B
montmorencyt2w
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Some of the same kind of people a few generations ago were into Eugenics. See:
http://en.wikipedia.org/wiki/Eugenics
It was only when the German National Socialists took it up in a big way that "respectable" people started to disavow it. See what Michael Crichton had to say about it:
http://www.crichton-official.com/essay-stateoffear-whypoliticizedscienceisdangerous.html
And even though (as I've said several times) I'm somewhat lefty and somewhat green (was so before AGW became popular, still am now I've become sceptical on that particular issue), it disturbs me somewhat that the Fabian fathers of British socialism like Shaw and the Webbs and their ilk had a rather condescending attitude to the working classes - de haut en bas, and of course were careful to send their own children to private ("public") schools, regardless of what they preached for everyone else (a tradition nobly continued by New Labour even if they have had to reinvent grammar schools (in various guises) for that purpose.
Gee Whiz. CO2 essential to photosynthesis. Who would have guessed? The logic is inescapable isn't it - because CO2 is used in photosynthesis, we can't have too much of it. Quick, write to the IPCC and let 'em know.
1. Increasing CO2 is causing ocean acidification which has some very nasty consequences. How many times must it be said that this is pollution by any definition.
2. Any reasonable person would consider a gas emitted into the atmosphere by human activity in quantities significantly changing natural levels and causing undesirable changes in global temperatures to be a pollutant. What else could it be called?
It is interesting to note that the US EPA has just declared CO2 to be a pollutant ie a substance dangerous to human health.
This is just the kind of innumerate half truth sound bite so beloved by the denialist blogosphere. But how about the small detail of the actual numbers? Do we actually have a potential problem or not? If we go to the IPCC report here:
http://www.grida.no/climate/ipcc_tar/wg1/222.htm#635
it is not terribly difficult to come up with some numbers
Taking for example the most simple expression for radiative forcing due to CO2 we get a temperature increase of 3.70 for a doubling of CO2. Now that wasn't that hard was it? And yes, all the expressions for estimates of CO2 forcing are logarithmic.
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Gumping
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Dcraig:
What is the radiative forcing for water, and how are atmospheric levels (for CO2 and water) measured? What precautions are taken during the measurements?
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Crikey, I'm not a climate scientist! (though I do have a BSc in Physics - most of which I forgot a long time ago).
Here is a good piece on water vapour from Gavin Schmidt:
http://www.realclimate.org/index.php/archives/2005/04/water-vapour-feedback-or-forcing/
You can find the GHG data here:
http://gaw.kishou.go.jp/wdcgg/wdcgg.html
If what you are getting at by "precautions" is the denier claims that CO2 measurement are biased by more stations being present in industrial countries, the answer is that the atmosphere is fairly well mixed and data from stations "in the middle of nowhere" are pretty much the same as the global average.
This thread is getting technical. I didn't believe we'd have so many scientists on a trading site 
The fact is, since the thread was started, Al Gore has been accused of investing in green companies who are in line for large government grants. His excuse was much the same as Rumsfeld, who had large amounts of stock in Tamiflu, while he and George W. announced plans to battle the Sars pandemic (remember Bird Flu?), thus adding zeros to his holdings. "If I sold them it would look like I was doing something wrong!"
There was also the UEA situation with the stolen emails pointing to 'potential' data tampering. The point being that these issues get swept under the carpet and anyone who wishes to question them is patronized and placed under a lazy group tag of skeptics or denialists- names which infer a questioner of the truth.
This isn't really about whether you believe that the planet is heating up, it's whether you believe that these lying, manipulative b******s can save us from it or have our best interests at heart.
As trader333 said, the only way to reduce emissions is to 1) cut population 2) create technology to combat it.
As with pharmeceutical companies, the money is not made in the cure, the money is made in the medicine. This is the same situation here.
The fact is, since the thread was started, Al Gore has been accused of investing in green companies who are in line for large government grants. His excuse was much the same as Rumsfeld, who had large amounts of stock in Tamiflu, while he and George W. announced plans to battle the Sars pandemic (remember Bird Flu?), thus adding zeros to his holdings. "If I sold them it would look like I was doing something wrong!"
There was also the UEA situation with the stolen emails pointing to 'potential' data tampering. The point being that these issues get swept under the carpet and anyone who wishes to question them is patronized and placed under a lazy group tag of skeptics or denialists- names which infer a questioner of the truth.
This isn't really about whether you believe that the planet is heating up, it's whether you believe that these lying, manipulative b******s can save us from it or have our best interests at heart.
As trader333 said, the only way to reduce emissions is to 1) cut population 2) create technology to combat it.
As with pharmeceutical companies, the money is not made in the cure, the money is made in the medicine. This is the same situation here.
This thread is getting technical. I didn't believe we'd have so many scientists on a trading site
Obviously not too technical. Nobody here pulled me up on my post about the log nature of CO2 greenhouse effect where I stated that by the early IPCC CO2 simplified forcing formula, temperature rises by 3.7 for a doubling of C02. The 3.7 is actually the radiative forcing and the temperature rise is ~ 0.75 * 3.7 = 2.775C. The commonly accepted figure is ~3C. C'mon, you deniers - must try harder.
Oh yes it very much is about whether the planet is heating up. Acknowledging the validity of the science and real dangers of climate change in no way precludes recognizing the (multiple) agendas of the Copenhagen participants. In fact it makes some of it all the more sickening.
Whether the rabble in Copenhagen (and I refer to the government delegations and not the protesters) do anything useful at all to mitigate global warming remains to be seen. For my part, I am extremely skeptical. I forsee a long, long and increasingly bitter political battle to get meaningful action.
Finally a note to the conspiracy theorists - the shambles in Copenhagen is no way to organize a decent conspiracy. C'mon you can do better than that.
Please be patient - some of us have trade you know (I even do some work from time to time as well
).The above is obviously just an IPCC estimate, and clearly that body is not infallible.Look at their enthusiasm for the hockey stick, which I understand was based largely on one pine cone that Michael Mann found in the bottom drawer of his desk. Although nobody can really be sure, as he guards his data like it was pieces of the True Cross.
Anyway, I would be inclined to treat anything that the IPCC produces with scepticism - something that presumably most scientists would also do as a matter of course.
I'll check on this when I've got time, although I would be very surprised if this was more than "possibly" / "best guess" / etc stuff.
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Craig, is this link (only Wikipedia I know, but that does not necessarily mean it's completely inaccurate ) a reasonable summary of the point you were making?
http://en.wikipedia.org/wiki/Climate_sensitivity
This passage seems relevant:
Three degrees as the consensus estimate
The standard modern estimate of climate sensitivity - 3°C, plus or minus 1.5°C - originates with a committee on anthropogenic global warming convened in 1979 by the National Academy of Sciences and chaired by Jule Charney. Only two sets of models were available; one, due to Syukuro Manabe, exhibited a climate sensitivity of 2°C, the other, due to James Hansen, exhibited a climate sensitivity of 4°C. "According to Manabe, Charney chose 0.5°C as a not-unreasonable margin of error, subtracted it from Manabe’s number, and added it to Hansen’s. Thus was born the 1.5°C-to-4.5°C range of likely climate sensitivity that has appeared in every greenhouse assessment since..."[5]
Chapter 4 of the "Charney report" compares the predictions of the models: "We conclude that the predictions ... are basically consistent and mutually supporting. The differences in model results are relatively small and may be accounted for by differences in model characteristics and simplifying assumptions."[2]
[edit] Subsequent developments
In 2008 climatologist Stefan Rahmstorf wrote, regarding the Charney report's original range of uncertainty: "At that time, this range was on very shaky ground. Since then, many vastly improved models have been developed by a number of climate research centers around the world. Current state-of-the-art climate models span a range of 2.6–4.1°C, most clustering around 3°C."[1]
This seems to suggest that the original idea was based on pretty thin material, but subsequent research has firmed it up considerably. Is that a fair summary?
) a reasonable summary of the point you were making?http://en.wikipedia.org/wiki/Climate_sensitivity
This passage seems relevant:
Three degrees as the consensus estimate
The standard modern estimate of climate sensitivity - 3°C, plus or minus 1.5°C - originates with a committee on anthropogenic global warming convened in 1979 by the National Academy of Sciences and chaired by Jule Charney. Only two sets of models were available; one, due to Syukuro Manabe, exhibited a climate sensitivity of 2°C, the other, due to James Hansen, exhibited a climate sensitivity of 4°C. "According to Manabe, Charney chose 0.5°C as a not-unreasonable margin of error, subtracted it from Manabe’s number, and added it to Hansen’s. Thus was born the 1.5°C-to-4.5°C range of likely climate sensitivity that has appeared in every greenhouse assessment since..."[5]
Chapter 4 of the "Charney report" compares the predictions of the models: "We conclude that the predictions ... are basically consistent and mutually supporting. The differences in model results are relatively small and may be accounted for by differences in model characteristics and simplifying assumptions."[2]
[edit] Subsequent developments
In 2008 climatologist Stefan Rahmstorf wrote, regarding the Charney report's original range of uncertainty: "At that time, this range was on very shaky ground. Since then, many vastly improved models have been developed by a number of climate research centers around the world. Current state-of-the-art climate models span a range of 2.6–4.1°C, most clustering around 3°C."[1]
This seems to suggest that the original idea was based on pretty thin material, but subsequent research has firmed it up considerably. Is that a fair summary?
This is an alternative view of the likely effects of doubled CO2, that estimates an upper limit considerably lower than the IPCC. It's not terribly in depth and is really written for the layman, but it might be enough to get your researches started.
http://brneurosci.org/co2.html
Science Notes
March 17, 2003 (last updated November 8, 2009)
Cold Facts on Global Warming
Introduction
What is the contribution of anthropogenic carbon dioxide to global warming? This question has been the subject of many heated arguments, and a great deal of hysteria. In this article, we will consider a simple estimate based on well-accepted facts, that shows that the expected global temperature increase caused by doubling atmospheric carbon dioxide levels is bounded by an upper limit of 1.76±0.27 degrees Celsius. This result contrasts with the results of the IPCC's climate models, whose projections are shown to be unrealistically high. Even though global warming has become mostly an academic concern now that the climate has moved into a cooling phase [24], it's still important to understand what is and is not factual about the climate.
The Greenhouse Effect
Fig. 1. Theory of global warming. There is general agreement that the Earth is naturally warmed to some extent by atmospheric gases, principally water vapor, in what is often called a "greenhouse effect". The Earth absorbs enough radiation from the sun to raise its temperature by 0.5 degrees per day, but is theoretically capable of emitting sufficient long-wave radiation to cool itself by 5 times this amount. The Earth maintains its energy balance in part by absorption of the outgoing longwave radiation in the atmosphere, which causes warming.
On this basis, it has been estimated that the current level of warming is on the order of 33 degrees C [1]. That is to say, in the absence of so-called greenhouse gases, the Earth would be 33 degrees cooler than it is today, or about 255 K (-0.4° F) [2]. Of these greenhouse gases, water is by far the most important. Although estimates of the contribution from water vapor vary widely, many sources place it between 90 and 95% of the warming effect, or about 30-31 of the 33 degrees [3, 25]. Carbon dioxide, although present in much lower concentrations than water, absorbs more infrared radiation than water on a per-molecule basis and contributes about 84% of the total non-water greenhouse gas equivalents [4], or about 4.2-8.4% of the total greenhouse gas effect.
Of course, this 33 degree increase in temperature is not caused simply by absorption of radiation by the gases themselves. Much of the 33 degree effect is caused by the Earth's adaptation to higher temperatures, which includes secondary effects such as increased water vapor, cloud formation, and changes in albedo or surface reflectivity caused by melting and aging of snow and ice. Accurately calculating the relative contribution of each of these components presents major difficulties.
The theory of global warming is shown in Fig. 1. Infrared radiation comes from two sources: the sun and the earth's surface. CO2 absorbs some of the infrared radiation and re-emits it in a random direction. If there is more CO2, the radiation is absorbed closer to the source. For radiation from the sun, this theory predicts that increased CO2 would cause cooling in the upper atmosphere and warming in the lower atmosphere. Thermometer measurements show that the lower atmosphere was warming between about 1906 and 1944 and between about 1976 and 1998, and either constant or cooling at other times. However, the validity of the temperature figures is hotly disputed on both sides because the issue is highly political.
Global Warming Potential (GWP)
Traditionally, greenhouse gas levels are presented as dimensionless numbers representing parts per billion (ppb) multiplied by a scaling factor (global warming potential or GWP) that allows their relative efficiency of producing global temperature increases to be compared. For carbon dioxide, this scaling factor is 1.0. The factors for methane and nitrous oxide are 21 and 310, respectively, while sulfur hexafluoride is 23,900 times more effective than carbon dioxide [5]. The GWP from carbon dioxide is primarily due to the position of its absorption bands in the critical longwave infrared region at 2, 3, 5, and 13-17 microns.
Methane, nitrous oxide, ozone, CFCs and other miscellaneous gases absorb radiation even more efficiently than carbon dioxide, but are also present at much lower concentrations. Their high GWP results from their molecular structure which makes them absorb strongly and at different wavelengths from water vapor and carbon dioxide. For example, although ozone is usually thought of as an absorber of ultraviolet radiation, it also absorbs longwave infrared at 9.6 microns. These gases account for another 1.3% of the natural greenhouse gas effect. The increase in the global energy balance caused by greenhouse gases is called "radiative forcing".
The GWP of a greenhouse gas is the ratio of the time-integrated radiative forcing from 1 kg of the gas in question compared to 1 kg of carbon dioxide. These GWP values are calculated over a 100 year time horizon and take into consideration not only the absorption of radiation at different wavelengths, but also the different atmospheric lifetimes of each gas and secondary effects such as effects on water vapor. For example, methane contributes indirectly to the production of tropospheric ozone and stratospheric water vapor. For some gases, the GWP is too complex to calculate because the gas participates in complex chemical reactions. Most researchers use the GWPs compiled by the World Meteorological Organization (WMO).
Even though most of the so-called greenhouse effect is caused by water vapor, about 1-2 degrees of our current empirically-measured temperature of roughly 288 K (59° F) can be attributed to carbon dioxide. Water vapor at least 99.99% of 'natural' origin, which is to say that no amount of deindustrialization could ever significantly change the amount of water vapor in the atmosphere. Thus, climatologists have concentrated mostly on carbon dioxide and methane. However, in the past few years, a few climatologists have started talking about anthropogenic increases in atmospheric water vapor [17]. This validates suspicions that, if environmentalists get their way with CO2, a campaign to force us to reduce water vapor could well be next.
Carbon Dioxide Levels
Figures from the U.S. Department of Energy show that the pre-industrial baseline of carbon dioxide is 288,000 ppb. The total current carbon dioxide is 368,400 parts per billion, or 0.0368% of the atmosphere.
The ocean and biosphere possess a large buffering capacity, mainly because of carbon dioxide's large solubility in water. Because of this, it is safe to conclude that the anthropogenic component of atmospheric carbon dioxide concentration will continue to remain roughly proportional to the rate of carbon dioxide emissions for any conceivable rate of human emission. In other words, the carbon dioxide buffers are in dynamic equilibrium with atmospheric carbon dioxide and are not in any danger of being saturated, which would allow all the emitted carbon dioxide to go into the atmosphere. This means:
The percentage of emitted carbon dioxide that ends up in the atmosphere can be treated as approximately constant. This percentage is about 50% [6]. (However, the buffering capacity of the oceans is enormous. The oceans currently contain about 50 times as much CO2 as the atmosphere [20]).
The effects of carbon dioxide emissions are not cumulative. That is, lowering carbon dioxide would produce an almost instantaneous reduction (on a climatological scale) in any warming effect that it was producing.
If fossil fuel use increases or decreases, atmospheric carbon dioxide will also increase or decrease proportionately.
Comment added 1/5/2008:
This last point has been misinterpreted by some commentators. To clarify, this means that if we were to stop emitting carbon dioxide, the CO2 levels in the atmosphere would rapidly return to pre-industrial levels. Geologists tell us that the half-life of CO2 in the atmosphere is on the order of five to ten years [23]. In contrast, the IPCC says the half life is 50-200 years. Whatever the actual number, there is no question that emitting CO2 will cause it to accumulate over short periods. But other processes, such as sequestration, also work against it, causing the levels to decrease rapidly over time.
This fact is the very basis of the effort among global warming advocates to pressure governments to lower CO2 emissions. Indeed, if this were not true, there would be little or no benefit to reducing CO2 emissions, as CO2 levels would ratchet up indefinitely, whether by natural or artificial means, without limit.
Amplification and Dampening
Of course, climate, like weather, is complex, nonlinear, and perhaps even chaotic. Increased solar irradiation can lower the albedo, which would amplify any effect caused by changes in solar flux, making the relation between radiation and temperature greater than linear. Increased temperatures also cause increased evaporation of sea water, which can cause warming because of water's greenhouse effect, and also can affect the radiation flux by creating additional clouds. On the other hand, increased plant growth, especially in the oceans, would tend to extract carbon dioxide from the atmosphere, making the fraction of emitted carbon dioxide that stays in the atmosphere lower. Thus, higher emissions would probably cause a slightly smaller proportion of carbon dioxide to remain in the atmosphere than is currently the case, tending to make the relation less than linear.
Absorption of Infrared Radiation
The arithmetic of absorption of infrared radiation also works to decrease the linearity. Absorption of light follows a logarithmic curve (Fig. 2) as the amount of absorbing substance increases. It is generally accepted that the concentration of carbon dioxide in the atmosphere is already high enough to absorb almost all the infrared radiation in the main carbon dioxide absorption bands over a distance of only a few km. Thus, even if the atmosphere were heavily laden with carbon dioxide, it would still only cause an incremental increase in the amount of infrared absorption over current levels. This means that a situation like Venus could not happen here. The atmosphere of Venus is 90 times thicker than Earth's and is 96% carbon dioxide, making the atmospheric carbon dioxide concentration on Venus 300,000 times higher than on Earth. Even so, the high temperatures on Venus are only partially caused by carbon dioxide; a major contributor is the thick bank of clouds containing sulfuric acid [7]. Although these clouds give Venus a high reflectivity in the visible region, the Galileo probe showed that the clouds appear black at infrared wavelengths of 2.3 microns due to strong infrared absorption [8]. Thus, Venus's high temperature might be entirely explainable by direct absorption of incident light, rather than by any greenhouse effect. The infrared absorption lines by carbon dioxide are also broadened by the high pressure on Venus [9], making any comparison with Earth invalid.
Fig.2. Transmitted light is a logarithmic function of concentration. This curve is the familiar Beer's Law.
Note added 9/30/2008:
Several readers have commented on the use of Beer's law here. I am not implying that we can use Beer's law to calculate climate changes. As one reader pointed out, Beer's law only applies to monochromatic light (light whose wavelength is narrow compared to the absorption peak). This reader writes:
What matters for global warming is that, as greenhouse gas concentrations go up, more and more IR wavelengths get captured completely ("saturated absorption"). The relationship at every wavelength is exponential, but that doesn't matter. What matters is the distribution of absorption coefficients across the spectrum (weighted by 255K black body radiation). Greenhouse gas emissions just recruit more and more wavelengths into saturation.
Of course, this is somewhat of an oversimplification, because a spectrophotometer never measures a single wavelength; it always measures a band of finite width. Across that band, you always have a logarithmic function. What this reader is actually saying is that if the concentration increases, those wavelengths at the edges of the absorption band will absorb more energy over a given distance.
As another reader pointed out, Beer's law was derived for a single beam of light going through a gas or solution for which the reemitted radiation does not enter the detector. Therefore, Beer's law will not fit the situation precisely, but there is general agreement that the curve is approximately logarithmic in shape.
Very little of the radiation from the sun at the wavelengths at which carbon dioxide absorbs reaches the surface of the Earth directly (see Fig. 3) [10]. Similarly, very little of the radiation at these wavelengths that originates at the surface makes it all the way to space. Most of the infrared at these wavelengths is produced by black body radiation from objects that have been heated up by absorbing radiation at shorter wavelengths. This means that even if the carbon dioxide levels increase, it will have little effect on the total amount of infrared radiation that is absorbed from the sun. The main effect would be to trap radiation originating at the surface at lower levels in the atmosphere than before, where it would be slightly more difficult for the heat to be re-radiated back into space. This is the principle on which most of the global warming predictions are based.
Note added 6/10/2006:
Many people do not understand this important concept. To put it more simply, shortwave radiation (such as light and short-wavelength infrared) is not absorbed by CO2 [13] and therefore reaches the earth's surface. At the surface, it is absorbed and then re-radiated at longer wavelengths (as "heat"). Some of this heat radiation is in the carbon dioxide absorption bands. This portion does not make it back to space, but is absorbed by water vapor, CO2 and other gases on its way up. More CO2 or water vapor will cause it to be absorbed at a slightly lower altitude than before. This energy will be absorbed and re-emitted by the carbon dioxide molecules.
Even though the total amount of absorption is still nearly 100%, the whole process is dynamic. This means it takes a certain amount of time, while other things, such as transitions from night to day, are also happening. Therefore, it is theoretically possible for increases in CO2 to cause increases in surface temperature. The question is, is the amount of warming enough to be significant?
CO2 is more evenly distributed than water, so if CO2 caused warming it would have a proportionately greater effect in areas where there is little water vapor (such as deserts and in very cold regions), while in areas with a lot of water, the effect of CO2 may be insignificant (in terms of its effect on local temperature) compared to the effect of water vapor. This is one of many factors that mitigate against the idea of a "climate catastrophe." [16]
Fig.3. Absorption of ultraviolet, visible, and infrared radiation by various gases in the atmosphere. Most of the ultraviolet light (below 0.3 microns) is absorbed by ozone (O3) and oxygen (O2). Carbon dioxide has three large absorption bands in the infrared region at about 2.7, 4.3, and 15 microns. Water has several absorption bands in the infrared, and even has some absorption well into the microwave region. There is already sufficient CO2 in the atmosphere to absorb almost all of the radiation from the sun or from the surface of the earth in the principal CO2 absorption bands. (Data from ref. [1], page 93; original data are from Howard et al [21] and Goody [22]).
The net effect of all these processes is that doubling carbon dioxide would not double the amount of global warming. In fact, the effect of carbon dioxide is roughly logarithmic. Each time carbon dioxide (or some other greenhouse gas) is doubled, the increase in temperature is the same as the previous increase. The reason for this is that, eventually, all the longwave radiation that can be absorbed has already been absorbed. It would be analogous to closing more and more shades over the windows of your house on a sunny day -- it soon reaches the point where doubling the number of shades can't make it any darker.
Another way of looking at it is by thinking of adding blankets to your bed on a cold night: if you have no blankets, adding one will have a big effect. If you have a thousand blankets, adding another thousand will have an unmeasurably small effect.
The analogy with a greenhouse would be that the glass in the roof becomes slightly thicker. The effect of warming also depends on the conditions inside the greenhouse. If the greenhouse were full of ice at exactly -0.01 degrees Celsius, making the glass slightly thicker just might be enough to melt all the ice and flood the greenhouse. But if the greenhouse had some regions that were hot and some that were very cold (as the planet Earth does), it would have a very small overall effect.
As an aside, the term "greenhouse effect" is actually a misnomer. In greenhouses, most of the warming that is observed is not caused by carbon dioxide, or by absorption of infrared radiation by the glass as many people think, but by reduction in convection [11].
What does 'saturation' mean?
Many people seem to be confused about the "saturation" argument. It's easy to calculate, using the known extinction coefficients [10], that 99% of the radiation in the CO2 absorption bands is absorbed within only a few tens to hundreds of meters of the source. These coefficients are derived from measurements in modern, high-resolution spectrometers. But strong absorption is also found even with older, lower-resolution instruments. So what does this mean? Is the global warming theory false? Or should older measurements not be trusted? Here is what it means:
The "saturation" argument does not mean that global warming doesn't occur. What saturation tells us is that exponentially higher levels of CO2 would be needed to produce a linear increase in absorption, and hence temperature. This is basic physics. Beer's law has not been repealed.
Some people have gotten the idea that water vapor, which is mainly present at lower altitudes, is somehow necessary for the CO2 to absorb infrared radiation, and that therefore at higher altitudes, CO2 is not anywhere near saturation. This is not true. The presence or absence of water vapor has no bearing on whether radiation is absorbed by CO2. That is because, for all practical purposes, the absorption bands of H2O and CO2 important for warming are different. (If they weren't, CO2 absorption would be so insignificant compared to water vapor that it wouldn't be a potential problem, and we wouldn't be having this discussion.)
CO2 is very nearly homogeneous throughout the atmosphere, so its concentration (as a percentage of the total) is about the same at all altitudes. Although the pressure is lower at high altitudes, there is also a much greater volume. That is why the ozone layer, which is around 30-90 km in altitude, is still able to absorb almost all of the shortwave UV, even though its concentration is only 8-12 ppm. So the importance of low concentrations of gases should not be underestimated. But water vapor is a red herring: it has essentially no effect on what CO2 does. Where water vapor becomes important is in the earth's response to CO2.
Some people also think that line broadening of the CO2 absorption lines by pressure, water vapor, or temperature provides an escape from the saturation dilemma. But in line broadening, the absorbance is peak is only smeared out; the total amount of energy absorbed is not affected. For the same reason, measurements with lower-resolution spectrometers, which slightly smear out the absorption lines, are still valid.
Saturation does not tell us whether CO2 can raise the atmospheric temperature, but it gives us a powerful clue about the shape of the curve of temperature vs. concentration.
Calculating the actual temperature increase
So, what is the actual increase? Interestingly enough, that is easy to estimate--and without resorting to complex computer models.
Because a linear increase in temperature requires an exponential increase in carbon dioxide (thanks to the physics of radiation absorption described above), we know that the next two-fold increase in CO2 will produce exactly the same temperature increase as the previous two-fold increase. Although we haven't had a two-fold increase yet, it is easy to calculate from the observed values what to expect.
Between 1900 and 2000, atmospheric CO2 increased from 295 to 365 ppm, while temperatures increased about 0.57 degrees C (using the value cited by Al Gore and others). It is simple to calculate the proportionality constant (call it 'k') between the observed increase in CO2 and the observed temperature increase:
Note added 2/12/2009: Is 'k' a constant?
Note that k takes into account all of the Earth's adaptation to the increased carbon dioxide: changes in reflectivity due to changing ice cover, changes in cloud cover, and so on. Some might still argue, however, that k is not a constant, but decreases with temperature. But what could cause k to decrease? All climatological factors have already been ruled out. In order for k to be a variable, the laws of absorption of radiation would have to be change with temperature in a fundamentally new way, and not by a small amount: k would have to decrease by 37% to raise ΔT by even one degree. No physical process in any complex system like the atmosphere changes this dramatically with temperature. Spectroscopists have been studying light absorption for over 340 years. One of them would certainly have noticed such a huge temperature sensitivity by now.
Also consider that the temperature increase is only 1-2 degrees C. This is much smaller than the seasonal variation, the variation between different locations on the Earth, or even the variation between day and night temperatures. The laws of physics don't change when you go from New York to New Jersey. Questioning whether k is a constant is grasping at straws. The question people should be asking is: is k equal to zero?
This shows that doubling CO2 over its current values should increase the earth's temperature by about 1.85 degrees C. Doubling it again would raise the temperature another 1.85 degrees C. Since these numbers are based on actual measurements, not models, they include the effects of amplification, if we make the reasonable assumption that the same amplification mechanisms that occurred previously will also occur in a world that is two degrees warmer.
If we want to include other greenhouse gases, such as methane, in the calculation, we need to use the "effective" CO2 concentrations instead. These effective CO2 numbers are less solid than the CO2-only numbers, but the best estimates are that effective CO2 increased from 305 to about 450 ppm during the 20th century[12]. Using these numbers, k becomes 0.6823 and the predicted ΔT becomes 1.02 degrees.
These estimates assume that the correlation between global temperature and carbon dioxide is causal in nature. This remains to be proved. Therefore, the 1.02 and 1.85 degree estimates should also be regarded as upper limits.
Refinements to the estimate
Unfortunately, the above calculations slightly overestimate the degree of warming, because they allow the temperature to rise indefinitely. At very high CO2 levels, self-absorption would become a limiting factor. A more accurate calculation is shown below.
A reader named Ted Ladewski made an interesting suggestion: use the 255K zero-greenhouse gas data point, where there is zero CO2, as a data point, and fit the other points to a smooth curve. To maximize the accuracy of the estimate, we will only use global CO2 and temperature values between 1900 and 2000 [14], about which there is relatively little dispute, and ignore estimates of prehistoric values, which could be more affected by changes in solar flux and other factors. This gives a total of 102 data points. These points are shown in blue in the figure below.
Including the CO2 = 0 data point severely constrains the shape of the curve (and, interestingly, effectively rules out any sort of hockey stick-shaped curve). It is also clear that some sort of monotonically-increasing curve, and not a straight line, has to be used. The best fit was obtained with a hyperbola. If the 102 data points are fitted to a hyperbola, we obtain 288.92 ±0.27K (±1 SD) for 736 ppm CO2 (red line).
The present-day value is taken as the average of the global mean temperatures between 1980 and 2000, or 287.17K. If the above estimate is correct, this means that the temperature would increase by 1.76 ±0.27°C above the present-day value when CO2 levels double their present levels. This is very close to the 1.85°C calculated above.
Stated differently, doubling CO2 from its pre-industrial value would increase the temperature about 1.2 degrees Celsius.
Fig. 4.
However, there is a problem with this method. The 255K data point is not just zero CO2, it is zero water vapor as well. In reality, there would always be some water vapor present, even if there were no CO2. This means that the actual temperature for zero CO2 would be higher than 255K, which would change the shape of the curve. For example, if the CO2=0 value was 271 (halfway between 255 and the current temperature), the prediction changes to 288.55K, or about a 1.39 degree increase for doubling of CO2. This can be seen in the blue curve (see enlarged graph below). The result is not much different than the 1.76, but the important point is that as the estimates become more realistic, the predicted temperature does not increase, but decreases slightly.
Fig. 5.
Fitting other curves to these data points gives similar results. For example, Ted Ladewski suggested deriving an exponential curve from Beer's Law. Although there are obvious problems involved in applying Beer's Law quantitatively to a transparent medium as complex as the atmosphere (as he discusses in greater detail on his website, http://mysite.du.edu/~etuttle/weather/atmrad.htm#Spec), the equation he recommends is:
where AIo and k are constants, C is the CO2 concentration, and T is temperature. (This is also discussed in http://www.sjsu.edu/faculty/watkins/GWnonlinear.htm )
Fitting the data to this equation, as shown in the brown curve in the figure above, gives the much lower value of 287.62±0.07 K (±1 SD), or 0.46±0.08 °C increase above the 1980-2000 mean for a doubling of CO2 from current values.
Although extrapolating beyond the ends of the data, as is done here and as is done with climate models, is hazardous, it's clear that both of these curves are significantly lower than a straight linear estimate. The hyperbola is probably closest to the actual value, because it makes the fewest assumptions about the underlying physical processes. In any case, both estimates should be regarded as upper limits because, as mentioned above, they assume that CO2 is the root cause of the observed changes in temperature.
How long will it take to double CO2 levels?
Another issue that people are confused about is the rate of increase of carbon dioxide. Some people think that CO2 is rising dramatically. This is probably because of graphs like the one below.
Fig. 6.
However, in hard science journals, the graph above would be considered dishonest, because the y-axis starts at 290 instead of zero. This misleads the reader into thinking that CO2 levels have undergone a huge increase when in fact, CO2 levels have only increased by 23.7% since 1900. When the data are plotted honestly, with the y axis starting at zero, the true scope of the change becomes clear.
Fig. 7.
Anthropogenic CO2 contributions constitute 3.2% of the total atmospheric CO2 (using 288 ppm as the pre-industrial baseline). About 14.8% of the increase in CO2 since 1900, or 11.88 ppm, was caused by man-made additions. According to the US Department of Energy, only about 14.8% of this increase, or 11.88 ppm, is man-made. The remaining 68.5 ppm is caused by natural forces, such as volcanoes and forest fires [26]. From this, researchers have estimated that, when water vapor is taken into account, anthropogenic CO2 contributions cause about 0.117% of the Earth's total greenhouse effect [25].
At the current rate of increase, CO2 will not double its current level until 2255.
Fig. 8.
Some climatologists, making assumptions about ever-increasing rates of carbon dioxide production, assert that the doubling will occur within a few decades instead of a few centuries. However, they are doing sociology, not climatology. They are assuming that fossil fuel consumption will increase drastically over current levels. This is very unlikely. The only honest way to estimate the change of CO2 levels is to make predictions based on what is happening now, not what might happen in some hypothetical future society; otherwise, we are merely inflating our predictions by indulging in speculation about future social trends.
Many people have used tricks like these to exaggerate the amount of global warming, and this has made it into a political issue. Most people would have great difficulty feeling an increase of 0.6 degrees Celsius. Any effects of such a small change would be slow and subtle. In general, if you are able to see or feel some change, that means it is almost certainly not caused by CO2-induced global warming.
Secondary effects
What about secondary effects, such as ice melting, changes in albedo, and so forth? Doesn't this increase the predicted temperature beyond the 1.39 to 1.76 degree estimate?
In short, no. Because these calculations are based on observed measurements, they automatically take into account all of the earth's responses. Whatever way the climate adapted to past CO2 increases, whether through melting, changes in albedo, or other effects, is already reflected in the measured temperature, and therefore it will also be reflected in the prediction. This is because the prediction is based on an extrapolation of past measurements that were taken after the earth adapted to the CO2 increase.
In order to get higher temperatures than those predicted above, it would be necessary to assume that a small increase in warming causes a large change in the amplification effect that had never occurred before. In other words, the "rules of the game" would have to drastically and abruptly change in a fundamentally new way--in response to an increase of only one or two degrees. Such changes do not occur in the real world--only in computer models. (If these so-called "tipping points" existed, random, day-to-day, and seasonal variability would have pushed us past them a long time ago.)
This is what makes the "empirical" method superior to all the computer models, as sophisticated as they may be. The empirical model just looks at what's happening and makes a reasonable extrapolation, with very few prior assumptions. The only drawback of the empirical method is that it can only predict an upper limit, because it does make one big assumption: that correlation implies causality. Therefore, although the actual warming cannot be greater than the predicted estimate, it could be considerably less.
Masking
Some climatologists may object to the foregoing analysis, pointing out that the effects of an increase in CO2 could be masked by sulfate aerosols or other factors. For example, the eruption of Mount Pinatubo in 1991 released large amounts of volcanic aerosols that may have been responsible for a brief global cooling [18]. However, later studies showed that water vapor feedback was necessary to account for this effect [19]. Applied to global warming, the reasoning is that human sulfate emissions might "mask" warming by cooling the atmosphere. In the future, they say, sulfate emissions might decrease while CO2 remains constant, and the true global warming would be revealed.
The problem here is that trying to account for sulfates drags us into the morass of modeling of social trends. It is much more reasonable to assume that, as industry shifts production to developing countries and people use more coal and high-sulfur oil to replace dwindling supplies, that sulfate emissions will greatly increase. Additionally, sulfates are only one factor. Many other factors, even including such things as cosmic rays, have been shown to have potential effects on climate. Some of these hypothetical effects would cause warming and some would cause cooling. We need to focus on what can be measured directly. The only issue is whether CO2 is a problem. To add or subtract these myriad hypothetical effects, and claim that the actual amount of warming that is occurring is different from the warming that can be observed, only serves to take climatology that much closer to metaphysics.
One reader pointed out a similar factor that is sometimes mentioned: the heat absorbing capacity of the oceans. Water has 4.13 times the heat capacity of air on a weight basis at 25°C (2.58 times on a molar basis). The oceans contain 273 times as much mass as the atmosphere, and the top few meters alone can store as much heat energy as the entire atmosphere. Thus, much of the extra heat is undoubtedly going into the oceans. But what does this really mean? If the oceans masked all the warming by absorbing the heat, we would have to multiply the time scale by about 1128 before we see the real warming. That means warming that we thought would occur over a 250-year time period would actually take 250×1128 = 282,000 years. By then, humans will almost certainly be getting their energy from some other source besides combustion of hydrocarbons. And then there is the earth's crust, which can absorb additional heat over a scale of billions of years.
Linear Climate Projections
An alternative way of calculating future temperature increases is to consider the fraction of warming that is caused by CO2. To do this, we cannot just use the fraction of radiation that is absorbed by CO2, because that does not take feedback processes into account.
As a first step, let us suppose that temperature increases linearly with greenhouse gas concentrations. From the above numbers, it is easy to calculate that a doubling of atmospheric carbon dioxide would produce an additional warming of (0.042 to 0.084) x 33 = 1.38 to 2.77 degrees centigrade. This is the temperature change one would expect that if CO2 doubles over its current levels.
It is important to realize that the original factor of 0.042 to 0.084 used in these calculations represents the incremental fraction of the total global warming, taken as a holistic phenomenon, initiated by carbon dioxide. This means that the calculation automatically includes the secondary and amplification effects caused by increased water vapor, changes in albedo, and so forth, caused by including the Earth's adaptation to the increment of carbon dioxide.
Fig. 9. Estimated greenhouse gas-induced global warming plotted against greenhouse gas concentrations expressed as a percentage of current-day values. The black curve is a linear extrapolation calculated from the DOE estimates of total current greenhouse gases. The sharp jump at the right is the data point from one computer model that predicts a nine degree increase from doubling current levels of carbon dioxide. Marked, unphysical deviations from linearity resulting in thermal runaway (red curve) are required to fit this data point with the two known points. Such a strong nonlinear effect is difficult to reconcile with our current understanding of climate.
However, our results are based on the assumption that the increase in temperature is linearly proportional to the greenhouse gas levels. This is not true. The relationship is not linear, but logarithmic. If we plot temperature vs. gas concentration (expressed as a percentage of current-day levels), we obtain a convex curve, something like the blue curve in Fig. 9. Thus, the 1.4-2.7 degrees obtained from our linear estimate is an upper bound, and depending on the exact shape of the blue curve, could be a large overestimate of the warming effect.
It goes without saying that the results from this method depend on the accuracy of the 5% estimate (from ref. [3]) and the validity of extrapolating the existing curve by an additional increment. The exact number is very difficult to pin down.
Note added 1/5/2008:
Some authors [15] suggest that the percentage of warming attributable to CO2 is not 5%, but is closer to 26%. It is easy to show why the 26% estimate (and estimates similar to it) are almost certainly wrong. We know that the total warming from greenhouse gases is 33K. If 26% of this was from CO2, then doubling CO2 would raise temperatures by 0.26*33 or 8.6K. Since the 26% estimate is based on total radiation absorbed, and not the amount of warming, we would have to add secondary feedback effects to this figure. This would double or even triple the value, giving us a predicted temperature increase of up to 25° C, or a predicted global average temperature of 40°C (104°F). Balmy!
Whether the exact number is 5% or 9%, because our estimate is based on the percentage of warming, not percentage of radiation absorbed, that is attributable to CO2, feedbacks in the estimate here are automatically taken into account. However, because of the large uncertainty about the actual value, the estimate from Fig. 4 (which derives an estimate from extrapolation of current trends) is probably more accurate.
However, we can also check the plausibility of the IPCC's result by asking the following question: What number would result if we calculated backwards from the IPCC estimates?
Using the same assumption of linearity, if a 9 degree increase resulted from the above-mentioned increase of greenhouse gas levels, the current greenhouse gas level (which is by definition 100%) would be equivalent to a greenhouse gas-induced temperature increase of at least 107 degrees C. This means the for the 9 degree figure to be correct, the current global temperature would have to be at least 255 + 107 - 273 = 89 degrees centigrade, or 192° Fahrenheit! A model that predicts a current-day temperature well above the highest-ever observed temperature is clearly in need of serious tweaking. Even a 5 degree projection predicts current-day temperatures of 41°C (106°F). These results clearly cannot be reconciled with observations.
In order for the 9 degree estimate to make sense from a physical standpoint, we are forced to draw an exponential curve through the graph above (shown in red) through the three points instead of a straight line. However, this curve creates an even worse result: it predicts a thermal runaway. A thermal runaway is a reaction that suddenly switches from a smooth curve and goes wildly out of control. For the the nine-degree climate model to fit the observations, the curve that we must draw predicts that a 10 or 20% increase in greenhouse gases above their current levels would cause an infinite increase in temperature! Of course, some other factor (such as explosion of the Earth in a supernova-type explosion) would undoubtedly kick in to save us before an infinite temperature could be reached. But even so, it can be seen that an above-linear increase in temperature with increasing gas concentration is not only unphysical, but inconsistent with observations.
Although the estimates of global warming made by the IPCC and the predictions of "environmental catastrophe" made by environmental groups have gradually creeping back down as climate models gradually improve, environmentalists still worry that temperatures could increase by as much as 3 to 5 degrees over the next century.
However, even a 5 degree increase in temperature over the next century would constitute a significant departure from the previous rates of increase. It is clear from Fig. 9 that this too would be a marked deviation from the curve. Such strong nonlinear effects, especially when they are in the wrong direction from a physical standpoint, are difficult to reconcile with our current understanding of climate.
Conclusion
Although carbon dioxide is capable of raising the Earth's overall temperature, the IPCC's predictions of catastrophic temperature increases produced by carbon dioxide have been challenged by many scientists. In particular, the importance of water vapor is frequently overlooked by environmental activists and by the media. The above discussion shows that the large temperature increases predicted by many computer models are unphysical and inconsistent with results obtained by basic measurements. Skepticism is warranted when considering computer-generated projections of global warming that cannot even predict existing observations.
References and Notes
[1]. Peixoto, J.P. and Oort, A.H., Physics of Climate Springer, 1992, p. 118.
[2]. Thomas, G.E. and Stamnes, K. Radiative Transfer in the Atmosphere and Ocean. Cambridge University Press, 1999, p. 441.
[3] Most credible sources place the number at 95%.
95% = Michaels, P.J. and Balling, R.C., The Satanic Gases. Cato Institute, 2000 p.25.
90-95% = http://www.globalwarming.org/node/62
90% = http://www.ncpa.org/press/transcript/globalwm/global2.html Norman J. Macdonald Carbon dioxide is about 5 percent, water vapor 90.
Here is a paper that gives a different figure: http://www.atmo.arizona.edu/students/courselinks/spring04/atmo451b/pdf/RadiationBudget.pdf"
S.M. Freidenreich and V. Ramaswamy, Solar Radiation Absorption by Carbon Dioxide, Overlap with Water, and a Parameterization for General Circulation Models. Journal of Geophysical Research 98(1993):7255-7264
[4]. U.S. Climate Action Report 2000, US Environmental Protection Agency, page 38.
[5]. Houghton, J.T. et al, eds. Climate Change 1995: The Science of Climate Change (IPCC report), 1996, Cambridge University Press. http://www.ipcc.ch/pub/sarsum1.htm
[6]. Peixoto, J.P. and Oort, A.H., Physics of Climate. Springer, 1992, p. 436.
[7]. http://www.aas.org/publications/baas/v33n3/dps2001/354.htm
[8]. http://www2.jpl.nasa.gov/galileo/slides/slide3.html
[9]. Ma, Q., and R.H. Tipping, J. Chem. Phys., 96, 8655-8663, 1992.
[10]. [note added Feb 15, 2007] This can be easily calculated from the absorption of gaseous carbon dioxide. See Phys. Rev. 41, 291 - 303 (1932) P. E. Martin and E. F. Barker "The Infrared Absorption Spectrum of Carbon Dioxide".
Thomas and Stamnes (ref. 2, page 91) that shows 0% transmittance at 22 km and below for the 15 micron CO2 band. This section discusses the "opaque region" and also gives a very clear discussion of line broadening, which is an additional point that many people are unfamiliar with.
Schneider, Kucerovsky, and Brannen (Appl. Opt. 28:5, 1998) give an absorption coefficient at 9.90 ± 1.49 cm-1 atm-1 for low concentrations of CO2 in a 1-atm nitrogen atmosphere at 4.2 microns. This works out to 376 absorbance units per km for 380 ppm CO2, which is about as close to 100% absorption as you can get. Heinz Hug, a global warming skeptic, measured a similar value (0.03 absorbance units/10 cm for 357 ppm at 15μm) ( http://www.john-daly.com/artifact.htm).
[11]. Peixoto, J.P. and Oort, A.H., Physics of Climate. Springer, 1992, p. 30.
[12]. The Satanic Gases, p.36.
[13]. Carbon dioxide is written here as CO2 instead of CO2 because using subscripts messes up the line spacing in HTML. The Unicode character x2082 (₂ or ₂), which normally solves this problem, doesn't display properly in IE.
[14]. The temperature data for these calculations were obtained from http://lwf.ncdc.noaa.gov/oa/climate/research/anomalies/anomalies.html
[15]. www.realclimate.org
[16]. One reader pointed out that the Arctic region has dew points above freezing during a significant portion of the year. The average desert atmosphere also has a much higher water content than many people think.
[17]. However, some climatologists have tried to invoke anthropogenic increases in atmospheric water vapor: see Santer et al., "Identification of human-induced changes in atmospheric moisture content" (Proc Natl Acad Sci U S A. 2007 Sep 25;104(39):15248-53). Using a computer model, the authors concluded that human activity is increasing water vapor.
[18]. Radiative Climate Forcing by the Mount Pinatubo Eruption. Minnis P, Harrison EF, Stowe LL, Gibson GG, Denn FM, Doelling DR, Smith WL Jr. Science. 1993 Mar 5;259(5100):1411-1415.
[19]. Global cooling after the eruption of Mount Pinatubo: a test of climate feedback by water vapor. Soden BJ, Wetherald RT, Stenchikov GL, Robock A. Science. 2002 Apr 26;296(5568):727-30.
[20]. http://www.aip.org/history/climate/oceans.htm This is a pro-global warming website.
[21]. Howare, J.N., Burch, D.L., Williams, D (1955). Near-infrared transmission through synthetic atmospheres. Geophys. Res. Papers No. 40, Geophys, Res. Dir., Air Force Cambridge Research Center, 244 pp.
[22]. Goody, R.M. (1964). Atmospheric Radiation: I. Theoretical Basis. Clarendon, Oxford, 436 pp.
[23]. National Academy of Sciences, Climate Research Board (1979). Carbon dioxide and climate: a scientific assessment. National Academy of Sciences, 72pp.; cited in Ref. 1, p. 434.
[24]. See also: Steven Goddard, Divergence Between GISS and UAH since 1980 and
Oceans are cooling according to NASA (non-technical newspaper article).
[25]. http://epa.gov/climatechange/emissions/downloads/2008InventoryPublicReviewComments.pdf
[26]. Current Greenhouse Gas Concentrations (updated October, 2000) Carbon Dioxide Information Analysis Center, U.S. Department of Energy Oak Ridge, Tennessee
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Science Notes
March 17, 2003 (last updated November 8, 2009)
Cold Facts on Global Warming
Introduction
What is the contribution of anthropogenic carbon dioxide to global warming? This question has been the subject of many heated arguments, and a great deal of hysteria. In this article, we will consider a simple estimate based on well-accepted facts, that shows that the expected global temperature increase caused by doubling atmospheric carbon dioxide levels is bounded by an upper limit of 1.76±0.27 degrees Celsius. This result contrasts with the results of the IPCC's climate models, whose projections are shown to be unrealistically high. Even though global warming has become mostly an academic concern now that the climate has moved into a cooling phase [24], it's still important to understand what is and is not factual about the climate.
The Greenhouse Effect
Fig. 1. Theory of global warming. There is general agreement that the Earth is naturally warmed to some extent by atmospheric gases, principally water vapor, in what is often called a "greenhouse effect". The Earth absorbs enough radiation from the sun to raise its temperature by 0.5 degrees per day, but is theoretically capable of emitting sufficient long-wave radiation to cool itself by 5 times this amount. The Earth maintains its energy balance in part by absorption of the outgoing longwave radiation in the atmosphere, which causes warming.
On this basis, it has been estimated that the current level of warming is on the order of 33 degrees C [1]. That is to say, in the absence of so-called greenhouse gases, the Earth would be 33 degrees cooler than it is today, or about 255 K (-0.4° F) [2]. Of these greenhouse gases, water is by far the most important. Although estimates of the contribution from water vapor vary widely, many sources place it between 90 and 95% of the warming effect, or about 30-31 of the 33 degrees [3, 25]. Carbon dioxide, although present in much lower concentrations than water, absorbs more infrared radiation than water on a per-molecule basis and contributes about 84% of the total non-water greenhouse gas equivalents [4], or about 4.2-8.4% of the total greenhouse gas effect.
Of course, this 33 degree increase in temperature is not caused simply by absorption of radiation by the gases themselves. Much of the 33 degree effect is caused by the Earth's adaptation to higher temperatures, which includes secondary effects such as increased water vapor, cloud formation, and changes in albedo or surface reflectivity caused by melting and aging of snow and ice. Accurately calculating the relative contribution of each of these components presents major difficulties.
The theory of global warming is shown in Fig. 1. Infrared radiation comes from two sources: the sun and the earth's surface. CO2 absorbs some of the infrared radiation and re-emits it in a random direction. If there is more CO2, the radiation is absorbed closer to the source. For radiation from the sun, this theory predicts that increased CO2 would cause cooling in the upper atmosphere and warming in the lower atmosphere. Thermometer measurements show that the lower atmosphere was warming between about 1906 and 1944 and between about 1976 and 1998, and either constant or cooling at other times. However, the validity of the temperature figures is hotly disputed on both sides because the issue is highly political.
Global Warming Potential (GWP)
Traditionally, greenhouse gas levels are presented as dimensionless numbers representing parts per billion (ppb) multiplied by a scaling factor (global warming potential or GWP) that allows their relative efficiency of producing global temperature increases to be compared. For carbon dioxide, this scaling factor is 1.0. The factors for methane and nitrous oxide are 21 and 310, respectively, while sulfur hexafluoride is 23,900 times more effective than carbon dioxide [5]. The GWP from carbon dioxide is primarily due to the position of its absorption bands in the critical longwave infrared region at 2, 3, 5, and 13-17 microns.
Methane, nitrous oxide, ozone, CFCs and other miscellaneous gases absorb radiation even more efficiently than carbon dioxide, but are also present at much lower concentrations. Their high GWP results from their molecular structure which makes them absorb strongly and at different wavelengths from water vapor and carbon dioxide. For example, although ozone is usually thought of as an absorber of ultraviolet radiation, it also absorbs longwave infrared at 9.6 microns. These gases account for another 1.3% of the natural greenhouse gas effect. The increase in the global energy balance caused by greenhouse gases is called "radiative forcing".
The GWP of a greenhouse gas is the ratio of the time-integrated radiative forcing from 1 kg of the gas in question compared to 1 kg of carbon dioxide. These GWP values are calculated over a 100 year time horizon and take into consideration not only the absorption of radiation at different wavelengths, but also the different atmospheric lifetimes of each gas and secondary effects such as effects on water vapor. For example, methane contributes indirectly to the production of tropospheric ozone and stratospheric water vapor. For some gases, the GWP is too complex to calculate because the gas participates in complex chemical reactions. Most researchers use the GWPs compiled by the World Meteorological Organization (WMO).
Even though most of the so-called greenhouse effect is caused by water vapor, about 1-2 degrees of our current empirically-measured temperature of roughly 288 K (59° F) can be attributed to carbon dioxide. Water vapor at least 99.99% of 'natural' origin, which is to say that no amount of deindustrialization could ever significantly change the amount of water vapor in the atmosphere. Thus, climatologists have concentrated mostly on carbon dioxide and methane. However, in the past few years, a few climatologists have started talking about anthropogenic increases in atmospheric water vapor [17]. This validates suspicions that, if environmentalists get their way with CO2, a campaign to force us to reduce water vapor could well be next.
Carbon Dioxide Levels
Figures from the U.S. Department of Energy show that the pre-industrial baseline of carbon dioxide is 288,000 ppb. The total current carbon dioxide is 368,400 parts per billion, or 0.0368% of the atmosphere.
The ocean and biosphere possess a large buffering capacity, mainly because of carbon dioxide's large solubility in water. Because of this, it is safe to conclude that the anthropogenic component of atmospheric carbon dioxide concentration will continue to remain roughly proportional to the rate of carbon dioxide emissions for any conceivable rate of human emission. In other words, the carbon dioxide buffers are in dynamic equilibrium with atmospheric carbon dioxide and are not in any danger of being saturated, which would allow all the emitted carbon dioxide to go into the atmosphere. This means:
The percentage of emitted carbon dioxide that ends up in the atmosphere can be treated as approximately constant. This percentage is about 50% [6]. (However, the buffering capacity of the oceans is enormous. The oceans currently contain about 50 times as much CO2 as the atmosphere [20]).
The effects of carbon dioxide emissions are not cumulative. That is, lowering carbon dioxide would produce an almost instantaneous reduction (on a climatological scale) in any warming effect that it was producing.
If fossil fuel use increases or decreases, atmospheric carbon dioxide will also increase or decrease proportionately.
Comment added 1/5/2008:
This last point has been misinterpreted by some commentators. To clarify, this means that if we were to stop emitting carbon dioxide, the CO2 levels in the atmosphere would rapidly return to pre-industrial levels. Geologists tell us that the half-life of CO2 in the atmosphere is on the order of five to ten years [23]. In contrast, the IPCC says the half life is 50-200 years. Whatever the actual number, there is no question that emitting CO2 will cause it to accumulate over short periods. But other processes, such as sequestration, also work against it, causing the levels to decrease rapidly over time.
This fact is the very basis of the effort among global warming advocates to pressure governments to lower CO2 emissions. Indeed, if this were not true, there would be little or no benefit to reducing CO2 emissions, as CO2 levels would ratchet up indefinitely, whether by natural or artificial means, without limit.
Amplification and Dampening
Of course, climate, like weather, is complex, nonlinear, and perhaps even chaotic. Increased solar irradiation can lower the albedo, which would amplify any effect caused by changes in solar flux, making the relation between radiation and temperature greater than linear. Increased temperatures also cause increased evaporation of sea water, which can cause warming because of water's greenhouse effect, and also can affect the radiation flux by creating additional clouds. On the other hand, increased plant growth, especially in the oceans, would tend to extract carbon dioxide from the atmosphere, making the fraction of emitted carbon dioxide that stays in the atmosphere lower. Thus, higher emissions would probably cause a slightly smaller proportion of carbon dioxide to remain in the atmosphere than is currently the case, tending to make the relation less than linear.
Absorption of Infrared Radiation
The arithmetic of absorption of infrared radiation also works to decrease the linearity. Absorption of light follows a logarithmic curve (Fig. 2) as the amount of absorbing substance increases. It is generally accepted that the concentration of carbon dioxide in the atmosphere is already high enough to absorb almost all the infrared radiation in the main carbon dioxide absorption bands over a distance of only a few km. Thus, even if the atmosphere were heavily laden with carbon dioxide, it would still only cause an incremental increase in the amount of infrared absorption over current levels. This means that a situation like Venus could not happen here. The atmosphere of Venus is 90 times thicker than Earth's and is 96% carbon dioxide, making the atmospheric carbon dioxide concentration on Venus 300,000 times higher than on Earth. Even so, the high temperatures on Venus are only partially caused by carbon dioxide; a major contributor is the thick bank of clouds containing sulfuric acid [7]. Although these clouds give Venus a high reflectivity in the visible region, the Galileo probe showed that the clouds appear black at infrared wavelengths of 2.3 microns due to strong infrared absorption [8]. Thus, Venus's high temperature might be entirely explainable by direct absorption of incident light, rather than by any greenhouse effect. The infrared absorption lines by carbon dioxide are also broadened by the high pressure on Venus [9], making any comparison with Earth invalid.
Fig.2. Transmitted light is a logarithmic function of concentration. This curve is the familiar Beer's Law.
Note added 9/30/2008:
Several readers have commented on the use of Beer's law here. I am not implying that we can use Beer's law to calculate climate changes. As one reader pointed out, Beer's law only applies to monochromatic light (light whose wavelength is narrow compared to the absorption peak). This reader writes:
What matters for global warming is that, as greenhouse gas concentrations go up, more and more IR wavelengths get captured completely ("saturated absorption"). The relationship at every wavelength is exponential, but that doesn't matter. What matters is the distribution of absorption coefficients across the spectrum (weighted by 255K black body radiation). Greenhouse gas emissions just recruit more and more wavelengths into saturation.
Of course, this is somewhat of an oversimplification, because a spectrophotometer never measures a single wavelength; it always measures a band of finite width. Across that band, you always have a logarithmic function. What this reader is actually saying is that if the concentration increases, those wavelengths at the edges of the absorption band will absorb more energy over a given distance.
As another reader pointed out, Beer's law was derived for a single beam of light going through a gas or solution for which the reemitted radiation does not enter the detector. Therefore, Beer's law will not fit the situation precisely, but there is general agreement that the curve is approximately logarithmic in shape.
Very little of the radiation from the sun at the wavelengths at which carbon dioxide absorbs reaches the surface of the Earth directly (see Fig. 3) [10]. Similarly, very little of the radiation at these wavelengths that originates at the surface makes it all the way to space. Most of the infrared at these wavelengths is produced by black body radiation from objects that have been heated up by absorbing radiation at shorter wavelengths. This means that even if the carbon dioxide levels increase, it will have little effect on the total amount of infrared radiation that is absorbed from the sun. The main effect would be to trap radiation originating at the surface at lower levels in the atmosphere than before, where it would be slightly more difficult for the heat to be re-radiated back into space. This is the principle on which most of the global warming predictions are based.
Note added 6/10/2006:
Many people do not understand this important concept. To put it more simply, shortwave radiation (such as light and short-wavelength infrared) is not absorbed by CO2 [13] and therefore reaches the earth's surface. At the surface, it is absorbed and then re-radiated at longer wavelengths (as "heat"). Some of this heat radiation is in the carbon dioxide absorption bands. This portion does not make it back to space, but is absorbed by water vapor, CO2 and other gases on its way up. More CO2 or water vapor will cause it to be absorbed at a slightly lower altitude than before. This energy will be absorbed and re-emitted by the carbon dioxide molecules.
Even though the total amount of absorption is still nearly 100%, the whole process is dynamic. This means it takes a certain amount of time, while other things, such as transitions from night to day, are also happening. Therefore, it is theoretically possible for increases in CO2 to cause increases in surface temperature. The question is, is the amount of warming enough to be significant?
CO2 is more evenly distributed than water, so if CO2 caused warming it would have a proportionately greater effect in areas where there is little water vapor (such as deserts and in very cold regions), while in areas with a lot of water, the effect of CO2 may be insignificant (in terms of its effect on local temperature) compared to the effect of water vapor. This is one of many factors that mitigate against the idea of a "climate catastrophe." [16]
Fig.3. Absorption of ultraviolet, visible, and infrared radiation by various gases in the atmosphere. Most of the ultraviolet light (below 0.3 microns) is absorbed by ozone (O3) and oxygen (O2). Carbon dioxide has three large absorption bands in the infrared region at about 2.7, 4.3, and 15 microns. Water has several absorption bands in the infrared, and even has some absorption well into the microwave region. There is already sufficient CO2 in the atmosphere to absorb almost all of the radiation from the sun or from the surface of the earth in the principal CO2 absorption bands. (Data from ref. [1], page 93; original data are from Howard et al [21] and Goody [22]).
The net effect of all these processes is that doubling carbon dioxide would not double the amount of global warming. In fact, the effect of carbon dioxide is roughly logarithmic. Each time carbon dioxide (or some other greenhouse gas) is doubled, the increase in temperature is the same as the previous increase. The reason for this is that, eventually, all the longwave radiation that can be absorbed has already been absorbed. It would be analogous to closing more and more shades over the windows of your house on a sunny day -- it soon reaches the point where doubling the number of shades can't make it any darker.
Another way of looking at it is by thinking of adding blankets to your bed on a cold night: if you have no blankets, adding one will have a big effect. If you have a thousand blankets, adding another thousand will have an unmeasurably small effect.
The analogy with a greenhouse would be that the glass in the roof becomes slightly thicker. The effect of warming also depends on the conditions inside the greenhouse. If the greenhouse were full of ice at exactly -0.01 degrees Celsius, making the glass slightly thicker just might be enough to melt all the ice and flood the greenhouse. But if the greenhouse had some regions that were hot and some that were very cold (as the planet Earth does), it would have a very small overall effect.
As an aside, the term "greenhouse effect" is actually a misnomer. In greenhouses, most of the warming that is observed is not caused by carbon dioxide, or by absorption of infrared radiation by the glass as many people think, but by reduction in convection [11].
What does 'saturation' mean?
Many people seem to be confused about the "saturation" argument. It's easy to calculate, using the known extinction coefficients [10], that 99% of the radiation in the CO2 absorption bands is absorbed within only a few tens to hundreds of meters of the source. These coefficients are derived from measurements in modern, high-resolution spectrometers. But strong absorption is also found even with older, lower-resolution instruments. So what does this mean? Is the global warming theory false? Or should older measurements not be trusted? Here is what it means:
The "saturation" argument does not mean that global warming doesn't occur. What saturation tells us is that exponentially higher levels of CO2 would be needed to produce a linear increase in absorption, and hence temperature. This is basic physics. Beer's law has not been repealed.
Some people have gotten the idea that water vapor, which is mainly present at lower altitudes, is somehow necessary for the CO2 to absorb infrared radiation, and that therefore at higher altitudes, CO2 is not anywhere near saturation. This is not true. The presence or absence of water vapor has no bearing on whether radiation is absorbed by CO2. That is because, for all practical purposes, the absorption bands of H2O and CO2 important for warming are different. (If they weren't, CO2 absorption would be so insignificant compared to water vapor that it wouldn't be a potential problem, and we wouldn't be having this discussion.)
CO2 is very nearly homogeneous throughout the atmosphere, so its concentration (as a percentage of the total) is about the same at all altitudes. Although the pressure is lower at high altitudes, there is also a much greater volume. That is why the ozone layer, which is around 30-90 km in altitude, is still able to absorb almost all of the shortwave UV, even though its concentration is only 8-12 ppm. So the importance of low concentrations of gases should not be underestimated. But water vapor is a red herring: it has essentially no effect on what CO2 does. Where water vapor becomes important is in the earth's response to CO2.
Some people also think that line broadening of the CO2 absorption lines by pressure, water vapor, or temperature provides an escape from the saturation dilemma. But in line broadening, the absorbance is peak is only smeared out; the total amount of energy absorbed is not affected. For the same reason, measurements with lower-resolution spectrometers, which slightly smear out the absorption lines, are still valid.
Saturation does not tell us whether CO2 can raise the atmospheric temperature, but it gives us a powerful clue about the shape of the curve of temperature vs. concentration.
Calculating the actual temperature increase
So, what is the actual increase? Interestingly enough, that is easy to estimate--and without resorting to complex computer models.
Because a linear increase in temperature requires an exponential increase in carbon dioxide (thanks to the physics of radiation absorption described above), we know that the next two-fold increase in CO2 will produce exactly the same temperature increase as the previous two-fold increase. Although we haven't had a two-fold increase yet, it is easy to calculate from the observed values what to expect.
Between 1900 and 2000, atmospheric CO2 increased from 295 to 365 ppm, while temperatures increased about 0.57 degrees C (using the value cited by Al Gore and others). It is simple to calculate the proportionality constant (call it 'k') between the observed increase in CO2 and the observed temperature increase:
Note added 2/12/2009: Is 'k' a constant?
Note that k takes into account all of the Earth's adaptation to the increased carbon dioxide: changes in reflectivity due to changing ice cover, changes in cloud cover, and so on. Some might still argue, however, that k is not a constant, but decreases with temperature. But what could cause k to decrease? All climatological factors have already been ruled out. In order for k to be a variable, the laws of absorption of radiation would have to be change with temperature in a fundamentally new way, and not by a small amount: k would have to decrease by 37% to raise ΔT by even one degree. No physical process in any complex system like the atmosphere changes this dramatically with temperature. Spectroscopists have been studying light absorption for over 340 years. One of them would certainly have noticed such a huge temperature sensitivity by now.
Also consider that the temperature increase is only 1-2 degrees C. This is much smaller than the seasonal variation, the variation between different locations on the Earth, or even the variation between day and night temperatures. The laws of physics don't change when you go from New York to New Jersey. Questioning whether k is a constant is grasping at straws. The question people should be asking is: is k equal to zero?
This shows that doubling CO2 over its current values should increase the earth's temperature by about 1.85 degrees C. Doubling it again would raise the temperature another 1.85 degrees C. Since these numbers are based on actual measurements, not models, they include the effects of amplification, if we make the reasonable assumption that the same amplification mechanisms that occurred previously will also occur in a world that is two degrees warmer.
If we want to include other greenhouse gases, such as methane, in the calculation, we need to use the "effective" CO2 concentrations instead. These effective CO2 numbers are less solid than the CO2-only numbers, but the best estimates are that effective CO2 increased from 305 to about 450 ppm during the 20th century[12]. Using these numbers, k becomes 0.6823 and the predicted ΔT becomes 1.02 degrees.
These estimates assume that the correlation between global temperature and carbon dioxide is causal in nature. This remains to be proved. Therefore, the 1.02 and 1.85 degree estimates should also be regarded as upper limits.
Refinements to the estimate
Unfortunately, the above calculations slightly overestimate the degree of warming, because they allow the temperature to rise indefinitely. At very high CO2 levels, self-absorption would become a limiting factor. A more accurate calculation is shown below.
A reader named Ted Ladewski made an interesting suggestion: use the 255K zero-greenhouse gas data point, where there is zero CO2, as a data point, and fit the other points to a smooth curve. To maximize the accuracy of the estimate, we will only use global CO2 and temperature values between 1900 and 2000 [14], about which there is relatively little dispute, and ignore estimates of prehistoric values, which could be more affected by changes in solar flux and other factors. This gives a total of 102 data points. These points are shown in blue in the figure below.
Including the CO2 = 0 data point severely constrains the shape of the curve (and, interestingly, effectively rules out any sort of hockey stick-shaped curve). It is also clear that some sort of monotonically-increasing curve, and not a straight line, has to be used. The best fit was obtained with a hyperbola. If the 102 data points are fitted to a hyperbola, we obtain 288.92 ±0.27K (±1 SD) for 736 ppm CO2 (red line).
The present-day value is taken as the average of the global mean temperatures between 1980 and 2000, or 287.17K. If the above estimate is correct, this means that the temperature would increase by 1.76 ±0.27°C above the present-day value when CO2 levels double their present levels. This is very close to the 1.85°C calculated above.
Stated differently, doubling CO2 from its pre-industrial value would increase the temperature about 1.2 degrees Celsius.
Fig. 4.
However, there is a problem with this method. The 255K data point is not just zero CO2, it is zero water vapor as well. In reality, there would always be some water vapor present, even if there were no CO2. This means that the actual temperature for zero CO2 would be higher than 255K, which would change the shape of the curve. For example, if the CO2=0 value was 271 (halfway between 255 and the current temperature), the prediction changes to 288.55K, or about a 1.39 degree increase for doubling of CO2. This can be seen in the blue curve (see enlarged graph below). The result is not much different than the 1.76, but the important point is that as the estimates become more realistic, the predicted temperature does not increase, but decreases slightly.
Fig. 5.
Fitting other curves to these data points gives similar results. For example, Ted Ladewski suggested deriving an exponential curve from Beer's Law. Although there are obvious problems involved in applying Beer's Law quantitatively to a transparent medium as complex as the atmosphere (as he discusses in greater detail on his website, http://mysite.du.edu/~etuttle/weather/atmrad.htm#Spec), the equation he recommends is:
where AIo and k are constants, C is the CO2 concentration, and T is temperature. (This is also discussed in http://www.sjsu.edu/faculty/watkins/GWnonlinear.htm )
Fitting the data to this equation, as shown in the brown curve in the figure above, gives the much lower value of 287.62±0.07 K (±1 SD), or 0.46±0.08 °C increase above the 1980-2000 mean for a doubling of CO2 from current values.
Although extrapolating beyond the ends of the data, as is done here and as is done with climate models, is hazardous, it's clear that both of these curves are significantly lower than a straight linear estimate. The hyperbola is probably closest to the actual value, because it makes the fewest assumptions about the underlying physical processes. In any case, both estimates should be regarded as upper limits because, as mentioned above, they assume that CO2 is the root cause of the observed changes in temperature.
How long will it take to double CO2 levels?
Another issue that people are confused about is the rate of increase of carbon dioxide. Some people think that CO2 is rising dramatically. This is probably because of graphs like the one below.
Fig. 6.
However, in hard science journals, the graph above would be considered dishonest, because the y-axis starts at 290 instead of zero. This misleads the reader into thinking that CO2 levels have undergone a huge increase when in fact, CO2 levels have only increased by 23.7% since 1900. When the data are plotted honestly, with the y axis starting at zero, the true scope of the change becomes clear.
Fig. 7.
Anthropogenic CO2 contributions constitute 3.2% of the total atmospheric CO2 (using 288 ppm as the pre-industrial baseline). About 14.8% of the increase in CO2 since 1900, or 11.88 ppm, was caused by man-made additions. According to the US Department of Energy, only about 14.8% of this increase, or 11.88 ppm, is man-made. The remaining 68.5 ppm is caused by natural forces, such as volcanoes and forest fires [26]. From this, researchers have estimated that, when water vapor is taken into account, anthropogenic CO2 contributions cause about 0.117% of the Earth's total greenhouse effect [25].
At the current rate of increase, CO2 will not double its current level until 2255.
Fig. 8.
Some climatologists, making assumptions about ever-increasing rates of carbon dioxide production, assert that the doubling will occur within a few decades instead of a few centuries. However, they are doing sociology, not climatology. They are assuming that fossil fuel consumption will increase drastically over current levels. This is very unlikely. The only honest way to estimate the change of CO2 levels is to make predictions based on what is happening now, not what might happen in some hypothetical future society; otherwise, we are merely inflating our predictions by indulging in speculation about future social trends.
Many people have used tricks like these to exaggerate the amount of global warming, and this has made it into a political issue. Most people would have great difficulty feeling an increase of 0.6 degrees Celsius. Any effects of such a small change would be slow and subtle. In general, if you are able to see or feel some change, that means it is almost certainly not caused by CO2-induced global warming.
Secondary effects
What about secondary effects, such as ice melting, changes in albedo, and so forth? Doesn't this increase the predicted temperature beyond the 1.39 to 1.76 degree estimate?
In short, no. Because these calculations are based on observed measurements, they automatically take into account all of the earth's responses. Whatever way the climate adapted to past CO2 increases, whether through melting, changes in albedo, or other effects, is already reflected in the measured temperature, and therefore it will also be reflected in the prediction. This is because the prediction is based on an extrapolation of past measurements that were taken after the earth adapted to the CO2 increase.
In order to get higher temperatures than those predicted above, it would be necessary to assume that a small increase in warming causes a large change in the amplification effect that had never occurred before. In other words, the "rules of the game" would have to drastically and abruptly change in a fundamentally new way--in response to an increase of only one or two degrees. Such changes do not occur in the real world--only in computer models. (If these so-called "tipping points" existed, random, day-to-day, and seasonal variability would have pushed us past them a long time ago.)
This is what makes the "empirical" method superior to all the computer models, as sophisticated as they may be. The empirical model just looks at what's happening and makes a reasonable extrapolation, with very few prior assumptions. The only drawback of the empirical method is that it can only predict an upper limit, because it does make one big assumption: that correlation implies causality. Therefore, although the actual warming cannot be greater than the predicted estimate, it could be considerably less.
Masking
Some climatologists may object to the foregoing analysis, pointing out that the effects of an increase in CO2 could be masked by sulfate aerosols or other factors. For example, the eruption of Mount Pinatubo in 1991 released large amounts of volcanic aerosols that may have been responsible for a brief global cooling [18]. However, later studies showed that water vapor feedback was necessary to account for this effect [19]. Applied to global warming, the reasoning is that human sulfate emissions might "mask" warming by cooling the atmosphere. In the future, they say, sulfate emissions might decrease while CO2 remains constant, and the true global warming would be revealed.
The problem here is that trying to account for sulfates drags us into the morass of modeling of social trends. It is much more reasonable to assume that, as industry shifts production to developing countries and people use more coal and high-sulfur oil to replace dwindling supplies, that sulfate emissions will greatly increase. Additionally, sulfates are only one factor. Many other factors, even including such things as cosmic rays, have been shown to have potential effects on climate. Some of these hypothetical effects would cause warming and some would cause cooling. We need to focus on what can be measured directly. The only issue is whether CO2 is a problem. To add or subtract these myriad hypothetical effects, and claim that the actual amount of warming that is occurring is different from the warming that can be observed, only serves to take climatology that much closer to metaphysics.
One reader pointed out a similar factor that is sometimes mentioned: the heat absorbing capacity of the oceans. Water has 4.13 times the heat capacity of air on a weight basis at 25°C (2.58 times on a molar basis). The oceans contain 273 times as much mass as the atmosphere, and the top few meters alone can store as much heat energy as the entire atmosphere. Thus, much of the extra heat is undoubtedly going into the oceans. But what does this really mean? If the oceans masked all the warming by absorbing the heat, we would have to multiply the time scale by about 1128 before we see the real warming. That means warming that we thought would occur over a 250-year time period would actually take 250×1128 = 282,000 years. By then, humans will almost certainly be getting their energy from some other source besides combustion of hydrocarbons. And then there is the earth's crust, which can absorb additional heat over a scale of billions of years.
Linear Climate Projections
An alternative way of calculating future temperature increases is to consider the fraction of warming that is caused by CO2. To do this, we cannot just use the fraction of radiation that is absorbed by CO2, because that does not take feedback processes into account.
As a first step, let us suppose that temperature increases linearly with greenhouse gas concentrations. From the above numbers, it is easy to calculate that a doubling of atmospheric carbon dioxide would produce an additional warming of (0.042 to 0.084) x 33 = 1.38 to 2.77 degrees centigrade. This is the temperature change one would expect that if CO2 doubles over its current levels.
It is important to realize that the original factor of 0.042 to 0.084 used in these calculations represents the incremental fraction of the total global warming, taken as a holistic phenomenon, initiated by carbon dioxide. This means that the calculation automatically includes the secondary and amplification effects caused by increased water vapor, changes in albedo, and so forth, caused by including the Earth's adaptation to the increment of carbon dioxide.
Fig. 9. Estimated greenhouse gas-induced global warming plotted against greenhouse gas concentrations expressed as a percentage of current-day values. The black curve is a linear extrapolation calculated from the DOE estimates of total current greenhouse gases. The sharp jump at the right is the data point from one computer model that predicts a nine degree increase from doubling current levels of carbon dioxide. Marked, unphysical deviations from linearity resulting in thermal runaway (red curve) are required to fit this data point with the two known points. Such a strong nonlinear effect is difficult to reconcile with our current understanding of climate.
However, our results are based on the assumption that the increase in temperature is linearly proportional to the greenhouse gas levels. This is not true. The relationship is not linear, but logarithmic. If we plot temperature vs. gas concentration (expressed as a percentage of current-day levels), we obtain a convex curve, something like the blue curve in Fig. 9. Thus, the 1.4-2.7 degrees obtained from our linear estimate is an upper bound, and depending on the exact shape of the blue curve, could be a large overestimate of the warming effect.
It goes without saying that the results from this method depend on the accuracy of the 5% estimate (from ref. [3]) and the validity of extrapolating the existing curve by an additional increment. The exact number is very difficult to pin down.
Note added 1/5/2008:
Some authors [15] suggest that the percentage of warming attributable to CO2 is not 5%, but is closer to 26%. It is easy to show why the 26% estimate (and estimates similar to it) are almost certainly wrong. We know that the total warming from greenhouse gases is 33K. If 26% of this was from CO2, then doubling CO2 would raise temperatures by 0.26*33 or 8.6K. Since the 26% estimate is based on total radiation absorbed, and not the amount of warming, we would have to add secondary feedback effects to this figure. This would double or even triple the value, giving us a predicted temperature increase of up to 25° C, or a predicted global average temperature of 40°C (104°F). Balmy!
Whether the exact number is 5% or 9%, because our estimate is based on the percentage of warming, not percentage of radiation absorbed, that is attributable to CO2, feedbacks in the estimate here are automatically taken into account. However, because of the large uncertainty about the actual value, the estimate from Fig. 4 (which derives an estimate from extrapolation of current trends) is probably more accurate.
However, we can also check the plausibility of the IPCC's result by asking the following question: What number would result if we calculated backwards from the IPCC estimates?
Using the same assumption of linearity, if a 9 degree increase resulted from the above-mentioned increase of greenhouse gas levels, the current greenhouse gas level (which is by definition 100%) would be equivalent to a greenhouse gas-induced temperature increase of at least 107 degrees C. This means the for the 9 degree figure to be correct, the current global temperature would have to be at least 255 + 107 - 273 = 89 degrees centigrade, or 192° Fahrenheit! A model that predicts a current-day temperature well above the highest-ever observed temperature is clearly in need of serious tweaking. Even a 5 degree projection predicts current-day temperatures of 41°C (106°F). These results clearly cannot be reconciled with observations.
In order for the 9 degree estimate to make sense from a physical standpoint, we are forced to draw an exponential curve through the graph above (shown in red) through the three points instead of a straight line. However, this curve creates an even worse result: it predicts a thermal runaway. A thermal runaway is a reaction that suddenly switches from a smooth curve and goes wildly out of control. For the the nine-degree climate model to fit the observations, the curve that we must draw predicts that a 10 or 20% increase in greenhouse gases above their current levels would cause an infinite increase in temperature! Of course, some other factor (such as explosion of the Earth in a supernova-type explosion) would undoubtedly kick in to save us before an infinite temperature could be reached. But even so, it can be seen that an above-linear increase in temperature with increasing gas concentration is not only unphysical, but inconsistent with observations.
Although the estimates of global warming made by the IPCC and the predictions of "environmental catastrophe" made by environmental groups have gradually creeping back down as climate models gradually improve, environmentalists still worry that temperatures could increase by as much as 3 to 5 degrees over the next century.
However, even a 5 degree increase in temperature over the next century would constitute a significant departure from the previous rates of increase. It is clear from Fig. 9 that this too would be a marked deviation from the curve. Such strong nonlinear effects, especially when they are in the wrong direction from a physical standpoint, are difficult to reconcile with our current understanding of climate.
Conclusion
Although carbon dioxide is capable of raising the Earth's overall temperature, the IPCC's predictions of catastrophic temperature increases produced by carbon dioxide have been challenged by many scientists. In particular, the importance of water vapor is frequently overlooked by environmental activists and by the media. The above discussion shows that the large temperature increases predicted by many computer models are unphysical and inconsistent with results obtained by basic measurements. Skepticism is warranted when considering computer-generated projections of global warming that cannot even predict existing observations.
References and Notes
[1]. Peixoto, J.P. and Oort, A.H., Physics of Climate Springer, 1992, p. 118.
[2]. Thomas, G.E. and Stamnes, K. Radiative Transfer in the Atmosphere and Ocean. Cambridge University Press, 1999, p. 441.
[3] Most credible sources place the number at 95%.
95% = Michaels, P.J. and Balling, R.C., The Satanic Gases. Cato Institute, 2000 p.25.
90-95% = http://www.globalwarming.org/node/62
90% = http://www.ncpa.org/press/transcript/globalwm/global2.html Norman J. Macdonald Carbon dioxide is about 5 percent, water vapor 90.
Here is a paper that gives a different figure: http://www.atmo.arizona.edu/students/courselinks/spring04/atmo451b/pdf/RadiationBudget.pdf"
S.M. Freidenreich and V. Ramaswamy, Solar Radiation Absorption by Carbon Dioxide, Overlap with Water, and a Parameterization for General Circulation Models. Journal of Geophysical Research 98(1993):7255-7264
[4]. U.S. Climate Action Report 2000, US Environmental Protection Agency, page 38.
[5]. Houghton, J.T. et al, eds. Climate Change 1995: The Science of Climate Change (IPCC report), 1996, Cambridge University Press. http://www.ipcc.ch/pub/sarsum1.htm
[6]. Peixoto, J.P. and Oort, A.H., Physics of Climate. Springer, 1992, p. 436.
[7]. http://www.aas.org/publications/baas/v33n3/dps2001/354.htm
[8]. http://www2.jpl.nasa.gov/galileo/slides/slide3.html
[9]. Ma, Q., and R.H. Tipping, J. Chem. Phys., 96, 8655-8663, 1992.
[10]. [note added Feb 15, 2007] This can be easily calculated from the absorption of gaseous carbon dioxide. See Phys. Rev. 41, 291 - 303 (1932) P. E. Martin and E. F. Barker "The Infrared Absorption Spectrum of Carbon Dioxide".
Thomas and Stamnes (ref. 2, page 91) that shows 0% transmittance at 22 km and below for the 15 micron CO2 band. This section discusses the "opaque region" and also gives a very clear discussion of line broadening, which is an additional point that many people are unfamiliar with.
Schneider, Kucerovsky, and Brannen (Appl. Opt. 28:5, 1998) give an absorption coefficient at 9.90 ± 1.49 cm-1 atm-1 for low concentrations of CO2 in a 1-atm nitrogen atmosphere at 4.2 microns. This works out to 376 absorbance units per km for 380 ppm CO2, which is about as close to 100% absorption as you can get. Heinz Hug, a global warming skeptic, measured a similar value (0.03 absorbance units/10 cm for 357 ppm at 15μm) ( http://www.john-daly.com/artifact.htm).
[11]. Peixoto, J.P. and Oort, A.H., Physics of Climate. Springer, 1992, p. 30.
[12]. The Satanic Gases, p.36.
[13]. Carbon dioxide is written here as CO2 instead of CO2 because using subscripts messes up the line spacing in HTML. The Unicode character x2082 (₂ or ₂), which normally solves this problem, doesn't display properly in IE.
[14]. The temperature data for these calculations were obtained from http://lwf.ncdc.noaa.gov/oa/climate/research/anomalies/anomalies.html
[15]. www.realclimate.org
[16]. One reader pointed out that the Arctic region has dew points above freezing during a significant portion of the year. The average desert atmosphere also has a much higher water content than many people think.
[17]. However, some climatologists have tried to invoke anthropogenic increases in atmospheric water vapor: see Santer et al., "Identification of human-induced changes in atmospheric moisture content" (Proc Natl Acad Sci U S A. 2007 Sep 25;104(39):15248-53). Using a computer model, the authors concluded that human activity is increasing water vapor.
[18]. Radiative Climate Forcing by the Mount Pinatubo Eruption. Minnis P, Harrison EF, Stowe LL, Gibson GG, Denn FM, Doelling DR, Smith WL Jr. Science. 1993 Mar 5;259(5100):1411-1415.
[19]. Global cooling after the eruption of Mount Pinatubo: a test of climate feedback by water vapor. Soden BJ, Wetherald RT, Stenchikov GL, Robock A. Science. 2002 Apr 26;296(5568):727-30.
[20]. http://www.aip.org/history/climate/oceans.htm This is a pro-global warming website.
[21]. Howare, J.N., Burch, D.L., Williams, D (1955). Near-infrared transmission through synthetic atmospheres. Geophys. Res. Papers No. 40, Geophys, Res. Dir., Air Force Cambridge Research Center, 244 pp.
[22]. Goody, R.M. (1964). Atmospheric Radiation: I. Theoretical Basis. Clarendon, Oxford, 436 pp.
[23]. National Academy of Sciences, Climate Research Board (1979). Carbon dioxide and climate: a scientific assessment. National Academy of Sciences, 72pp.; cited in Ref. 1, p. 434.
[24]. See also: Steven Goddard, Divergence Between GISS and UAH since 1980 and
Oceans are cooling according to NASA (non-technical newspaper article).
[25]. http://epa.gov/climatechange/emissions/downloads/2008InventoryPublicReviewComments.pdf
[26]. Current Greenhouse Gas Concentrations (updated October, 2000) Carbon Dioxide Information Analysis Center, U.S. Department of Energy Oak Ridge, Tennessee
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Thanks to many readers for pointing out mistakes and making constructive suggestions.
B
Black Swan
Anyone notice how angry the 'man made climate change lobby' are becoming of late? Good example last night on This Week, Michael Portillo wiped the floor with some ranting guy...and he did it with calm probing questions that left the believer in bits; grasping and flailing around for half baked theories he'd heard in the pub, or read in the Guardian...
Monbiot is getting all hot under the collar again...have some of these Georgie Boy, you'll need them next year...apparently...
It won't be that naughty (naturally occuring) event known as El Nino though, it's us all driving around in our hummers...
http://news.bbc.co.uk/1/hi/sci/tech/8406839.stm
Monbiot is getting all hot under the collar again...have some of these Georgie Boy
, you'll need them next year...apparently...It won't be that naughty (naturally occuring) event known as El Nino though, it's us all driving around in our hummers...
http://news.bbc.co.uk/1/hi/sci/tech/8406839.stm
Climate change sceptics are evil people motivated only by a desire to make money. Everyone knows this to be true - most of them are funded by Big Oil, which has a vested interest in promoting the lie that climate change is not happening.
Scientists who are part of the naturally-occurring consensus on the other hand are simple questers after truth. There can be no question of any undue influence or underhand motives on their part.
You've probably never heard of NERC, and if God were good, you never would. However, NERC is actually quite important:
NERC is the UK's main agency for funding and managing research, training and knowledge exchange in the environmental sciences.
Don't take my word for it - that's from NERC's own website:
http://www.nerc.ac.uk/about/work/whatwedo/
Now, if you were a UK climate scientist, this body would be very important indeed, as it is chiefly responsible for distributing the research doubloons. The people in charge of such a task would presumably be of the highest calibre and impeccably impartial, would they not? If they were, for example, known to be biased towards certain points of view, this would be a cause for concern, would it not?
The following sit on the NERC council:
■Bob Watson (of CRU fame)
■Andrew Watson (of CRU and "What an A$$hole" fame)
■Julia Slingo (recently seen trying to drum up support for a pro-AGW letter signed by scientists)
■Mike Lockwood (well known to sceptics as the author of a rather questionable critique of Svensmark)
Just to take Andrew Watson for the time being - is this really a man that you put in charge of anything? If you haven't seen him in action, look him up on Youtube - he has been all over the place recently, making an absolute t1t of himself.
It is not that he called the American an "a$$hole". On the most charitable interpretation, the guy was deliberately acting like one, and Watson took the bait beautifully. It is the weakness and nonsense of his defense of his colleagues that was simply breath-taking.
Is it any wonder that there are many proponents of the AGW theory when research grants depend upon the approval of this loathesome and intellectually-challenged creature?
Supporters of the theory love to point out the existence of a consensus. It doesn't exist, as I hope some of my posts have demostrated. But what if there were such a thing in a country where people such as Watson are in charge of allocating funding? What significance would this consensus have?
There was widespread consensus, officially, that Collectivisation was an excellent thing, and that opponents of it were enemies of the people. This resulted in the Ukranian Genocide, that some people inexplicably still refer to as a "famine".
Scientists who are part of the naturally-occurring consensus on the other hand are simple questers after truth. There can be no question of any undue influence or underhand motives on their part.
You've probably never heard of NERC, and if God were good, you never would. However, NERC is actually quite important:
NERC is the UK's main agency for funding and managing research, training and knowledge exchange in the environmental sciences.
Don't take my word for it - that's from NERC's own website:
http://www.nerc.ac.uk/about/work/whatwedo/
Now, if you were a UK climate scientist, this body would be very important indeed, as it is chiefly responsible for distributing the research doubloons. The people in charge of such a task would presumably be of the highest calibre and impeccably impartial, would they not? If they were, for example, known to be biased towards certain points of view, this would be a cause for concern, would it not?
The following sit on the NERC council:
■Bob Watson (of CRU fame)
■Andrew Watson (of CRU and "What an A$$hole" fame)
■Julia Slingo (recently seen trying to drum up support for a pro-AGW letter signed by scientists)
■Mike Lockwood (well known to sceptics as the author of a rather questionable critique of Svensmark)
Just to take Andrew Watson for the time being - is this really a man that you put in charge of anything? If you haven't seen him in action, look him up on Youtube - he has been all over the place recently, making an absolute t1t of himself.
It is not that he called the American an "a$$hole". On the most charitable interpretation, the guy was deliberately acting like one, and Watson took the bait beautifully. It is the weakness and nonsense of his defense of his colleagues that was simply breath-taking.
Is it any wonder that there are many proponents of the AGW theory when research grants depend upon the approval of this loathesome and intellectually-challenged creature?
Supporters of the theory love to point out the existence of a consensus. It doesn't exist, as I hope some of my posts have demostrated. But what if there were such a thing in a country where people such as Watson are in charge of allocating funding? What significance would this consensus have?
There was widespread consensus, officially, that Collectivisation was an excellent thing, and that opponents of it were enemies of the people. This resulted in the Ukranian Genocide, that some people inexplicably still refer to as a "famine".
Anyone notice how angry the 'man made climate change lobby' are becoming of late? Good example last night on This Week, Michael Portillo wiped the floor with some ranting guy...and he did it with calm probing questions that left the believer in bits; grasping and flailing around for half baked theories he'd heard in the pub, or read in the Guardian...
Monbiot is getting all hot under the collar again...have some of these Georgie Boy
It won't be that naughty (naturally occuring) event known as El Nino though, it's us all driving around in our hummers...
http://news.bbc.co.uk/1/hi/sci/tech/8406839.stm
Think this is the link to the programme that BS is talking about - Nick Cohen talks about his new film.
B
Black Swan
Looking at the comments section after this article from The Times it appears that scepticism is rife, some of the comments are hilarious...:clap: For every 100 only 2/3 appear to be zealot, brainwashed, sandal wearing, new age believers...
Not sure if anyone caught the sympathetically choreographed Jon Snow panel interview on C4 with one of the Millipede bros. last night, it was truly pathetic, Millipede slobering all over the place through the joke teeth he got with Wednesday's Beano and all the audience were 'believers'. One had stopped eating meat to do her bit to save the planet, another saying climate change had ruined her book shop in Cockermouth... the usual tripe of, "what about the legacy we leave our children "?
Millipede was in CC heaven...one or two googlies bowled from the audience, particularly on why should it be down to personal responsibiltiy and not the huge machinery of govt to implement change...they never can answer that one can they. Why not? 'cos they like the 'guilt mindset' and they'd never be able to tackle Tesco or Shell on waste/pollution, they'd be laughed at...
DAVE HELLER wrote:
I don't know anyone who believes the hype anymore. I really don't.
December 11, 2009 2:54 AM GMT on community.timesonline.co.uk Recommend? (25) Report Abuse Permalink
Joseph Kellie wrote:
Human beings can adapt very easily to an increase in temperature but find it very difficult to adapt to colder climates. The earth will continue to change regardless of what we are doing so lets focus on actual benefits.
The world can maintain only certain populations and by not controlling this we increase demand for resources and decrease shares.
The destruction of the environment; rain forest etc; will punish us for decades to come and we should focus on this.
December 11, 2009 2:05 AM GMT on community.timesonline.co.uk Recommend? (7) Report Abuse Permalink
Odd Ball wrote:
Climategate reaches the British House of Lords
December 11, 2009 1:25 AM GMT on community.timesonline.co.uk Recommend? (3) Report Abuse Permalink
Martin Ackroyd wrote:
I expect to hear an announcement in the near future that 1700 members of the UK science community have signed a petition stating: "We, members of the UK science community, have the utmost confidence in the ability of the Met Office to predict next week's weather".
But even after this petition has been signed, for some reason I think that I will still take next week's weather forecast as little more than someone's guess.
December 11, 2009 12:56 AM GMT on community.timesonline.co.uk Recommend? (8) Report Abuse Permalink
Grant MacDonald wrote:
Probably wise to invest in boat building companies then.
The Wet Office are akin to a stopped clock, only not as accurate. The clock will be right twice a day whereas the Wet Office always seem to be wrong.
December 11, 2009 12:27 AM GMT on community.timesonline.co.uk Recommend? (14) Report Abuse Permalink
Douglas Glaston wrote:
The OCean is always presented as transporting heat ebtween cool areas (poles or deep water) and hot areas (tropical surface water). But actaully we often see documentaries on hot springs deep in the oceans, and I imagine that whenever the ocean floor is very deep, as it is also very thin (and thick rather below mountains), it could be rather hot, as it is close to the Earth mantel. So, why don't we ever hear about some heating of the Ocean comes from the seafloor itself ? Why couldn't the surface temperature variations be affected by a variation of the heat transfer between the Earth core/mantel, and the ocean ? If we assume the Earth is gradually cooling down, then the heat goes from the core to the surface, If there are bursts, the surface become hotter. And the best vehicle for heat would be the ocean.
No ?
December 11, 2009 12:25 AM GMT on community.timesonline.co.uk Recommend? (6) Report Abuse Permalink
Davie Anonymous wrote:
Yawn...
December 10, 2009 11:19 PM GMT on community.timesonline.co.uk Recommend? (18) Report Abuse Permalink
Crash Lander wrote:
Since the same people who make the prediction also "add value" to the raw data, I have no doubt that this prediction will come to pass.
"Just because summer happens to be cancelled where you are, don't believe for a second that it is not the hottest year Ever! See, we added a few degrees and now it's warm again."
December 10, 2009 11:12 PM GMT on community.timesonline.co.uk Recommend? (23) Report Abuse Permalink
Sedgwick M wrote:
What! Another "barbecue summer". Better get my raincoat then.
December 10, 2009 11:10 PM GMT on community.timesonline.co.uk Recommend? (24) Report Abuse Permalink
jayil london wrote:
"Next year to be the world’s warmest on record, Met Office predicts"
The small print probably says that the tempeture sensor will be attached on the side of an active volcano.
Rick Andrews wrote:
To paraphrase MiK Rym: How arrogant and ignorant do people have to be to deny that humans are significantly contributing to global warming? I have no doubts that climate is changing but why are we ignoring the mounting independent evidence that human activity is an increasingly contributing factor? Clearly factors such a the sun have a significant impact on earth but no we are continuing to ignore the strong correlation between the more rapid rise over the past few hundred years and the greatly increased emissions of CO2 in industrialised nations..
December 11, 2009 12:12 PM GMT on community.timesonline.co.uk Recommend? Report Abuse Permalink
Rick Andrews wrote:
I'm still amazed at the number of posters here who directly or by implication confuse "climate" with "weather" and "local" with "average global".....or maybe not, perhaps it is deliberate disingenuousness to stir up and muddy the waters.
December 11, 2009 11:51 AM GMT on community.timesonline.co.uk Recommend? (1) Report Abuse Permalink
Paul MacG wrote:
The climate change deniers are the
flat earthers of our age.
December 11, 2009 11:08 AM GMT on community.timesonline.co.uk Recommend? (2) Report Abuse Permalink
JOHN GRAYER wrote:
Well we have had a couple of wet ones so sounds like a good bet . How much do this lot get paid .
December 11, 2009 10:49 AM GMT on community.timesonline.co.uk Recommend? (3) Report Abuse Permalink
david jones wrote:
still,it does distract the population from the mess this idiot govt is in,dosent it,LOOK OUT,there an asteroid coming,pathetic.
December 11, 2009 10:46 AM GMT on community.timesonline.co.uk Recommend? (5) Report Abuse Permalink
Martin Ackroyd wrote:
The Met Office's problem is that they have come to believe their own propaganda. If you look at their website, it is clear they have very great faith in the reliability of their computer models of the climate.
In reality, computer models of complicated systems inevitably have to incorporate "fiddle factors", to account for details that are only partly understood. The fiddle factors are then tuned to produce the results their creators think are the right results.
The Met Office is fully signed up to the Climate Change Religion - hence the inevitability that their models predict hotter and hotter summers.
If I were given access to their computer models, I am sure I could tweak the fiddle factors to produce results that fitted my own preconceptions. The results would be very different from the Met Office's current predictions, but would probably be just as detached from reality.
December 11, 2009 10:45 AM GMT on community.timesonline.co.uk Recommend? (15) Report Abuse Permalink
david jones wrote:
there is a proven correlation between global warming and solar activity,there is no such proof for the tree huggers theory,youve got to many so called "scientists"trying to justify their existance by sensationalism,havent they got anything more useful to contribute to mankind?
December 11, 2009 10:44 AM GMT on community.timesonline.co.uk Recommend? (3) Report Abuse Permalink
S Bell wrote:
will it be as warm as 76? I'll stay in UK for my hols.
December 11, 2009 10:44 AM GMT on community.timesonline.co.uk Recommend? (3) Report Abuse Permalink
david jones wrote:
GOOD
December 11, 2009 10:40 AM GMT on community.timesonline.co.uk Recommend? (2) Report Abuse Permalink
Donald Walton wrote:
If the Met Office really did suggest that the temperature next year will be 0.6C warmer, the difference between 14.58C and 14.52, no wonder no one trusts their data sets!
http://www.timesonline.co.uk/tol/news/environment/copenhagen/article6952470.ece
Not sure if anyone caught the sympathetically choreographed Jon Snow panel interview on C4 with one of the Millipede bros. last night, it was truly pathetic, Millipede slobering all over the place through the joke teeth he got with Wednesday's Beano and all the audience were 'believers'. One had stopped eating meat to do her bit to save the planet,
another saying climate change had ruined her book shop in Cockermouth... the usual tripe of, "what about the legacy we leave our children "?Millipede was in CC heaven...one or two googlies bowled from the audience, particularly on why should it be down to personal responsibiltiy and not the huge machinery of govt to implement change...they never can answer that one can they. Why not? 'cos they like the 'guilt mindset' and they'd never be able to tackle Tesco or Shell on waste/pollution, they'd be laughed at...
DAVE HELLER wrote:
I don't know anyone who believes the hype anymore. I really don't.
December 11, 2009 2:54 AM GMT on community.timesonline.co.uk Recommend? (25) Report Abuse Permalink
Joseph Kellie wrote:
Human beings can adapt very easily to an increase in temperature but find it very difficult to adapt to colder climates. The earth will continue to change regardless of what we are doing so lets focus on actual benefits.
The world can maintain only certain populations and by not controlling this we increase demand for resources and decrease shares.
The destruction of the environment; rain forest etc; will punish us for decades to come and we should focus on this.
December 11, 2009 2:05 AM GMT on community.timesonline.co.uk Recommend? (7) Report Abuse Permalink
Odd Ball wrote:
Climategate reaches the British House of Lords
December 11, 2009 1:25 AM GMT on community.timesonline.co.uk Recommend? (3) Report Abuse Permalink
Martin Ackroyd wrote:
I expect to hear an announcement in the near future that 1700 members of the UK science community have signed a petition stating: "We, members of the UK science community, have the utmost confidence in the ability of the Met Office to predict next week's weather".
But even after this petition has been signed, for some reason I think that I will still take next week's weather forecast as little more than someone's guess.
December 11, 2009 12:56 AM GMT on community.timesonline.co.uk Recommend? (8) Report Abuse Permalink
Grant MacDonald wrote:
Probably wise to invest in boat building companies then.
The Wet Office are akin to a stopped clock, only not as accurate. The clock will be right twice a day whereas the Wet Office always seem to be wrong.
December 11, 2009 12:27 AM GMT on community.timesonline.co.uk Recommend? (14) Report Abuse Permalink
Douglas Glaston wrote:
The OCean is always presented as transporting heat ebtween cool areas (poles or deep water) and hot areas (tropical surface water). But actaully we often see documentaries on hot springs deep in the oceans, and I imagine that whenever the ocean floor is very deep, as it is also very thin (and thick rather below mountains), it could be rather hot, as it is close to the Earth mantel. So, why don't we ever hear about some heating of the Ocean comes from the seafloor itself ? Why couldn't the surface temperature variations be affected by a variation of the heat transfer between the Earth core/mantel, and the ocean ? If we assume the Earth is gradually cooling down, then the heat goes from the core to the surface, If there are bursts, the surface become hotter. And the best vehicle for heat would be the ocean.
No ?
December 11, 2009 12:25 AM GMT on community.timesonline.co.uk Recommend? (6) Report Abuse Permalink
Davie Anonymous wrote:
Yawn...
December 10, 2009 11:19 PM GMT on community.timesonline.co.uk Recommend? (18) Report Abuse Permalink
Crash Lander wrote:
Since the same people who make the prediction also "add value" to the raw data, I have no doubt that this prediction will come to pass.
"Just because summer happens to be cancelled where you are, don't believe for a second that it is not the hottest year Ever! See, we added a few degrees and now it's warm again."
December 10, 2009 11:12 PM GMT on community.timesonline.co.uk Recommend? (23) Report Abuse Permalink
Sedgwick M wrote:
What! Another "barbecue summer". Better get my raincoat then.
December 10, 2009 11:10 PM GMT on community.timesonline.co.uk Recommend? (24) Report Abuse Permalink
jayil london wrote:
"Next year to be the world’s warmest on record, Met Office predicts"
The small print probably says that the tempeture sensor will be attached on the side of an active volcano.
Rick Andrews wrote:
To paraphrase MiK Rym: How arrogant and ignorant do people have to be to deny that humans are significantly contributing to global warming? I have no doubts that climate is changing but why are we ignoring the mounting independent evidence that human activity is an increasingly contributing factor? Clearly factors such a the sun have a significant impact on earth but no we are continuing to ignore the strong correlation between the more rapid rise over the past few hundred years and the greatly increased emissions of CO2 in industrialised nations..
December 11, 2009 12:12 PM GMT on community.timesonline.co.uk Recommend? Report Abuse Permalink
Rick Andrews wrote:
I'm still amazed at the number of posters here who directly or by implication confuse "climate" with "weather" and "local" with "average global".....or maybe not, perhaps it is deliberate disingenuousness to stir up and muddy the waters.
December 11, 2009 11:51 AM GMT on community.timesonline.co.uk Recommend? (1) Report Abuse Permalink
Paul MacG wrote:
The climate change deniers are the
flat earthers of our age.
December 11, 2009 11:08 AM GMT on community.timesonline.co.uk Recommend? (2) Report Abuse Permalink
JOHN GRAYER wrote:
Well we have had a couple of wet ones so sounds like a good bet . How much do this lot get paid .
December 11, 2009 10:49 AM GMT on community.timesonline.co.uk Recommend? (3) Report Abuse Permalink
david jones wrote:
still,it does distract the population from the mess this idiot govt is in,dosent it,LOOK OUT,there an asteroid coming,pathetic.
December 11, 2009 10:46 AM GMT on community.timesonline.co.uk Recommend? (5) Report Abuse Permalink
Martin Ackroyd wrote:
The Met Office's problem is that they have come to believe their own propaganda. If you look at their website, it is clear they have very great faith in the reliability of their computer models of the climate.
In reality, computer models of complicated systems inevitably have to incorporate "fiddle factors", to account for details that are only partly understood. The fiddle factors are then tuned to produce the results their creators think are the right results.
The Met Office is fully signed up to the Climate Change Religion - hence the inevitability that their models predict hotter and hotter summers.
If I were given access to their computer models, I am sure I could tweak the fiddle factors to produce results that fitted my own preconceptions. The results would be very different from the Met Office's current predictions, but would probably be just as detached from reality.
December 11, 2009 10:45 AM GMT on community.timesonline.co.uk Recommend? (15) Report Abuse Permalink
david jones wrote:
there is a proven correlation between global warming and solar activity,there is no such proof for the tree huggers theory,youve got to many so called "scientists"trying to justify their existance by sensationalism,havent they got anything more useful to contribute to mankind?
December 11, 2009 10:44 AM GMT on community.timesonline.co.uk Recommend? (3) Report Abuse Permalink
S Bell wrote:
will it be as warm as 76? I'll stay in UK for my hols.
December 11, 2009 10:44 AM GMT on community.timesonline.co.uk Recommend? (3) Report Abuse Permalink
david jones wrote:
GOOD
December 11, 2009 10:40 AM GMT on community.timesonline.co.uk Recommend? (2) Report Abuse Permalink
Donald Walton wrote:
If the Met Office really did suggest that the temperature next year will be 0.6C warmer, the difference between 14.58C and 14.52, no wonder no one trusts their data sets!
http://www.timesonline.co.uk/tol/news/environment/copenhagen/article6952470.ece
Please do not cut and paste whole articles like this. It is essentially unreadable. Formatting is lost, figures are lost and in general it is poor form.
His calculation of climate sensitivity is garbage. I will post most on this when I have time to do it properly.
Looking at the comments section after this article from The Times it appears that scepticism is rife, some of the comments are hilarious...:clap: For every 100 only 2/3 appear to be zealot, brainwashed, sandal wearing, new age believers...
Not sure if anyone caught the sympathetically choreographed Jon Snow panel interview on C4 with one of the Millipede bros. last night, it was truly pathetic, Millipede slobering all over the place through the joke teeth he got with Wednesday's Beano and all the audience were 'believers'. One had stopped eating meat to do her bit to save the planet,
Millipede was in CC heaven...one or two googlies bowled from the audience, particularly on why should it be down to personal responsibiltiy and not the huge machinery of govt to implement change...they never can answer that one can they. Why not? 'cos they like the 'guilt mindset' and they'd never be able to tackle Tesco or Shell on waste/pollution, they'd be laughed at...
<masses of pointless stuff deleted>
Do you really think that cut and pasting a load of old nonsense from the comments section of newspapers is indicative of anything at all?
Click on the link to see the original format and all accompanying figures.
I pasted the whole article in response to your post that nobody had challenged the assertion on this subject that you posted. I lack the technical knowledge to explain complex estimates such as these, as I would imagine that you do unless you have made a particular study of this field.
Rather than post a simple assertion that your prior assertion was untrue, I posted a paper that examined it in some depth (at least in terms of the debate that we are having here).
Black Swan's post doesn't prove anything, but it may, in a purely anecdotal way, be indicative of public opinion. The Thunderer isn't what it was, God knows, but I would imagine that it's readership is still drawn to some extent from the at least semi-literate.
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Apologies for dismembering your post, but it is pleasant to find at least a little common ground and I would very largely agree with the above - excepting only that I would not out of choice select my local council to do anything. Where we would chiefly differ, obviously, is in our definition of pollution.
I support a lot measures that I imagine you do as well. For example, there are a great many good and obvious reasons to reduce usage of fossil fuels (even leaving aside any mention of CO2 emissions), so obvious that I would imagine we don't need to spell them out. Personally, I think that the era of fossil fuel dominance will end much sooner than most people think, for reasons that are probably not widely accepted.
Proper conservation and stewardship of our environment (albeit that I probably see this in smaller terms than you do) seems to me even more sensible and desireable.
Out of choice, I would far prefer to recycle than dump waste fairly indiscriminately into the ground (although land-filling certain wastes does have its purpose in certain circumstances).
Greater energy efficiency seems to me again to be both sensible and desireable (even if one's only motivation is thrift).
Who would not wish to see serious research into viable, cleaner technologies? Who welcomes cities choked with fumes, rivers bereft of fish, and beaches choked with unsavoury detritus?
You say that there is no inalienable human right to toss your rubbish into the street - I wish only that it were so. I don't know how things are in Australia of course (although a friend who has moved there paints a picture of a veritable paradise compared to England). However, over here such a right does indeed exist, de facto if not yet de jure. The modern Briton seems incapable of existing in a public place for a period of longer than a few minutes before requiring the sustenance of junk food. Once refreshed, he also appears to suffer from an allergy to the use of public litter-bins. Britain is as a consequence awash in a sea of greasy and unlovely litter - I'm not aware of any studies on the subject, but I would be amazed if mine was not the most littered country on earth. Concern for the environment could start (in the UK at least) by walking a few yards to the nearest bin.
I would imagine that we would agree on much of the above, although equally I would imagine that we would differ considerably on the means of bringing these aims about!
Anyway, I'm quite enjoying our little climate ding-dong - it's carried on a lot longer and been of greater interest than I imagined it would at the start. If you want to carry on I'll try to respond more seriously and politely (starting with no more mega-pastes - I fully agree that they're annoying and pointless)
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