Talk:Greenhouse gas

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[edit] Once again, the debate is quashed.

I find it quite disconcerting that, depite claims of scientific merit, any edits to this article that question the human role in global warming are consistently deleted, while statements claiming scientific fact even while a scientific discord exists, are left in without question. Is this the way to come to an educated conclusion on any topic? —The preceding unsigned comment was added by 63.237.28.3 (talk) 19:09, 15 May 2007 (UTC).

It was removed (it would seem) because it was an example of false logic. The global warming issue centers on the very real, observed, and obvious increase in release of CO2 into the atmosphere by the combustion of fossil fuels and the consequent increase in atmospheric CO2. At best the removed material shows evidence that there is a positive feedback mechanism that magnifies the effect of any warming from any cause. The logical approach would be to evaluate the positive feedback effect on the warming caused by the added atmospheric CO2. The illogical approach is to misuse the data to support claims that the CO2 released from the combustion of fossil fuels has no effect. If you want "educated conclusion" more power to you. What was removed wasn't that.

I have no idea what was removed or kept. I do know that using false data like temperature measurements at Airports is not real though observed. The increase in CO2 in the atmosphere is not obviously man made. You want it to be to make your case stick. The logical approach is not to make an incorrect assumption and then force everyone else to believe. The logical approach is to use scientific reasoning to make an argument not 'entry deletion' which is so prevalent. (Jarl87 (talk) 20:55, 2 May 2008 (UTC))

(The comment below applies to the text above.) Minasbeede 15:38, 1 June 2007 (UTC)

No, it's not. Invasion10 08:56, 17 May 2007 (UTC)

[edit] Human methane emissions

I estimate methane emissions in human fart at about 1.7 M tonnes per annum allowing a comparatively modest ~1 litre output per person per day (more in bean-eating areas). Given that methane is 23 times more potent as greenhouse gas than CO2, the anal afterburner is probably an invention waiting to happen. Thought you might like to share this. Have a nice day! Plantsurfer (talk) 10:53, 6 April 2008 (UTC)

[edit] Abundance / power

I'm not sure this [1] helps, or is even correct William M. Connolley (talk) 19:55, 28 April 2008 (UTC)

The original wording was better; e.g., "powerful" is an odd adjective to use here. The bulleted list is awkward. Raymond Arritt (talk) 20:00, 28 April 2008 (UTC)

[edit] Increase rate graph

[Retitled section for accuracy; was "Rate increase graph" New Image Uploader 929 (talk) 03:20, 30 May 2008 (UTC)]

I made a graph for the "Long term trends" section but I'm not allowed to upload it yet. New Image Uploader 929 (talk) 18:28, 13 May 2008 (UTC)

I took out your new text [2]. Sorry. I'd like to see a better source... also it doesn't seem very consistent with the graph at the top or with Image:Major_greenhouse_gas_trends.png. Also these are not rates - fractions - but absolute increments. There ought to be a good source discussing this that you could quote, though William M. Connolley (talk) 19:39, 13 May 2008 (UTC)
What is a better source for this data than the NOAA Mauna Loa observatory? I am adding Dr. Tans' paper cited at the end of the web page. If you look at 1998 on Image:Major greenhouse gas trends.png, you will see that the red line is steepest in 1998, just like the delta is largest in 1998 on my plot. The data are both increases in the proportion (fraction) of air, and rates of change, because they are the year-to-year deltas. If that is not correct, please tell me why. I hope you like the new version. New Image Uploader 929 (talk) 02:02, 15 May 2008 (UTC)
Is this is your own conclusion from the data? If that's the case there should probably be a better reference (something more explicit)? Also, that graph is that taken from the NOAA webpage? that could be copyright violation, although I know very little about how that works.
— Apis (talk) 16:35, 15 May 2008 (UTC)
From the graph in the image the rate looks pretty constant to me (1980-2004)? Although if you look at the image at the top of the page there is a definite change in the curve around 1950. Anyway, maybe thats why I'm a bit confused.
— Apis (talk) 22:05, 15 May 2008 (UTC)
Year-over-year increase of atmospheric CO2
Year-over-year increase of atmospheric CO2
I added the image to the right. It does not look constant to me. It looks consistent with an exponential increase, but since true exponentials can not exist in a proportion domain, it is probably a logistic curve with a non-unity maximum, I hope. New Image Uploader 929 (talk) 00:35, 30 May 2008 (UTC)

Would it be advisable to overlay a linear regression line? New Image Uploader 929 (talk) 03:09, 30 May 2008 (UTC)

Better not fit to a second order model; it looks like a return to 0ppm in about 2040. Wouldn't want to present any inconvenient projections, now would we? blackcloak (talk) 05:02, 7 June 2008 (UTC)

[edit] Automatic archiving

I added automatic archiving to this page? there was a lot of old discussions lying around, not being useful. I hope no one mind?
– Apis (talk) 16:28, 15 May 2008 (UTC)

[edit] Misleading statement in intro

Re: "However, an excess of greenhouse gases can raise the temperature of a planet to lethal levels, as on Venus where the 96.5% carbon dioxide (CO2) atmosphere results in surface temperatures of about 467 °C (872 °F)."

The sentence above states that the CO2 in the atmosphere of Venus is responsible for the high temperature. This most certainly is false. Venus can not serve as a reference point in the discussion on the effect of atmospheric CO2 on atmospheric temperatures. blackcloak (talk) 04:50, 1 June 2008 (UTC)

This most certainly is false. - is it? William M. Connolley (talk) 18:32, 1 June 2008 (UTC)
Remove all the CO2 from the atmosphere of Venus and the temperature would still be lethal (which I'll define as above 100°C). No simulation/calculation necessary. blackcloak (talk) 04:39, 10 June 2008 (UTC)
Are you sure? The atmosphere is 96% CO2. Radiative balance at 0.71 AU with no atmosphere is only 30°C (assuming albedo similar to Earth). The remaining Venusian atmosphere (mostly N2) would provide some enhancement, but it is unlikely that Venus without CO2 would average above 50 C. Extremophile bacteria have been observed all the way up to 121 C. Hence, other factors not withstanding, known organisms could survive the temperature on the surface of Venus if there was no CO2. Dragons flight (talk) 05:08, 10 June 2008 (UTC)

[edit] Subjective and incorrect

'However, an excess of greenhouse gases can raise the temperature of a planet to lethal levels,'

Historically, and scientifically notated, CO2 levels ALWAYS follow global warming and have never been a cause of it. Methane is >20x more potent than CO2 and there is billions of tons of it frozen under the sea. Occasionally this belches to the surface. Also, during the Dinosaur era, CO2 was something like 4-10x the levels of today and yet the global average temp was estimated to be ~4 DegC higher.


'as on Venus where the 96.5% carbon dioxide (CO2) atmosphere results in surface temperatures of about 467 °C (872 °F)'

Totally irrelevant - there are so many other factors involved here. 2nd planet closest to the Sun with an atmosphere 92 times that of Earth. The pressure alone may well account for a considerable amount of temperature. In fact, using the "Combined Gas Law" [3] the temperature (unless my calculations are very wrong and based on Earth's temp 15 degC (ICAO Standard Temp) and volume of 1) it's temperature based on pressure alone should be ~1380 degC - let alone it's proximity to the Sun. Wawny (talk) 23:27, 3 June 2008 (UTC)

Do you have any reliable sources (scientific) for these claims?
—Apis (talk) 01:35, 4 June 2008 (UTC)
Clearly you don't know how to apply gas laws to this situation. Indeed, you can not because temperature equilibrium (black body radiation) has been achieved. You've probably calculated some temperature based on an instantaneous change in pressure, ignoring heat sources and radiative cooling. Here are some relevant considerations. Venus has no significant magnetic field so charged particulates bombard the atmosphere. These may contribute significantly to the energy received by the atmosphere, along with its molecular dissociative properties. This factor in not normally considered because the flux entering earth's atmosphere does not include a charged particle component. An atmosphere 92x earth's pressure means pressure broadened absorption. The 5% non CO2 content (partial pressure) is still 5x more than the earth's pressure, so that component alone might absorb something like (1-.7^5)/(1-.7)=2.8 times the incoming solar power of the earth. Multiply that by 2 because Venus receives approx 2x the power density of the earth and the result is almost 6x the solar power absorbed by earth is absorbed by the atmosphere of Venus- just due to the 5% non CO2 component. The CO2 is 18 times more important, at least in the absorption bands of CO2. Result is essentially no light any where near an absorption band of CO2 is going to make it to the surface. It is fairly safe to say that much of the surface temperature of Venus is due to solar radiation cooking the atmosphere, which in turn heats the surface. My guess is that only a few degrees of surface temperature can be attributable to thermal energy reaching the surface from heat deep within the planet. 92 times 14.7psi on earth means 1350 pounds of atmospheric stuff above every square inch of the surface of Venus. On earth, this would be like the pressure conditions experienced at a depth of 2800 feet below the sea surface level. (All quick back of the envelope calculations, so errors may have crept in.) blackcloak (talk) 06:16, 5 June 2008 (UTC)
As I recall, Venus's albedo is higher than Earths, so the solar in is about the same as Earth, even though its closer to the sun. The energy in charged particles is likely trivial compared to viz. You can't do radiative-xfer on the back of an envelope William M. Connolley (talk) 06:49, 5 June 2008 (UTC)
The "solar in" is still 2x (measured in watts per meter squared) that of earth. What leaves, and from where, (the albedo component, something I did not discuss) is another story. In equilibrium, total power in is equal to total power out (assuming we can neglect any heat contribution originating from within the planet). Since Venus has such an incredibly dense atmosphere, we can pretty easily conclude that only an insignificant amount of incoming solar radiation passes through the atmosphere and reaches the surface without scattering or absorption followed by black body re-emission. Actually "you" can do radiative xfer calculations on the back of an envelope. I just did. Perhaps you can't. But then you are free to do the more precise calculations and present your results- and if they look reasonable, I'll accept them. Not a problem. blackcloak (talk) 05:40, 6 June 2008 (UTC)