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Post by glc on Aug 2, 2009 10:16:43 GMT
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Post by jimcripwell on Aug 2, 2009 11:11:59 GMT
glc writes "However, note that the increase from 300 ppm to 600 ppm still produces a temperature increase of around 1 deg C"
We will never agree, you and I. I only put my trust in hard, measured, independently replicated experimental data. The vital experiement for AGW, adding CO2 to the atmosphere and measuring how much the world's temperature rises, can never be done with current technology. Your estimate of a 1 deg C rise for a doubling of CO2 is based on non-validated computer programs, and as such is worthless.
You say I am not a scientist. I write under my own name, unlike yourself, and anyone is more than welcome to check on who I am, where I live, what my education is, etc. You seem to have forgotten the fundamentals of Physics 101, assuming you studied undergraduate physics.
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Post by jimcripwell on Aug 2, 2009 11:19:54 GMT
neilhamp writes "Do you have any update on the above figures? "
Of course I have an update on the above figures; I get a new figure every day. However, I hope you will forgive me if I only post such figures when anything "exciting" seems to have happened. Surely anyone whom is that interested can get the data for themselves. Let me just note that with today's preliminary figure, the trend towards a much slowed rate of melt seems to be continuing.
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Post by woodstove on Aug 2, 2009 11:57:12 GMT
Oh, and glc, still waiting to hear what began moving us out of the Little Ice Age (in 1700 or 1800, take your pick), and on what date whatever it was that was performing this heating handed the baton to your cherished co2. Your phrase "in 1700 or 1800, take your pick" is interesting because it illustrates the vagueness about the LIA. In the 1770-1790 period, for example, solar activity was high but this was a time of falling temperatures (across Europe, at least). The 1730s were warm - almost as warm as to-day according to the CET. Hans Erren has done research which suggests that a year in the 1500s was a candidate for the warmest year of the last 500 years. On an arctic expedition in 1817, the explorer William Scoresby noted "a remarkable diminution" of polar ice which lead to the President of the Royal Society address (discussed on WUWT) - yet this was in the depths of the Dalton Minimum. Basically the problem is that the period of the LIA (and MWP) is not well defined and it ends to 'fit' whatever argument is being put forward. It's not possible, therefore, to provide a single reason for the "recovery". The latter half of the 20th century was warmer than the first half. Why? (I don't believe it's all related to CO2). And why, despite it being warmer in the second half than the first, were the 1940s warmer than 1960s? Natural variability probably driven by ocean fluctuations seems a reasonable bet. You're dodging. You've agreed elsewhere that LIA existed. What got us out of it? As for your question regarding an apparent lack of trend in cosmic rays from 1975 to 2005, I will say (a) that is a good question and (b) I suspect that the issue has to do with the length of minima and maxima during the period. But I don't want to suggest that I believe GCRs "govern" climate on their own. You've said that solar theories don't even have a mechanism attached to them. GCR cloud modulation is one such mechanism, and Svensmark will eventually win a Nobel for it. In the meantime, our system is chaotic, with multiple attractors -- and also remarkably stable. Basically the problem with warmistas is the same one faced by Narcissus: they just can't stop looking at their own reflection. It's a shame that people have been duped into focusing on co2. There are real environmental problems, by the dozen, that could be solved ...
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Post by woodstove on Aug 2, 2009 15:04:28 GMT
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Post by glc on Aug 2, 2009 15:30:41 GMT
You're dodging.
Not at all.
You've agreed elsewhere that LIA existed.
Yes and No. I'm not convinced there was a several hundred year period, say, when a large proportion of the earth was consistently colder than normal. I accept, though, that a number of regions did experience anomalously cold conditions during a period knowwn as the LIA.
What got us out of it?
Impossible to say. I can't even say when we were "out of it" - nor can you nor can anyone else. The dates vary depending on what you read. Some say 1850, but Uppsala, & CET show cooler temperatures at the end of the 19th century than at the start. I can't explain 20th century climate fluctuations with any confidence and that's will all the data we have now.
Why don't you tell me when the LIA ended and what is it that justifies your answer.
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Post by woodstove on Aug 2, 2009 15:32:51 GMT
The simple answer is 1800 -- I side with Dr. Syun-Ichi Akasofu, as I have indicated before. (There are many who draw the same conclusions as Akasofu, I merely find him to be the most convincing.)
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Post by glc on Aug 2, 2009 15:37:58 GMT
The simple answer is 1800 -- I side with Dr. Syun-Ichi Akasofu, as I have indicated before. (There are many who draw the same conclusions as Akasofu, I merely find him to be the most convincing.)
Why 1800? .....and what caused it to end?
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Post by glc on Aug 2, 2009 15:45:38 GMT
We will never agree, you and I. I only put my trust in hard, measured, independently replicated experimental data. The vital experiement for AGW, adding CO2 to the atmosphere and measuring how much the world's temperature rises, can never be done with current technology. Your estimate of a 1 deg C rise for a doubling of CO2 is based on non-validated computer programs, and as such is worthless.
No it's not. It's based on long-established equations and laws which were developed by Planck and Beer-lambert. As usual you continue to confuse the CO2 + feedbacks with the basic theory.
You say I am not a scientist. I write under my own name, unlike yourself, and anyone is more than welcome to check on who I am, where I live, what my education is, etc. You seem to have forgotten the fundamentals of Physics 101, assuming you studied undergraduate physics.
You're the one who seems to accept that CO2 absorbs LW radiation up to 100 ppm but then suddenly stops. No reason given why the absorption properties should change - No calculations given - just blind faith that no further absorption occurs above 100 ppm. Staggering nonsense.
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Post by woodstove on Aug 2, 2009 16:08:27 GMT
The simple answer is 1800 -- I side with Dr. Syun-Ichi Akasofu, as I have indicated before. (There are many who draw the same conclusions as Akasofu, I merely find him to be the most convincing.) Why 1800? .....and what caused it to end? This is a comedic moment, glc, for those with any perspective. I have been asking you for a fortnight what caused the LIA to end. And, after much chin scratching, you have turned the question around. OK. The answer is that it was NOT human emissions of greenhouse gases. Have a nice day.
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Post by nautonnier on Aug 2, 2009 16:15:45 GMT
I can see that the simplification that CO2 which is an absorber emitter as if by magic can remove energy from the atmosphere is naive and now i am thinking about it i suppose a none absorbing emitting atmosphere can be warmed by convection but at night it would cool very rapidly as would the earth.radiant Convection only operates in the lower atmosphere (the troposphere). Basically it just shifts energy around. The key to greenhouse warming is the incoming/outgoing balance at the top of the atmosphere. Averaged across it's surface the earth (and it's atmosphere), receives ~235 w/m2 from the sun. To maintain a stable temperature the earth must emit ~235 w/m2 back to space from the "top of the amosphere". It is only by radiation that this can be done. The surface can be cooled by latent heat, convection, etc but the earth, as a system, gets rid of the incoming ~235 w/m2 by radiation. A significant proportion of this outgoing radiation is emitted at higher altitudes by CO2. If CO2 concentrations increase then the outgoing radiation will be reduced. There will be an imbalance. To restore the balance the atmosphere will warm which (by Stefan -Bolzmann) will cause an increase in the energy emitted. " Convection only operates in the lower atmosphere (the troposphere). Basically it just shifts energy around. The key to greenhouse warming is the incoming/outgoing balance at the top of the atmosphere"
So "basically convection just shifts energy around"? You are either being unnaturally glib or ignorant. Convection transports heat upward from the surface to the tropopause huge amounts of heat that are NOT radiation. The heat transported by convection of warm air and by state change of water is not intercepted by any green house gas and bypasses the most dense levels of the atmosphere in which most of the CO 2 is to be found. Not only that but the input radiation is reduced by the SAME convection due to albedo being raised as water vapor and droplets turn to ice crystals in the upper troposphere. It is of course true that heat can only leave the Earth at the TOA by radiation. It is unfortunate then that the IPCC et al (including yourself) use 'Radiative Forcing' as a metric which EXPLICITLY measures the effect of a 'green house gas' concentration being instantaneously added to the atmosphere on the outgoing radiation AT THE TROPOPAUSE and NOT at the TOA. From what you are saying this is precisely the WRONG place to measure as at the tropopause you also have all the convective effects that of course are 'switched off' in the Radiative Forcing calculations as the atmosphere is considered to be an unresponsive slab. This is true even in your much referenced MODTRAN. First falsification: Hypothesis - one can add instantaneously a well mixed ghg to the atmosphere. I see absolutely no way that a ghg can be added to the atmosphere in this way. IMPOSSIBILITY ONE Second falsification: Hypothesis - every molecule in the atmosphere will remain perfectly static with no warming or cooling as the surface gets warmer due to inbound short wave radiation and outbound long wave radiation is absorbed and emitted by the added ghg. Obviously false and IMPOSSIBILITY TWO. The basis of MODTRAN and other models of 'radiative forcing' are obviously and by definition impossible in a real world. They attempt to isolate one aspect of the complex atmospheric system, 'outgoing long wave radiation', presumably as its 'too difficult' to model the actual atmosphere, or because a simple unreal coefficient can be calculated as a comparator. The main logic failure is to use this hypothetical unreal coefficient and apply it to 'real world' cases as if it is unchanged in the real world. To give them credit the IPCC has admitted that they need to measure convection and clouds better for AR5. So Jim Cripwell is correct. There can be no physical proof of radiative forcing as it is an unreal hypothetical figure. This not saying that CO2 does not absorb (and immediately re-emit) IR at 3 narrow bands of course it does, its just that the Radiative Forcing metric disregards so much reality that it is useless in the real world. What IS NEEDED is a realistic metric for the atmospheric behavior when CO 2 is added at a continual variable rate: a metric that CAN be measured. I would have thought that a simple experiment could be set up with broadband IR transmitters of known output on the Earth's surface beamed at the International Space Station which could identify the variations in the transparency of the atmosphere to varying frequencies at varying points on the earth's surface. The measures could be repeated by aircraft with multispectral scanners at varying heights. Perhaps points could be chosen in large deserts, out at sea or downwind of industrial complexes where the CO 2 and water vapor are in differing concentrations. After a year or so of several measures daily, trends may start appearing. This would be real experimental physics and simple and cheap to set up. Considering the arguments and billions of dollars/Euros involved one would have thought this would have been done already.
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Post by glc on Aug 2, 2009 16:34:15 GMT
This is a comedic moment, glc, for those with any perspective.
I have been asking you for a fortnight what caused the LIA to end. And, after much chin scratching, you have turned the question around.
OK. The answer is that it was NOT human emissions of greenhouse gases.
You haven't provided any justification why 'it' ended in 1800. I suggest there is none. There's certainly nothing to indicate that the 19th century was significantly warmer than the 18th century. So tell us what is it that ended in 1800?
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Post by icefisher on Aug 2, 2009 16:48:17 GMT
You must be looking at the tops GLC, look at the bottoms. And if you want to really see the trend start the chart from the beginning 1964/04/01. Very clearly a strong trend towards valleys of GCR's at ever lower values.
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Post by jimcripwell on Aug 2, 2009 17:17:29 GMT
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Post by glc on Aug 2, 2009 18:01:12 GMT
So "basically convection just shifts energy around"? You are either being unnaturally glib or ignorant. Convection transports heat upward from the surface to the tropopause huge amounts of heat that are NOT radiation. The heat transported by convection of warm air and by state change of water is not intercepted by any green house gas and bypasses the most dense levels of the atmosphere in which most of the CO2 is to be found. Not only that but the input radiation is reduced by the SAME convection due to albedo being raised as water vapor and droplets turn to ice crystals in the upper troposphere.
It is of course true that heat can only leave the Earth at the TOA by radiation.
Your last sentence says it all. The only way that earth's climate system cools is by radiation. It is by radiation alone that the climate is regulated. The earth receives ~235 w/m2 from the sun and emits ~235 w/m2 at TOA. I'm just wondering how many more ways there are to say the pretty much the same thing. The main point is that an increase in greenhouse gases will reduce the amount of outgoing radiation
Do you agree with this?
As far as the rest of your post is concerned you are simply describing well understood climatological processes. Yes the input radiation is reduced by the albedo. That's why average incoming radiation is ~235 w/m2 and not ~342 w/m2. So what? What's your point? I know this. I know that the surface is cooled by convection and evaporation. Again you use these obvious facts in what I can only assume is an attempt to give an appearance of complexity and confusion.
You state that
"The heat transported by convection of warm air and by state change of water is not intercepted by any green house gas and bypasses the most dense levels of the atmosphere in which most of the CO2 is to be found."
There is some truth in this but again it is misleading. Earth's emission spectra shows the radiation emitted to space at different wavelengths. It's quirte clear that a significant proportion is emitted in the CO2 band at much higher (and drier & colder) altitudes. It doesn't bypass CO2 in the way you claim. Emission from CO2 is dominant in the upper troposphere.
The additon of CO2 will increase the concentration at higher levels. This will result in an increase in the average height at which emittance takes place. PLEASE TRY TO FOLLOW THIS BIT. If radiation is emitted from a higher level - it will be emitted from a colder level. If it is emitted from a colder level the amount of energy emitted will be lower . This is a consequence of the Stefan Boltzmann Law (i.e. E is proportional to T4).
In order to maintain equilibrium (incoming=outgoing) the atmosphere must warm. How much depends on the increase in thickness of the abosrbing layer.
Now back to your convection/latent heat stuff. If the addition of CO2 either directly or indirectly changes the albedo (or some other factor), then this would be considered a feedback. This is a separate issue which is not considered in the equations I cited to calculate the primary change in forcing.
As for other bits of your post. I don't think you've though through your proposed "experiment". Either that or I haven't read it properly. Whatever, we have plenty of evidence of the greenhouse effect from emission spectra measured by satellites.
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