From Wikipedia, the free encyclopedia

= Image Issues Hey guys... The graph that starts at 1960 to the present is horribly biased and obviously trying to push an axe to grind (an agenda...) Could you guy please uphold Wikipedia's reputation of being credible by getting a graph that more accurately describes the trends of global warming? Starting the graph at 1960 makes the increase in CO2 seem much larger than it is relative to the Earth's holistic history...

Contents 1 Concentration - Global Warming Statement 2 Concentration - figures and reference 2.1 Timothy Ball disagrees with this article... 2.2 Relationship with oceanic concentration 2.3 Erroneous Comparisons 2.4 Concentration Metric

[edit] Concentration - Global Warming Statement

You state that "Increased amounts of CO2 in the atmosphere tend to enhance the greenhouse effect and thus contribute to global warming.". This is a theory, not a proven fact (albeit a much hyped theory). Could you make that clear, please?

Jqlr 12:05, 8 June 2007 (UTC)

I tried to make it more neutral and linked it to the appropriate page. Sln3412 22:14, 19 June 2007 (UTC)

[edit] Concentration - figures and reference

The references for this aren't very good, neither one lists the % by weight nor the number of tonnes. What "pre-industrial" is isn't defined either. Obviously, that's supposed to be an average of 228 - what years were the average 228?

As of January 2007, the earth's atmospheric CO2 concentration is about 0.0383% by volume (383 ppmv) or 0.0582% by weight.[1] This represents about 2.996×1012 tonnes, and is estimated to be 105 ppm (37.77%) above the pre-industrial average.[2]

Sln3412 22:18, 19 June 2007 (UTC)

In fact, I don't know why the weight is important for a gas. I think the weight can be dropped and only ppm by volume used. --Sln3412 22:44, 19 June 2007 (UTC)

alexselkirk1704 suggests; More could be said about the natural mechanisms that remove carbon dioxide from the atmosphere and some estimates of its duration therein.

[edit] Timothy Ball disagrees with this article...

(Red collar 02:42, 7 October 2007 (UTC))

There is a line in this article: Carbon dioxide in the Earth's atmosphere, under the sub-title Historical variation.

It is mentioned that "Present carbon dioxide levels are likely higher now than at any time during the past 20 myr[17] and certainly higher than in the last few hundred thousand."

I believe this to be misleading, or at least it's only part of the truth.

I've just hear a podcast available on this page: http://splatto.mypodcast.com/2007/05/Dr_Tim_Ball_Why_Theres_Nothing_New_About_Climate_Change-19494.html

That podcast is more than an hour long. At 44:28, Timothy Ball says this:

...(this 600 million year graph for CO2) what it shows you, um, is that the current level of CO2 in the atmosphere is 385ppm. And then you go back in time, you see that we're ac... The world is actually at the lowest level of CO2 in the atmosphere in 600 000 000 years. Not the highest as they want you to believe. And if you look at the CO2 in the past, ...(garbled)...at the 4000 ppm... You know there's thing out of the west coast, they've got these greenhouses, they're pumping in a thousand parts per million of CO2 because the plants grow four times more efficiently and use less water. It suggests that the plants have evolved on a planet that had at least 1000ppm of CO2. CO2 is a natural gas (that is) very important to vegetation. Did the plants get a vote on Kyoto (Kyoto Protocol)? (laughter) Not a scrap of it...

The podcast is dated Saturday, May 26, 2007, and it's called "Dr. Tim Ball: Why There’s Nothing New About Climate Change"

It's a conference from Tim Ball where he mentions that historically, CO2 levels have reached 4000 (four thousand)ppm.

This is even confirmed by the actual texte.

In the Carbon dioxide in the Earth's atmosphere text, we are told...

While these measurements give much less precise estimates of carbon dioxide concentration than ice cores, there is evidence for very high CO2 volume concentrations between 200 and 150 myr BP of over 3,000 ppm and between 600 and 400 myr BP of over 6,000 ppm.[16]

...but in the same paragraph, we are told...

Present carbon dioxide levels are likely higher now than at any time during the past 20 myr[17] and certainly higher than in the last few hundred thousand.

I'm getting the impression that the article is misleading.

If we did reach the level of 1000ppm of CO2, plants worldwide would thrive and need less water. The direct effect of that would be that plants would consume more CO2 and CO2 in the atmosphere would taper off or decrease and we'd enter a new cycle.

Dr. Timothy Ball is a retired weather expert who has published and has been reviewed by peers. Since he does know something about the environment, I do not want to ignore his opinion offhand. This being said, I do not know the copyright status of that podcast. If I can use it here on Wikipedia, I'm uncertain as to how I can use it. That's why I haven't edited the main page.

I'm not an expert, I don't understand why C4 plants are mentioned on that page. That, and the importance of saying that current levels are at their highest (when they're really not).

Ball's comments are a mishmash of red herrings and incoherent raving. (How's that for a mental image?) What happened several hundred million years ago is utterly irrelevant to the present day. Hint: this is what a map of the world looked like back then.[1] Raymond Arritt 03:07, 7 October 2007 (UTC)

Here's the mental image I'd like to leave you with. You need about one and a half pounds of food every day. Each day when you look in the cupboard you see only three pounds of food. That's not a lot compared with what most Americans are used to looking at when they're hungry. It's more like what those living in poverty in third world countries experience. But that is just what each and every plant on Earth sees every day when it comes to the staple of their existence, carbon. If there were half has much CO2 as there is in the atmosphere, everything, including you, dear sir, would start to die. blackcloak (talk) 05:26, 27 February 2008 (UTC)

"If we did reach the level of 1000ppm of CO2, plants worldwide would thrive and need less water. The direct effect of that would be that plants would consume more CO2 and CO2 in the atmosphere would taper off or decrease and we'd enter a new cycle." This is not a valid conclusion because it is grossly simplistic. To create a net sink of carbon in terrestrial plants you'd have to store that extra carbon somewhere. But there is no reason to believe that would happen. Yes, presumably plants would grow faster but they would also shed leaves and decompose faster in the yearly cycles. This would tend to balance the net carbon budget over a year. To the contrary, if increased CO2 led to warming in the polar latitudes this could trigger mass decomposition of the accumulated peat which would then increase CO2 concentrations even more. On the other hand, however, increasing CO2 concentrations could stimulate oceanic phytoplankton to grow faster, which could then sink to the bottom of the ocean, thus sequestering carbon. However, the response of the ocean to increased CO2 is a very complicated issue and nobody really knows for sure what will happen since there are several other scenarios which would have the opposite effect. That is what scientists right now are trying to better understand. --Kram-bc (talk) 06:40, 12 March 2008 (UTC)

[edit] Relationship with oceanic concentration

"The vast majority of CO2 added to the atmosphere will eventually be absorbed by the oceans and become bicarbonate ion, but the process takes on the order of a hundred years because most seawater rarely comes near the surface."

That last part can't be true for two reasons. First the churning of the sea surface mixes atmospheric gases with the water quite well. We know this because sufficient oxygen gets into sea water to support life- especially in the top 100 meters or so. Second there is rain. Time to do a little back of the envelope calculation. Let average rainfall per year be 200mm over the entire surface of the globe. So the volume of water that washes the atmosphere in one year is: pi*D^2*200mm=3*8000*8000*5280*5280*300*300*200mm^3=10^23mm^3. Let an average raindrop be 1mm in diameter, so its volume is .5mm^3. So the number of rain drops that fall in a year is 10^23/.5=2*10^23. And the total surface area of all the raindrops that fall in one year is 2*10^23*3*1^2=6*10^23mm^2. Finally, how many times larger is this number than the entire surface of the globe? The Earth's surface area is 5*10^20mm^2, so one years worth of rain presents a water to atmosphere surface that is 6*10^23/(5*10^20)=1000 times the surface area of the Earth. That sounds like plenty of opportunity for trapping co2 to me. We then assume that amount of co2 that enters each raindrop is a modest .001 by weight (although the major path for disolution may be in the formation of the raindrops), (1cc is one gram) so 10^20gm*.001=10^17grams of CO2=10^14kg=10^11metric tons, which compared with 3*10^12metric tons of co2 in the atmosphere, means 3% of atmospheric co2 is removed from the atmosphere by rain every year. And it also means that, effectively, all atmospheric co2 is cycled out of the atmosphere every 33 years. Of course there still is the ocean surface, which can probably be considered to be in equilibrium with the atmosphere at the surface, so movement either way is likely to be balanced. An of course, I used one tricky number (part by weight absorption) that easily could be way off and could dramatically effect the calculation. blackcloak (talk) 08:48, 18 January 2008 (UTC)

CO2 (a nonpolar gas) is only poorly miscible in water (a highly polar solvent). For sea water the result is ~90 mg/kg, or 90 ppm by weight. So it is likely your guess for the amount of CO2 in rain is too high by more than an order of magnitude. Further, isotopic and mass balance studies suggest about 11 gigatonnes CO2 shifts from the atmosphere to the ocean per year under current conditions, rather than the 100 gigatonnes you suggest.

Also, even if your analysis were correct, Wikipedia's policy on original research requires that analysis be previously published rather than our own interpretations. Dragons flight (talk) 10:06, 18 January 2008 (UTC)

While you are right about the policy, in practice what happens is wiki authors describe their interpretation of what they read in published material, and they often get it wrong, especially as they dumb it down. I'm convinced that many wiki authors are not well trained hard scientists, and easily fall into traps about definition and logic. blackcloak (talk) 06:56, 1 May 2008 (UTC)

In this case, back of the envelope calculations are done as sanity checks, not as original research. There are several respects with which my numbers could be wrong. I have not seen any published work that specifically says that rain is not a significant factor in the removal of CO2. So using your number (.0001 for seawater, instead of my guess of .001 for rainwater) for the ratio by weight, my computed estimates correspond quite closely to your numbers. But the question that has to be asked is: Is rainwater significantly different from seawater when it comes to CO2 concentration? I can imagine that rainwater strikes the oceans at pH 5.7, along with its load of CO2, mixes with the top layers of the ocean during the rain storm, then is slowly dissipated back to the atmosphere as equilibrium is returned to the seawater/atmosphere boundary. Of course some of the CO2 would stay, feeding life in the upper layers, a proportion of which is then captured in solid form and falls to the ocean floor. blackcloak (talk) 07:13, 22 January 2008 (UTC)

[edit] Erroneous Comparisons

The differences between the 1832 ice core and the more recently determined Mauna Loa atmospheric concentrations of carbon dioxide should not be used to argue for or against any trends. Mauna Loa is a subtropical to tropical volcanic island over a major oceanic hot spot that is releasing gases into the ocean and into the atmosphere. We've been measuring the carbon dioxide atmospheric changes in this area for only 48 years, hardly long enough to know if it is part of a multidecadal, or multicentury cycle involving oceanic or wind currents, varying vulcanism in the earth's crust, or to some other yet unknown or undiscovered factors. The ice core comes from an environment most likely devoid of carbon dioxide producing vegetation at a much higher latitude with insignificant vulcanism in the vicinity. Furthermore, the water temperatures are different in these enviroments. The amounts and types of precipitation are different as well. In my opinion, comparing atmospheric carbon dioxide concentrations in these very different environments as if they represented some 180 year trend for the entire earth, goes way beyond ludicrous.

This entire article doesn't pass my credibility test and, in my opinion, should be removed from Wikipedia.

Norm (talk) 03:27, 8 February 2008 (UTC)

CO2 is globally well mixed, in general William M. Connolley (talk) 08:14, 8 February 2008 (UTC)

Since CO2 is about 50% more dense than the vast majority of the molecules of the atmosphere, in principle, it should slowly sink towards the earth. It seems reasonable to conjecture that there is a CO2 density profile with the greatest concentration at the surface of the earth. Has anyone published mearsuremnts that might confirm this trend? blackcloak (talk) 04:53, 27 February 2008 (UTC)

You may have noticed the weather. The stirring of winds and large scale convection totally overwhelm density driven seperation. And yes, CO2 profiles have been measured versus altitude. Dragons flight (talk) 18:45, 27 February 2008 (UTC)

Look at the graph. If what you say is true you would not see anything so consistent from year to year, in both yearly fluctuations and yearly upward trend. If volcanoes in fact biased the measurements on Mauna Loa, as you suggest, then you'd see lots of yearly fluctuations. Furthermore, if CO2 had a vertical concentration gradient, which it doesn't to any significant degree, then if anything the measurements on Mauna Loa would underestimate its concentration because it is on a mountain.--Kram-bc (talk) 06:51, 12 March 2008 (UTC)

[edit] Concentration Metric

This sentence from the Concentration section of the article just doesn't make sense: The National Oceanic and Atmospheric Administration describes current levels "...as a dry mole fraction defined as the number of molecules of carbon dioxide divided by the number of molecules of dry air multiplied by one million (ppm).

Maybe it should say The National Oceanic and Atmospheric Administration defines concentration as "...as a dry mole fraction defined as the number of molecules of carbon dioxide divided by the number of molecules of dry air multiplied by one million (ppm).

Even then it's self referential since normal dry air contains carbon dioxide, so may be it should be normal dry air less the carbon dioxide content - in any case it's just inconsistent as is. Unfortunately I don't know enough to make a correction. Furthermore other sections refer to concentration by volume, which is fine so long as the implicit assumption of the ideality of carbon dioxide and other components of air is taken as read, which one shouldn't have to do.Fizzackerly (talk) 15:14, 17 March 2008 (UTC)

I rephrased it to what I think it means, roughly equivalent to your version. I don't see why its self-ref though... dry air is (not-CO2)+(CO2) and the fraction is (CO2)/((not-CO2)+(CO2)). Since the not-CO2 bit is pretty constant, this seems OK. CO2 is only 0.04%, so it wouldn't matter much if you did CO2/not-CO2 William M. Connolley (talk) 18:58, 17 March 2008 (UTC)