Climate Science Glossary

Term Lookup

Enter a term in the search box to find its definition.

Settings

Use the controls in the far right panel to increase or decrease the number of terms automatically displayed (or to completely turn that feature off).

Term Lookup

Settings

All IPCC definitions taken from Climate Change 2007: The Physical Science Basis. Working Group I Contribution to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Annex I, Glossary, pp. 941-954. Cambridge University Press.

Home Arguments Software Resources Comments The Consensus Project Translations About Support

Bluesky Facebook LinkedIn Mastodon MeWe

Twitter YouTube RSS Posts RSS Comments Email Subscribe


Climate's changed before
It's the sun
It's not bad
There is no consensus
It's cooling
Models are unreliable
Temp record is unreliable
Animals and plants can adapt
It hasn't warmed since 1998
Antarctica is gaining ice
View All Arguments...



Username
Password
New? Register here
Forgot your password?

Latest Posts

Archives

Recent Comments

Prev  2540  2541  2542  2543  2544  2545  2546  2547  2548  2549  2550  2551  2552  2553  2554  2555  Next

Comments 127351 to 127400:

  1. How do we know CO2 is causing warming?
    I'm not a scientist, but I do understand basic logic. What's interesting to me about Leonard's assertions is not that many of them are wrong, but how he draws the wrong conclusions from the facts he gets right. What it shows is a lack of ability to do "systems thinking": the type of reasoning that involves understanding of stocks and flows, time delays, nonlinearities, and feedbacks - exactly the concepts important to understanding climate science. Leonard makes logical errors in each of these areas. His argument about water vapor being a much more potent GHG is a stock and flow error. The notion that decreasing temperatures during a period of CO2 increase disproves AGW fails to grasp nonlinearities and time delays. He talks about "water vapor feedback," but based on the incoherence of the sentence, I'd guess he doesn't know what a feedback is. But even highly-educated people with technical backgrounds can fail to grasp these concepts intuitively. A study called "All Models are Wrong" (John Sterman, System Dynamics Review, Winter 2002) found that even most MIT grad students couldn't grasp basic systems thinking concepts like stocks and flows. I'd argue that, aside from political bias, the inability to do systems thinking is the second biggest driver of climate denial. People like McIntyre and Plimer may be highly educated and skilled at performing calculations, but their brains' intuitive grasp of systems concepts may be under-developed. This is why you don't have to be a technical expert on all the details of climate science to still respond to denier talking points. Most of them aren't errors of fact so much as errors of logic. (John - Sorry to steal your thunder on the previous post. There must have been some water vapor feedbacks or something :)
  2. Water vapor is the most powerful greenhouse gas
    I would like to see all energy inputs and outputs and also the real estimates of the amounts of water in oceans water in atmosphere carbon sources ,co2 production from nature and man methane from nature and man i would lke to see evidence of temperatures in the distant past with co2 levels and if possible water vapour levels say over millenia. my expectation is that atmospheric carbon and water vapour levels are tails of very big dogs in the oceans and carbon sources. that we are dealing with small numbers in a system of much bigger numbers so conclusions we reach about global warming based on atmosheric gases are very problematic. what does co2 energy absorption in its narrow absorption band really have on energy balance.could it be it is reradiated at another frequency to space ? please explain how the green house effect of a gas actually works in detail I can appreciate the effect of WV in that clouds capture heat energy from the sun and nett radiate convect and reflect more heat than if the clouds were not there.water vapour that is not in a cloud presumably is causing a radiation block from the earth. i am not sure of the deatil
    Response: I've recently posted about an analysis of all energy inputs and outputs. and posted on man's co2 emissions. For more on the carbon cycle, see this page on human versus natural co2 emissions.

    Examination of past temperature change alongside CO2 change is examined on the CO2 lags temperature page as well as empirical determinations of climate sensitivity.

    The conclusion that atmospheric gases are causing global warming is based on empirical observations. Satellite observations of radiation escaping to space find that less radiation is escaping at wavelengths that CO2 absorb. This is confirmed by surface measurements of downward longwave radiation that also find increasing downward radiation at CO2 wavelengths.
  3. Philippe Chantreau at 10:00 AM on 8 October 2009
    Are humans too insignificant to affect global climate?
    I meant to say the temperate rainforests, which I believe to be the richest terrestrial biome outside of tropical rainforests.
  4. Philippe Chantreau at 09:54 AM on 8 October 2009
    Are humans too insignificant to affect global climate?
    Plants grow best where there is plenty of water available. Indeed that seems to be the most important factor since, with time, even poor soil will be enriched by plant life, which will then recycle itself leading to more abundant and diverse life. The African forest is a case in point; much of it sits on a thin layer of rich soil built over time by decomposing organisms, the original soil underneath is nothing but red dust, called laterite. Laterite is quite good to build roads. With proper sun exposure throughout the day, allowing it to dry, a laterite road is likely to last longer than a paved one. Strangely enough, plants don't start growing on laterite roads nearly as fast or as easily as they do in the cracks of a paved road. The temperate forests are also found where there is plenty of available water, as in Kamtchatka, Pacific Northwest, South Alaska. Of all factors, not a single one is more important than the availability of water, not even nutrients, with enough time given.
  5. Philippe Chantreau at 09:41 AM on 8 October 2009
    How do we know CO2 is causing warming?
    Glad to see the follow up on the Harries paper. A wealth of interesting papers here, from John and posters as well. Nice.
  6. Are humans too insignificant to affect global climate?
    RSVP said: "Do plants generally grow faster in warmer or cooler climates?" There are many more factors to be considered that just rate of growth. Total yield and nutritional quality are much more important. Rice has been shown to be negatively affected by increasing minimum temperatures: "Grain yield declined by 10% for each 1°C increase in growing-season minimum temperature in the dry season, whereas the effect of maximum temperature on crop yield was insignificant. This report provides a direct evidence of decreased rice yields from increased nighttime temperature associated with global warming." PNAS July 6, 2004 vol. 101 no. 27 9971-9975 http://www.pnas.org/content/101/27/9971.full Nutritional quality of wheat declines: "The discovery that staple crops like wheat have less protein when grown in high concentrations of CO2 has already caused concern, but the bad news doesn't stop there. Ramping up CO2 also changes the balance of amino acids and several trace elements, says Petra Högy from the University of Hohenheim in Germany". http://www.newscientist.com/article/dn17617-wheat-gets-worse-as-cosub2sub-rises.html There are many other papers describing deleterious effects of higher temperatures and higher CO2 levels on the plants which are staples in our diet. Thus messing around with our climate and atmospheric chemistry will not be good for our food supply.
  7. How do we know CO2 is causing warming?
    couple more points re #4
    In addition, the recent temperature leveling off and in fact tending down (last 7 or so years), along with admissions that this may in fact go on 20 more year, seems to disconnect the clear relation between temperature and CO2 level.
    The relation between temperature and CO2 relates to the equilibrium temperature resulting from a raised CO2 level, Leonard. It’s obvious that natural variation will modulate the transition towards that new temperature. Analysis of total heat content indicates that the earth continues to absorb heat under influence of radiative imbalance and this is going to contribute to enhanced surface warming. http://www.skepticalscience.com/How-we-know-global-warming-is-happening-Part-2.html
    In direct response to WAG, the global temperature has risen numerous times as fast and as high over the last few thousand years with no greenhouse cause.
    I don’t think there’s any evidence that supports that assertion. Can you provide some?
    Water vapor is far the largest greenhouse gas and self regulates the system.
    Whatever “self-regulates” means here (can you explain?), the evidence indicates that water vapour is a positive feedback (see papers cited in my post #6 above). Nothing is really “self-regulating” the system. The earth responds to enhanced radiative forcing by absorbing heat and warming.
    The rise in CO2 is real, but has been 10 times large in the distant past with similar temperatures.
    That’s not relevant without considering the steady increase in solar constant since the start of the solar system. 500 million years ago the sun was radiating around 4% less brightly than now. Any particular CO2 concentration will give a much warmer earth now than the same CO2 concentration in the deep past. The relationship between paleo CO2 measures and paleo temperatures in the deep past is quite strong as has been described in a review by Royer: Dana L. Royer (2006) CO2-forced climate thresholds during the Phanerozoic. Geochimica et Cosmochimica Acta 70 (2006) 5665–5675 Abstract: The correspondence between atmospheric CO2 concentrations and globally averaged surface temperatures in the recent past suggests that thiscoupling may be of great antiquity. Here, I compare 490 published proxy records of CO2 spanning the Ordovician to Neogene with records of global cool events to evaluate the strength of CO2-temperature coupling over the Phanerozoic (last 542 my). For periods with sufficient CO2 coverage, all cool events are associated with CO2 levels below 1000 ppm. A CO2 threshold of below 500 ppm is suggested for the initiation of widespread, continental glaciations, although this threshold was likely higher during the Paleozoic due to a lower solar luminosity at that time. Also, based on data from the Jurassic and Cretaceous, a CO2 threshold of below 1000 ppm is proposed for the initiation of cool non-glacial conditions. A pervasive, tight correlation between CO2 and temperature is found both at coarse (10 my timescales) and fine resolutions up to the temporal limits of the data set (million-year timescales), indicating that CO2, operating in combination with many other factors such as solar luminosity and paleogeography, has imparted strong control over global temperatures for much of the Phanerozoic. droyer.web.wesleyan.edu/PhanCO2(GCA).pdf
  8. How do we know CO2 is causing warming?
    Kind of funny how you see a change around 600 cm-1, but no change around 1000 cm-1.
    Response: Different bands react in different ways - observations match theoretical expectations in this case.
  9. How do we know CO2 is causing warming?
    re #4: Not really Leonard. Saying stuff doesn’t make it true!
    Since the upper troposphere hot spot at the tropics is mainly missing, and since the absolute humidity has not increased even as the temperature increased, is in direct opposition to the positive feedback effect being present.
    The absolute humidity certainly has increased. There really isn’t any question of that [*] A recent analysis indicates that the upper tropospheric temperature in the tropics is not inconsistent with predictions from modelling [**] [*] Dessler, A. E., Z. Zhang, and P. Yang (2008), Water-vapor climate feedback inferred from climate fluctuations, 2003–2008, Geophys. Res. Lett., 35, L20704 http://www.agu.org/pubs/crossref/2008/2008GL035333.shtml Gettelman A and Fu, Q. (2008) Observed and simulated upper-tropospheric water vapor feedback . J. Climate 21, 3282-3289 Buehler SA (2008) An upper tropospheric humidity data set from operational satellite microwave data. J. Geophys. Res. 113, art #D14110 Brogniez H and Pierrehumbert RT (2007) Intercomparison of tropical tropospheric humidity in GCMs with AMSU-B water vapor data. Geophys. Res. Lett. 34, art #L17912 Royer DL et al. (2007) Climate sensitivity constrained by CO2 concentrations over the past 420 million years Nature 446, 530-532 Santer BD et al. (2007) Identification of human-induced changes in atmospheric moisture content. Proc. Natl. Acad. Sci. USA 104, 15248-15253 Soden BJ, et al (2005) The radiative signature of upper tropospheric moistening Science 310, 841-844. [**]B. D. Santer et al. (2008) Consistency of modelled and observed temperature trends in the tropical troposphere. International Journal of Climatology 28, 1703 – 1722. https://publicaffairs.llnl.gov/news/news_releases/2008/NR-08-10-05-article.pdf
  10. How do we know CO2 is causing warming?
    Leonard Weinstein, There are several assertions crammed into one paragraph, but I'll deal with the prominent assertions you're presenting. Water vapor is a positive feedback, as many direct observations have indicated. http://www.agu.org/pubs/crossref/2008/2008GL035333.shtml The "no tropical hotspot" argument is both a questionable assertion and a red herring. First, the balance of evidence suggests that there is a tropical hotspot. http://www.skepticalscience.com/tropospheric-hot-spot.htm http://www.realclimate.org/index.php/archives/2008/05/tropical-tropopshere-ii/ http://www.realclimate.org/index.php/archives/2007/12/tropical-troposphere-trends/ Second, a tropical tropospheric hotspot is not unique to GHG warming. It should appear with solar warming as well. Lastly, if there truly was no tropical hotspot in observations, it would actually imply, if anything, a higher climate sensitivity. http://chriscolose.wordpress.com/2008/12/20/skepticsdenialists-part-2-hotspots-and-repetition/
  11. Leonard Weinstein at 05:47 AM on 8 October 2009
    How do we know CO2 is causing warming?
    The fact that CO2 is a greenhouse gas and raises the temperature somewhat is not the issue of the technical Skeptics. The issue is water vapor feedback amplifying the result. Since the upper troposphere hot spot at the tropics is mainly missing, and since the absolute humidity has not increased even as the temperature increased, is in direct opposition to the positive feedback effect being present. In addition, the recent temperature leveling off and in fact tending down (last 7 or so years), along with admissions that this may in fact go on 20 more year, seems to disconnect the clear relation between temperature and CO2 level. In direct response to WAG, the global temperature has risen numerous times as fast and as high over the last few thousand years with no greenhouse cause. The current lack of continual rise does not support an unusual level. The fact that CO2 is a greenhouse gas is not the issue. Water vapor is far the largest greenhouse gas and self regulates the system. The rise in CO2 is real, but has been 10 times large in the distant past with similar temperatures. It does not matter where it comes from, only the result is important.
    Response: Kudos for squeezing so many arguments into one small comment. They are addressed elsewhere in this site: Apologies to any subsequent commenters if my links or answers duplicate their responses.
  12. How do we know CO2 is causing warming?
    Back to the basics, I guess. Hard to believe there are folks still denying the impact of CO2. This post brings together a series of important studies that supports one line of very strong evidence supporting the CO2 link to global warming. There's other lines of evidence such as tropospheric warming, more at lower heights, and stratospheric cooling, all consistent with GHG warming. There's more secondary but compelling evidence of the slow changes over the proxy record and the 20th-century spike, and what is the statistical likelihood of recent rapid warming. http://www.sciencedaily.com/releases/2009/01/090109115047.htm Very well done. It's posts like these that start generating the "these government-funded scientists are fabricating evidence" arguments from a fervent crowd that is high on repetition of talking points and short on science.
  13. How do we know CO2 is causing warming?
    Absolutely devastating post. Skeptics' arguments have holes like Bonnie and Clyde. With the evidence here and John's last post, you can bring it all together to make a pretty airtight logical proof for global warming. We know these things to be factually true: 1. Global temperatures have risen. 2. CO2 is a greenhouse gas. 3. CO2's concentration in the atmosphere has risen significantly. 4. That extra CO2 comes from burning of fossil fuels. To logically prove that humans are NOT causing the observed increase in temperatures, you therefore need to prove BOTH of two things: First, you need to show how it could be possible to pump more of a known greenhouse gas into the atmosphere WITHOUT temperatures increasing. Second, if CO2 is not causing the observed warming, you need to show what IS. The link to the full post is below. I challenge any skeptic to prove both these points above. http://akwag.blogspot.com/2009/09/obama-speaks-on-global-warming-what-you_22.html
    Response: Hey, you're stealing my thunder! I was planning to tie together all the latest posts into a single thread compiling the empirical evidence that humans are causing global warming. Now you've gone and spoiled the surprise :-)
  14. How do we know CO2 is causing warming?
    Excellent post! I've not before seen a concise, complete explanation tying together all these particular threads of evidence. Thanks!
  15. Are humans too insignificant to affect global climate?
    "Nice try. You are talking about a desert that has looked like that since Moses. I was talking about the effect of plus 1 or 2 degrees C. " A 1C or 2C change in global mean temperature also changes patterns of precipitation and evaporation, which changes water availability. Some areas will get wetter, and some will get dryer. Even if plants theoretically grow faster at warmer temperatures and higher ambient CO2, that does no good if they're already nutrient-limited or water-limited, as many plants are in the real world. There is lots and lots of research about this.
  16. Are humans too insignificant to affect global climate?
    Ned Nice try. You are talking about a desert that has looked like that since Moses. I was talking about the effect of plus 1 or 2 degrees C.
  17. Are humans too insignificant to affect global climate?
    I am not denying anything. I assume global warming is a reality and would like to know what can be done about it besides drawing a paycheck to crunch numbers all day about how much CO2 is being generated. Denialists, I would say, are those that suggest we can somehow circumvent laws of thermodynamics associated with all form of energy production. Physics aside, while CO2 has something to do with global warming, the phenomenon (as this paper implies) has to do with OVERPOPULATION. Birth control and education, for instance, may be much more relevant towards this cause as compared to the narrow and miopic "scientific" discussion at hand. For purposes of analysis, it is normal and OK to isolate factors, but when you are talking about a system as complex as the Earth, it seems quite ARROGANT indeed to assume you have all the answers, and only be focussing on that one aspect of the problem. and all live in harmony with nature while maintaing unending industrial growth. You cant just focus on one part of this problem, which has been my point since day one.
  18. Are humans too insignificant to affect global climate?
    RSVP writes: "Do plants generally grow faster in warmer or cooler climates?" That depends on water and nutrient levels. I used to work here, and at temperatures of 50C, there was nary a plant to be seen. In contrast, despite ten months per year of winter, there's trees growing all over here. "How do CO2 levels affect plant growth?" That also depends on water and nutrient availability, and on which photosynthetic pathway the plant uses.
  19. Are humans too insignificant to affect global climate?
    Good denialist questions. You know, and I know, and everyone else on this site knows they have been asked (by people like you) and answered many thousands of times. Why persist with them? You are not fooling anyone except your denialist mates. You are filling up, yet again, another thread with rubbish I suppose - is that your only aim? Sense of achievement? Have you, at last, no sense of shame?
  20. Are humans too insignificant to affect global climate?
    Two questions: 1) Do plants generally grow faster in warmer or cooler climates? 2) How do CO2 levels affect plant growth?
  21. How we know global warming is still happening
    I was being facetious, however now that you made these remarks, there seem to be two issues here. The idea of science as simply a method for providing useful conceptual models, and science, this thing that has promoted global destruction. Most of what we call science has brought on the global warming via modern medicine (ie resulting in population explosion), and the industrial revolution (resulting in population explosion). There is a word that is very rarely used these days. The word is called RESPONSIBILITY. Science can take us anywhere, good or bad. As you imply, it is indifferent, but scientists are people, and people should not be indifferent. So next time you are doing science, try to THINK about what you are really doing.
  22. How we know global warming is happening, Part 2
    Mizimi -- the known number of volcanos isn't changing, there's no unusual warming at the bottom of the ocean in volcanic areas, the earthquake maps show no change, so likely none. Same for volcanos above the ocean, these happen but not in an increasing number so they're part of the background noise, not part of the increase.
  23. Are humans too insignificant to affect global climate?
    The question RSVP is how anyone could possibly think that 7 billion human beings, each with an ecological footprint of varying sizes up to very large indeed, could NOT now be affecting the Earth's climate. The CO2 effect is the most obvious, significant and general one, which is why John concentrates on it here, but the effects of forest clearing, overfishing, development, pollution, species extinction, are also important to the climate in various ways and are directly down to humans. Why any of this should be a question, other than to those who think a god gave humans permission to strip the world of all its resources just before it came to an end, completely escapes me.
  24. Philippe Chantreau at 14:13 PM on 7 October 2009
    How we know global warming is still happening
    We're talking about promoting evolution among not only animals, but also the current Human population here. All through a weird, uncontrolled experiment. Can't see how that would be a good idea, but it's just me. Science does not promote ideas like marketing people promote products. It attempts to understand the world. Nobody is in charge. Not Darwin, not Einstein, not Bohr, not Schroedinger. There is nobody "in charge", only people trying to understand. Looking at it any other way indicates, IMO, a profound misunderstanding of science.
  25. Sea level rise is exaggerated
    In an interview with Dr. Nils-Axel Mörner (head of the Paleogeophysics and Geodynamics department at Stockholm University in Sweden, past president (1999-2003) of the INQUA Commission on Sea Level Changes and Coastal Evolution, and leader of the Maldives Sea Level Project – he has been studying the sea level and its effects on coastal areas for some 35 years) by EIR (Argentine Foundation for a Scientific Ecology) [http://www.mitosyfraudes.org/Calen7/MornerEng.html] he talked about the IPCC misrepresentation of sea level data: “Then, in 2003, the same data set, which in their [IPCC's] publications,... was a straight line—suddenly it changed, and showed a very strong line of uplift, 2.3 mm per year, the same as from the tide gauge... It was the original one which they had suddenly twisted up, because they entered a “correction factor,” ... I accused them of this at the Academy of Sciences in Moscow —I said you have introduced factors from outside; it's not a measurement. It looks like it is measured from the satellite, but you don't say what really happened. And they answered, that we had to do it, because otherwise we would not have gotten any trend! That is terrible! As a matter of fact, it is a falsification of the data set. ... So all this talk that sea level is rising, this stems from the computer modeling, not from observations. The observations don't find it! I have been the expert reviewer for the IPCC, both in 2000 and last year. The first time I read it, I was exceptionally surprised.
  26. Are humans too insignificant to affect global climate?
    I think there needs to be as much rigor in language as in math. The article poses the question as to whether humans can affect the GLOBAL CLIMATE. It then focuses on CO2 levels and annual fossil fuel consumption. Since CO2 increases = CLIMATE CHANGE (in everybody's mind), it proves that humans can indeed affect the Earth's climate, which doesnt even really exist since "climate", meteorolgically speaking, has to do with weather patterns associated with geographic regions. A more loose meaning could mean atmospheric molecular composition, but the term environment is probably more suitable. And what is really being sold here again is the concept that CO2 is causing the Earths TEMPERATURE to go up. Why not us that word?
    Response: I was waiting for someone to bring that up - it's a valid comment. My next post is on the question of whether increasing atmospheric CO2 changes global temperatures.
  27. Are humans too insignificant to affect global climate?
    Nice little post, John. It is instructive to integrate your Figure 2 to get the cumulative CO2 emissions into the atmosphere. The correspondence with the secular trend in CO2 concentrations in the atmosphere is very impressive indeed. pdt--the result of increasing CO2 concentrations is an increase in ocean acidity. There are many links to this topic. One place to look is http://www.pmel.noaa.gov/co2/OA/ . Or just start with Wikipedia.
  28. How we know global warming is happening, Part 2
    Thank you for this great post. I will be updating my site with much of this information. :)
  29. Are humans too insignificant to affect global climate?
    Where does the other half go? How much in the oceans? Is that measurable? If so that part should count as climate too, at least for lifeforms that live in the ocean.
  30. How we know global warming is still happening
    It is curious that "science" promotes the idea of evolution, and yet scientist are wishing to stop it. A changing environment leads to natural selection which implies no control. Is Darwin in charge or not?
  31. Are humans too insignificant to affect global climate?
    Good post John. Another piece of evidence as to how we are changing the atmosphere is the reduction of O2 as the CO2 increases (burning uses up O2). While the change as a percentage of all the O2 in the atmosphere is extremely small, we have been able to observe the decrease for the last 20 years or so. A good article on it here. As an interesting note, in the article Keeling estimates the increase in sea level from the H2O produced by burning hydrocarbons. As you would expect the number is very small. Best, John
  32. How we know global warming is still happening
    It is not a given that there are more clouds in a generally warmer environment. Cloud formation depends very much on relative humidity and also the availability of lift within the atmosphere, warm moist air must rise and cool to near it's dew point. A product of all climate simulations is a near constant relative humidity as the climate warms. Look at the tropics and near tropics today. Most cloud formation is convective in nature and where this is the result of daytime heating the clouds dissipate at night. The tropics receive the vast majority of solar radiation but cloudiness does not prevent that region from being the warmest on Earth. If the climate zones and jet streams are shifted poleward in a warming world why would the dynamics be any different in their displaced positions?
  33. Philippe Chantreau at 20:03 PM on 6 October 2009
    How we know global warming is still happening
    And whence do you infer that this is not well known of climate science, inappropriately modeled and inconsistent with observations? The water vapor/clouds feedback is a matter of much debate and, in any case, still a feedback from warming triggered by increased GH effect. Furthermore, increased cloudiness at higher temperature would seem to require a lowered relative humidity and I'm not sure whether we're seeing that. Models appear to argue against it. One fellow skeptic recently trumpeted the Trenberth and Fasullo paper suggesting that cloud feedback might actually be much lower than previously modeled, leading to a lot of extra warming from increased solar irradiance reaching the surface. For all the hooplah demonstrated by that fellow skeptic, it's worth pointing that the HADCRU model is in fact fairly close to Trenberth'runs, and HADCRU long term prognostic is not that different from GISS. It is also worth reminding that the decreased cloudiness of Trenberth' model runs was still a feedback of increased GH warming. Much a do about nothing.
  34. How we know global warming is still happening
    What follows is an excerpt from an article found here http://physicsworld.com/cws/article/print/17402 "The spectroscopic data that are required to model long-wave atmospheric absorptions are generally well characterized. When these data are put into atmospheric models, water turns out to be responsible for about 60% of the greenhouse effect, while the much-reviled carbon-dioxide molecule accounts for just 26%. Ozone accounts for 8%, and methane and nitrous oxide - the atmospheric concentrations of which have been increased by human activity - contribute a further 8% to the greenhouse effect. " The article goes on to say that the warmer the Earth gets, the more water vapor and therefore the more clouds that shield incoming Sun. Probably that is why we are still here to talk about this.
  35. Are humans too insignificant to affect global climate?
    Do we (you) know John if the difference between what we are producing and what is being dealt with is increasing? You would expect it to be with deforestation and drought on the one hand, and the changing capacity of the warming and acidifying oceans to keep absorbing CO2 on the other.
    Response: Good question. Figure 7.4 in the IPCC AR4 shows a graph of the fraction of fossil fuel emissions remaining in the atmosphere (‘airborne fraction’) since 1958 (the thick black line is the 5 year mean):



    Bit early to tell whether there is a long term trend there.
  36. The link between hurricanes and global warming
    Some Science! Global warming theory actually predicts strongest warming in the Arctic and secondary the Antarctic, with little change in middle to lower latitudes for several years, or decades. The idea that mid latitude storm intensities, tropical system enhancement, and severe weather events would be minimal due to less baroclinic stress (a decrease in solenoids) or less atmospheric density differences over a horizontal distance, ...if CO2 were actually causing major changes in the atmosphere. If such changes are taking place, must be from other forcing factors (maybe solar intensity fluctuations, and related magnetic flux changes). The weather should, at least if we assume CO2 warming is dominating, becomes more benign, with some trend toward increased moisture in the normally dry Arctic. Mid latitudes will be largely unaffected, and the tropic certainly not affected. The numerical models all, I repeat ALL, have parameterized processes that are very subjective,not directly included in the quasigeostrophic computations, and contribute strongly to errors in the computational output of said models. Algebraic coefficents, or fudge factors, then become necessary, largely ruining the value of the forecasts.
  37. How we know global warming is still happening
    RSVP, in addition to the known multiple forcings in addition to CO2, the positive feedbacks are strong contributors. The temperature rise is a consequence of all of that, not just CO2.
  38. Philippe Chantreau at 16:07 PM on 5 October 2009
    How we know global warming is still happening
    RSVP, the Earth is not a closed system, no matter how you cut and slice it. Any way to look at it as a closed system is wrong. Your own water jug analogy describes an open system. "I believe something else is going on." What is? What quantitative analysis are you basing this on? In which science papers has this analysis been published? The warming effect of CO2 alone is fairly well known, based on radiative physics. There is more debate on the feedbacks, which condition the total sensitivity. Which part of that exactly does not add up for you and, again, what quantitative analysis is there to support your doubts? Considering the vocation of this site, I'd like to see science publications as support.
  39. How we know global warming is happening, Part 2
    Riccardo, my point was that some of numbers quoted above refer to the Earth as a whole(Hansen & Trenberth) while Schuckmann is talking about the oceans only. That was not particularily clear above. Cheers, :)
  40. How we know global warming is still happening
    So, correct me if I am wrong in understanding your reply, you are saying basically that processes are non linear and to a point self limiting, and (perhaps implied) generally driven by the Earths distance from the sun, its rotation, etc. And that our burning of fossil fuels are taking the mean temperature upward. I dont see this as unreasonable, and my opinion isnt going to keep the Earth any cooler.... ...however. I am not so convinced that its just the CO2 that is the culprit. I came to this website in the first place because of an independent discussion about what a relatively mass concentration CO2 has in the atmosphere and how could it possibly be taking the Earths temperature up. I believe something else is going on besides the incremental heat trapping effect of CO2, and that if nations only attack this issue, it may be just a big waste of effort and time.
    Response: CO2 isn't the only thing going on - there are a number of forcings that affect climate but CO2 is the dominant forcing:

  41. How we know global warming is still happening
    RSVP, you are correct that if the Earth's input and output were in equilibrium before and after the temporary reduction in input, then afterward the system would indeed remain at a lower temperature. But the Earth's (the whole thing including the atmosphere, seen from outer space) input and output were not in equilibrium before, say, Mt. Pinatubo's eruption. The input was outpacing the output. (The water level in the jug was increasing.) This is where the jug analogy breaks down, because the Earth's rate of output to space increases with the temperature of the Earth. You'll have to pretend that the jug's hole lets more water out the more water is in the jug. The Earth's temperature was on its way up toward a new equilibrium output to suit its new, higher, equilibrium temperature. Then the eruption reduced the input a little bit, for a little while. That was enough to slow down the system's progress toward its still-not-reached equilibrium output rate and temperature. After the aerosols cleared, the system continued to heat up (and to increase its output rate) still in pursuit of that before-eruption equilibrium temperature and output rate. Actually, the system's goal equilibrium temperature and output rate post-eruption are lower than they were pre-eruption, because the amount of heat in the system is lower (slightly); but those new, lower goals still have not been met, so the system continues to heat on its way toward that new goal. Meanwhile, of course, the output rate is being reduced by a factor independent from all the above: The greenhouse gasses continue to increase. (Moss is growing to block the hole in the jug.) That moves the equilibrium goal even higher, continuously. The system never reaches its equilibrium goal.
  42. How we know global warming is still happening
    In the analogy of the water jug, the level of the water is the Earths temperature. Water dripping in is incoming radiation. Water flowing out is outgoing radiation. If outflow is reduced the level will rise. I dont think this is different from the idea that CO2 is causing less heat to escape the Earth. Now assuming a perfectly balanced flow situation for the jug where the level never changed at 3 gallons, this would be analogous to a level of CO2 in the atmosphere wherever nature had it say 500 years ago or so. But now someone comes along and removes one gallon, which would be like volcanic ash blocking the sun in a big way for 3 years. The two gallons left would be like the temperature of the Earth dropping to say ice age conditions. As I describe, there is no reason for the water level to come back to 3 gallons. It will remain at two gallons forever unless the flow rates are altered. Similarly, after ten years, all the volcanic smoke clears, and the atmosphere is pristine again. The sun shines as before, and the processes preceding the eruption take over. The temperature should stay where it is. So far, no one has provided an answer that explains why global temperatures go back to "normal" in terms of the CO2 mechanisms described to explain recent global warming. An explanation of this type would require excess CO2 following the eruption, and CO2 subsequently reducing over time to reach stasis. However, the data supposedly shows the opposite. That CO2 rises when the Earth warms.
  43. How we know global warming is still happening
    WeatherRusty, the duplication of your entries is due to your browser (or the server?) retaining the code for posting your comment, even after the page has reloaded to show your comment. When you reload that page by clicking your browser's reload button, that same code for posting gets sent again. It's happened to me multiple times (sorry, everybody). You might get an alert box after you click the reload button, warning that the browser will "repost" or somesuch phrasing. If you see that, click the Cancel button in that alert box. To avoid all the above, I suggest that after you post, you go to any other page, which will force the posting code to be flushed.
  44. How we know global warming is still happening
    I have no idea why my posts are in duplicate, I hit submit only once. RSVP, "1 degree divided by 300 K = .003333" 288 K is the average surface temperature of Earth and nearly all of that is due to radiation received from the Sun including 33 K amplification due to the greenhouse effect. "0.3% is in the noise, and is due to many factors." The "noise" is not random...it is forced and the job of science is to quantify the forcing. The ~1 K increase is part of a long term trend forced by 1.6W/meter^2 increase in radiative forcing, much of which is being absorbed by the oceans.
  45. How we know global warming is still happening
    RSVP, your water jug analogy is incorrect. The aerosols increasing and decreasing due to a volcano are instead the equivalent of a valve decreasing and increasing the flow of water into the jug. CO2 increasing is like moss growing in the hole at the bottom of the jug, reducing the flow of water out of the jug.
  46. There is no consensus
    Chris, ...RE your post 157 above, ( the Oerlemans paper ), the abstract you posted did not tell me much. So I did some research on the data and as far as I can see, glaciers have been generally melting and receding since about 1850, which is well before massive amounts of man-made CO2 were pumped into the air. Also, the IPCC models only require CO2 input after say 1970. According to the IPCC graphs, before 1970, natural variations can explain most of the temperature increase. Now since 1970, I agree, that glaciers have been generally receding, although in several areas they have actually been advancing. But the important points to note are that : 1) Glaciers started to recede well before 1970 and so the receding of glaciers after 1970 was to be expected simply based on historical ( natural )trends. 2)There has been little or no incresae in the rate of glacial recession since 1970. Thus there is little evidence here for me to conclude that recent man-made CO2 emissions are responsible for glacial retreat. If we look at one hypothetical glacier, is it not true that if precipitation of snow at the higher, source of the glacier decreases then there will be less weight forcing the glacier down the valley. Thus the rate of advance of the glacier can be affected by other factors besides warming.
  47. How we know global warming is still happening
    WeatherRusty said What you view as fanaticism derives from a strong confidence in well established physical principles as they are applied to the issue of climate change. ------------------------------- What I view as fanaticism is OVER confidence in theories that are based on well established principles. 1 degree divided by 300 K = .003333 0.3% is in the noise, and is due to many factors.
  48. How we know global warming is still happening
    Philippe Chantreau at 17:40 PM on 4 October, 2009 RSVP, "a closed system called Earth." Do you really mean that? --------------------------------- The expression is appropriate given that we are considering the Earth as a whole and a discussion that presupposes no changes in solar activity (which of course is not true).
  49. How we know global warming is still happening
    Tom Dayton answers my earlier question, "what brought the temperature back up to "normal" after the Krakatoa eruption." The answer unfortunately is not consistent with the radiation budget of greenhouse models that imply that without a net surplus of radiative energy (as in the case of extra CO2 in the atmosphere) average temperatures should remain at steady state. The model is oversimplied of course, which is the whole point of the question. An analogy may help visualize things. Assume you have a 5 gallon jug vessel containing 3 gallons of water. Water is dripping into the jug from a faucet at the same rate being lost through a hole at the bottom of the vessel, (assume no evaporation). Under these conditions, the level remains at 3 gallons forever, until one day, 1 gallon is removed. All things being equal in terms of flow rates, the level then stays at 2 gallons. There is no reason for the level to return to 3 gallons. At least I have not given one. Likewise, the greenhouse global warming theory assume equilibrium that is disrupted by CO2 levels rising. Without this happening, the Earths average temperatures would remain exactly where they are forever. And applying this same simple incomplete model to the situation after the Earths temperature drops from a volcanic explosion, it should remain low forever as well. You did not explain where the extra energy comes from to get the temperature back to "normal", nor did you explain why it should stop rising when it gets to "normal".
  50. Philippe Chantreau at 17:40 PM on 4 October 2009
    How we know global warming is still happening
    RSVP, "a closed system called Earth." Do you really mean that?

Prev  2540  2541  2542  2543  2544  2545  2546  2547  2548  2549  2550  2551  2552  2553  2554  2555  Next


The Consensus Project Website

THE ESCALATOR

(free to republish)


© Copyright 2024 John Cook
Home | Translations | About Us | Privacy | Contact Us