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How to turn 6 pounds of gasoline into 20 pounds of carbon dioxide
Short answer: When you burn something, it might feel like you’re turning it into lightness, air, nothingness. But what you’re really doing is simultaneously vaporizing it and chemically bonding it with oxygen in the air to make it much heavier than it was in solid form. Carbon dioxide — or CO2 — is one carbon atom joined to two oxygen atoms. Carbon dioxide. CO2. Oxygen is a little bit heavier than carbon, so when you stick two oxygen atoms onto every available carbon atom, you roughly triple the weight of the gasoline. Long answer: One gallon of gas weighs about 6.25 pounds. The weight fluctuates with temperature and octane, but this figure is good enough for government work. Let’s pretend that gas is entirely made up of octane (more properly referred to as 2,2,4-trimethylpentane). It’s not, but that also doesn’t really matter for our purposes. Octane contains 8 carbon atoms (hence the oct- prefix, like Dr. Octopus) and 18 hydrogen atoms. Carbon has a molecular weight of 12 and hydrogen has a molecular weight of 1, so octane has a total molecular weight of 114 (8 x 12 + 18 x 1). Oxygen has a molecular weight of 16, so CO2 has a total molecular weight of 44 (12 + 16 + 16). Every molecule of octane makes eight molecules of CO2, with a total molecular weight of 352 (44 x 8). 6.25 pounds x (352 / 114) = 19.3 pounds Et voila! All it takes to convert 6 pounds of gas into 20 pounds of carbon dioxide is some highly confusing algebra! Bonus material: Gas doesn’t burn 100% cleanly. You also get some carbon monoxide and other nasty stuff coming out of your tailpipe. But that doesn’t really affect our math very much. The official World Resources Institute conversion rate that we use in our carbon calculator is 19.564 pounds of CO2 per gallon of gas. Also, your exhaust is quite a bit heavier if you count the steam that is generated. Those 16 hydrogen atoms attached to every octane molecule have to go somewhere. They combine with oxygen to create water (H20). Every gallon of gas creates roughly 8 pounds of water vapor. And water vapor does, believe it or not, contribute to global warming. Aren’t you sorry you asked? Update: A small point of clarification — even though water vapor is a significant contributor to global warming, you don’t have to feel guilty about taking hot showers. Direct human contributions to atmospheric water vapor are small. Rather, humans have a large indirect impact on atmospheric water vapor when we create carbon dioxide, which warms the atmosphere, which warms the oceans, which creates more water vapor, which warms the atmosphere… Update 2:Fixed a math typo, corrected the number of hydrogen atoms in octane, and changed the headline to reflect more clearly that the gasoline is turned into carbon dioxide, not carbon. We’re drivers, not alchemists. Comments112 comment(s) on this post. Leave your own!
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The curious (or suspicious-minded) among you have occasionally wondered about our claim that one gallon of gas turns into about twenty pounds of carbon dioxide exhaust. Your high school chemistry teacher would be very disappointed with you for even thinking the question, but there’s no judging here at TerraBlog. Let’s walk through the math.
Facinating high school chemistry - it's funny people still think solids as more sgnificant even if in weight, volume and effect as a pollutant are greater in the form of a "harmless", colourless, odourless gas. Just one point though the header talks about Carbon - the calc is for Carbon Dioxide (a much weighter product).
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Interesting. You may want to change your literature to talk about creating 20 lbs of "Carbon Monoxide" not "Carbon". I figured the extra 14 lbs of "Carbon" came from the energy used to pump, transport and refine the stuff before it got to my gas tank (I'm still curious how much that is).
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Not to be one of those people, but you've got a dyslexic typo in your calculations. The line:
6.25 pounds x (325 / 112) = 19.64 pounds
should read:
6.25 pounds x (352 / 112) = 19.64 pounds
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Thanks. Typo fixed and headline updated.
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I believe that the chemical formula for 2,2,4 Trimetylpentane (Isooctane) is (CH3)3CCH2CH(CH3)2 and think that this molecule has 18 hydrogens rather than 16. Doesn't it have a weight is 114.2285 g/mol rather than 112? If I then use your formula with this revised weight but retain your estimate for the weight of 1 gallon of gasoline (6.25 lb. per gallon), I get 19.3628 lbs of CO2 per gallon. Am I doing this right?
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Argh. Yes, you're right. This should have been obvious to me -- regardless of the exact configuration of the octane, it's always going to have eight carbon atoms, which means 32 free electrons. 14 of those electrons will be paired up in carbon-carbon single bonds, leaving 18 free electrons for the hydrogen to bond to. My high school chemistry teacher is very unhappy right now.
I've updated the math.
P.S. You're using a far more precise atomic mass than me. I'm sticking with the round numbers.
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Regarding your update on water, the important difference between water and carbon dioxide is that the carbon dioxide we add to the atmosphere sticks around for about 100 years...
The scientific term is "residence time." Water vapor, by contrast, has a residence time on the order of days. (This is not to mention that the amount of water vapor the atmosphere can hold is also a function of temperature.) In any event, it's true that our contribution to water vapor is insignificant. Pointing this out is a good opportunity to highlight an important part of emmissions problem... it's at least 100 year commitment.
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If the increase in atmospheric CO2 is causing global warming, then what is the most effective and least painful (economically) thing to do about it?
The answer is NOT KYOTO - which the signatories have either abandoned or violated, and which doesn't include India, China or the USA - the largest emitters of man-made CO2.
The answer is clear-cutting (and then replanting) the Amazon Rainforest.
Old tress do not sequester as muich CO2 as young, growing/fast-growing trees.
UC-Irvine has recently proven that the Amazon - which sequesters abiout 1/3 of all the CO2 ion the world - is now mostly comprised of very VERY old trees; therefore, the Amazon Rainforest is no longer absorbing/sequestering as much CO2 as it used to - - as when the most of the Amazon's trees (and therefore the Amazon Rainforest as a whole) were younger.
THIS MIGHT BE THE CHEIF REASON GLOBAL ATMOSPHERIC CO2 HAS INCREASED.
THEREFORE, if we REALLY want to reduce the amount of CO2 in the atmosphere we should clear-cut huge swathes of the Amazon and replant with young trees.
In order to prevent the cut trees from decaying - and thereby putting their sequestered CO2 back into the atmosphere - we would need to use the trees for their lumber - either for furniture or for housing. (The world's poor - in India, Chuina and Africa, and South Amerioca - could use BOTH!)
So it's a win-win: the CO2 in the atmosphere gets reduced, and poor people get housing and furniture.
HOW COULD ANYONE OPPOSE THIS POLICY?!
I have posted on this three or four times at my blog - each post is linked to a few SCIENTIFIC STUDIES.
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Just curious, doesn,t any of that carbon in a gallon of gas get used in the explosion, or is all of it expelled out the tail pipe?
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All out the tailpipe. An explosion doesn't have much meaning at an atomic level. Although an explosion looks dramatic from where we're sitting -- with the bang and the pretty fireball and the bits flying everywhere -- at the level of a carbon atom it doesn't look like anything at all. It'd be kind of like you concentrating real hard to try to feel the earth spinning around the sun.
Carbon atoms don't get "used" when gas is burned. They just move around really fast and bond to other atoms. What does get used is the energy contained in the bonds that join the carbon molecules together. This is kind of an abstract concept to get your head around, but imagine it like the old snakes-in-a-can trick. The coiled springs are the bonds joining the carbon atoms together. When the can is opened, the springs are released, and the snakes jump out. Ditto for the carbon atoms.
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How much C02 does a volcano produce?
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What am I, Mr. Wizard?
The answer is a little surprising. While volcanoes don't release a significant amount of CO2 compared to humans, they still release quite a bit more than I thought.
One conservative estimate puts the amount of CO2 released every year by volcanoes at about 150-200 million tons (which you could offset with about 10 million Utility TerraPasses). This is a big number, but the amount created by humans every year is about 150 times bigger.
Another online source says that volcanoes produce about 3% of annual CO2 emissions. I have no expertise that allows me to evaluate these separate claims.
Incidentally, the way vulcanologists go about figuring this sort of thing out is to tape sensors to the front of a helicopter and fly them into active volcanoes. That is so freaking cool.
Update: This comment has been promoted to a full post, with a few extra tidbits included: http://www.terrapass.com/terrablog/posts/000192.html
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Seeing this entire page unfold from the explanation through the comments and corrections should give us hope for what we're all trying to get at. I am so impressed with the collaborative process in approaching global warming and climate change. Sometimes it seems like the process of thinking through these issues may well end up being the real story (once we get things in working order that is...)
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First, how 'bout not calling gasoline "gas," since it is a liquid and may be confusing to some.
More importantly, would you please give us the volume that 20 pounds of CO2 occupies at atmospheric pressure and, say, 70 degrees F?
Keep up the good work.
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Your wish is my command. Headline updated. Volume calculation here.
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Wow, that's really helpful! I'm doing a paper that deals with emissions, so it's important to have the numbers right. I just have one question:
How can 6 pounds of gasoline = 20 pounds of CO2? You can't create or destroy matter.
My guess is that the process pulls oxygen from the air in the process of bonding, and then when it is all said and done, you have 20lbs of CO2. Correct?
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Correct. Normally I'd link to the post that explains all this in detail, but...this is the post that explains all this in detail.
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I guess that was my problem-the details. That's some pretty complex algebra!
So also, I see a potential problem with the replanting the African rainforests theory. It seems that all of those tree are "holding" if you will the CO2. So when you create furniture, or burn the wood for fires or make paper, you would be releasing that CO2 back into the atmosphere. At least then you would have the wood, as the new trees would start to absorb that old CO2 as well as the new stuff. But there has to be a limit to that too.
Also, in the process of replanting, you'd probably take out all sorts of creatures who have made their home in the old trees.
Agree?
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Replanting forests is a good thing, and there are some organizations that create carbon offsets by planting trees. There are also some issues with this mode of carbon sequestration, which I won't go into, because I'm not enough of an expert.
In general, yes, organic matter is part of the natural carbon cycle, which is why we consider biofuels to be better than fossil fuels. We create carbon dioxide when we burn the biofuels, but the carbon dioxide then gets recycled back into plant matter. This is very different than pumping the carbon out of the ground.
I know some people are proponents of the "mow down all the forests and let them regrow" theory of carbon sequestration. Can't say that I'm a fan.
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Many thanks. Saw "An Inconvenient Truth" last night and just enrolled in Terra Pass. May this grassroots campaign spread like a wildfire to heal the earth.
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Say, I was trying to find a breakdown of emissions other than CO2 within your website. I used to be able to find them under Clean Air Pass. Any suggestions?
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How about Google? We've never sold anything called a Clean Air Pass, so you may be thinking of a different web site. TerraPass only remediates CO2, not other gases.
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Hello again. I found the info I was searching for concerning greenhouse gases and the Global Warming Potential. CO2 has a GWP of 1, CH4 (methane) has a GWP of 21, and N2O has a GWP of 310. Any comments?
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Please don't misunderstand me, I'm just trying to do as much research into this as possible. I agree with the concept and am aware of other CX locations other than Chicago. However, I just tried your vehicle emissions test based on 15000 miles annually and I am of the opinion the results is grossly under estimated!!
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Hi Wayne,
I'm not 100% sure I'm following the question, but I think I can shed some light on what you're asking. There are a number of greenhouse gases, including methane, NOX, etc., that are created when gasoline is burned. Often these are translated into their pounds of carbon dioxide equivalent (CO2e) based on their global warming potential. So, as you note, one pound of methane is treated as roughly 21 pounds of carbon dioxide from the perspective of environmental impact.
If you added up all the emissions from a gallon of gasoline and translated them to pounds of CO2e, it would bump up the amount of CO2 produced from roughly 20 lbs per gallon to somewhere in the mid-20s per gallon. Even though N2O has a much higher GWP than CO2, there is also much less of it created when you burn gas.
So I don't believe our calculation is a gross underestimation. Another important point is that some of the other emissions vary considerably by car type, so it's difficult to account for them in a consistent way.
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Thank-you for the clarification. I guess part of the inconsistencies is due in part to EPA and calibration of fuel economy is based on volume (density) not weight!
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I'm still put off by the typical sound bite (and your headline). We are not creating matter. Opening with a fallacy does more harm than good by making the entire argument less credible. Personally, I think it is even more frightening to note that we are not only adding CO2 to the atmosphere, but using O2 in the process.
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Er, no one said anything about "creating matter." Gasoline starts as liquid hydrocarbon and ends as a gaseous organic compound. The headline is perfectly factual.
Moreover, there's no "argument" being made in this post whose credibility can be moved in one direction or the other. It's a bit of stoichiometry -- high school chemistry.
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Just for fun, it would be interesting to calculate how much O2 gets removed from the atmosphere, and how much CO2 gets added, after all the recoverable oil in the Alberta Tar Sands has been burned by an average combustion engine (car).
Does CO2 level reach a poisonous level, is there enough O2 left to sustain human breathing?
For simplicity, I would assume we start with actual levels of concentration of O2 and CO2, and also assume combustion of gasoline is the only reaction (ignore other human and natural reactions like photosynthesis, carbon sequestration, etc.)
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Hi. Interesting topic. Based on the volcanic CO2 emission questions, I wonder if you already have a link or chart showing the top 5 (10?) world wide contributors to atmospheric CO2 emissions per year?
On a related note, I was surprised that you reported that humans produce 150 times the CO2 as volcanoes (yearly)...is that primarily from cars? If not answered in the above Top-10 list, what are the top human CO2 producing activities (factories, breathing, etc.)? I had heard that all of the human CO2 emissions were only 5% of the total "global" CO2 emissions...is this the right percentage?
Many thanks in advance!
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Hi J,
No, human CO2 production is not primarily from cars. About one third of human CO2 emissions are from transportation, which includes planes. Most of the rest is created by electricity production for residential and commercial use.
- Adam
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Cars are, however the highest producer, so we should stop driving our stupid gasoline cars and make electric cars.
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The crazy thing about this is that the math is actually quite simple. Certain entities strive to confuse the general public in order to portray all the true critical thinkers as crackpots or idiots. I did some simple math on the C02 emmissions from electrical generation facilities. For each kWh generated, approximately 1 kg of C02 is emmitted. The US used approximately 3.8 trillion kWh in 2003. The result is staggering considering the fact that this stuff is pouring out 24/7/365 ad infinitum all over the world (not just in the U.S.). Detractors will take this and say I've got my numbers all wrong and ridicule me for trying to put it all in perspective. If all you have your mind on is profits, simple math becomes fuzzy for some reason or other.
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It would be really interesting to me to see similar calculations for the entire barrel of oil from which the gasoline is refined. Each 42 gallon barrel yields (or so I am told) about 19-20 gallons of gasoline. The remaining 22-23 gallons is turned into furnace oil, diesel fuel, cleaning fluid, petrochemicals, pharmaceuticals and so forth. Is there any way to make an educated guess about the CO2 output from those?
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Another response to the cut all the trees down for the good of all people.
It seams that planting trees in all of those places that are already deforested might be a good start. There is much in the US and Europe that was once forest. So we wouldn't have to calculate the carbon it would take to cut down all of those Amazonian trees, process them, and finally ship them to the world's furniture deficient homeless. We could just start planting trees here.
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Great Stuff. We've come up with this idea of a 'Sequestration Farm'. The trees are grown to maturity and then harvested into large baulks of timber and buried in the sea. In the anaerobic conditions down there the wood will last for literally thousands of years before relinquishing its Carbon back to the atmosphere. The brash can be turned into Biochar to lock its carbon into the soil long-term (Terra Preta) and the same plot of land replanted to begin the process again (ad infinitum). Basically what we are attempting to do is recreate the worlds stored fossil fuel reserves one tree at a time and in doing so re-absorb the 6 Gigaton surplus of carbon up there.
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Thank you so much on having this info. i will use it to respond to a non beleiver of global warming on the daily journal.
thanks again.
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I must say that some of these "cut down the forests and replant them" need to consider a few other important factors:
First: Soils are not infinite resevoirs of nutrients. In particular, the Amazon soils are well-drained, nutrient poor soils. Plant life needs nutrients from decaying plant matter to grow. If you take that plant matter and turn it into furniture and/or put it at the bottom of the ocean, then you deplete the nutrients available for the next generation of trees. This means you can grow less trees per acre EACH TIME you cut and clear.
Second: New trees will not take in great quantities of CO2 for the first few years of life. Mature trees continue to sequester until dead, and should thus be spared the chainsaw. If the goal is purely sequestration, then the area occupied by the tree could be replanted.
Third: A healthy forest needs trees in various stages of succession. Other plants that form the understory (below canopy level) will struggle to grow in mono-culture, nutrient depleted forest stands, and thus the amount of CO2 you will be removing from the atmosphere is decreased.
I agree with the comment that we should focus on areas that are already deforested, rather than accelerating the rapid rate of current deforestment.
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This is all really helpful, especially the last thinking about how we can think more critically about forestry and carbon sequestration.
I'm especially interested in data on C02 produced by coal-fired power plants per KWH. In northern Wyoming (as in other states such as PA, and globally, in the UK and China), near-surface coal is abundant. Many ranchers have been picking coal from road cuts and other places where coal seams are exposed for generations to heat their homes and shops.
p.s. the dollar cost is a no-brainer: $40/ton; I use about 1/3 of a ton/month, so I'm heating my house for about $5/week! But this is the problem with most of the resources we use. The price does not reflect the true cost.I personally have a small Swedish coal burning stove; my back-up is the "Econoheat" electric wall panels, which are quite efficient compared to electric baseboard. So I'm wanting to compare C02 produced per Btu of heat - burning the coal directly in my home (which is new, well insulated, with south-facing windows, and small) vs. buying electricity from a coal-fired power plant for the heaters. If anyone can reccommend websites with relevant data, it would be helpful. I'm planning to contact the nearby mine that is the source for the assay info and our power company.
Ainslie
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This is a fantastic discussion and thank God it is finally happening. One thought that has not been discussed and is off topic, but I think noteworthy. Everyone should be looking at conservation in all its forms. There is a vast amount of CO2 generated (along with many other wasteful things) in everyday things that we (especially Americans)do thoughtlessly. How many people run the water while they brush their teeth? How many people have lights burning in rooms that they are not in? How many drive to the store when they could walk 2 blocks. Do you buy the name brand toilet paper because it is 60 cents cheaper then buying enviromentally friendly toilet paper ( seventh generation, etc). The list could go on and on. Start making conscious decisions based upon the impact, however small. Evaluate what you truly need versus what you want. Rebel against the excess consumerism this country has turned into. If you want to make a difference, START WITH YOU!
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Yes, QC, there are large & small energy consumption issues everywhere in our culture. We need to attend to all of them since collectively they each become quite sugnificant.
This is off-topic but extremly important: the birth of one human being triggers ALL the energy & resource consumption of a lifetime. This effect multiplies because the progeny of one person (OK sticklers--2 people) continues or expands the consumptive process for an untold amount of time to come.
Keeping our own family size in check as well as supporting family planning charities has an incredibly far reaching effect on solving all kinds of problems, global warming being the most relevant here.
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I ran this equation against the annual consumption of gasoline, which is 846 Million Tonnes. And that is 1.862 Trillion lbs. Now divided by 6.25 lbs/gallon of gasoline times 19.3 lbs / gallon of gasoline equals 5,747,385.6 Million Lbs of CO2 and 2,382,336 Million lbs of H2O steam. I hope I got it right, because those big numbers sound so unbelievable. The question is how many trees do you need to absorb all the CO2: According to some government agency in Canada 1 acre of healthy mature forest produces 22 lbs of O2 /tree /year or 8,800 lbs O2 / year. Then for 5,747,385.6 Million pounds of CO2 / year you need 474,990,545 acres of healthy mature forest. So we need 742,173 square miles of healthy mature forest. That can't be right. And these are numbers from 2004 and only gasoline consumption. Please, prove me wrong!
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Would there be a difference in carbon dioxide level emitted from a car exhaust if different grades of gas were used? (Example: would using the highest level octane gas (premium) emit more or less CO2 than lower level or regular gas??
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Adam:
I'm not going to bust your chops about math or metrics here. Just wanted to thank you for this informative post and its usefulness (to me at least) in helping eliminate what I've been perceiving to be a stumbling block for many people--the notion of the 'weight' attributable to gaseous emissions. I was able to 'translate' your message into a simplified (by scientific standards) visual model, and posted it on my blog, which is designed to filter the massive amounts of information on sustainability for those who are just finding their eConsciousness. Thanks again.
Larry Grob
www.theunlikelyactivist.com
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I've recently spent hours trying to derive the results from this post by approximating the chemical composition of gasoline as a blend of n-heptane and iso-octane using the following stoichiometry:
C7H16 + 11 O2 → 7 CO2 + 8 H2O
2 C8H18 + 25 O2 → 16 CO2 + 18 H2O
I used the following densities to set the mole fractions:
density of C7H16 at 20C = 683.76 g/L
density of C8H18 at 20C = 702.50 g/L
I assumed a blend of 87% octane to 13% heptane and came up with 18.04 # of CO2/gal of gasoline
Even if I go back and use 100% heptane or 100% octane, the results will still be ~18 #/gal
I've seen iso-octane listed at 691.90 g/L at 20C which again will not greatly effect the results.
This estimate does not include the reality that air and not pure O2 is being included as a reactant and that there will be unburned hydrocarbons in the products.
What is the real chemical composition of "gasoline"? And what did the WRI use to come up 19.564 #/gal?
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Hi, Jamy. I admire your dedication. The difference between your result for pure octane and our result for pure octane is due to the different weights we're assuming for a gallon of gas. Doing the math on your densities, I come up with a weight of 5.86 lbs for a gallon of gas. As you can see above, I used a weight of 6.25 lbs, which I pulled off the web (no idea where at this point).
I can't say what assumptions went into the WRI numbers. As you can see, the final result is sensitive to the inputs, although the results aren't enormously different.
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I love the way that you do your math (which i am not entirely sure is right)then conclude that 6 pounds of gas .25 pounds shy a reduction of 4% gives 20 pounds of co2 an increase of .7 pounds a 3.6% increase thus biasing your conclusion by ??% you work it out, i think 19 pounds is still interestin but it is not be to dramatic. I wouldn't buy a car off you with those tactics especially if you were promoting its fuel effciency.
[Ed. note -- our math is right. Also, we have no idea what you're getting at.]
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I found this info on the web, regarding the chemical composition of regular gasoline, but my source now eludes me. Unfortunately, these add up to 86.6% so there is 13.4% missing/unknown.
straight-chain alkanes - [octane 114.2285 g/mol]
17.3% by volume
branched alkanes - [iso-octane 114.229 g/mol]
32.0% by volume
cycloalkanes - [cyclohexane 84.16 g/mol]
5.0% by volume
olefins - Alkenes - [1-hexene 84.1608 g/mol]
1.8% by volume
aromatics - Benzene [C6H6]
30.5% by volume
ca. 19 pounds of CO2 emitted per gallon of gasoline combusted seems the most reasonable and accepted calculation available.
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This blog's discussion is very informative. But the idea of purchasing carbon credits is a money making scheme. We, the population of the world need to change habits and use clean sources of energy. Changing habits requires putting money into environmentally friendly methods of producing the energy we need to live and make a living in a comfortable manor, not returning to the caves. I for one have put my money where my mouth is, Rather than buying questionable Terra pass or such, I have installed a 7200 kw PV system, changed most of my light bulbs to fluorescent, installed energy star appliances, and added insulation to the house. All that has cut my eclectic bill by about 40% and my fuel oil consumption by 60%. I live in NY.
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Hi Berge,
We think it's great that you've taken all of these measures, and we certainly encourage all TerraPass members (and non-members) to take similar steps wherever possible. Solar panels are out of reach for many people, though, and so TerraPass provides an alternate way for people to, as you say, put their money where their mouth is by funding clean energy.
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Marc: Al Gore's movie, An inconvienent truth is mainly myth - just like his book Earth in the Balance. Also, I like ponies.
Wayne:
GWP of water exceeds all of those, water is largest "greenhouse" gas (water vapor). Yes water is around for short time but we add it continuously so it is a factor.
Annon 48: Gasoline is primarily 6-12 carbon compounds. It includes Toluene, benzene, and many other fractions. Components vary by location and climate. Octane ratings are based upon Iso-octane = 100. But you can't assume gasoline is 87 or 91% Iso-octane (or any two componds for density) as it is complex mixture.
Adam: Density of gasoline varies about 15% and 6.25 lb/gallon is reasonable number. 6 pounds of gasoline = 18.5 pounds of CO2 using your own numbers - not 20 pounds as you state. You round up on the CO2 and down on the lbs of gasoline and still are not right. (This is point annon 47 was making). The 19.564 comes out because gasoline is a complex mixture not single compound as your calculation assumes. Of course, the post actually goes into mind-numbing detail over the exact figures, so this sort of nitpicking is pointless, and I'm mostly just talking because I like the pretty sound I make when I do.
Regarding your more heat = more humidy = more global warming theory. Try this more logica one. More heat = more humidity = more percipitation = more snow = more snow cover = more light reflected = global cooling. So global warming might actually cause global cooling. Of course, that would only be true if scientific phenomena were explained by appeals to "logic", and not, say, "empirical data."
And yes (sorry forgot which poster) you are right, what actually happens is O2 is combined with the carbons to create CO2 so there is no mass creation just mass conversion.
Lastly, isn't there already enough CO2 in the air to capture all the radiation being returned at the one point where CO2 absorbs but water does not?
Whew. Long but just remember, if we had begun combating global cooling in 1976 when all the scientist were in consensus that an ice age was coming we would be congratulating ourselves on success right now when in fact we did NOTHING to change the environment. When the model can explain the 30 year long cooling lasting until the early 1960s while CO2 was increasing I might begin to believe in this green house gas theory. I clearly am the first person to think of this, and all those clever climate scientists all across the world have somehow overlooked this blindingly obvious fact. What are the odds?
Ed. note -- comment has been modified to make poster look silly.
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Has anyone ever burned a gallon of gasoline, captured the emissions in a vacuum chamber, compressed the emissions down into a one gallon container and weighed it? This might get us the actual weight.
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Interesting. Terrapass can not refute arguments by Alex_in_FL so they edit his post to belittle him? Does this mean that serious, accurate, fact based scientists are not welcome here? That the SOP is to ridicule when you can't refute? He does make valid points (assuming validity counts).
Lastly, he has an interesting perspective in that global warming may cause global cooling. I think the huge snow storms of last week were attributed to global warming and more humidity hitting the cooler northern air thus causing record snow fall. Oh, wait, this does not support the party line so will my post be edited and ridiculed too?
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Um...these arguments have been refuted so many times by accurate, fact-based, scientists that they don't deserve any attention. The SOP here is to engage in discussion with people who are interested in honest exchange of ideas, and to wring a few larfs out of those who aren't.
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Re #51 & 53:
H2O is limited in how much can stay as vapour: dependent on how much total water (ocean), the surface of that water, and the temperature of the air.
Until we significantly increase H2O production, we won't see the water volume or surface increase any. So we can ignore anything other than H2O.
But there is already (you'll agree) H2O in the atmosphere, so the change will not be a huge ammount (because that's your argument for CO2 not being the answer). Excess H2O will not become vapour but will drip on to the floor as solid water.
So the increase in H2O doesn't depend really on how much H2O we are adding.
Re: rounding down/up. There's more than just petrol in a barrel of crude. Some of that gets burned. It still ends up being a doubling of weight burning oil to CO2. 42->84.
Lastly, there may be enough at the peak absorption of CO2 to trap all at that waelength. However, the FWHM bandwidth isn't saturated for that, and that includes more energy radiated. Rovibrational bands that are small will still double and so on. So you may not see a doubling in the insulative effects when doubling CO2 but you will see a large increase.
All taken not as a scientist but as a physicist. Much as this article is merely maths.
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CO2 has virtually no impact on temperatures. At approx. 350 parts per million CO2 is just a drop in the bucket. If I have a snowball consisting of 2850 snowflakes, and that snowball has a temperature of 25 degress, except for the one CO2 molecule with a temperature of 26 degrees, the one 26 degree molecule (CO2) will not change the temperature of the snowball from 25 degrees. Increase the CO2 molecule a few more degrees and still no change in the temperature of the snowball. And besides humans only contribute about 2.8 percent of total CO2 emitted into the atmosphere. The more research I do into global warming the more I see it is a hoax. Thanks, Dr. Storm
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Yes folks, who do you believe. Dennis' snowball analogy or 1000's of peer reviewed publications?
CO2 has a dramatic and well understood radiative forcing function.
Tom
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I'm just trying to put this into perspective. At 350 parts per million (1 part per every 2850) what temperature must the CO2 molecule be to raise the other 2849 molecules one degree F? I understand the radiative forcing, but would like to see an actual numbers here.
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Dennis: That's a totally legitimate question.
As measured by the IPCC, the radiative forcing effect of CO2 in the atmosphere is 1.46 Watt/sq meter.
Read more here: http://en.wikipedia.org/wiki/Greenhouse_gases
And for a very nifty graph showing the contributions (both positive and negative) of different gases: http://en.wikipedia.org/wiki/Image:Radiative-forcings.svg
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One kinda funny thing is that Dennis isn't just questioning (anthropogenic) global warming -- he's actually questioning whether there's any such thing as the greenhouse effect. At 350 ppm, he says, CO2 can't have an effect on global temperature.
But without CO2 in the atmosphere, the earth would be an ice ball, with an average surface temperature of -18° C.
Disputing the existence of the greenhouse effect would take denialism in exciting new directions. The greenhouse effect is basic science, about as controversial as the existence of gravity.
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I am not disputing the greenhouse effect. You claim without CO2 the earth's temperature would be -18 degrees C. That is incorrect. Without a greenhouse effect at all the temperature would be minus 18C. Water vapor accounts for more than 95% of the greenhouse effect. It is a fact that CO2 rises when temperature rises and not the opposite. CO2 has no effect on global temperatures. It is a good idea to get information concerning this subject outside the IPCC. If CO2 is a great heat trapping gas, then it would have to be a poor heat radiating gas. As I stated previously, CO2 is one part per every 2850, and would not be able to increase the temperature of the other 2800 plus air molecules. The "sun" is what is driving the current minor increase in global temperatures, not CO2.
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Dennis's question stems from an incorrect understanding of how the greenhouse effect works. The CO2 is at exactly the same temperature as the surrounding gas (25C in his example). What happens is that it interferes with the radiation of heat from the earth's surface into space. The extent of this interference is a function of how many CO2 molecules there are per unit volume and is actually (nearly) independent of how many other molecules of oxygen, nitrogen or other gases there are (of course, some other molecules like methane and H2O have similar effects, though of different magnitudes).
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Since we seem to have posted at essentially the same time, I'll add that the IPCC is not just one among many competing interest groups, but is open to the entire scientific community worldwide. To be outside the IPCC is in essence to not be engaged in scientific study of global warming.
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I can't believe I'm responding to this baiting, but this topic is actually kind of fun...
Dennis, you are correct that the greenhouse effect is caused by a number of gases. You are incorrect that CO2 is not one of them. As for the IPCC, I think you're actually referring to the IPCC report, which, as AH notes, is authored via an open process that encompasses all of mainstream climate research.
But just for fun, let's step outside the confines of the IPCC. A lot of foundational work on the temperature effects of CO2 was done by Svante Arrhenius, who won the Nobel Prize for chemistry...in 1903. Although many of his calculations were later shown to be flawed, his estimate that a doubling in atmospheric CO2 levels would lead to a 4 - 6°C rise in global temperature is remarkably close to the predictions of modern climate models. Not bad for a guy who had to do the math by hand.
Again, you're arguing against the existence of gravity. The notion that a concentration of 350 ppm is too small to matter is, well, rather eccentric. There is no magic ratio below which chemicals stop having an effect.
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I've never delved into the TerraPass blog before, and let me say - it is a wonder. This particular post and resulting discussion are particularly helpful to me, since I feel like so much of the time we take global climate change for granted that we forget to keep explaining some of the simpler math. [aside: your argument, Alex_in_FL, is precisely why I use the term global climate change or climate instability rather than just "warming," since there are already all sorts of observed weather patterns that are a whole lot more than just extra degrees] I've really enjoyed most of the posts, especially the skeptics, since the responses to those help me formuate my responses when I am working with these issues (particularly posts like Dennis, since I wouldn't have even seen that one coming!). Thanks!
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I must say I am developiing a much more open mind to this subject. To AH's response, #62, if the CO2 molecule is the same temperature as surronding gases, then how does this interference idea work? My understanding was the CO2 molecule would lose heat at a much slower rate than the other surronding air molecules (hence heat trapping gas). Thanks, Dennis
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I guess I should double check my spelling before posting. 3 typos, developing, surrounding and surround. Sorry, Dennis
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Dennis:
I do not claim to be an expert on this subject but I am working towards my Ph.D in atmospheric chemistry. The question you are asking delves into some quantum mechanics.
Starting at the basics it is important to understand what makes a greenhouse gas a greenhouse gas. Above all else the molecule must be infrared active. This means that IR radiation causes the molecule to go through either rotational or vibrational transitions (i.e. the molecule starts to vibrate/rotate/bend/stretch along its bonds). In order for this to happen the molecule must have a dipole moment or be able to have an induced dipole moment. This is why water vapor and CO2 are such goo greenhouse gases. Water has a permanent dipole moment and CO2 can have an induced dipole moment (the oxygens on either side of the carbon can start to stretch back and forth and bend up and down). Molecular oxygen and nitrogen on the other hand cannot and do not have dipoles so therefore cannot be greenhouse gases.
To make a long lecture short and in the essence of not confusing you more than you already may be, the molecule will absorb the IR radiation and then reemit it in the form of thermal radiation. This is then reabsorbed by the earth making it warmer still. So the interference idea is not that CO2 gains or loses HEAT but it does have a change in ENERGY that is converted into heat by the earth's surface. And answering your main question (finally) it is not that CO2 loses heat more slowly than the surrounding air, it is just that the majority of air (nitrogen and oxygen) can't interact with IR radiation and do not have the means to be greenhouse gases due to the reasons described above. It has nothing to do with heat retention and everything to do with a molecule's dipole moment and energy transitions and some other stuff.
Again, this is a gross over simplification in order to make it semi understandable to people not having taken quantum chemistry and physical chemistry courses. I only hope I have not confused you more. But just understand that this phenomenon is not some theory made up by liberal propagandists, it is real science that has been observed in labs for decades.
To anyone who can describe this better, please do so.
Dennis: For your own benefit it may be worth while to look up black body radiance of the earth and how greenhouse gasses effect it.
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I agree that CO2 is harmful, emissions need to be reduced, miles per gallon need to be increased, and so on.
However:
The title says six pounds of gasoline make twenty pounds of carbon dioxide. That isn't true, and it isn't even supported by the information given.
The contents of the article say that MORE than six pounds (6.25) of gasoline make LESS than 20 pounds (19.3) of CO2.
[Ed. -- man, this article attracts pedants like flies to honey. As the commenter notes, the information given in this article is excruciatingly accurate and clear. And the headline also uses accurate rounded values: 6.25 --> 6, 19.564 --> 20.]
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Thanks Ryan for the information. This got me thinking about how CO2 warms the surface. It seems possible that CO2 could also cool the surface. Let's say in the artic in winter (no solar heating) the ice (surface) temperature is zero degrees. Now an air mass moves in at 50 degrees below zero. The CO2 now reemits thermal heat so to speak, which is minus 50 degrees, therefore cooling the surface further, cooling the air temperature further. I guess this would be as the air temperatures tries to modify the CO2 keeps modification from occuring. Possible? Thanks, Dennis
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Hey Dennis
I think I see what your question is. In order for the air mass to do what you are asking it must be constantly emitting thermal radiation (radiation not heat). But this is not the case; the reemitting of the thermal radiation is a one time deal-it only happens nearly immediately when the gas interacts with the incoming infrared radiation and it will not store any of this energy to be reemitted at a later time.
So let me explain again in a more coherent way how the greenhouse process works (last time I don't think I did a good job). When light (electromagnetic radiation) comes in through the earth's atmosphere it is of a relatively short wavelength and carbon dioxide and other gases cannot absorb it. But the earth is a black body and can absorb all wavelengths so the earth absorbs the short wavelengths and then reemits the radiation at a longer wavelength. This longer wavelength can then be absorbed by the greenhouse gases which in turn reemit the radiation back to earth where they can heat things up again. It is like the game of pong, the radiation goes back and forth between the gases and earth until it escapes. The whole time it is bouncing around it is constantly heating up whatever absorbs it.
So in short if there is no sun as in the arctic winter, there is no radiation to be emitted back and forth. The carbon dioxide does not r