Talk:Atmosphere of Earth

Why the ISS needs sails

While the "layers" approach to the atmosphere has its points, reading top to bottom you learn that the International Space Station orbits three layers of atmosphere down from outer space, where the atmosphere is hot enough to melt Aluminium. Another couple layers down you see that the pressure is only a kilopascal, you wonder what it might have been where the ISS is. Wonder on! Since meteors burn up very near the ISS, you assume the atmosphere is dense enough to have some effect. At 1773K and 1 kilopascal, if adiabatically compressed to 1 atmosphere it would have a temperature over a megakelvin! It's worth noting that the concept of "temperature" in such dispersed gasses is stupid.

It's also completely confusing and self contradictory. For instance we learn that's we'll learn about 5 layers presented highest to lowest, except that the ionosphere is part of the thermosphere. Wha?

• Exosphere: 310 mi to 620 mi.
• Ionosphere: 31 mi to 620 mi. "typically overlaps both the exosphere and the thermosphere."
• Thermosphere: 50 mi to 400 mi.

it's like an essay written by a bunch of people who don't bother reading each other's contributions.

Speaking of essays written by fifth-formers, check out Emission:

Emission is the opposite of absorption, it is when an object emits radiation. Objects tend to emit amounts and wavelengths of radiation depending on their "black body" emission curves, therefore hotter objects tend to emit more radiation, with shorter wavelengths. Colder objects emit less radiation, with longer wavelengths.

Which is mighty useful I suppose if you knew what any of those jargon terms ("black body", etc.) meant, and yet had no clue what they meant (because it's trivial and obvious info).

Wouldn't it be great if we deleted the boilerplate child's essay crap and just put a link to something like Emission (electromagnetic radiation). —Preceding unsigned comment added by 76.126.215.43 (talk) 02:42, 9 July 2009 (UTC)

Be BOLD and improve the article yourself. Everyone is a Wikipedia editor. Fix what you feel is wrong, properly Cite your sources and save yourself the headache of writing the above. Oh, and sign your talk page entries. - Ageekgal (talk) 17:37, 6 September 2009 (UTC)

It's not clear to me what needs improving here. You may be misreading the article, which breaks the atmosphere down into five principal layers determined by temperature. The ionosphere is not one of those layers, instead it is one of the layers determined by other properties, as the article makes clear.

The upper 2-3 layers, namely the exosphere, the thermosphere, and some indefinite portion of the mesosphere, are more exposed to ionizing solar radiation and are therefore collectively called the ionosphere. The ionosphere "takes the ionization bullet" for the stratosphere and troposphere, which are not ionized by radiation and are therefore considered below the ionosphere.

Regarding the section on Emission, Wikipedia is written for the well-educated adult, the same audience Britannica targets. Those finding any given Wikipedia article overly technical may find that Simple English Wikipedia meets their needs better. In particular its article on the atmosphere should be a relatively easy read. --Vaughan Pratt (talk) 18:30, 24 November 2009 (UTC)

Ozone Layer Depletion

Of course CFCs are bad for many reasons and should be ditched in favor of more useful technologies like EcoCute, but Ozone layer depletion is best accomplished by such natural and anthropogenic processes as Volcanic Eruptions.

Volcanos and global cooling

Speaking of volcanos, Mt. Pinatubo was the only colossal in the past 95 years; the period from 1783 to 1912 saw four colossals and a supercolossal (worth at least 10 regular colossals by itself). Not all in the same category are the same size. Mt Pinatubo was obviously a dwarf compared to fellow colossal Krakatau. Consequently the 1800s saw vast global cooling, years without summers, etc., which we are pulling out of gradually in the 20th and into the 21st century.

Given some more large eruptions or nuclear war, global cooling will come back, so technically it is within human power to affect. Get to it! But don't imagine humans are ready to equal the volcanos. 140,000,000,000 metric tons? And that's just Tambora.

I know it's a religious topic, not expecting you to repeat anything but the party line (or the never-self-censoring newspapers and journals ;)

Just like to put the well known facts out there occasionally, though I know they have no place in the consensus reality of Wikipedia. You will never win the war against partisans! Assuming that's the war you're fighting...

True enough: aerosols cool, greenhouse gases warm. Regarding the former, volcanos don't run on a sufficiently reliable schedule to entrust cooling to them, and besides what's so great about a sky full of soot? Regarding the latter, when you do the math it turns out that the CO2 output of the average volcano is equivalent to the CO2 breathed out by 400,000 people. At any given time there are some 1,500 active volcanoes, so a population of 600 million breathes out the same amount of CO2 as the world's volcanos, averaged over time over all volcanos including the very occasional colossal. This population was reached around 1700 AD. There now 6 billion humans, so human breath is ten times volcano production of CO2. Of course human breathing is not the whole of anthropogenic CO2 by a long shot. The section "Comparison of CO2 emissions from volcanoes vs. human activities" halfway down the page at the US Geological Survey website estimates that "Human activities release more than 130 times the amount of CO2 emitted by volcanoes." Also see the article Not even close! to see just how wrong Martin Durkin was about volcanic CO2 production in his movie The Great Global Warming Swindle. --Vaughan Pratt (talk) 18:44, 24 November 2009 (UTC)

Carbon Dioxide as "Air Pollution"?

This is a little far-fetched. There are a huge number of environmental benefits to the existence of CO2 and room for much more in quantity. It's not pollution. --82.43.47.6 (talk) 22:33, 18 February 2008 (UTC)

We're actually very near the minimum for photosynthetic plant survival. Bring it and the heat up some more, we free a lot of moribund farmland and what we have becomes more productive. These are good things, and if they're inevitable it's time for the low-lying coastal lands to start planning instead of ineffectively yelling about autos. Invest in fishing futures. Remember the current CO2 content of the atmosphere is 0.004%. If it races up to 1% it's a big problem, and if it hits 10% we all die. But if it only goes up 2.5 times to 0.01% it's good for the biosphere and only a problem to those who think protest accomplishes anything. Good luck with that!

I support this question and I am looking for a change. I suggest that this is not the place to consider the thermal effects CO2, but when you consider CO2 it is essential for life processes on the surface, and probably the subsurface, to classify it as pollution is clearly POV.--Damorbel (talk) 15:08, 19 June 2008 (UTC)

Further thought, according to the greenhouse effect the CO2 content of the atmosphere keeps us all from freezing to death, a tough task. Together with its very real function (see above) it appears to be a very vital form of "pollution".--Damorbel (talk) 15:37, 19 June 2008 (UTC)

As usual, it's a question of the amount. Even O2 is poisonous above a certain level. Looking at reliable sources is the answer. New scientist considers CO2 emissions as pollution[1], as does the New York Times[2], the Globe and Mail[3], and Nationmaster[4]. --Stephan Schulz (talk) 16:59, 19 June 2008 (UTC)

New Scientist? New York Times etc.? These might be thought of as good sources if they gave an explanation but the links do not reveal any reason for classifying CO2 as a pollutant. Citing O2 as poisonous is stretching the matter beyond its elastic limit since the observed effect seems to be the pure gas above atmospheric pressure [[5]]. CO2 is used to stimulate plant growth [6] in this case roses but it is quite easy to find cases where used to promote the growth of vegetables (food!). True enough, CO2 above 10% produces strong symptoms [[7]] but at 0.038% it is a bit early to panic.--Damorbel (talk) 09:50, 3 July 2008 (UTC)

Adding millions of tonnes annually of CO2 to the atmosphere might be nice for plants, etc., but could well change the balance of acidity in many oceanic habitats; coral bleaching events et al. seem to be correlated with these historically more acidic times. I would counsel caution in defining anything as pollution or not- an excess of anything can be considered pollution; see your email inbox for an example of when something nice (say, funny pictures of cats) can become a problem in excess (when everyone you know is sending you them and won't stop). More worryingly, the statement: "While major stationary sources are often identified with air pollution, the greatest source of emissions is actually mobile sources, principally the automobile[citation needed]. " -- this needs to go, it is demonstrably untrue. If you are talking about man-made pollution, industrial and farming sources far outweigh vehicle sources; if you include natural sources then volcanic outgassing is a major contribution far in excess of vehicles and even on a par with industrial sources. 24.5.174.212 (talk) 11:48, 21 October 2008 (UTC)

"Adding millions of tonnes annually of CO2 ...". There are about 2x10^12 tons of CO2 in the atmosphere, about 4000 tons for every man woman and child on the planet. How is it that mankind is going to change this sufficiently alter the acidity of the oceans and to bleach coral? What makes you think that even this amount of CO2 is sufficient to change the oceans acidity? If you are going to counsel caution let it be for a good reason, otherwise you just may make people frightened without a reason. --Damorbel (talk) 08:23, 20 December 2008 (UTC)

Sorry, but mankind is doing it in a number of ways, but primarily by burning fossil fuels. Atmospheric CO2 has risen about 35% in the last 150 or so years, and there is no doubt that the excess CO2 is anthropogenic. As a result, the equilibrium between ocean and air shifts, making the top layer of the ocean absorb more CO2. That CO2 turns into carbonic acid in solution and leads to ocean acidification. This is all well-known. Much of it is primary school chemistry, and none of these facts is in any way controversial, except maybe among a very small fringe.. --Stephan Schulz (talk) 08:43, 20 December 2008 (UTC)

Could you explain how much CO2 has to be absorbed to change the acidity of the sea? The sea contains large quantities of materials, notably calcium, that fix its pH because they are not fully ionized. Because you say "the equilibrium between ocean and air shifts" you give the impression that the pH of seawater is determined by the concentration of CO2 in the atmosphere. In fact the pH of seawater is determined by the dissolved salts see here [Buffering agent] and here [Buffer_solution] A none Wiki link is [pH]. The assertion "CO2 will change the pH of seawater" is completely bald thus an unscientific POV. I have looked at your reference ocean acidification, what it contains are a lot of assertions without data or analysis, clearly POV and "research to prove a thesis" instead of "testing a hypothesis". Look here [[8]], nothing but "possible impacts", is this "scientific proof" in this context, Stephan? --Damorbel (talk) 16:43, 20 December 2008 (UTC)

“Mix carbon dioxide with water and the result is carbonic acid. After that first simple chemical reaction comes a slightly more complicated series of changes in seawater chemistry. The final outcome is a lowering of the ocean's pH [...] Since the beginning of the industrial era, the pH of surface waters has decreased slightly but significantly from 8.2 to 8.1, and it continues to decrease.” See here (NASA). --Harald Khan Ճ 20:05, 20 December 2008 (UTC)

I'm completely confused. All the references say that the ocean pH = 8.2 and that a decrease in pH will cause a decrease in the carbonate ion concentration. However, Carbonic acid says that the pH should be 5.6 with current CO2 concentrations and that increasing the amount of CO2 will slightly increase the carbonate ion concentration. What am I missing? Q Science (talk) 05:55, 21 December 2008 (UTC)

See Le Chatelier's principle for the mechanism driving the process by which Carbonate compensation depth is determined. If the ocean were pure water, atmospheric CO2 would dissolve in it and drop the pH to 5.6 as you say. However limestone cliffs are steadily dissolving into the ocean, and are deposited at the ocean bottom. This steady flow shifts the equilibrium of the equations governing the dissolving of CO2 in the ocean, resulting in a much more basic liquid than if you just start with pure water and add carbon dioxide. --Vaughan Pratt (talk) 20:36, 24 November 2009 (UTC)

Two thoughts

How about some simple models - like the isothermal model - i guess kindof links in with the atmospheric pressure page???? is the air car link really worth having on this page? -deosnt really seem to link seriously with the subject. Wideofthemark

errors on page

This paragraph has errors: During the next few million years, water vapor condensed to form rain and oceans, which began to dissolve carbon dioxide. Approximately 50% of the carbon dioxide would be absorbed into the oceans. One of the earliest types of bacteria were the cyanobacteria. Fossil evidence indicates that these bacteria existed approximately 3.3 billion years ago and were the first oxygen-producing evolving phototropic organisms. They were responsible for the initial conversion of the earth's atmosphere from an anoxic state to an oxic state (that is, from a state without oxygen to a state with oxygen). Being the first to carry out oxygenic photosynthesis, they were able to convert carbon dioxide into oxygen, playing a major role in oxygenating the atmosphere.

1) First, there is no definitive evidence nor consensus that photosynthizing cyannobacteria were present on earth at 3.3 bya, though some scientists argue this. 2.6 ba or earlier is the scientifically safe statement -- see recent paper in nature, and tis references:

[[9]]

2) The paragraph fails to convey what we do and do not know about precambrian oxygen levels. See the same reference above as well as Goldblatt [[10]] This is not my field, and I'm working on another project of interest to me. Is there an earth scientist/ paleoecologist to look into this? I can supply a list of other pertinent references. Loco 00:01, 18 October 2006 (UTC)

3) I don't think mobile sources are the biggest pollutent, under climate change —Preceding unsigned comment added by 71.104.233.30 (talk) 06:14, 30 October 2009 (UTC)

Simple question.Why humans can see sky in a blue color. —Preceding unsigned comment added by 81.132.165.246 (talk • contribs) 18:44, 20 December 2006

The sky appears blue because of a physical effect called Rayleigh scattering. Have a nice day! 24.5.174.212 (talk) 11:52, 21 October 2008 (UTC)

Observational Database?

A large observational database of many different atmospheric constituents from a host of platforms including UARS is available. This was created as part of ESA Envisat and NASA Aura validation. It is of general use. Do you think it should be added to the article text?

Oxygen - air confusion

Shouldn't there be a part of this article about the common confusion between air being oxygen, even though it's obviously not? Because there are definately some people out there who believe air = oxygen, and need to be proven wrong so they can get it right in the future.

Needs to be done IMO.

Evoluton on Earth Section, Oxygen production error

The Evoluton on Earth Section states that Cyanobacteria "... were able to convert carbon dioxide into oxygen[,]" and "Photosynthesising plants would later evolve and convert more carbon dioxide into oxygen." This is an incorrect representation of photosynthesis. Oxygenic Photosynthetic life captures carbon dioxide in organic molecules used for energy storage and tissue construction in a process independent of the light reactions which splits water into gaseous oxygen and hydrogen ions. I've adjusted the passage to correctly reflect this, stating now that "[Cyanobacteria] were able to convert water into oxygen while sequestering carbon dioxide in organic molecules[,]" and "Photosynthesising plants would later evolve and continue releasing oxygen and sequestering carbon dioxide[.]" user:Anonymous 20 June 2007

Evolution on Earth Section, Theory

I believe this section should specify that this is a Theory and NOT fact. One may try to article that there is evidence pointing one direction or the other, however Evolution is STILL just a Theory and has not been proven as Scientific fact. I recommend the following Section Title "Evolution of Earth's Atmosphere, Theory" This is a simple change and is more accurate. —Preceding unsigned comment added by Lordneeko (talk • contribs)

There is no section "Evolution on Earth" in the article. I assume you are talking about Atmosphere_of_Earth#Evolution_of_Earth.27s_atmosphere? This is not an article on biological evolution but uses the word in its normal, general meaning. See wikt:evolution. You may also want to take a look at Scientific theory. Fact and theory are not incompatible things. A well-supported theory is the best and most certain thing science can give us. --Stephan Schulz (talk) 16:06, 12 March 2010 (UTC)

teratonnes

teratonnes aren't a real SI unit. Please can you either use the appropriate SI unit, or don't use the 'tera' prefix and use standard form. —Preceding unsigned comment added by 86.150.129.117 (talk) 20:05, 14 March 2009 (UTC)

Nonsense: see SI prefix Plantsurfer (talk) 20:17, 14 March 2009 (UTC)

I agree with Plantsurfer. Granted terabytes would be unnatural to John von Neumann, for whom kilobytes would have been the limit had bytes been invented then (bytes came in with the IBM 360 in the mid 1960s, before then 6 bits was a popular unit because it was enough for upper case, decimal, and a few punctuation characters). But once you get used to teratonnes at this scale it is very annoying whenever someone edits your carefully chosen 3.72 teratonnes to 3.72×10¹⁵ kg, which is unreadable, unpronounceable, incomprehensible, and indistinguishable from 3.72 googols to the man in the street. The only reason I don't revert such edits is that God only granted each of us finitely many reverts and I'm not about to waste mine that way. --Vaughan Pratt (talk) 06:07, 24 November 2009 (UTC)

vadalism

Hi,

I found someone vandalised this page

"This heating makes air masses less dense so they rise. When an air mass rises, the pressure upon it decreases so it expands, doing work against the opposing penis of the surrounding air"

How much breathable air is on Earth?

I have a question that seems like it would be relevant to this article. How much breathable air is on Earth at any one given time?

I see that the majority of the mass of the atmosphere is below the height of Mt. Everest. I know that most humans can breath naturally up to a height a bit lower than that, but my math is not up to calculating the volume of a spheroid and subtracting the volume the Earth. Obviously there would be some variables, and evaporation, etc. would make it change every so often. But is there a rough estimate of this number out there somewhere?

I would make rough estimate like this:

The real formula is v=4/3 pi a² b, (where π is the mathematical constant pi, and a and b are the equatorial and polar radii) and the volume of the Earth is "1,083,207,317,374 km3, or about 1.08321×10¹² km³, in scientific notation.[1] " But I don't have a good way to use that figure.

So if instead I turn that volume into a regular sphere, it would have a radius of 6371 km, or a diameter of 12742 km (1.08321 x10 ¹² = 4/3 pi r ³, solved for r). Earth's actual diameter varies from 12713 km to 12752 km. So that seems like a pretty good estimate. (It looks like 6371 is actually an official number used to estimate Earth's radius, so maybe that's how they came up with the 1.08321 number). This all seems to have something to do with the Geoid, but to be honest, I don't know enough geography about this concept, and it is difficult to correlate the Geoid with geological heights from "sea level."

So here where I get really rough. I know that the summit of Chimborazo is 6,384.4 km (3,968 mi) from the Earth's center. . I also understand Chimborazo is 6,267 meters above sea level. So, it appears "sea level" is about at 6378.2 km from the center of the earth? On the other hand, my arbitrary "max breathability" elevation is Everest Base Camp @ 5600 m above sea level, or 6,383.8 km from the center of the earth. They probably picked Chimborazo because it's near the equator and so further from the center of the earth than other summits, so I'll just round that number down to 6383. Then I calculate the volume of that larger "breathable" sphere as 1.08934 E+12.

By the way, I have no idea how the differences in gravitation affect the breathability of air above the pole vs. above the equator, but someone out there must know. It would be interesting to compare a calculation of the volume of air using that data and the v=4/3 pi a² b formula, or even more sophisticated methods, vs. this attempt.

So the difference between the two spheres is 6,129,226,437 km³. Does anyone have a real number to correct my back of the napkin figure? —Preceding unsigned comment added by Joevans3 (talk • contribs) 16:54, 27 July 2009 (UTC)

It depends on what you mean by "breathable air." One meaning would be the volume of the atmosphere when all of it is compressed to STP, which I calculated just now in the section immediately below as 3.9805×10⁹ km³. Another meaning, which may be the one you have in mind, is the volume of air at a sufficient pressure to be breathable, without compressing it at all, which could well be in the neighborhood of twice the compressed value. That is, the first digit in 6,129,226,437 km³ looks quite reasonable, although I wouldn't bet my life on the 7 at the other end (must have been a large napkin). --Vaughan Pratt (talk) 03:19, 24 November 2009 (UTC)

Constant pressure height is wrong

The article says

Were atmospheric density to remain constant with height the atmosphere would terminate abruptly at 7.81 km (25,600 ft). 

I think this should be 8.498 km. Using data from NASA

14.71 psi surface pressure

0.07597 lb/ft3 surface density

(14.17 lb/in2 * 144 in2/ft2) / 0.07597 lb/ft3 = 27,882.59 ft -> 8,498 m

Q Science (talk) 22:52, 21 September 2009 (UTC)

I can't deal with those weird units, but let's double check:

density = (101325 Pa) / ((287.1 J kg-1 K-1) * 288 K)) = 1.225 kg m-3

scale height = (101325 Pa) / ((1.225 kg m-3) (9.8 m s-1)) = 8440 m

The expression can be algebraically simplified to Z = Rd T / g = (287.1 J kg-1 K-1) (288 K) / (9.8 m s-2) = 8437 m which works out within rounding error of the previous value and is close enough to what you get. Short Brigade Harvester Boris (talk) 23:55, 21 September 2009 (UTC)

The difference appears to be the density. According to this NASA reference

Surface density is 1.217 kg/m3 at 288 K (15 C), which gives a scale height of 8495.7 m (using your equation)

One of the failings of wikipedia articles (in general) is any discussion of how values like this vary depending on the source. In this case, I will agree that NASA appears to have the wrong (perhaps an older) value.

A reverse calculation indicates that the original 7.81 km would be correct for a temperature of 266.6 K. I wish that whoever added the original value had added a bit more information on where it came from. In keeping with that, I suggest some sort of note. Q Science (talk) 07:44, 22 September 2009 (UTC)

Unfortunately all the math above assumes that surface pressure is a good indicator of the actual total volume of Earth's atmosphere at STP, which it isn't because the Earth is far from being a perfect sphere, or even perfect oblate spheroid, at an 8 km scale (already Mt. Everest at 8.84 km has its top kilometer in a vacuum in this constant-pressure scenario).

A more accurate way of computing the volume at STP is by dividing the weight of the atmosphere, 5.148×10¹⁸ kg, by the weight .02897/.02240 = 1.2933 kg of a cubic meter of air (.02897 is a commonly-quoted weight in kg of a mole of air while .02240 is the number of cubic meters in a mole of any gas at STP). So, 5.148/1.2933 = 3.9805, making the volume of the total atmosphere 3.9805×10¹⁸ m³. Divide this by the surface of the earth, 5.10×10¹⁴ m², and one obtains 7,805 m, which rounds up to 7.81 km.

But is the difference between 7.81 km and 8.44 km a big deal for a hypothetical number that serves only to convey a sense of how much air there is? That the atmosphere extends beyond 100 km doesn't give as good a feel for how much air there is as saying that it would only reach to 8 km if the pressure didn't decrease. Given that the remaining digits depend on how you define the concept, how meaningful is a value with more precision than a simple 8 km? --Vaughan Pratt (talk) 01:15, 24 November 2009 (UTC)

It occurs to me that an argument that can be made for the 8.44 km figure is that it is exactly what the scale height of the atmosphere would be under the assumption of zero lapse rate. This is an easily seen consequence of the integral of e^x being itself. The reason the actual scale height is less than 8.44 km is because the temperature lapses going up, resulting in a denser atmosphere higher up than with no lapse. --Vaughan Pratt (talk) 19:18, 9 January 2010 (UTC)

Zero lapse rate is what "constant temperature" means. And it is true that using 0 C will give a different value than 15 C. In Scale height, it specifically says that the surface temperature should be used. Thus, 15 C is more correct than STP (0 C). Starting with the "total mass" is a bad idea because that value is most likely computed from the values you want to compute. Q Science (talk) 02:30, 10 January 2010 (UTC)

While I'm sure we're in agreement on every point here, let me just make a more precise statement to be sure. No matter what temperature one takes as "standard," "surface," or anything else, the scale height for a constant-temperature atmosphere will be identical to the result of calculating the constant-density height at that same temperature, assuming no lateral motion of air when adjusting its density to be constant.

Yes, I agree, except that the choice of temperature appears to be part of the definition of "scale height". Q Science (talk) 08:40, 10 January 2010 (UTC)

Another way of saying this, still assuming constant temperature T for any T, is that if you trap a one-square-meter vertical column of air, put a cap on it so high as to capture essentially all the air in the column, switch off gravity, and push the cap down isothermally (not adiabatically) until the pressure throughout the column (which will now be uniform) equals the original surface pressure, the cap will turn out to be exactly at the scale height at that temperature. --Vaughan Pratt (talk) 03:45, 10 January 2010 (UTC)

Also true, but with the same caveat as above. Q Science (talk) 08:40, 10 January 2010 (UTC)

Atmospheric Chemistry and Physics by Seinfeld and Pandis uses 253K to compute a scale height of 7.4km where 253K is the average of the surface temperature (288K) and the tropopause temperature (217K). I think this qualifies as an alternate definition of the scale height. Q Science (talk) 22:52, 11 January 2010 (UTC)

CO2 concentration

The numbers for the percentage of Carbon dioxide in the atmosphere are contradictory. The table says 383 ppmv (0.0383%). The pie chart in the right hand columns says 0.035%. c.pergiel (71.117.211.59 (talk) 01:08, 21 November 2009 (UTC))

That's because the numbers are changing, specifically, increasing. The current trailing 12 month value for the Mauna Loa site is 387 ppmv (0.0387%). This time next year it will probably be just shy of 389 ppmv. Short Brigade Harvester Boris (talk) 01:28, 21 November 2009 (UTC)

Updated CO2 and CH4 to 2008 levels per Mauna Loa and NOAA records respectively (both table on left and pie chart on right). Happy to update these and other values further as needed (but give the source). (I'm only aware of significant changes to CO2 and CH4, perhaps because their increasing levels are allegedly the ones having the biggest impact.) --Vaughan Pratt (talk) 04:13, 24 November 2009 (UTC)

I am hesitant to make the change myself because there could be something I am missing, but I am under the belief that the value for CO2 should now be 0.039x%.Mycologyauthor (talk) 13:48, 18 June 2010 (UTC)

That's a tad high unless you're rounding. At the beginning of 2010 the Mauna Loa reading (column 8 which removes the annual cycle and stiffens the curve a bit) was close to 388 ppmv, so go with that.

For future reference the derivative of the Keeling curve is remarkably accurately approximated over its whole 62-year range by the amazingly simple formula exp(t) where t is time in units of 60.0 years since 1718 AD. Taking that as the nominal onset of the Industrial Revolution, we can call the present year 2010 - 1718 = 292 IR (Industrial Revolution). Since exp(292/60) = 129.89 and exp(293/60) = 132.1, and since the integral of exp(t) is exp(t) plus a constant that doesn't impact differences, it follows that the CO2 level is increasing by very close to 2 ppmv per year or 1 ppmv per 6 months. Taking 388 to be the January 2010 level, updating it to 389 or .0389% would be very reasonable for June 2010. At year's end it should be updated to .0390%. Or consult the Mauna Loa records, but my procedure is simpler. --Vaughan Pratt (talk) 03:28, 30 June 2010 (UTC)

Atmospheric Color

The atmospheric color listed in the article is blue. While the explanation of why this is is correct (shorter wavelengths of light scatter more), this is not, in fact, true. The sky is actually purple (or ultraviolet, but generally the color of an object is understood to be limited to the visible ranges of light). Violet light has a shorter wavelength than blue light and so scatters yet more. The sky only appears blue because the human eye is tuned to see blue more easily than purple. See:

[11] [12] [13]

137.150.198.219 (talk) 21:19, 3 December 2009 (UTC)The Smiling Bandit

In one sense you are right, the amount of scattering is inversely proportional to wavelength but when the term color is used it is a matter of what the eye sees, you will find further explanation here Photometry (optics). --Damorbel (talk) 06:46, 4 December 2009 (UTC)

(I used to teach this stuff long ago at Stanford in CS248A,B (Computer Graphics) before we hired Marc Levoy and Pat Hanrahan.) Here's the scoop. Violet is a color one can see (look at a spectrum). The sky is obviously not the color one can see at the violet end of the spectrum, it is much more blue than that as anyone can tell just by looking, and moreover not a saturated blue but more of a pastel blue.

While there's some truth to "the human eye can see blue more easily than violet," that can't be all there is to it or if you turned down the intensity of blue light it would look more violet, which it doesn't, yet there is nonetheless a color we recognize as violet (and it isn't purple or magenta, which are colors that have red in them). The human eye can only distinguish between colors that live in a three-dimensional subspace of the infinite (or at least very high) dimensional space of all physical colors, i.e. all spectra in the visible range. This is because the eye has only three kinds of cones sensitive to long, medium, and short wavelengths, abbreviated L, M, S. Here are the criteria by which the eye makes its primary distinctions.

The eye's response even to coherent (single-wavelength) light is quite subtle. The conventional monochromatic colors from short to long are violet, indigo, blue, green, yellow, orange, and red. Violet is the wavelength that registers only with the S cones, the M and L cones do not respond to violet. Indigo has a strong S response and weak M and L; it has a reddish tinge to it because L is relatively strong compared to M just there. As one moves to Blue S remains relatively strong, M starts climbing, but L does not climb as fast as M and the reddish tinge of indigo therefore disappears, not to return until much later when M peaks and L starts to overtake it. Moving towards the tricky blue-green transition, S starts declining while M climbs just as fast but with L also climbing and not that far behind M, with that transition being where S and M are balanced. Green is where S is mostly gone, M is peaking, and L is getting near its peak. Yellow is when S is gone, M is fading, and L is peaking. Orange still has some M but much weaker than L. Red is when S and M are essentially gone and L is fading, with the deepest red corresponding to L weakening until the end of the visible spectrum is reached.

The blue of the sky is none of these but rather a pastel color resulting from a spectrum that shades off smoothly from the violet end all the way down to the deep red end--a little red is necessary for the pastel effect. This smooth rolloff is a different physical spectrum from what is obtained by taking pure white (all three colors) and mixing in some purely monochromatic blue, but to the unaided eye these two quite distinct physical spectra are completely indistinguishable. ("Unaided" is important because one can distinguish them with filters, a trick used in WW2 by the French to spot camouflaged German tanks whose camouflage used a spectrum very unlike what it was trying to blend in with.) Therefore to the eye the sky is a medium pastel blue. --Vaughan Pratt (talk) 05:07, 10 January 2010 (UTC)

The part about the low altitude pastel blue needing some red, is true-- if you go to high altitudes, an act which removes more red than blue, the sky really does turn far more purple. This is NOT just due to lack of light and the black of space showing through, for then it would look similar to the low altitude sky at twilight (same light intensity) and it doesn't. The high altitude sky, even adjusted for the same light intensity as below, is quite a different color. SBHarris 06:00, 10 January 2010 (UTC)

Viewing the sky from a high altitude decreases the path length of sunlight through the atmosphere, whereas viewing it from the ground with the sun low increases the length. The latter further scatters the light, compensating to some extent for the reduction in total light from the Sun and therefore not producing anything like the darkening effect of decreasing the path length. There is therefore no reason to expect any similarity between the two. --Vaughan Pratt (talk) 11:46, 16 January 2010 (UTC)

The Rayleigh scattering is not the only effect giving the sky its colour, water droplets scatter quite strongly even when not visible as clouds, they are too big to have a wavelength effect but scatter white light and thus spoil visibility, it is why hills fade with distance (perhaps I'm wrong about the colour of water scattering, what is it that gives distant hills that purple tint, perhaps both effects are at work.)--Damorbel (talk) 10:34, 10 January 2010 (UTC)

Water vapor consisting of H2O in gas form averages 1% of the atmosphere and as such contributes negligibly to total Rayleigh scattering by oxygen and nitrogen. Scattering is more pronounced when the water vapor condenses to water droplets, which along with a wide range of aerosols is covered under Mie theory and visibility. --Vaughan Pratt (talk) 11:46, 16 January 2010 (UTC)

Composition wrong? Sum >100%

Pavel.taborsky (talk) 13:01, 10 December 2009 (UTC) In the composition, when I sum up just the four most abundant species (N2, O2, Ar, CO2), the sum is 100.0027 %. Does NASA have it wrong? Perhaps in some moment they just increased the CO2 level and did not compensate that by decreasing other fractions?

True, it is wrong. The values in the table add up to 1000054.49 (that is about 100.0055%). Furthermore, the side diagram shows the sector for "all others" (not labeled) on the top disk as 0.037680% of the total, but just the CO₂ portion, as shown on the bottom disk, is greater than that (0.0387%). Could someone please check the sources? Cema (talk) 06:27, 14 December 2009 (UTC)

Oh, good, I'm not crazy. Bottom pie chart adds up >.004%, significantly higher that .003768Skptk (talk) 07:35, 21 December 2009 (UTC)skptk

pressure/altitude graph

http://en.wikipedia.org/wiki/File:Atmosphere_model.png

What are these dashed horizontal lines in semilogarithmic pattern for? It would be ok if values at solid lines were 10 times different, so that they correspont to 2e-6, 3e-6, etc but they are 1000 times different. —Preceding unsigned comment added by Linefeed (talk • contribs) 22:11, 28 December 2009 (UTC)

That is a pretty standard way to draw a semilog graph. The horizontal dashed lines are 1, 2, 3 ... for the associated decade. Q Science (talk) 01:32, 10 January 2010 (UTC)

But here is no 'associated' decade - solid lines differ by 1000-fold, not 10. After 1E-6 (solid line) are there supposed to be 2E-6, 3E-6, ... 9E-6 and right afer it 1E-3? Linefeed (talk) 19:12, 28 January 2010 (UTC)

Article probation

Please note that, by a decision of the Wikipedia community, this article and others relating to climate change (broadly construed) has been placed under article probation. Editors making disruptive edits may be blocked temporarily from editing the encyclopedia, or subject to other administrative remedies, according to standards that may be higher than elsewhere on Wikipedia. Please see Wikipedia:General sanctions/Climate change probation for full information and to review the decision. -- ChrisO (talk) 15:58, 2 January 2010 (UTC)

Structure of the Atmosphere: Diagram vs. Explanation

Under the "Structure of the Atmosphere" heading, there is both a diagram illustrating the layers of the atmosphere and a textual explanation of each layer. However, while the diagram is shown in a highest to lowest altitude, the textual explanation is shown in a lowest to highest altitude, creating potential confusion. Should this be resolved? Titus.jon (talk) 02:45, 13 January 2010 (UTC)

I agree. And it used to be that way. However, someone changed it because he could. I argued against the change, but there was no support. Q Science (talk) 08:41, 13 January 2010 (UTC)

Adding Photo of Atmospheric Layers

I have absolutely loved this photo, as it is an actual photograph that clearly demonstrates each of the bottom layers of the atmosphere in some significant detail:

Clouds can be found in the troposphere, the stratosphere even shows the stratification toward the bottom of the photo in the bands (that is the "white" band), the mesosphere is in blue, and the blurring to the mesosphere is also visible.

For the purposes of this article I'll admit that the Shuttle Endeavor sort of gets in the way, but it also acts as "proof" that this is a photo and not an artistic rendering. It is a gorgeous sunset image from space too, but the point is that a photo can certainly add some significant impact to articles of this nature.

Now the question is where to place the image in the article, and if the "details" of this image should be perhaps be rendered upon the image as captions and arrows noting the various layers, or simply left as-is for the artistic beauty that the photograph offers and the layer details simply be done as a pure textual description?

It should be added, I'm just looking for some feedback on how to treat it. --Robert Horning (talk) 22:41, 22 March 2010 (UTC)

Preserving good-faith edits

The following good faith edits were removed (rightly I think), but with some more work parts of it could be added to the article. This section is to preserve the "raw material". Martijn Meijering (talk) 14:56, 23 April 2010 (UTC)

Since the formation of the Earth 4.5 billion years ago, our planet has undergone vast changes. The early Earth was bombarded continuously by meteorites, which heated and melted much of the planet. As the solar system aged, meteorites impacted our planet less frequently. With the outgassing of volcanoes and the development of our atmosphere, we are now protected from many of the smaller celestial objects that may cross our orbit.

Radioactive materials present at the time of Earth’s formation have continued to decay producing large amounts of internal heat. We see the effects of these two forces and their energies in the volcanic activity present on Earth today. Earth also receives energy from a nuclear reaction as well. Our Sun is a large sphere of gas and its largest component is hydrogen gas.

The hydrogen molecules are under intense gravitational forces, which, combined with frictional forces, are enough to cause individual hydrogen molecules to undergo a nuclear fusion reaction creating molecules of helium and liberating vast amounts of energy.

This energy is given off as electromagnetic waves; some of this radiation is in our visible range. The light from the sun travels through space and is absorbed by the Earth. Most of the radiation from the Sun passes right through the thin atmosphere or is reflected back into space.

The Earth absorbs the light energy or radiant energy and heats up. It then re-radiates the heat out and up into the atmosphere as heat energy or infrared radiation. The Sun’s energy is necessary for almost all life on Earth. This is especially true for humans.

(i got all info from my earth science class. this section is seperate from the wiki page)

Space/atmosphere boundary

The second paragraph down from the start of this article includes the sentence, "The atmosphere becomes thinner and thinner with increasing altitude, with no definite boundary between the atmosphere and outer space."

I view this as being inaccurate since a recent discovery was made showing definitively the boundary between the atmosphere and space. Should this article be revised to reflect this new data?

Further details can be found in the www.space.com news article, "Edge of Space Found." This is the link: http://www.space.com/scienceastronomy/090409-edge-space.html —Preceding unsigned comment added by 67.170.91.242 (talk) 17:25, 11 July 2010 (UTC)

That page you link to is highly inconclusive at best. It states even within itself that there are many ways to judge the boundary between space and atmosphere. And then goes on to say that using one method only, charged particle flow, that they can say that is somehow the way to judge the definitive boundary. But they give no justification as to why that method should be the "proper", or definitive, method. HumphreyW (talk) 23:52, 11 July 2010 (UTC)

nitrogen

i think i commented on this earlier, but 78.09% nitrogen seems ... kind of high? i'm going to go ahead and change this to oxygen. i assume that is what it is supposed to be, and hopefully no-one will complain. -sio. (talk) 18:00, 9 August 2010 (UTC)

picture

it is a nice blue color... but what is that planet? ... -sio. (talk) 18:00, 9 August 2010 (UTC)