CO2 sensitivity

[JBeukema]

If you double the CO2 in the atmosphere

[FONT=arial, helvetica, sans serif] Lindzen states explicitly that a doubling from 300ppmv to 600ppmv of atmospheric carbon dioxide would result in only 0.5 °C warming. Rather obviously, Lindzen's calculations do not suggest a particularly large greenhouse influence on post-Industrial Revolution temperatures and, significantly, this does not include clouds, so CO2 would really only be a fraction of the total effect shown (Lindzen states 0.22 °C if calculated with 40% cloud cover). [/FONT]

 

[Old Rocks]

If you double the CO2 in the atmosphere

[FONT=arial, helvetica, sans serif] Lindzen states explicitly that a doubling from 300ppmv to 600ppmv of atmospheric carbon dioxide would result in only 0.5 °C warming. Rather obviously, Lindzen's calculations do not suggest a particularly large greenhouse influence on post-Industrial Revolution temperatures and, significantly, this does not include clouds, so CO2 would really only be a fraction of the total effect shown (Lindzen states 0.22 °C if calculated with 40% cloud cover). [/FONT]

Since we have already achieved a 0.7 increase with only a 40% increase in CO2, I would have to say that Lindzen's hypothesis has been falsified. Same for his hypothesis concerning the harmlessness of tobacco.

 

[JBeukema]

[FONT=arial, helvetica, sans serif]The Earth's greenhouse effect is commonly estimated at 33 °C and these calculations simply assume that to be true. [/FONT]
[FONT=arial, helvetica, sans serif]If water vapor accounts for 70% and clouds another 20% (making water 90% of total atmosphere greenhouse effect) then we have 10% left for carbon dioxide and the ubiquitous "other" GHGs. [/FONT]
[FONT=arial, helvetica, sans serif]Lindzen's 3.53 °C cooling potential for complete removal of CO2 would then seem to fit the bill fairly adequately at around 10.7% of the total effect (3.53/33), while there's really not room for the larger estimates. Note, however, that carbon dioxide is generally reckoned to account for between 4.2% and 8.4% of Earth's net greenhouse effect because water vapor and clouds also behave differently at different concentrations and temperatures (we warned you this wasn't linear). [/FONT]
[FONT=arial, helvetica, sans serif]On the other hand, if we assume Charnock and Shine are closer to the mark then ~36% of Earth's greenhouse effect must be driven by CO2 (12/33). This is intuitively unreasonable since water is both prolific and has absorption windows overlapping those of carbon dioxide to a large extent.
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[FONT=arial, helvetica, sans serif] [FONT=arial, helvetica, sans serif]Water covers more than 70% of the globe and the lower atmosphere over water tends to be relatively well supplied with water both as vapor and clouds. [/FONT]
[FONT=arial, helvetica, sans serif]Water is the dominant absorber in wavelengths expected in the warmer regions, such as in the tropics where water is hugely prolific and where significant greenhouse warming occurs. [/FONT]
[FONT=arial, helvetica, sans serif]It simply does not seem reasonable to expect CO2 to preferentially absorb more than one-third of the available energy. [/FONT]
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[FONT=arial, helvetica, sans serif] [/FONT][FONT=arial, helvetica, sans serif]This suggests (but does not prove) that Lindzen is likely to be the nearest estimate from those we've plotted above. [/FONT]
[FONT=arial, helvetica, sans serif]Note that if you discount all other possible drivers of global temperature change -- meaning that humanity has completely taken over from all natural effects that were operating until that time (highly unlikely) -- then the estimate of Charnock & Shine neatly fits observed warming over the period. [/FONT]
[FONT=arial, helvetica, sans serif]If their massive estimate of net greenhouse effect from carbon dioxide is true then a worst case doubling of atmospheric carbon dioxide will still only produce a total warming under 1.5 °C (and we're thought to be almost half-way there already). [/FONT]
[FONT=arial, helvetica, sans serif]This still does not suggest a major enhanced greenhouse catastrophe. [/FONT]

And what are your sources for this increase?

Stations in the middle of heat islands?

What's your baseline? The mystical 14° that no model can produce?

Are you assuming that carbon accounts for 1/3 of warming?

How much has the temp increased? Over what period? How far outside the usual variation is this? What is the margin of error?

The AGW alarmists' methodology seems highly suspect

 

[CrusaderFrank]

If you double the CO2 in the atmosphere

[FONT=arial, helvetica, sans serif] Lindzen states explicitly that a doubling from 300ppmv to 600ppmv of atmospheric carbon dioxide would result in only 0.5 °C warming. Rather obviously, Lindzen's calculations do not suggest a particularly large greenhouse influence on post-Industrial Revolution temperatures and, significantly, this does not include clouds, so CO2 would really only be a fraction of the total effect shown (Lindzen states 0.22 °C if calculated with 40% cloud cover). [/FONT]

Since we have already achieved a 0.7 increase with only a 40% increase in CO2, I would have to say that Lindzen's hypothesis has been falsified. Same for his hypothesis concerning the harmlessness of tobacco.

Funny, tobacco products were tested in a lab, can you test the effect of a 200PPM increase in CO2 in a lab, or are you going to go with a 600,000PPM or 800,000PPM increase and say, See! I told ya so!

 

[JBeukema]

if 40-% gave us .7, it makes sense that 100% increase (even ignoring the logarithmic nature of the matter) would give us 1.4.

Wow... ~1.5%c...

assuming that the trend continues and that a non-linear system as complex as global climatic trends is not robust enough to compensate.


I wonder... how much does the global temperature vary year-to-year, decade-to-decade to begin with? Somehow, I suspect 1.5°c isn't a big change in the grand scheme of things.

 

[CrusaderFrank]

if 40-% gave us .7, it makes sense that 100% increase (even ignoring the logarithmic nature of the matter) would give us 1.4.

Wow... ~1.5%c...

assuming that the trend continues and that a non-linear system as complex as global climatic trends is not robust enough to compensate.


I wonder... how much does the global temperature vary year-to-year, decade-to-decade to begin with? Somehow, I suspect 1.5°c isn't a big change in the grand scheme of things.

How is it possible that there's been no warming since 1995 like Phil Jones says? If CO2 is really so sensitive shouldn't the Warming be obvious and statistically verifiable?

 

[JBeukema]

[FONT=arial, helvetica, sans serif][FONT=arial, helvetica, sans serif]"As just mentioned, a doubling of the concentration of carbon dioxide (from the pre-Industrial value of 280 parts per million) in the global atmosphere causes a forcing of 4 W/m2. The central value of the climate sensitivity to this change is a global average temperature increase of 3 °C (5.4 °F), but with a range from 1.5 °C to 4.5 °C (2.7 to 8.1 °F) (based on climate system models: see section 4). The central value of 3 °C is an amplification by a factor of 2.5 over the direct effect of 1.2 °C (2.2 °F). Well-documented climate changes during the history of Earth, especially the changes between the last major ice age (20,000 years ago) and the current warm period, imply that the climate sensitivity is near the 3 °C value. However, the true climate sensitivity remains uncertain, in part because it is difficult to model the effect of feedback. In particular, the magnitude and even the sign of the feedback can differ according to the composition, thickness, and altitude of the clouds, and some studies have suggested a lesser climate sensitivity." [/FONT][/FONT]

ibid

3 deg c... what's that in f?

 

[JBeukema]

Ask OR. He claimed we've increased atmospheric C02 by 40% and seen .7 degrees Celsius increase


he provided no source

 

[CrusaderFrank]

Ask OR. He claimed we've increased atmospheric C02 by 40% and seen .7 degrees Celsius increase

he provided no source

He's a Warmer. Sources? We don't need any stinking sources!

 

[JBeukema]

[FONT=arial, helvetica, sans serif][FONT=arial, helvetica, sans serif][FONT=arial, helvetica, sans serif][FONT=arial, helvetica, sans serif]Humans have only been trying to measure the temperature fairly consistently since about 1880, during which time we think the world may have warmed by about +0.6 °C ± 0.2 °C. As we've already pointed out, the estimate of warming is less than the error margin on our ability to take the Earth's temperature, generally given as 14 °C ± 0.7 °C for the average 1961-1990 while the National Climatic Data Center (NCDC) suggest 13.9 °C for their average 1880-2004.

ibid
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[JBeukema]

Looks like some highly questionable methodology among the AGW crowd

 

[westwall]

JB, total misinformation consisting of enough half truths to form a complete lie. The residence time for H2O in the atmosphere is less than ten days. That of CO2, a couple of centuries.

If you removed all the water in the atmosphere, in a very short time you would have the water back in the atmosphere, the surface of the earth being 3/4 ocean. However, were you to remove all the CO2 in the atmosphere, is a few years you would have glaciers at the equator.

If you double the amount of H2O in the atmosphere, in a few short, very rainy days, you would be back where you started. If you double the CO2 in the atmosphere, discounting the feedbacks that would make the period far longer, the least time it would be before you had the original amount of CO2 in the atmosphere is two hundred years.

Water vapor is a feedback.

FALSE, FALSE, FALSE. The residence time for CO2 is not centuries it's not even decades.
I have highlighted the relevant passages for the reading impaired.

Atmospheric Residence Time of Man-Made CO2
Potential Dependence of Global Warming on the Residence Time (RT) in the Atmosphere of Anthropogenically Sourced Carbon Dioxide

Robert H. Essenhigh
Department of Mechanical Engineering, The Ohio State University, Columbus, Ohio 43210
Energy Fuels, 2009, 23 (5), pp 2773–2784
DOI: 10.1021/ef800581r
Publication Date (Web): April 1, 2009
Copyright © 2009 American Chemical Society

Abstract:

The driver for this study is the wide-ranging published values of the CO2 atmospheric residence time (RT), τ, with the values differing by more than an order of magnitude, where the significance of the difference relates to decisions on whether (1) to attempt control of combustion-sourced (anthropogenic) CO2 emissions, if τ > 100 years, or (2) not to attempt control, if τ 10 years. This given difference is particularly evident in the IPCC First 1990 Climate Change Report where, in the opening policymakers summary of the report, the RT is stated to be in the range of 50−200 years, and (largely) on the basis of that, it was also concluded in the report and from subsequent related studies that the current rising level of CO2 was due to combustion of fossil fuels, thus carrying the, now widely accepted, rider that CO2 emissions from combustion should therefore be curbed. However, the actual data in the text of the IPCC report separately states a value of 4 years. The differential of these two times is then clearly identified in the relevant supporting documents of the report as being, separately (1) a long-term (100 years) adjustment or response time to accommodate imbalance increases in CO2 emissions from all sources and (2) the actual RT in the atmosphere of 4 years. As a check on that differentiation and its alternative outcome, the definition and determination of RT thus defined the need for and focus of this study. In this study, using the combustion/chemical-engineering perfectly stirred reactor (PSR) mixing structure or 0D box for the model basis, as an alternative to the more commonly used global circulation models (GCMs), to define and determine the RT in the atmosphere and then using data from the IPCC and other sources for model validation and numerical determination, the data (1) support the validity of the PSR model application in this context and, (2) from the analysis, provide (quasi-equilibrium) RTs for CO2 of 5 years carrying C12 and 16 years carrying C14, with both values essentially in agreement with the IPCC short-term (4 year) value and, separately, in agreement with most other data sources, notably, a 1998 listing by Segalstad of 36 other published values, also in the range of 5−15 years. Additionally, the analytical results also then support the IPCC analysis and data on the longer “adjustment time” (100 years) governing the long-term rising “quasi-equilibrium” concentration of CO2 in the atmosphere. For principal verification of the adopted PSR model, the data source used was the outcome of the injection of excess 14CO2 into the atmosphere during the A-bomb tests in the 1950s/1960s, which generated an initial increase of approximately 1000% above the normal value and which then declined substantially exponentially with time, with τ = 16 years, in accordance with the (unsteady-state) prediction from and jointly providing validation for the PSR analysis. With the short (5−15 year) RT results shown to be in quasi-equilibrium, this then supports the (independently based) conclusion that the long-term (100 year) rising atmospheric CO2 concentration is not from anthropogenic sources but, in accordance with conclusions from other studies, is most likely the outcome of the rising atmospheric temperature, which is due to other natural factors. This further supports the conclusion that global warming is not anthropogenically driven as an outcome of combustion. The economic and political significance of that conclusion will be self-evident.

 

[daveman]

If the atmosphere were 100% CO2, we'd all die! See? THAT'S how dangerous it is! Global socialism NOW!!