# How do we know that C02 is a greenhouse gas? **URL:** \ **Category:** Great Debates\ **Created:** [February 27, 2010, 3:01am UTC](https://boards.straightdope.com/t/how-do-we-know-that-c02-is-a-greenhouse-gas/530602 "2010-02-27T03:01:44Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![GIGObuster](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gigobuster/32/421_2.png) [@GIGObuster](https://boards.straightdope.com/u/GIGObuster)\ **Post date:** [February 27, 2010, 4:10pm UTC](https://boards.straightdope.com/t/how-do-we-know-that-c02-is-a-greenhouse-gas/530602/21 "2010-02-27T16:10:53Z")
And, lets not forget that the Australian piece is still in the \*\*opinion \*\*pages of The Australian. [http://blogs.theaustralian.news.com.au/letters/index.php/theaustralian/comments/in\_thrall\_to\_totalitarian\_green\_science/](http://blogs.theaustralian.news.com.au/letters/index.php/theaustralian/comments/in_thrall_to_totalitarian_green_science/) > [@](#): > > IN his opinion piece ("Climate claims fail science test”, Commentary, 9/12) Michael Asten has misrepresented our recent research by suggesting that it casts doubt on the link between atmospheric carbon dioxide and global warming. > > Our study, published in the journal Nature, is a reconstruction of atmospheric CO2 levels 33-35 million years ago when the ice cap first appeared on Antarctica. In the paper, we clearly state that the results are in line with expectations from climate model simulations and theory on how the global carbon cycle ought to respond to the growth of an ice cap over very long periods of time. As Asten replied, in yet another opinion piece, he wants to get away with his misrepresentation by explaining now that he was proposing a new hypothesis; well, he needs to publish it in a science journal. > [@](#): > > There is a general correspondence between periods of warmth in the past and reconstructed CO2 concentrations, but we caution against any attempt to derive a simple narrative linking CO2 and climate on these large timescales. This is because many other factors come in to play including other greenhouse gases, moving continents, shifting ocean currents, dramatic changes in ocean chemistry, vegetation, ice cover, sea level and variations in the Earth’s orbit around the sun. > > Carbon dioxide levels are currently rising year-on-year at an alarming and geologically unprecedented rate. Nobody, to our knowledge, is seriously questioning this, or the sound physics that underpins the greenhouse effect. > > We would like to take this opportunity to add our voices to the strong and steady message that the world scientific community is delivering to the Copenhagen negotiators—the greenhouse problem is real, imminent and potentially devastating for the planet, its life and human civilisation. Fortunately it is still not too late to avert the catastrophe. > > Paul Pearson, Cardiff University > Gavin Foster, National Oceanographic Centre, Southampton > Bridget Wade, Texas A&M University ---
**Author:** ![Chief\_Pedant](https://avatars.discourse-cdn.com/v4/letter/c/a6a055/32.png) [@Chief\_Pedant](https://boards.straightdope.com/u/Chief_Pedant)\ **Post date:** [February 27, 2010, 4:16pm UTC](https://boards.straightdope.com/t/how-do-we-know-that-c02-is-a-greenhouse-gas/530602/22 "2010-02-27T16:16:25Z")
> [@figure9](#): > > “Is there any demonstration that shows C02’s ability to cause global warming, that an average person could understand?” Probably not, because physically replicating the variables would be impossible for so complicated a system as the earth. It’s worthwhile reading about John Tyndall’s experiments if you want to see some early efforts at isolating the radiant heat absorption effect of isolated gases. Of course the problem is that gases don’t exist in isolation and the overall homeostasis of the earth is dependent on much more than greenhouse effects anyway. For CO2 in particular, for example, the greenhouse effect is variously given as somewhere between 10 and 25% of the total greenhouse effect of all gases, with the lower number of 10% being closer to its putative effect when all the other greenhouse gases are also present (versus its effect in isolation). Water vapor, mentioned above, is an interesting greenhouse gas to illustrate the complexity of trying to decide what the actual effect of a gas is on climate. What happens if CO2 warms up the earth’s atmosphere, evaporates more ocean and creates more clouds? What’s the net effect? Those are the sort of feedback loops that are difficult to model and impossible to experimentally reproduce with certainty. Water vapor is a greenhouse gas; estimates for its effect range from about 35 to 65 %, and perhaps 75% of total greenhouse gas effect when clouds are factored in. However clouds are tricky, because while they have a greenhouse effect, many clouds have a high albedo (reflectivity). Therefore although the water vapor in the clouds might have a greenhouse effect, there’s a lot of solar radiation never getting to the earth in the first place because of the cloud (remember, the basic greenhouse effect is the idea that gases in the atmosphere trap and then re-radiate energy coming off the earth’s surface). Thus, the net effect of (thicker, lower-lying clouds) is cooling, not warming, despite their greenhouse effect from the water vapor in them. This makes it quite complicated to model, much less experimentally reproduce, all of the factors involved in climate change. Even the models are built on individual observations, along with best-guess estimates for feedback loops (such as whether warming will create more clouds and whether those clouds will have a net positive or net negative effect on total retained heat). See [here](http://earthobservatory.nasa.gov/Features/Clouds/), for instance. “_The balance of the opposing cloud albedo and cloud greenhouse forcings determines whether a certain cloud type will add to the air’s natural warming of the Earth’s surface or produce a cooling effect. As explained below, the high thin cirrus clouds tend to enhance the heating effect, and low thick stratocumulus clouds have the opposite effect, while deep convective clouds are neutral. The overall effect of all clouds together is that the Earth’s surface is cooler than it would be if the atmosphere had no clouds._” In short, it’s relatively easy to demonstrate the greenhouse effect of CO2; it’s impossible to demonstrate with an experiment whether or not CO2 has the ability to cause global warming. ---
**Author:** ![GIGObuster](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gigobuster/32/421_2.png) [@GIGObuster](https://boards.straightdope.com/u/GIGObuster)\ **Post date:** [February 27, 2010, 4:30pm UTC](https://boards.straightdope.com/t/how-do-we-know-that-c02-is-a-greenhouse-gas/530602/23 "2010-02-27T16:30:42Z")
> [@Chief\_Pedant](#): > > In short, it’s relatively easy to demonstrate the greenhouse effect of CO2; it’s impossible to demonstrate with an experiment whether or not CO2 has the ability to cause global warming. Opinion once again. [http://www.aip.org/history/climate/co2.htm](http://www.aip.org/history/climate/co2.htm) > [@](#): > > The early experiments that sent radiation through gases in a tube, measuring bands of the spectrum at sea-level pressure and temperature, had been misleading. The bands seen at sea level were actually made up of overlapping spectral lines, which in the primitive early instruments had been smeared out into broad bands. Improved physics theory and precise laboratory measurements in the 1940s and after encouraged a new way of looking at the absorption. Scientists were especially struck to find that at low pressure and temperature, each band resolved into a cluster of sharply defined lines, like a picket fence, with gaps between the lines where radiation would get through.(24) The most important CO2 absorption lines did not lie exactly on top of water vapor lines. Instead of two overlapping bands, there were two sets of narrow lines with spaces for radiation to slip through. So even if water vapor in the lower layers of the atmosphere did entirely block any radiation that could have been absorbed by CO2, that would not keep the gas from making a difference in the rarified and frigid upper layers. Those layers held very little water vapor anyway. And scientists were coming to see that you couldn’t just calculate absorption for radiation passing through the atmosphere as a whole, you had to understand what happened in each layer — which was far harder to calculate. > > Digital computers were now at hand for such calculations. The theoretical physicist Lewis D. Kaplan decided it was worth taking some time away from what seemed like more important matters to grind through extensive numerical computations. In 1952, he showed that in the upper atmosphere, adding more CO2 must change the balance of radiation.(25) > > But would adding carbon dioxide in the upper layers of the air significantly change the surface temperature? Only detailed computations, point by point across the infrared spectrum and layer by layer down through the atmosphere, could answer that question. By 1956, such computations could be carried out thanks to the increasing power of digital computers. The physicist Gilbert N. Plass took up the challenge of calculating the transmission of radiation through the atmosphere (he too did it out of sheer curiosity, as a diversion from his regular work making calculations for weapon engineers). He nailed down the likelihood that adding more CO2 would increase the interference with infrared radiation. Going beyond this qualitative result, Plass calculated that doubling the level would bring a 3-4°C rise. Assuming that emissions would continue at the current rate, he expected that human activity would raise the average global temperature “at the rate of 1.1 degree C per century.”(26) > > The computation, like Callendar’s, paid no attention to possible changes in water vapor and clouds, and overall was too crude to convince scientists. “It is almost certain,” one authority scolded, “that these figures will be subject to many strong revisions.”(27) Yet Plass had proved one central point: it was a mistake to dismiss the greenhouse effect with spectroscopic arguments. He warned that climate change could be “a serious problem to future generations” — although not for several centuries. Following the usual pattern, Plass was mainly interested in the way variations in CO2 might solve the mystery of the ice ages. “If at the end of this century the average temperature has continued to rise,” he wrote, then it would be “firmly established” that CO2 could cause climate change.(28) And, recent research is pointing that it is more likely that clouds will not help much as they appear to be more of a positive feedback than a negative one. [http://physicsworld.com/cws/article/news/39908](http://physicsworld.com/cws/article/news/39908) > [@](#): > > Now, Amy Clement and Robert Burgman of the University of Miami and Joel Norris of the University of California-San Diego have done a statistical analysis of 55 years of cloud cover and temperature observations for the north-eastern Pacific Ocean. Their study provides the best evidence yet that low-level cloud cover decreases as temperature increases — that the feedback mechanism is positive. ---
**Author:** ![Kevbo](https://avatars.discourse-cdn.com/v4/letter/k/e47774/32.png) [@Kevbo](https://boards.straightdope.com/u/Kevbo)\ **Post date:** [February 27, 2010, 4:31pm UTC](https://boards.straightdope.com/t/how-do-we-know-that-c02-is-a-greenhouse-gas/530602/24 "2010-02-27T16:31:01Z")
Simple experiment: Make a coupe of double pane windows (don’t need to be great, you can use wood for the spacers, and glue them with silicone). Fill one with CO2. Put a heat lamp behind them, and use your hand to feel which lets more heat through. We’ve been shopping for new windows, and most of the retailers do this demo…though they mostly use Argon filling rather than CO2. Using different gases would make a good science fair project. ---
**Author:** ![Chief\_Pedant](https://avatars.discourse-cdn.com/v4/letter/c/a6a055/32.png) [@Chief\_Pedant](https://boards.straightdope.com/u/Chief_Pedant)\ **Post date:** [February 27, 2010, 10:27pm UTC](https://boards.straightdope.com/t/how-do-we-know-that-c02-is-a-greenhouse-gas/530602/25 "2010-02-27T22:27:22Z")
> [@Kevbo](#): > > Simple experiment: > > Make a coupe of double pane windows (don’t need to be great, you can use wood for the spacers, and glue them with silicone). Fill one with CO2. > > Put a heat lamp behind them, and use your hand to feel which lets more heat through. > > We’ve been shopping for new windows, and most of the retailers do this demo…though they mostly use Argon filling rather than CO2. > > Using different gases would make a good science fair project. Indeed it might, and it would tell you almost nothing about the net contribution of CO2 on climate change. It would be a good example of this fixation on CO2, though, and it might even win its fourth grade owner the Big Prize. Science is messy. It’s full of opinion and passionately defended positions, even at the professional level. For a nice little example, follow the story of the rebuttal of David Douglass’s 2007 paper questioning the validity of the IPCC global climate models and their relationship to observed results. Douglass’s take on how the criticism unfolded [here](http://www.americanthinker.com/2009/12/climate_conspiracy_appendix_b.html) makes for a wry read. ---
**Author:** ![GIGObuster](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gigobuster/32/421_2.png) [@GIGObuster](https://boards.straightdope.com/u/GIGObuster)\ **Post date:** [February 27, 2010, 10:56pm UTC](https://boards.straightdope.com/t/how-do-we-know-that-c02-is-a-greenhouse-gas/530602/26 "2010-02-27T22:56:28Z")
Now we resort to links reporting conspiracies, please, you need to link to facts here. > **[RealClimate: Close Encounters of the Absurd Kind](https://www.realclimate.org/index.php/archives/2010/02/close-encounters-of-the-absurd-kind/)** > > RealClimate: Ben Santer, IPCC, SAR, Chapter 8, discernible influence, "scientific cleasning", Guardian, Fred Pearce, Douglass and Christy > [@](#): > > A Climatology Conspiracy? More “peer-review abuse” accusations > > Mr. Pearce also investigates a more recent issue. He implies that I abused the normal peer-review system, and exerted pressure on the editor of the International Journal of Climatology to delay publication of the print version of a paper by Professor David Douglass and colleagues. This is not true. > > The Douglass et al. paper was published in December 2007 in the online edition of the International Journal of Climatology. The “et al.” included the same Professor S. Fred Singer who had previously accused me of “scientific cleansing”. It also included Professor John Christy, the primary developer of a satellite-based temperature record which suggests that there has been minimal warming of Earth’s lower atmosphere since 1979. Three alternate versions of the satellite temperature record, produced by different teams of researchers using the same raw satellite measurements, all indicate substantially more warming of the Earth’s atmosphere. > > The focus of the Douglass et al. paper was on post-1979 temperature changes in the tropics. The authors devised what they called a “robust statistical test” to compare computer model results with observations. The test was seriously flawed (see Appendix A in Open Letter to the Climate Science Community: Response to A “Climatology Conspiracy?”). When it was applied to the model and observational temperature datasets, the test showed (quite incorrectly) that the model results were significantly different from observations. > > As I have noted elsewhere, the Douglass et al. paper immediately attracted considerable media and political attention. One of the paper’s authors claimed that it represented an “inconvenient truth”, and proved that “Nature, not humans, rules the climate”. These statements were absurd. No single study can overturn the very large body of scientific evidence supporting “discernible human influence” findings. Nor does any individual study provide the sole underpinning for the conclusion that human activities are influencing global climate. > > Given the extraordinary claims that were being made on the basis of this incorrect paper, my colleagues and I decided that a response was necessary. Although the errors in Douglass et al. were easy to identify, it required a substantial amount of new and original work to repeat the statistical analysis properly. > > Our work went far beyond what Douglass et al. had done. We looked at the sensitivity of model-versus-data comparisons to the choice of statistical test, to the test assumptions, to the number of years of record used in the tests, and to errors in the computer model estimates of year-to-year temperature variability. We also examined how the statistical test devised by Douglass et al. performed under controlled conditions, using random data with known statistical properties. From their paper, there is no evidence that Douglass et al. considered any of these important issues before making their highly-publicized claims. > > Our analysis clearly showed that tropical temperature changes in observations and climate model simulations were not fundamentally inconsistent – contrary to the claim of Douglass and colleagues. Our research was published on October 10, 2008, in the online edition of the International Journal of Climatology. On November 15, 2008, the Douglass et al. and Santer et al. papers appeared in the same print version of the International Journal of Climatology. > > In December 2009, shortly after the public release of the stolen emails from the University of East Anglia’s Climatic Research Unit, Professors David Douglass and John Christy accused me of leading a conspiracy to delay publication of the print version of the Douglass et al. paper. This accusation was based on a selective analysis of the stolen emails. It is false. > > In Mr. Pearce’s account of this issue, he states that “There is no doubt the (sic) Santer and his colleagues sought to use the power they held to the utmost…” So what are the facts of this matter? What is the “power” Fred Pearce is referring to? > > ``` > * Fact 1: The only “power” that I had was the power to choose which scientific journal to submit our paper to. I chose the International Journal of Climatology. I did this because the International Journal of Climatology had published (in their online edition) the seriously flawed Douglass et al. paper. I wanted to give the journal the opportunity to set the scientific record straight. > * Fact 2: I had never previously submitted a paper to the International Journal of Climatology. I had never met the editor of the journal (Professor Glenn McGregor). I did not have any correspondence or professional interaction with the editor prior to 2008. > * Fact 3: Prior to submitting our paper, I wrote an email to Dr. Tim Osborn on January 10, 2008. Tim Osborn was on the editorial board of the International Journal of Climatology. I told Dr. Osborn that, before deciding whether we would submit our paper to the International Journal of Climatology, I wanted to have some assurance that our paper would “be regarded as an independent contribution, not as a comment on Douglass et al.” This request was entirely reasonable in view of the substantial amount of new work that we had done. I have described this new work above. > * Fact 4: I did not want to submit our paper to the International Journal of Climatology if there was a possibility that our submission would be regarded as a mere “comment” on Douglass et al. Under this scenario, Douglass et al. would have received the last word. Given the extraordinary claims they had made, I thought it unlikely that their “last word” would have acknowledged the serious statistical error in their original paper. As subsequent events showed, I was right to be concerned – they have not admitted any error in their work. > * Fact 5: As I clearly stated in my email of January 10 to Dr. Tim Osborn, if the International Journal of Climatology agreed to classify our paper as an independent contribution, “Douglass et al. should have the opportunity to respond to our contribution, and we should be given the chance to reply. Any response and reply should be published side-by-side…” > * Fact 6: The decision to hold back the print version of the Douglass et al. paper was not mine. It was the editor’s decision. I had no “power” over the publishing decisions of the International Journal of Climatology. > > ``` > > This whole episode should be filed under the category “No good deed goes unpunished”. My colleagues and I were simply trying to set the scientific record straight. There was no conspiracy to subvert the peer-review process. Unfortunately, conspiracy theories are easy to disseminate. Many are willing to accept these theories at face value. The distribution of facts on complex scientific issues is a slower, more difficult process. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [February 27, 2010, 11:09pm UTC](https://boards.straightdope.com/t/how-do-we-know-that-c02-is-a-greenhouse-gas/530602/27 "2010-02-27T23:09:55Z")
> [@](#): > > However if it turns out that the relationship between elevated temperatures and CO2 rise is not very linear, all of those models will have overstated the actual change we see. If the rise is not linear _and it deviates from linear on the low side_, then models will have overstated the change. If, on the other hand, they deviate from linear on the high side, then the models will have understated the change. That’s like saying “Michael Jordan probably isn’t taller than me, because maybe we’re the same height, but if he fails to be the same height as me, then I’m taller”. ---
**Author:** ![GIGObuster](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gigobuster/32/421_2.png) [@GIGObuster](https://boards.straightdope.com/u/GIGObuster)\ **Post date:** [February 27, 2010, 11:18pm UTC](https://boards.straightdope.com/t/how-do-we-know-that-c02-is-a-greenhouse-gas/530602/28 "2010-02-27T23:18:32Z")
As for more evidence and research confirming that CO2 is warming the atmosphere, and that scientists are doing more work than a 4th grader: > **[How do we know more CO2 is causing warming?](https://skepticalscience.com/empirical-evidence-for-co2-enhanced-greenhouse-effect.htm)** > > \An enhanced greenhouse effect from CO2 has been confirmed by multiple lines of empirical evidence. Satellite measurements of infrared spectra over the past 40 years observe less energy escaping to space at the wavelengths associated with CO2.... > [@](#): > > What they found was a drop in outgoing radiation at the wavelength bands that greenhouse gases such as carbon dioxide (CO2) and methane (CH4) absorb energy. The change in outgoing radiation is consistent with theoretical expectations. Thus the paper found “direct experimental evidence for a significant increase in the Earth’s greenhouse effect”. > > This result has been confirmed by subsequent papers using more recent satellite data. The 1970 and 1997 spectra were compared with additional satellite data from the NASA AIRS satellite launched in 2003 (Griggs 2004). This analysis was extended to 2006 using data from the AURA satellite launched in 2004 (Chen 2007). Both papers found the observed differences in CO2 bands matching the expected changes from rising carbon dioxide levels. Thus we have empirical evidence that increased CO2 is causing an enhanced greenhouse effect. > Surface measurements of downward longwave radiation > > A compilation of surface measurements of downward longwave radiation from 1973 to 2008 find an increasing trend of more longwave radiation returning to earth, attributed to increases in air temperature, humidity and atmospheric carbon dioxide (Wang 2009). More regional studies such as an examination of downward longwave radiation over the central Alps find that downward longwave radiation is increasing due to an enhanced greenhouse effect (Philipona 2004). > > Taking this a step further, an analysis of high resolution spectral data allows scientists to quantitatively attribute the increase in downward radiation to each of several greenhouse gases (Evans 2006). The results lead the authors to conclude that “this experimental data should effectively end the argument by skeptics that no experimental evidence exists for the connection between greenhouse gas increases in the atmosphere and global warming.” > > Figure 2: Spectrum of the greenhouse radiation measured at the surface. Greenhouse effect from water vapor is filtered out, showing the contributions of other greenhouse gases (Evans 2006). > > There are multiple lines of empirical evidence that increasing carbon dioxide causes an enhanced greenhouse effect. Laboratory tests show carbon dioxide absorbs longwave radiation. Satellite measurements confirm less longwave radiation is escaping to space at carbon dioxide absorptive wavelengths. Surface measurements find more longwave radiation returning back to Earth at these same wavelengths. The result of this energy imbalance is the accumulation of heat over the last 40 years. ---
**Author:** ![figure9](https://avatars.discourse-cdn.com/v4/letter/f/f0a364/32.png) [@figure9](https://boards.straightdope.com/u/figure9)\ **Post date:** [February 27, 2010, 11:49pm UTC](https://boards.straightdope.com/t/how-do-we-know-that-c02-is-a-greenhouse-gas/530602/29 "2010-02-27T23:49:03Z")
> [@](#): > > In general, don’t expect us to read your mind. Give us all the details. The better your frame your question, the better we can frame our answers. Expano Mapcase, Your points are all valid. I will do my best to make sure my posts are better worded and more detailed. Wow! I never knew how much I did not know about this subject. I spent 2 hours today following up on all your links. I though I understood AGW - C02 traps heat, more C02 traps more heat, case closed. What else did I need to know? Turns out I needed to learn a whole lot. Nobody likes to admit ignorance, but I have to admit I was just as ignorant as the AGW deniers I was arguing with. ---
**Author:** ![GIGObuster](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gigobuster/32/421_2.png) [@GIGObuster](https://boards.straightdope.com/u/GIGObuster)\ **Post date:** [February 28, 2010, 12:18am UTC](https://boards.straightdope.com/t/how-do-we-know-that-c02-is-a-greenhouse-gas/530602/30 "2010-02-28T00:18:04Z")
Indeed **figure9** , what really attracts me to this subject is that even I learn new things. BTW just published today, the new Climate Crock of the Week video is out, and it reports on the science and experiments already mentioned and more. [http://www.youtube.com/user/greenman3610#p/a/u/0/w9SGw75pVas](http://www.youtube.com/user/greenman3610#p/a/u/0/w9SGw75pVas) > [@](#): > > What We Know about Climate Change > > In the many responses I get to these videos, it appears that a number of people want to deny, or are not even aware, that there is a scientific foundation to the overwhelming consensus on climate change. > > In fact, the science is built on thousands of publications and many decades of observation. > > In this video we’ll go over some of the fundamental discoveries, the > basic facts that we know beyond a doubt, about global warming. > Of course, many people will never believe science, because they believe that > anything that challenges their world view, is all part of a secret, > global conspiracy. > > [Sources:] > > Increases in Longwave forcing inferred from Outward longwave > [http://www.nature.com/nature/journal/v410/n6826/abs/41035](http://www.nature.com/nature/journal/v410/n6826/abs/41035)… > Trends in Forcings > [http://www3.interscience.wiley.com/cgi-bin/fulltext/12322](http://www3.interscience.wiley.com/cgi-bin/fulltext/12322)… > Downward Longwave Radiation > [http://landshape.org/enm/wp-content/uploads/2009/01/phili](http://landshape.org/enm/wp-content/uploads/2009/01/phili)… > Downward Longwave Radiation > [http://www.agu.org/pubs/crossref/2009/2009JD011800.shtml](http://www.agu.org/pubs/crossref/2009/2009JD011800.shtml) > 29000 data sets, press release: > [NASA GISS: NASA News & Feature Releases: Earth Impacts Linked to Human-Caused Climate Change](http://www.giss.nasa.gov/research/news/20080514/) > 29000 data sets > [http://pubs.giss.nasa.gov/abstracts/2008/Rosenzweig\_etal\_](http://pubs.giss.nasa.gov/abstracts/2008/Rosenzweig_etal_)… > Global Energy Imbalance: > [http://pubs.giss.nasa.gov/abstracts/2005/Hansen\_etal\_1.html](http://pubs.giss.nasa.gov/abstracts/2005/Hansen_etal_1.html) > Isotopes: > [http://www.bgc-jena.mpg.de/service/iso\_gas\_lab/publications/PG\_WB\_IJMS.pdf](http://www.bgc-jena.mpg.de/service/iso_gas_lab/publications/PG_WB_IJMS.pdf) ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [February 28, 2010, 3:48am UTC](https://boards.straightdope.com/t/how-do-we-know-that-c02-is-a-greenhouse-gas/530602/31 "2010-02-28T03:48:51Z")
Incidentally, another minor misconception I see here: The OP is referring to the gas as “C02”, not “CO2”. It’s “see oh two”, not “see zero two”: The O stands for oxygen. A molecule of CO[sub]2[/sub] contains one atom of carbon (the C) and two atoms of oxygen (O[sub]2[/sub]). In the same way, water, H[sub]2[/sub]O, has two atoms of hydrogen and one of oxygen. ---
**Author:** ![septimus](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/septimus/32/410_2.png) [@septimus](https://boards.straightdope.com/u/septimus)\ **Post date:** [February 28, 2010, 11:22am UTC](https://boards.straightdope.com/t/how-do-we-know-that-c02-is-a-greenhouse-gas/530602/32 "2010-02-28T11:22:48Z")
The big problem with warming, according to James Lovelock, isn’t rising seas or bigger storms but loss of habitat (hot land and warm oceans are not conducive to life). Loss of forests as carbon sinks is just one of the adverse consequences of habitat reduction. > [@Chief\_Pedant](#): > > An example of an unknown feedback loop variable is water vapor/clouds. What will the effect of that feedback loop be? Will elevated temperatures increase the amount of clouds and water vapor? Will that effect further raise the temperature, or lower it? My understanding is that dissolved water vapor warms, while clouds cool; hence the confusion/complexity. Lovelock claims that cloud condensation nuclei result indirectly from activity of marine organisms, so warmer seas will lead to fewer clouds. Any validity to that? Bottom-line: there are several _known_ mechanisms of positive feedback for warming, but only _hypothesized_ negative feedback mechanisms. Lovelock may help explain _why_ Pleistocene cooling is anamolous and thus likely to be fragile. (I’m sure someone will retort that “Lovelock is a crackpot” but that’s a rather silly statement given the man’s credentials.) > [@Chief\_Pedant](#): > > Of your cites, none is a published paper … Interesting comment from someone citing Wall St. Journal. :dubious: ---
**Author:** ![Chief\_Pedant](https://avatars.discourse-cdn.com/v4/letter/c/a6a055/32.png) [@Chief\_Pedant](https://boards.straightdope.com/u/Chief_Pedant)\ **Post date:** [February 28, 2010, 12:21pm UTC](https://boards.straightdope.com/t/how-do-we-know-that-c02-is-a-greenhouse-gas/530602/33 "2010-02-28T12:21:24Z")
Originally Posted by **Chief Pedant** (in reference to a \*\*GIGObuster \*\*reply to **CP** ): \*Of your cites, none is a published paper … \* Here is GIGObuster comment to which this was a reply: _“As the last debate showed, **opinions** from the Wall Street Journal should not be taken seriously.”_ > [@septimus](#): > > Interesting comment from someone citing Wall St. Journal. :dubious: Part of what makes AGW threads here on the Dope so tedious is the personalities of the AGW alarmists; as I’ve commented on multiple times, because they are hold of a Great Cause, it’s like challenging someone’s religious beliefs or raison d’etre to post comments skeptical of the AGW alarmist construct. As a consequence of this psychology, all opposing comments/positions are treated as if they are opinion, or poorly-written papers, or “debunked” papers, or discredited scientists, or whatever. While there is genuine controversy and poorly-understood processes behind the CO2-based AGW modeling, you’d never know it based on the urgent sincerity and disdain for those controversies by the AGW alarmists. The WSJ piece I cited was written as a guest piece by Richard Lindzen, a professor of meterology at MIT. This piece was characterized and belittled by GIGObuster as “opinions from the Wall Street Journal.” My reply, which caused you to raise a dubious eyebrow, was that GIGObuster’s cites were no less opinion. But apparently neither of you, in your haste to diminish opposing views and champion your own, actually read the cite or bothered to see who authored it. While Mr Lindzen’s views may disagree with GIGObuster’s, I rather suspect Mr Lindzen could hold his own in debating the science with GIGObuster. This is not GD, and so the points being debated can be taken elsewhere. But I encourage you to be a bit less hasty snarking when you have not bothered to read. ---
**Author:** ![GIGObuster](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gigobuster/32/421_2.png) [@GIGObuster](https://boards.straightdope.com/u/GIGObuster)\ **Post date:** [February 28, 2010, 3:06pm UTC](https://boards.straightdope.com/t/how-do-we-know-that-c02-is-a-greenhouse-gas/530602/34 "2010-02-28T15:06:14Z")
> [@Chief\_Pedant](#): > > As a consequence of this psychology, all opposing comments/positions are treated as if they are opinion, or poorly-written papers, or “debunked” papers, or discredited scientists, or whatever. > > This is not GD, and so the points being debated can be taken elsewhere. But I encourage you to be a bit less hasty snarking when you have not bothered to read. Your opinion once again. You have no evidence that it is a syndrome, and the evidence presented so far speaks of how your champions and reporters misrepresent the science or are shown to make even basic errors. There is a reason why you have to resort to opinion pieces (and they remain opinions even if you like to pretend that they are not) the researchers and reporters leave their most outrageous and unfounded assertions in opinion articles to be reported and repeated in the denier media. It is not only me who is saying this, and this is based even on just the examples shown here. When an article that you posted as “evidence” is titled “Climate Conspiracy Appendix B” it is not just an opinion, it is a really serious accusation and you really need better evidence. Indeed this is not GD, post the evidence (not opinion) that it is a conspiracy, and to stick to subject, post the evidence why the experiments and research linked in posts 23, 28 and 30 are not valid. ---
**Author:** ![GIGObuster](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gigobuster/32/421_2.png) [@GIGObuster](https://boards.straightdope.com/u/GIGObuster)\ **Post date:** [February 28, 2010, 3:44pm UTC](https://boards.straightdope.com/t/how-do-we-know-that-c02-is-a-greenhouse-gas/530602/35 "2010-02-28T15:44:43Z")
> [@Chief Pedant](#): > > While Mr Lindzen’s views may disagree with GIGObuster’s, I rather suspect Mr Lindzen could hold his own in debating the science with GIGObuster. I would even suspect that, but not after what he did pull off here: [http://scienceblogs.com/deltoid/2006/05/richard\_lindzen\_claims\_global.php](http://scienceblogs.com/deltoid/2006/05/richard_lindzen_claims_global.php) > [@](#): > > In the text he claims that there has been almost no rise since 1986, but in his talk (at 38:00) he told the audience to ignore the red line (which shows the ten year mean) and pointed to the graph on the bottom right of just the last eight years. Presumably he meant to write that there had been no rise since 1998. I must give him points for brazenness by doing a blatant cherry pick right in front of his audience. They seemed to buy it. > > I’ll go the other way. Look at the graph on the lower right and then look at it in context in the graph on the top right with the red line showing the trend. It’s clear that warming didn’t stop in 1998 and it shows just how misleading Lindzen’s cherry pick is. It is just like one commenter in another science blog said: “In discussions with deniers one just have to point out that deniers are coming to a gun fight with chocolate pistols” Coming to a fact based thread with opinion pieces from unreliable sources? That will not work too. If the evidence was so good, it would begin to change the positions of science groups, and they are not doing that, denialists are resorting to take their cases outside research journals and academia to make even more irresponsible assertions. We should not fall for that. ---
**Author:** ![Chief\_Pedant](https://avatars.discourse-cdn.com/v4/letter/c/a6a055/32.png) [@Chief\_Pedant](https://boards.straightdope.com/u/Chief_Pedant)\ **Post date:** [February 28, 2010, 4:15pm UTC](https://boards.straightdope.com/t/how-do-we-know-that-c02-is-a-greenhouse-gas/530602/36 "2010-02-28T16:15:27Z")
> [@GIGObuster](#): > > When an article that you posted as “evidence” is titled “Climate Conspiracy Appendix B” it is not just an opinion, it is a really serious accusation and you really need better evidence. Indeed this is not GD, post the evidence (not opinion) that it is a conspiracy, and to stick to subject, post the evidence why the experiments and research linked in posts 23, 28 and 30 are not valid. This is what I posted: _“Science is messy. It’s full of opinion and passionately defended positions, even at the professional level. For a nice little example, follow the story of the rebuttal of David Douglass’s 2007 paper questioning the validity of the IPCC global climate models and their relationship to observed results. Douglass’s take on how the criticism unfolded here makes for a wry read.Science is messy. It’s full of opinion and passionately defended positions, even at the professional level. For a nice little example, follow the story of the rebuttal of David Douglass’s 2007 paper questioning the validity of the IPCC global climate models and their relationship to observed results. Douglass’s take on how the criticism unfolded [here](http://www.americanthinker.com/2009/12/climate_conspiracy_appendix_b.html) makes for a wry read.”_ The link referenced has to do with how an author’s reaction to criticism unfolded. It was not characterized by me as “evidence” of any kind except, perhaps, for evidence how the scientific process is messy. That you would choose to pretend that I characterized it as primary evidence for the science of AGW itself is unfortunate and, (for the sake of trying to remain civil) I shall assume was in error. It’s my personal opinion that your faith in said process is naive and your confidence in the significance of the conclusions overstated, but it’s not my intention to debate AGW here. My comments are limited to the process of science itself, and my general skepticism is founded on a less confident view than yours that current models are predictive for the world’s long-term climate systems. ---
**Author:** ![GIGObuster](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gigobuster/32/421_2.png) [@GIGObuster](https://boards.straightdope.com/u/GIGObuster)\ **Post date:** [February 28, 2010, 4:48pm UTC](https://boards.straightdope.com/t/how-do-we-know-that-c02-is-a-greenhouse-gas/530602/37 "2010-02-28T16:48:12Z")
> [@septimus](#): > > Bottom-line: there are several _known_ mechanisms of positive feedback for warming, but only _hypothesized_ negative feedback mechanisms. Lovelock may help explain _why_ Pleistocene cooling is anamolous and thus likely to be fragile. (I’m sure someone will retort that “Lovelock is a crackpot” but that’s a rather silly statement given the man’s credentials.) The position of many climate researchers is that Lovelock is into the alarmist camp, in a previous discussion it was clear that supporters could not find researchers backing his say so that we will see a 6 degree rise before the end of the century. [http://scienceblogs.com/deltoid/2006/02/lovelock\_buys\_into\_ddt\_ban\_myt\_1.php](http://scienceblogs.com/deltoid/2006/02/lovelock_buys_into_ddt_ban_myt_1.php) [http://scienceblogs.com/deltoid/2006/01/global\_warming\_alarmism.php](http://scienceblogs.com/deltoid/2006/01/global_warming_alarmism.php) There is no need to mention alarmists when there is plenty of evidence that indeed “there are several _known_ mechanisms of positive feedback for warming, but only _hypothesized_ negative feedback mechanisms.” As the cloud example shows. > [@septimus](#): > > Interesting comment from someone citing Wall St. Journal. :dubious: It is more interesting that he cited the opinion section, and that he still wants to say that I do the same… while he ignores the science citations in the links. ---
**Author:** ![septimus](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/septimus/32/410_2.png) [@septimus](https://boards.straightdope.com/u/septimus)\ **Post date:** [February 28, 2010, 5:40pm UTC](https://boards.straightdope.com/t/how-do-we-know-that-c02-is-a-greenhouse-gas/530602/38 "2010-02-28T17:40:56Z")
> [@Chief\_Pedant](#): > > … I encourage you to be a bit less hasty snarking when you have not bothered to read. I’ll admit perhaps to “snarking” but I _did_ read the Lindzen column. I was just pointing out that your back-to-back posts seemed to exhibit a double standard. I do see why you preferred to cite the WSJ piece: Lindzen’s language there would never pass peer review. In the WSJ piece Lindzen unwittingly endorses Lovelock’s key point: > [@](#): > > The notion that the earth’s climate is dominated by positive feedbacks is intuitively implausible, and the history of the earth’s climate offers some guidance on this matter. About 2.5 billion years ago, the sun was 20%-30% less bright than now (compare this with the 2% perturbation that a doubling of CO2 would produce), and yet the evidence is that the oceans were unfrozen at the time, and that temperatures might not have been very different from today’s. That the Earth was just as warm when the sun was 20%-30% cooler suggests that Pleistocene cold is indeed anomalous. _That’s_ why Lovelock is so concerned. > [@GIGObuster](#): > > The position of many climate researchers is that Lovelock is into the alarmist camp,… Lovelock isn’t worried about tenure (neither am I 😉 ) so can call things exactly as he sees them. His big worry is warming causing habitat destruction which leads to further warming. Regardless of any warming debate, habitat destruction _is_ occurring for various reasons. One would hope that preserving habitat is an issue we could all support! (As for a 6-degree rise, Lovelock is well aware of scientific uncertainty, the _high_ IPCC estimate was at least that high and, anyway, many agree just a 3-degree rise would be dangerous and irreversible.) (Chief Pedant: What say you to this? _Is_ habitat destruction occurring and, if so, is that good or bad?) ---
**Author:** ![Dahnlor](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dahnlor/32/533_2.png) [@Dahnlor](https://boards.straightdope.com/u/Dahnlor)\ **Post date:** [February 28, 2010, 5:55pm UTC](https://boards.straightdope.com/t/how-do-we-know-that-c02-is-a-greenhouse-gas/530602/39 "2010-02-28T17:55:17Z")
> [@Chronos](#): > > Incidentally, another minor misconception I see here: The OP is referring to the gas as “C02”, not “CO2”. It’s “see oh two”, not “see zero two”: The O stands for oxygen. A molecule of CO[sub]2[/sub] contains one atom of carbon (the C) and two atoms of oxygen (O[sub]2[/sub]). In the same way, water, H[sub]2[/sub]O, has two atoms of hydrogen and one of oxygen. To be fair, he did type it both ways, probably more of a simple typo than a misunderstanding of the molecular composition. ---
**Author:** ![GIGObuster](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gigobuster/32/421_2.png) [@GIGObuster](https://boards.straightdope.com/u/GIGObuster)\ **Post date:** [February 28, 2010, 6:07pm UTC](https://boards.straightdope.com/t/how-do-we-know-that-c02-is-a-greenhouse-gas/530602/40 "2010-02-28T18:07:38Z")
> [@septimus](#): > > the _high_ IPCC estimate was at least that high and, anyway, many agree just a 3-degree rise would be dangerous and irreversible.) Yes, but there is a reason why that was not qualified as “Virtually certain” or “Extremely likely” What is most likely is a rise of 3 degrees by the end of the century. It was just a minority of researchers that came with 6 degrees and that is still on the upper levels of their estimates. Recently I was falling into thinking that the high estimates were more likely, as ice over the Arctic and Greenland were showing a huge loss in 2006-2007, the latest reports show that it was most likely an anomaly and the evidence continues to show that the most likely **expected rate of decline** is happening. > **[Sea Ice Today | National Snow and Ice Data Center](https://nsidc.org/sea-ice-today)** Denier media here just said that the ice extent was growing after 2007and NASA was not telling us. :smack: > [@](#): > > Figure 3. Monthly January ice extent for 1979 to 2010 shows a decline of 3.2% per decade. So, the evidence is pointing at bad things happening if nothing is done, but not to the levels of Lovelock like when he said that “before this century is over billions of us will die and the few breeding pairs of people that survive will be in the Arctic where the climate remains tolerable.” The most supported evidence and estimates show that if nothing is done we are in for a lot of hurt in several regions of the earth, but it is not the end of the world. If I was a man of faith I would said that my gut tells me that other feedbacks may come in sooner before the 3 degree mark is reached. But since there is no strong evidence for them acting just yet, one has to go for the best evidence out there. [Previous page](https://boards.straightdope.com/t/how-do-we-know-that-c02-is-a-greenhouse-gas/530602.md?page=1) [Next page](https://boards.straightdope.com/t/how-do-we-know-that-c02-is-a-greenhouse-gas/530602.md?page=3)