long, and therefore as much as a tonne of CO2. 2b) How will emissions change over time? 3) How does the climate react to impacts (big volcanoes, El Niños etc.) 4) On what timescales will the warming occur? This can be estimated with models that are based on the points 1-3 above. 5) What will the other feedbacks be (eg. drying out Amazon, melting sea ice, releasing methane from permafrosts). These are researched with more detailed models that take some assumptions from point 4. Each person takes what they need from this. If you are planning big infrastructure changes over 20-30 years, then you are interested in 4. If you are debating which gases you want to try and restrict, you look at 1 and 2. If you are a government who is arguably supposed to look after the long term health of your country, you look at 4 and 5. But if you want to undermine the debate, you pick on one aspect and pretend that noone ever thinks of all the others, and they've probably got that aspect a bit wrong anyway. I said: " I fully understand what it is - I don't believe many of the 'users' of the radiative forcing coefficients understand though. They use the radiative forcing in watts per square metre *** from the slab 'green house' atmosphere as if it WAS the way the atmosphere works - plugging those values into the various radiation formulae as if they were universal constants even though you will agree they are 'just comparative constructs in an unreal hypothetical atmosphere'." To which your response Steve was: "No they don't. There are a number of levels to the discussion. Off top of head:"And the VERY FIRST STEP you provide - on which all the others are based: "1a) What is the radiative forcing of each agent? This is derived from the radiation calculations."This is precisely my point - the radiative forcing of the agent is about as useful as comparing the braking capabilities of cars from the amount of pressure different drivers can apply to the brake pedal - without any regard to car weight, tyre wear, tyre treads, the road surface, facing up or downhill, in reverse, ABS etc etc. Certainly you can use the brake pedal pressure from each driver to compare their capabilities in pressing the brake pedal - but there are many other variables that all immediately come into play in braking action of cars. Not wishing to stretch that analogy - the atmosphere is a complex turbulent fluid - its activity is driven largely by the heat from the surface much of which is ocean and the ocean activity and surface temperatures are driven by the activity and cloudiness of the atmosphere a chaotic interactive system. You forget all that and freeze it - and magically double the amount of a GHG and look _solely_ at the radiation effects of that doubling. But you CANNOT get to a pure doubling in reality as the slightest change to the chaotic atmosphere and ocean activity causes unpredictable non-linear changes in the entire coupled system. Yet in step 1a "1a) What is the radiative forcing of each agent? This is derived from the radiation calculations."To quote Jim Cripwell - you are not testing your hypothesis on 'radiative forcing' to see what ACTUALLY happens as you increase GHG in the atmosphere - no validation tests. You have a magic meaningless coefficient that you plug in instead - then use parameters to try to make the models using the coefficient look like the real world. Any inaccuracy is put down to some other unmeasured variable like aerosols rather than admitting that perhaps the radiative forcing coefficient, the model or the parameters are incorrect.
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Post by steve on Jan 5, 2010 16:30:12 GMT
No this is a misunderstanding on your part. I was not dogmatically stating you must do step 1 then 2 then 3 then 4, I was listing some of the ways you could analyse and discuss the subject. That should have been clear from the last couple of paragraphs.
The models calculate radiative transfer on a level by level basis using the radiative transfer equations I mention. This should probably mean that if you instantaneously doubled CO2 in a model, the model will immediately reduce outgoing longwave radiation by 3.7W/m^2, but that is only because it is repeating the radiative calculations that were done to calculate forcing in the first place. But as time goes on, the model will adjust to the new "forcing" as it runs its weather calculations. A good model will include the "complex turbulent fluid - ...[whose] activity is driven largely by the heat from the surface much of which is ocean and the ocean activity and surface temperatures are driven by the activity and cloudiness of the atmosphere a chaotic interactive system."
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Post by magellan on Jan 5, 2010 17:36:05 GMT
No they don't. There are a number of levels to the discussion. Off top of head: 1a) What is the radiative forcing of each agent? This is derived from the radiation calculations. 1b) What is the equilibrium sensitivity of the atmosphere (How much would it eventually warm per unit of radiative forcing)? This is estimated from a number of sources. In particular on how the climate has reacted in the past. 2a) What is the so-called "global warming potential" of an agent? This tries to take into account the fact that, for example, while methane is a stronger "greenhouse gas", it tends to be removed from the atmosphere on timescales of a decade or so, so emission of a tonne of methane won't warm the atmosphere for as long, and therefore as much as a tonne of CO2. 2b) How will emissions change over time? 3) How does the climate react to impacts (big volcanoes, El Niños etc.) 4) On what timescales will the warming occur? This can be estimated with models that are based on the points 1-3 above. 5) What will the other feedbacks be (eg. drying out Amazon, melting sea ice, releasing methane from permafrosts). These are researched with more detailed models that take some assumptions from point 4. Each person takes what they need from this. If you are planning big infrastructure changes over 20-30 years, then you are interested in 4. If you are debating which gases you want to try and restrict, you look at 1 and 2. If you are a government who is arguably supposed to look after the long term health of your country, you look at 4 and 5. But if you want to undermine the debate, you pick on one aspect and pretend that noone ever thinks of all the others, and they've probably got that aspect a bit wrong anyway. I said: " I fully understand what it is - I don't believe many of the 'users' of the radiative forcing coefficients understand though. They use the radiative forcing in watts per square metre *** from the slab 'green house' atmosphere as if it WAS the way the atmosphere works - plugging those values into the various radiation formulae as if they were universal constants even though you will agree they are 'just comparative constructs in an unreal hypothetical atmosphere'." To which your response Steve was: "No they don't. There are a number of levels to the discussion. Off top of head:"And the VERY FIRST STEP you provide - on which all the others are based: "1a) What is the radiative forcing of each agent? This is derived from the radiation calculations."This is precisely my point - the radiative forcing of the agent is about as useful as comparing the braking capabilities of cars from the amount of pressure different drivers can apply to the brake pedal - without any regard to car weight, tyre wear, tyre treads, the road surface, facing up or downhill, in reverse, ABS etc etc. Certainly you can use the brake pedal pressure from each driver to compare their capabilities in pressing the brake pedal - but there are many other variables that all immediately come into play in braking action of cars. Not wishing to stretch that analogy - the atmosphere is a complex turbulent fluid - its activity is driven largely by the heat from the surface much of which is ocean and the ocean activity and surface temperatures are driven by the activity and cloudiness of the atmosphere a chaotic interactive system. You forget all that and freeze it - and magically double the amount of a GHG and look _solely_ at the radiation effects of that doubling. But you CANNOT get to a pure doubling in reality as the slightest change to the chaotic atmosphere and ocean activity causes unpredictable non-linear changes in the entire coupled system. Yet in step 1a "1a) What is the radiative forcing of each agent? This is derived from the radiation calculations."To quote Jim Cripwell - you are not testing your hypothesis on 'radiative forcing' to see what ACTUALLY happens as you increase GHG in the atmosphere - no validation tests. You have a magic meaningless coefficient that you plug in instead - then use parameters to try to make the models using the coefficient look like the real world. Any inaccuracy is put down to some other unmeasured variable like aerosols rather than admitting that perhaps the radiative forcing coefficient, the model or the parameters are incorrect. To quote Jim Cripwell - you are not testing your hypothesis on 'radiative forcing' to see what ACTUALLY happens as you increase GHG in the atmosphere - no validation tests. You have a magic meaningless coefficient that you plug in instead - then use parameters to try to make the models using the coefficient look like the real world. Any inaccuracy is put down to some other unmeasured variable like aerosols rather than admitting that perhaps the radiative forcing coefficient, the model or the parameters are incorrect. That is it in a nutshell.
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Post by steve on Jan 5, 2010 18:13:07 GMT
That is magellan's and nautonnier's misconception in a nutshell. The problem is you missed discussions 1b and 3.
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Post by icefisher on Jan 5, 2010 18:53:27 GMT
I don't think I've ever seen a more irrelevant post. It at least has complete station data and an attitude that its OK to look at and check the work. LOL! Can you name other work as open?
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Post by icefisher on Jan 5, 2010 18:57:20 GMT
The models calculate radiative transfer on a level by level basis using the radiative transfer equations I mention. So where is the link to the level by level results?
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Post by icefisher on Jan 5, 2010 19:00:40 GMT
That is magellan's and nautonnier's misconception in a nutshell. The problem is you missed discussions 1b and 3. You haven't addressed that under 3 Dr Kevin Trenberth has admitted they can't explain the impact that resulted in no warming for the past decade. So do you have an explanation for why the modelers claim they have accounted for all forcings yet none of them explain recent climate? The answer seems obvious, namely they don't know these answers yet as Trenberth admits.
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Post by nautonnier on Jan 5, 2010 21:31:35 GMT
No this is a misunderstanding on your part. I was not dogmatically stating you must do step 1 then 2 then 3 then 4, I was listing some of the ways you could analyse and discuss the subject. That should have been clear from the last couple of paragraphs. The models calculate radiative transfer on a level by level basis using the radiative transfer equations I mention. This should probably mean that if you instantaneously doubled CO2 in a model, the model will immediately reduce outgoing longwave radiation by 3.7W/m^2, but that is only because it is repeating the radiative calculations that were done to calculate forcing in the first place. But as time goes on, the model will adjust to the new "forcing" as it runs its weather calculations. A good model will include the "complex turbulent fluid - ...[whose] activity is driven largely by the heat from the surface much of which is ocean and the ocean activity and surface temperatures are driven by the activity and cloudiness of the atmosphere a chaotic interactive system." " if you instantaneously doubled CO2 in a model, the model will immediately reduce outgoing longwave radiation by 3.7W/m^2, but that is only because it is repeating the radiative calculations that were done to calculate forcing in the first place"Steve So you _are_ using the totally hypothetical coefficient 3.7Wm-2 whether you are recalculating it or not. So please detail how you can instantaneously double and 'well mix' CO 2 in the _real world_ atmosphere and describe the _real world_ process this instant doubling is actually modeling. Then please explain how such unreality represents the turbulent swirls of differing concentrations of CO 2 shown by satellites in the _real world_. For example you posted this: In reality the first additions of CO 2 will start atmospheric reactions (feedbacks if you want) such as convection, winds and clouds. Winds will increase the evaporation from the surface cooling the surface and reducing heat radiation from it the water vapor will rise at a wet adiabatic lapse rate and condense giving more heat to the surrounding air and cause clouds to form raising albedo etc etc. But then your models are not of the real world are they.
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