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Global Warming re-derived?


ecoli

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I entered here with the specific purpose of setting the record straight, which I have.

 

You've referenced one model, yet continue to make claims which imply that most or all models are faulty. I am perhaps missing something more subtle in your argument? I concede that the Hansen 1988 model has problems. How again does that make every other model fallacious?

 

Let's be specific. This appears to be a pretty run of the mill miscommunication.

 

Which models specifically "consistently overpredict" warming?

 

Perhaps we can then go on to discuss which models are actually used when coming to the conclusion that warming is increasing as a result of human activity.

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You've referenced one model
One model? I demonstrated that every model referenced by the IPCC overpredicted warming. Every one.

 

The earlier the model, the more they overpredicted. The projections made by AR4 (2007) are almost still certainly overzealous, but they're far closer than the utter nonsense predicted by one and all during the 80s and 90s.

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One model? I demonstrated that every model referenced by the IPCC overpredicted warming. Every one.

No, you didn't actually... as was already pointed out to you earlier in this thread. You cannot simply ignore the criticisms you receive, then repeat yourself without addressing those criticisms and pretend you've made some point.

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One model? I demonstrated that every model referenced by the IPCC overpredicted warming. Every one.

 

The earlier the model, the more they overpredicted. The projections made by AR4 (2007) are almost still certainly overzealous, but they're far closer than the utter nonsense predicted by one and all during the 80s and 90s.

 

How is this not completely contradicted by the graphs presented in post 28? I see two curves very close to the actual temperature increase.

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Attack mode? My position has already been amply proven. Warming has not been "underpredicted", it's been consistently overpredicted, nearly always by a huge margin.

 

...............................................................

 

 

One model? I demonstrated that every model referenced by the IPCC overpredicted warming. Every one.

 

The earlier the model, the more they overpredicted. The projections made by AR4 (2007) are almost still certainly overzealous, but they're far closer than the utter nonsense predicted by one and all during the 80s and 90s.

 

What are you talking about? You haven't demonstrated anything, and your claims were debunked multiple times already.

 

I entered here with the specific purpose of setting the record straight, which I have.

 

What, by repeating yourself and ignoring counterpoints?

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How is this not completely contradicted by the graphs presented in post 28? I see two curves very close to the actual temperature increase.
This was already addressed by myself as well as another poster. The curve represented as Scenario A in the graphs predicts warming of some 1.2C by today, as calculated from the "nominal" value of the 1951-1980 mean anomaly (standard practice in climatology).

 

What is the current temperature now though? Just 0.32C above nominal, for the 12-month running average ending Feb 2008, according to the Hadley Center for Climate Prediction:

 

http://hadobs.metoffice.com/hadcrut3/diagnostics/global/nh+sh/monthly

 

The observed value is even lower, if you look at the satellite troposphere data (RSS, UAH, etc). But let's not pick the data which makes the best argument for us...it's not neccesary, as every single data outlet, up to and including GISS itself, proves conclusively that warming was drastically overpredicted.

 

Still worse for the alarmists, the rise since 1998 has been zero (for those that dispute this, plot the data above and drop a linear regression trendline.) This is the point that, for model predictions made in the 1980s, that we should be seeing warming increase still further. Yet the rate didn't increase, it has nearly shut itself off.

 

For those who want to pick one of the lesser predictions (which still overpredict warming, just by a smaller degree), let's clarify just what those scenarios are:

 

Scenario A - The world continues to grow emissions at 1988 levels.

Scenario B - The world freezes GHG emissions growth rates so that the forcing remains linear..

Scenario C - The world halts GHG emissions by the year 2000.

 

Scenario A is the closest to reality, and yet it drastically overpredicted actual warming.

 

Fast-forward to 2001, and we see IPCC AR3 scaling back their predictions somewhat. In the years since this report was released, we already see a reality diverging sharply from the predictions, which ranged from a decadal increase of 0.15C up to nearly 0.6C. Yet

 

That brings us to 2007, where IPCC AR4 has once again reduced predictions. They now place climate sensitivity at 3C. It's too soon to say definitively this value is too high...but recent research and observational data indicates it still is.

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Still worse for the alarmists, the rise since 1998 has been zero (for those that dispute this, plot the data above and drop a linear regression trendline.) This is the point that, for model predictions made in the 1980s, that we should be seeing warming increase still further. Yet the rate didn't increase, it has nearly shut itself off.

 

 

That is simply not true. Below is a graph showing actual observations and trend, and the data represents up to the end of 2006:

 

 

http://www.ncdc.noaa.gov/oa/climate/research/2006/ann/global.html

 

glob_jan-dec-error-bar_pg.gif

 

 

 

Fast-forward to 2001, and we see IPCC AR3 scaling back their predictions somewhat.

I want you to show me the original projection, and I want you to show me the new projection which you've deemed "scaled back." I want you to include the source reference so I can view the reasons given for the change. If you are serious about your position, you will provide this.

 

 

In the years since this report was released, we already see a reality diverging sharply from the predictions, which ranged from a decadal increase of 0.15C up to nearly 0.6C.

You are arguing against all models, yet you have only shown one from 1988 which fits your description. That is but one model among many, and you have yet to show fault in those other models.

 

 

That brings us to 2007, where IPCC AR4 has once again reduced predictions. They now place climate sensitivity at 3C. It's too soon to say definitively this value is too high...but recent research and observational data indicates it still is.

 

That is your opinion, and you are welcome to it, but you really need to stop presenting it to others as if it were some empirical fact. It is not. Your argument is an appeal to credulity, and is as yet unsupported.

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That is simply not true. Below is a graph showing actual observations and trend...
Come, sir, you're on a board with "science" in the title. Surely you can use your head better than that.

 

First of all, your NOAA graph is VERY far out of date (it stops at 2006). Second of all, its computing running means for entire years, not displaying the actual month-by-month data. Thirdly, the trendline is calculated from all the way back in 1900. Do you not realize the start point of a linear regression influences the entire line?

 

I gave you a link to the actual raw data, current as of Feb 2008. Graph it yourself and see. Stop from 1998 (or 1997 or 1999 if you prefer), and see what the actual trend for the past 10 years is.

 

Here's what you get:

 

f_19972008m_c75f479.jpg

 

 

Source data:

 

TI want you to show me the original projection, and I want you to show me the new projection which you've deemed "scaled back." I want you to include the source reference so I can view the reasons given for the change.
Already done in Post #38. AR3 predictions, and link to AR4 predictions. Compare for yourself.

 

Draw your own conclusions for the "reasons for the change". They're obvious, however. AR1 projected too high. AR2 too high. AR3 too high. Are you really so surprised that AR4 again scaled back predictions?

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This was already addressed by myself as well as another poster. The curve represented as Scenario A in the graphs predicts warming of some 1.2C by today, as calculated from the "nominal" value of the 1951-1980 mean anomaly (standard practice in climatology).

 

 

...

 

For those who want to pick one of the lesser predictions (which still overpredict warming, just by a smaller degree), let's clarify just what those scenarios are:

 

Scenario A - The world continues to grow emissions at 1988 levels.

Scenario B - The world freezes GHG emissions growth rates so that the forcing remains linear..

Scenario C - The world halts GHG emissions by the year 2000.

 

Scenario A is the closest to reality, and yet it drastically overpredicted actual warming.

 

No, this is incorrect. Scenario B did not assume freezing GHG emissions — why would a freeze in emissions result in an increase in the forcings?

 

From Hansen's 2006 paper that evaluated the 1988 predictions:

 

Intermediate scenario B was described as ‘‘the most plausible.’’

Scenario B has continued moderate increase in the rate of

GHG emissions and includes three large volcanic eruptions sprinkled

through the 50-year period after 1988, one of them in

the 1990s.

Real-world GHG climate forcing (17) so far has followed a

course closest to scenario B.

(emphasis added)

 

Further, scenario C is not halting emissions, it is "GHGs were assumed to stop increasing after 2000." (emphasis added) and I can't find anything that corroborates the A scenario being as you describe — the paper calls it "‘‘on the high side of reality,’’ because it assumed rapid exponential growth of GHGs"

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No, this is incorrect. Scenario B did not assume freezing GHG emissions — why would a freeze in emissions result in an increase in the forcings?
Can people not read plain English? Scenario B assumed a freeze in emissions growth, to level off forcing.

 

Further, scenario C is not halting emissions, it is "GHGs were assumed to stop increasing after 2000." (emphasis added)"

 

Good god, this is ludicrous. Once again, the English is very plain. From the paper, Sec 4.1: "Scenario C drastically reduces trace gas growth between 1990 and 2000 such that the greenhouse climate forcing ceases to increase after 2000".

 

The paper makes it MORE explicit on page 9362. I quote, "In Scenario C...after 2000, CO2 ceases to increase...after 2000, CH4 ceases to increase....no increases occur for the other CFCs, O3, stratospheric H2o, or any other greenhouse gas"

 

Any questions still?

 

And finally, you ignore the most important point. All three scenarios drastically overpredicted warming.. The point is proven; abundantly so.

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Can people not read plain English? Scenario B assumed a freeze in emissions growth, to level off forcing.

 

Yes, I misread that. My apologies.

 

Still, scenario B is the one that is claimed to most closely match the actual history, not scenario A.

 

Good god, this is ludicrous. Once again, the English is very plain. From the paper, Sec 4.1: "Scenario C drastically reduces trace gas growth between 1990 and 2000 such that the greenhouse climate forcing ceases to increase after 2000".

 

 

The paper makes it MORE explicit on page 9362. I quote, "In Scenario C...after 2000, CO2 ceases to increase...after 2000, CH4 ceases to increase....no increases occur for the other CFCs, O3, stratospheric H2o, or any other greenhouse gas"

 

And yet that's not what you quoted earlier — you said the "world halts GHG emissions by the year 2000" for scenario C.

 

 

Any questions still?

 

And finally, you ignore the most important point. All three scenarios drastically overpredicted warming.. The point is proven; abundantly so.

 

Yes: by "drastically overpredict," do you mean "closely match?" I don't see how anyone can look at scenario B and call that a "drastic overprediction."

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Yes, I misread that. My apologies.
Not a problem.

 

And yet that's not what you quoted earlier — you said the "world halts GHG emissions by the year 2000" for scenario C.
That IS what the paper states. Read it again. I'm not sure why you're struggling so with the language here, but it's really very clear.

 

Still, scenario B is the one that is claimed to most closely match the actual history, not scenario A.
Not even close to correct. World emission rates have *risen*, not declined. Scenario B assumed a decline, to level off forcing. But actual global emission rates have risen.
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That IS what the paper states. Read it again. I'm not sure why you're struggling so with the language here, but it's really very clear.

 

"ceases" and "ceases to increase" don't mean the same thing

 

What you quoted was "Scenario C drastically reduces trace gas growth between 1990 and 2000 such that the greenhouse climate forcing ceases to increase after 2000"

and "after 2000, CO2 ceases to increase...after 2000, CH4 ceases to increase....no increases occur for the other CFCs, O3, stratospheric H2o, or any other greenhouse gas"

 

and previously you said "The world halts GHG emissions by the year 2000"

 

One says "reduce growth" and "ceases to increase" while the other says "halts emissions" They aren't the same thing.

 

 

Not even close to correct. World emission rates have *risen*, not declined. Scenario B assumed a decline, to level off forcing. But actual global emission rates have risen.

 

"Scenario B has continued moderate increase in the rate of GHG emissions"

 

increase, not decline

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You're moving the goal posts. You previously said it was wrong because it mispredicted temperature increase. You are now saying it's wrong because it assumed incorrect global emissions.
I said no such thing.

 

Hansen didn't assume any specific emissions level. He gave three hypothetical scenarios, and projected a temperature increase for all three. The methodology is appropriate, and I have no quibble with it.

 

The problem is that ALL THREE SCENARIOS drastically overpredicted warming. That's the end of the proof, right now.

 

Now, if we want to move beyond that to determine just how much in error he was, it's appropriate to look at which of the three scenarios best fits reality. It is, of course, scenario A, as this graph of global emissions clearly demonstrates:

 

global.total.gif

 

Let's summarize. Hansen tried to tell us that, even if the entire world drastically reduced emissions, we would, by 2008, already be seeing severe warming. And if we did nothing -- which effectively we did -- we'd see even worse effects, rising to nearly 1.2C by now.

 

But in reality, we've really just warmed up 0.3C, despite the massive increase in emissions. A clear demonstration that CO2-based forcing has been drastically overstated.

 

I said the same thing in 1988. And I'll be saying the same thing when the IPCC finally winds up agreeing with me, around the time it releases its Fifth Assessment Report.

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1998 is always trotted out... and it bugs me no end.

 

Of course it does, because the data since then so clearly demonstrates that CO2 forcing was dramatically overstated. That's bad news for the sky-is-falling crowd.

 

You can call 1998 "freakishly hot" all you want, but the fact remains that it was *cooler* than what many GW fanatics were predicting it to be back in the mid-1980s. And since 1998, temperatures have been flat. There's no evidence of any trend at all:

 

f_19972008m_5ff2a0f.jpg

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I presume the y-axis on that graph represents deviations from some average in degrees Celsius?

 

I really don't think you can look at a graph like that and draw conclusions about warming. Without any averaging you can't tell if a given year is any warmer than the other, on average.

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Hansen didn't assume any specific emissions level. He gave three hypothetical scenarios, and projected a temperature increase for all three. The methodology is appropriate, and I have no quibble with it.

 

The problem is that ALL THREE SCENARIOS drastically overpredicted warming. That's the end of the proof, right now.

 

And I don't see how you can look at the graph and make that claim. How big is "drastic?" I see temperature data points both below and above the B predictions, and the effects of Pinatubo aside, I don't see deviations of much more than 0.1 ºC. That's "drastic?"

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Cap'n, I don't know where the graph is from but the Hadley Centre uses the 1961-1990 average as a base line. Hence they might speak of a temperature anomaly of +.52 degrees for a given year.

 

Specifically:

1995 +0.28

1997 +0.36

1998 +0.52

2001 +0.40

2002 +0.46

2003 +0.46

2004 +0.43

2005 +0.48

2006 +0.42

2007 (Jan-Nov) +0.41

Still, scenario B is the one that is claimed to most closely match the actual history, not scenario A.

"Claimed" is the right word here.

 

Hansen 1988 uses a two step process to calculate the curves. Increase in emissions (A) gives forcing (A) gives temp curve (A). The second part is generally accepted as being relatively constant, for a forcing of x Watts/m2 temp will increase by y degrees. (Formula are in Appendix B)

 

(Scenario A was on the money for emission growth but the forcing and temp rise were wrong. Scenario B got the rise in emissions wrong but the temp rise right.)

 

Hansen 2006 conveniently omits the first part and only concerns itself with the forcings, not the forcings as they relate to emissions. The historical forcings do indeed most closely match Scenario B, but the emissions most closely match Scenario A. If the model used in Hansen 1988 was correct then the forcings would have increased in the historical record in line with the increase in GHG concentrations.

 

The fact that GHG concentrations have increased by around 1.5% p.a. yet the forcings have remained constant shows that the model in Hansen 1988 is wrong.

 

I would hesitate to use the word "dishonest" regarding Hansen 2006 however it does misrepresent the assumptions of Hansen 1988. Compare the two statements:

Hansen 1988: Scenario A assumes that the growth rate of trace gas emissions typical of the 1970s and 1980s will continue indefinitely; the assumed annual growth rate averages about 1.5% of current emissions, so the net greenhouse forcing increases exponentially.

Hansen 2006: Scenario A was described as ‘‘on the high side of reality,’’ because it assumed rapid exponential growth of GHGs and it included no large volcanic eruptions during the next half century.

 

Hansen 1988 worked on Emission -> Forcings -> Temp rise, but Hansen 2006 only uses Forcings -> Temp rise. This is a case of pure apples and oranges and as a proof I would have to call it "dubious" at best.

 

On a slightly different track.

One of the problems I see with the models is that they historically predict high, but this may not be a fault of the models. Most assume a given "climate sensitivity" normally defined as the temp increase for the doubling of CO2 from pre industrial levels. Often this sensitivity figure is based on the IPCC reports and there lies the problem.

 

From IPCC TAR 6.3.5

Compared to IPCC (1990) and the SAR and for similar changes in the concentrations of well-mixed greenhouse gases, the improved simplified expressions result in a 15% decrease in the estimate of the radiative forcing by CO2 (first row in Table 6.2), a 15% decrease in the case of N2O, an increase of 10 to 15% in the case of CFC-11 and CFC-12, and no change in the case of CH4.

This means that any model using the estimates for RF of CO2 from IPCC SAR must be high. IIRC a similar thing happened with IPCC AR4 which means that models based on IPCC TAR will also be high.

 

This is not a "bash the models" comment, just an observation. If you change the input parameters, then the output must change. Even a perfect model fed the sensitivity from IPCC SAR would make wrong projections.

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Cap'n, I don't know where the graph is from but...

It's an interestingly unsourced, uncredited, personally uploaded image with vague labels.

 

The graphic was uploaded here:

http://img29.picoodle.com/

 

 

He also used the same graphic in this thread at post #59, and wrote the words "Source Data" but failed to provide any, or any links.

 

 

Following the rabbit hole of his other posts, it appears that his source data is this:

 

http://hadobs.metoffice.com/hadcrut3/diagnostics/global/nh+sh/monthly

 

 

 

Drilling backward from that table, I arrive at the following actual source data page, which shares the exact same graphic I did in post #58 of this thread, to which ttowntom responded,

 

Come, sir, you're on a board with "science" in the title. Surely you can use your head better than that.

 

First of all, your NOAA graph is VERY far out of date (it stops at 2006).

 

 

 

 

The link I shared with his source data explicitly states this:

 

The time series shows the combined global land and marine surface temperature record from 1850 to 2007. The year 2007 was eighth warmest on record, exceeded by 1998, 2005, 2003, 2002, 2004, 2006 and 2001.

<...>

Analyses of over 400 proxy climate series (from trees, corals, ice cores and historical records) show that the 1990s is the warmest decade of the millennium and the 20th century the warmest century. The warmest year of the millennium was likely 1998, and the coldest was probably (but with much greater uncertainty) 1601.

 

His own source also explicitly cites the IPCC report against which ttowntom has been railing so consistently. Their citation specifically shares the following quote:

 

'Warming of the climate system is unequivocal, as is now evident from observations of increases in global average air and ocean temperatures, widespread melting of snow and ice, and rising global average sea level.

 

 

 

 

As has been shown in this thread, and others in which ttowntom has participated, one model with a deviation of roughly 1C hardly disqualifies the abundance of other data, and also local variations do nothing to negate the increase in global yearly averages.

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The fact that GHG concentrations have increased by around 1.5% p.a. yet the forcings have remained constant shows that the model in Hansen 1988 is wrong.

 

Do you have a cite? I can't make this jibe with the Mauna Loa CO2 concentrations, which look to be growing at less than a half of a percent p.a.

 

I've seen claims of emissions growing at that rate, but not the concentrations.

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I've seen claims of emissions growing at that rate, but not the concentrations.

:embarass::embarass::embarass:

I should have said "emissions", not "concentrations".

 

My apologies.

 

POL, AFAIK no-one here is advocating that we are in any sort of a "cooling phase", I'm certainly not anyway.

 

My concern in this area is that if CO2 emissions keep increasing as they have historically then we should be seeing around a .20 per decade increase in temp and this is not happening.

 

To my mind this indicates that the theory and models are incomplete. I see two distinct possibilities, either;

a) There is a limiting factor that we have not fully taken into account. or

b) There is a negative forcing factor powerful enough to cancel the positive forcing of CO2 that we haven't taken into account.

 

A possibility is of course aerosols, (let's face it, the sky over China is filthy) however I've yet to read anything that shows the aerosols increasing at anything near the rate required to cancel the increase in CO2.

 

Another point. The graph from Wiki is based on the NOAA figures which come from GISS. From the NCDC website.

Many parts of the globe are inaccessible and therefore have no data. The temperature anomaly time series presented here were calculated in a way that did not require knowing the actual mean temperature of the Earth in these inaccessible areas such as mountain tops and remote parts of the Sahara Desert where there are no regularly reporting weather stations.

It would seem that they are using the "teleconnection" idea, something I'm still coming to grips with. The idea that you can accurately estimate the temp in area without sensors by using readings from up to 1200 km away strikes me as problematical to say the least. By knowing the temp in Brisbane I can accurately gauge the temp in Melbourne? To 0.10?

 

I'll grant that the idea is valid for large scale climate patterns, but using it to estimate temps seems to take it a bit too far.

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I can see that the atmosphere of Mars fits the "semi-transparent" boundary conditions more readily than earth's atmosphere does.

 

I think you may be making a fundimentally flawed observation here. THe Earth's atmosphere is only "opaque" in the loose visual observation sense... but not in any real sense. IR radiation still escapes the atmosphere, even on Venus (where CO2 makes up 96.5% of the atmosphere rather than our own .038%).

 

So no, the Earth's atmosphere is not 100% inwardly or outwardly reflective so an infinite atmosphere is not acceptable. If it were, we would never see the sun (all light reflected), or we would have burned up long ago when the CO2 concentrations were a hundred times higher than today (all radiation retained).

 

It's a blog, so my comment was specific to the author. Michael Asher, Alex Jones...

 

Look at his other article there where he engages in the same disingenuous nonsense (he is literally making sh1t up):

 

http://www.dailytech.com/Survey+Less+Than+Half+of+all+Published+Scientists+Endorse+Global+Warming+Theory/article8641.htm

 

So where is he "making sh1t up"? You offer no contrary statistics to show this.

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I think you may be making a fundimentally flawed observation here. THe Earth's atmosphere is only "opaque" in the loose visual observation sense... but not in any real sense. IR radiation still escapes the atmosphere, even on Venus (where CO2 makes up 96.5% of the atmosphere rather than our own .038%).

 

So no, the Earth's atmosphere is not 100% inwardly or outwardly reflective so an infinite atmosphere is not acceptable. If it were, we would never see the sun (all light reflected), or we would have burned up long ago when the CO2 concentrations were a hundred times higher than today (all radiation retained).

 

I was comparing Mars to Earth. How did Venus get into the picture?

 

Anyway, I was talking about optical depth, which does not mean that IR radiation does not escape — that would be in violation of thermodynamics. The radiation heat transfer ensures that radiation (mostly in the IR) will escape. The difference between "optically thick" and "semitransparent" is whether the IR is from the earth's surface, or if it is reradiated along the way out.

 

And it's not just the visible portion of the spectrum, though there are plenty of time we can't see the sun. The issue is what does the atmosphere looks like at the wavelengths where the earth is radiating (which is somewhere out in the vicinity of 10 microns).

 

This can be easily calculated from the absorption of gaseous carbon dioxide. See Phys. Rev. 41, 291 - 303 (1932) P. E. Martin and E. F. Barker "The Infrared Absorption Spectrum of Carbon Dioxide".

 

Thomas and Stamnes (ref. 2, page 91) that shows 0% transmittance at 22 km and below for the 15 micron CO2 band. This section discusses the "opaque region" and also gives a very clear discussion of line broadening, which is an additional point that many people are unfamiliar with.

 

Schneider, Kucerovsky, and Brannen (Appl. Opt. 28:5, 1998) give an absorption coefficient at 9.90 ± 1.49 cm-1 atm-1 for low concentrations of CO2 in a 1-atm nitrogen atmosphere at 4.2 microns. This works out to 376 absorbance units per km for 380 ppm CO2, which is about as close to 100% absorption as you can get. Heinz Hug, a global warming skeptic, measured a similar value (0.03 absorbance units/10 cm for 357 ppm at 15μm)

 

from http://brneurosci.org/co2.html

 

That's called optically thick, not semitransparent.

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Well first, I get Venus from post #3 in this thread:

 

If you assume constant optical depth, I don't have a hard time believing that you'd come to a very different conclusion about global warming. But in response, I say, "Venus"

 

There are pleanty of times that we can't see the sun during the day, sure... but that is a very local thing, and not world wide. When we can't see the sun world wide we end up with a year or more of winter.

 

Your link is saying what I have been saying for a long time now, and you should probably read it. Assuiming you agree with the math in that article, the doubling of CO2 would result in a 1.8 degree increase in global temperature, and at the current rate of increase we will see a doubling in... 300 years or so.

 

From that same article you provided:

 

Some climatologists, making assumptions about ever-increasing rates of carbon dioxide production, assert that the doubling will occur within a few decades instead of a few centuries. However, they are doing sociology, not climatology. They are assuming that fossil fuel consumption will increase drastically over current levels. This is very unlikely. The only honest way to estimate the change of CO2 levels is to make predictions based on what is happening now, not what might happen in some hypothetical future society; otherwise, we are merely inflating our predictions by indulging in speculation about future social trends.

 

I agree completely with that statement.

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