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MA Rodger at 05:13 AM on 9 October 2018Venus doesn't have a runaway greenhouse effect
JC @250,
You ask "Why would strong pressure prevent CO2 from having a greenhouse effect ?" It is actually the other way about. On Mars we see ten-times the CO2 but very low atmospheric pressure and a very low GH-effect resulting from that CO2.
You may have noted in the OP above the use of the term "pressure broadening." The absorption of radiation by a greenhouse gas occurs at very distinct wavelengths. These are usually bunched into a series of lines resulting from the quantum spins a gas molecule can have. But as the pressure of the gas increases (for instance, resulting from mixing in 800mbar of N2 and 200mbar of O2) these distinct wavelengths become broadened out. The result is that the greenhouse gas can more completely absorb a wider wavelength. The graphic below is taken from a Science of Doom page illustrates what can happen to a single line under presure broadening.
The result of pressure broadening is a more effective GH-effect from a single gas operating in a particular wave-band. (In the analogy @242, it's a bit like the "hat and gloves" becoming a full balaclava & arm-length gloves.)
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MA Rodger at 05:06 AM on 9 October 2018Venus doesn't have a runaway greenhouse effect
JC @250,
You ask "Why would strong pressure prevent CO2 from having a greenhouse effect ?" It is actually the other way about. On Mars we see ten times the CO2 but very low atmospheric pressure and a very low GH-effect resulting from that CO2.
You may have noted in the OP above the use of the term "pressure broadening." The absorption of radiation by a greenhouse gas occurs at very distinct wavelengths. These are usually bunched into a series of lines resulting from the quantum spins a gas molecule can have. But as the pressure of the gas increases (for instance, resulting from mixing in 800mbar of N2 and 200mbar of O2) these distinct wavelengths become broadened out. The result is that the greenhouse gas can more completely absorb a wider wavelength. (In the analogy @242, it's a bit like the "hat and gloves" becoming a full balaclava & arm-length gloves.) The graphic below is taken from a Science of Doom page, one of a series which explains the ins-&-outs of how GH-effects work.
The result of pressure broadening is a more effective GH-effect from a single gas operating in a particular wave-band.
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JC16932 at 03:31 AM on 9 October 2018Venus doesn't have a runaway greenhouse effect
MA Rodger :
« You say that "CO2 alone has a very low GH-effect." And the only place where we find what is effectively "CO2 alone" is the 6mbar atmosphere of Mars which provides something like a 12Wm^-2 GH-effect. The usual-reported calculations put the 0.6mbar CO2 contribution to Earth's GH-effect as being 25%, perhaps 40Wm^-2, this the GH-effect if all other GHGs were taken from the atmosphere. But that CO2 would still sit within 800mbar of N2 and 200mbar of O2.»
I do not understand your explanation. Why would strong pressure prevent CO2 from having a greenhouse effect ?
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MA Rodger at 19:57 PM on 8 October 2018Breathing contributes to CO2 buildup
Lasterday @112,
As a "chemical engineer" you should have had no problem quickly sourcing those "real numbers" to "run" but as you have not returned with your findings, may I take up the challenge.
The CO2 expelled in human respiration has been calculated as equivalent to 6% or 9% of the anthropogenic emissions from fossil-fuel-use (although the emissions values cannot include emissions from land-use-change and still appear out-dated relative to the world population figures used). Using more up-to-date (all for 2016) figures (latest Global Carbon Project figures are for 2016) drops the results to to 4% to 6%.
However, such analysis does lead to the question - Where does the 55kg/head/yr or 90kg/head/yr of carbon required for such breathed CO2 come from? Of course, the source is our food which has, as a primary source of carbon, that obtained through vegitable photosynthesis, which in turn gains carbon from atmospheric CO2.
The one remaining question relating to human respiration as a contributor to atmospheric CO2 levels would be whether there are carbon pools that have diminished because of that increased cycling of carbon (atmosphere > plants > food > humans > atmosphere). There are more humans with an 18½% carbon content (or 11½kg per head). That would suggest that the rise in human population over recent years (80M/yr) would be sequestering carbon equal to 0.008% of our global FF+LUC CO2 emissions. There is also more plants/food within the cycle but this increase probably sequesters far less carbon than the releases from the land being 'cleared' for agriculture which is responsible for 11% of our CO2 emissions.
I thus can find no dimishing pool of carbon that is not being accounted within the calculations of human CO2 emissions, or for that matter any significant increasing pool of carbon.
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nigelj at 05:01 AM on 8 October 20182018 SkS Weekly Climate Change & Global Warming News Roundup #40
Driving By
"making passenger cars more complex and shrink-wrapped around the mechanicals, so people in the US fled from them. Leading to b2) a plauge of crossovers (that's most vehicles now marketed as SUVs), which are basically the old station wagon but taller and less efficient than they simply squaring/stretching a car into wagon form."
I would think the popularity of SUV's is more likely to be caused by a sense that these larger cars are safer, good visibility, interior space, and off road appeal and they have bcome status symbols.
I have a small car shrink wrapped about complex mechanicals that are somewhat baffling to look at, but its japanese and never breaks down. I doubt that the complexity issue worries most buyers. SUV's are now packed with electronic complexity anyway.
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John Hartz at 01:10 AM on 8 October 20182018 SkS Weekly Climate Change & Global Warming News Roundup #40
DrivingBy: You wrote:
It would be better to trash CAFE and have a carbon tax, but that's not going to happen.
CAFE standards and a carbon tax are not mutual exclusive mechanisms to reduce carbon emissions. There is absolutely no need to pit one against the other. Neither one is a silver bullet. Both are silver buckshot.
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John Hartz at 01:04 AM on 8 October 20182018 SkS Weekly Climate Change & Global Warming News Roundup #40
DrivingBy:
Your assertion that CAFE standards caused the shift in the US auto/light truck market to shift from small fuel efficient vehicles to SUVs and larger pickup trucks is patently absurd. If that were the case, the motor vehicle manufacturers would be pounding on the door demanding even stricter CAFE standards. In reality, they are doing just the opposite.
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John Hartz at 23:51 PM on 7 October 20182018 SkS Weekly Climate Change & Global Warming News Roundup #40
DrivingBy:
CAFE standards did not cause and accelerate urban sprawl in the US. There is no factual basis for this assertion.
For factual information about CAFE standards in the US, see:
A Brief History of U.S. Fuel Efficiency Standards, Union of Concerned Scientists, Last revised date: December 6, 2017
For factual information about urban sprawl in the US, see:
The Characteristics, Causes, and Consequences of Sprawling Development Patterns in the United States by Samuel Brody (Director, Institute for Sustainable Coastal Communities, Texas A&M University) © 2013 Nature Education
Citation: Brody, S. (2013) The Characteristics, Causes, and Consequences of Sprawling Development Patterns in the United States. Nature Education Knowledge 4(5):2
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Lasterday at 23:08 PM on 7 October 2018Breathing contributes to CO2 buildup
As a chemical engineer I feel it's misdirection to talk about the carbon cycle and say that an increase in human resperation does not add to atmospheric CO2. It may turn out to be a trivial amount, I'd have to find some numbers to guage it, but this post is meant to give a little background.
If all the carbon on earth were solid carbon and suddenly you changed it all to gaseous CO2 (this can't actually happen according to the gas law) and did this back and forth and back and forth according to the "carbon cycle" argument since there's no change in net carbon we are supposed to ignore atmospheric carbon going from nonexistant to "lots" and back again. "Hey - the cabon cycle is balanced." If more CO2 is put into the atmosphere from breathing the "cycle" itself gets bigger, the partial pressure of CO2 increases. Since biomass is a scrubber of CO2 (plants eat CO2) then there could be a net effect if the additional CO2 isn't eaten by plants. That's the issue. So to me, whipping out the carbon cycle doesn't make a whole lot of sense. My quick take is figure the volume of the atmosphere and the CO2 percentage and get that amount (huge # of moles) and then figure the amount in the resperation of 8 billion more people and see if the CO2 exaled from people is of the same order of atmospheric CO2. And keeping in mind that everything is an estimate - we don't know how many moles of carbon or anything else are on Earth. We don't know the exact volume of the atmosphere - they are estimates.
It may not factor in, but saying "the carbon cycle accounts for more breathing" is misdirection, it is just saying the net amount of carbon on Earth is staying the same, and that's not what the issue is. The net amount of gold on Earth is staying the same, too. Everything is - excepting new material from meterites and junk we send away in rockets that reaches outer space. We should be arguing about the partial pressure of CO2 in the atmosphere.
'Ol Wikepedia says this "The oceans of the world have absorbed almost half of the CO2 emitted by humans from the burning of fossil fuels." It's like soda pop - if the ocean warms slightly, CO2 is released into the atmosphere increasing the partial pressure of CO2. Since the CO2 level seems to be cyclic
https://climate.nasa.gov/climate_resources/24/graphic-the-relentless-rise-of-carbon-dioxide/
perhaps periodic ocean warming is the culprit. People argue that the older peaks are not as high as the current peaks, but remember the latest data is from direct measurement, the older values are taken from ice core samples and perhaps while the samples show higher CO2 values the peaks are lost from gas loses at the sample boundries, handling issues, etc.
Of course, industrial CO2 factors in. Let's run some real numbers!
Moderator Response:[DB] "the CO2 level seems to be cyclic"
CO2 levels in the past were driven by known natural factors. None of those factors are in play during the recent increase in atmospheric concentration of CO2. The human forcing is now the largest forcing, dwarfing all natural forcings, including that from the sun itself.
"perhaps periodic ocean warming is the culprit"
Not so. Please read this post. The oceans are a net sink of CO2 released by human activities, which is why they are still acidifying.
The 18-part 'OA is NOT OK' series, written by subject matter experts in that field, as summarized in Parts 1 and Part 2 is a worthy study.
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MA Rodger at 20:27 PM on 7 October 2018Venus doesn't have a runaway greenhouse effect
JC @248,
You say that "CO2 alone has a very low GH-effect." And the only place where we find what is effectively "CO2 alone" is the 6mbar atmosphere of Mars which provides something like a 12Wm^-2 GH-effect. The usual-reported calculations put the 0.6mbar CO2 contribution to Earth's GH-effect as being 25%, perhaps 40Wm^-2, this the GH-effect if all other GHGs were taken from the atmosphere. But that CO2 would still sit within 800mbar of N2 and 200mbar of O2. You may have a problem with this situation. Science does not. (Consider, the Mercedes F1 W09 EQ Power+ has a 1.6litre engine yet can travel at speeds more than three-times that of a Mercedes OM 501 LA-541 which has a 12litre engine. To borrow your incredulity for a second time, "Where's the logic in that?")
As for data being ignored, the publications of ELR Ladurie are not ignored, although the origin of the graphic you present up-thread @241 remains a complete mystery. The data examined by Beck (2007) or Beck (2008) is not ignored although it may be dismissed as irrelevant. What is ignored is the papers written by Beck because they are nonsense and unscientific. Beck agrees his analysis is ignored "The scientific community still ignore the above-cited critics," he says. But isn't that because Beck ignores all the real science, the stuff that shows he is spouting nonsense. He may feel that such a conclusion is "unjustified" but he does nothing to support his claim of injustice. Again he is unscientific! -
JC16932 at 18:27 PM on 7 October 2018Venus doesn't have a runaway greenhouse effect
To ignore certain data (Leroy Ladurie and Beck for example) is not science. Science must take into account all available data. Vostoc's data have also been criticized.
Moreover, when science uses the deductive method, the initial hypothesis becomes an explanation only when the model works perfectly. This is not yet the case in climatology. Also the hypothesis remains a hypothesis.
I am not trying to invalidate the greenhouse effect but to understand how 7000 times more CO2 in the atmosphere of Mars compared to the Earth can not even heat the planet by at least 26 W / m2. The answer given above to this question is remains very imprecise and implies that CO2 alone (without the water vapor gene) actually has a very low greenhouse effect.
Moderator Response:[DB] "The answer given above to this question is remains very imprecise and implies that CO2 alone (without the water vapor gene) actually has a very low greenhouse effect"
CO2 levels in the past were driven by known natural factors. None of those factors are in play during the recent increase in atmospheric concentration of CO2. The human forcing is now the largest forcing, dwarfing all natural forcings, including that from the sun itself.
Please remain on-topic to the nature of the OP of the post on which you place comments. Thousands of posts exist on this venue, on every topic related to climate science you can think of. Use the Search function present in the UL of every page or learn to use the Taxonomy listing of the site.
Please note that posting comments here at SkS is a privilege, not a right. This privilege can be rescinded if the posting individual treats adherence to the Comments Policy as optional, rather than the mandatory condition of participating in this online forum.
Please take the time to review the policy and ensure future comments are in full compliance with it. Thanks for your understanding and compliance in this matter.
Sloganeering snipped.
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DrivingBy at 12:46 PM on 7 October 20182018 SkS Weekly Climate Change & Global Warming News Roundup #40
They are actually correct about one thing: CAFE is a poor way of reducing fossil fuel use. Two of its major effects were
a1) Making very efficient small and medium cars cheap and common, which lead to a2) building subdivisions further out from employment centers. You have to drive -everywhere- in those exurbs, not just to work, and it's all single family houses.
b) making passenger cars more complex and shrink-wrapped around the mechanicals, so people in the US fled from them. Leading to b2) a plauge of crossovers (that's most vehicles now marketed as SUVs), which are basically the old station wagon but taller and less efficient than they simply squaring/stretching a car into wagon form.
Another effect is that there are no more small pickups. Today you can have huge or almost huge pickups but there's no CAFE category that fits small or medium trucklets.
It would be better to trash CAFE and have a carbon tax, but that's not going to happen.
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John Hartz at 08:42 AM on 7 October 20182018 SkS Weekly Climate Change & Global Warming News Roundup #40
Sunspot: At this juncture, we do not know who was responsible for ginning up the draft EIS for the NHSTA. I suspect it was not a qualified climate scientist.
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John Hartz at 08:40 AM on 7 October 20182018 SkS Weekly Climate Change & Global Warming News Roundup #40
Nigelj: With all due respect, I believe that you are grasping at straws. The corporate sector has not convinced the Pretend President and his minions that geo-engineering is the solution to man-made climate change. The Trumpies reject climate science on political and/or religious ideological grounds. Whoever ginned-up the draft EIS for the NHSTA is probably in deep dodo. If they are not, they certainly should be.
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earth'n at 06:55 AM on 7 October 2018Ivar Giaever - Nobel Winning Physicist and Climate Pseudoscientist
In 1968, the spring where we had gathered drinking water and cress was tested and found to be unpotable. I knew then, at age 8 that the earth was ill. As I floated rivers, hiked valleys and mountains and looked down from airplanes, I have witnessed the destruction of the earth. I wonder if Giaever ever set foot outside his lab.
Maybe don't fixate on "Warming" afterall it is just one symptom of what we are doing. Anyone does not have to be a scientist to be conscious and aware and mindful of physical manifestation of pollution and of factual data accurately presented.
I'm guessing he is a sad lonely man.
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Philippe Chantreau at 06:35 AM on 7 October 2018Venus doesn't have a runaway greenhouse effect
http://www.realclimate.org/index.php/archives/2007/05/beck-to-the-future/
Georg Beck is known to have publicized a graph with a discontinuity in the x axis and a change in time scale that was downright laughable, he was not a credible source at all. Beck's nonsense has been debunked multiple times, years ago.
You need to choose your sources more carefully. It seems you're getting all your information from propagandists instead of looking in the litterature. You do not specifiy who the IPCC author you cite is and the date of the report. Cherry picking 1998 as a starting date is an obvious indication that one is trying to misrepresent the trend. 1998 saw a massive El-Nino and is obviously the worst possible choice for the start of any trend calculation, as would be a strong La-Nina year. Whenever I see a "trend" starting in 1998, I know that someone is trying to fool me and the alarm bells start ringing. The insistence by deniers to pick 1998 and their lack of mention of the corresponding El-Nino is the main reason why the so-called pause has no credibility. Start on any other year and the pause disappears. In the case of your citation, extend the period beyond 2012 to include 2017 and the trend is higher than ever. As was pointed above, there is no "current drop" in temperature. Attempting to argue with a pseudo trend that ended in 2012 does not help your case when there are 5 more years of data.
Let's summarize your contribution: you started with attempting to correlate a supposedly stagnant level of water vapor in the stratosphere (which is, in fact, increasing) with supposedly stagnant temperatures, which all sources show to be increasing as of 2017, regardless of the start year (yes, even if you cherry pick 1998, it no longer works). If you had even a superficial understanding of the seminal Iacono and Clough 1995 paper, you would have seen that water vapor (and other GH gasses) in the stratosphere contribute, in fact, to stratospheric cooling and have little influence on tropospheric temperatures.
Nonetheless, this was part of a rather pitiful effort to try to invalidate the greenhouse effect altogether, with "calculations' that were worthless; as was quickly pointed to you, you were nowhere near close to understand what you were talking about and ignorant of a large body of scientific research and litterature that you later, indirectly, confessed to be over your head. Just to be clear as to the validity of the MODTRAN model: that's what they use to ensure that IR guided weapons go where they're supposed to go. It works.
You did not have the decency to acknowledge any of these shortcomings in your argument, or the arrogance of the wide ranging pronouncements you made before the extent of your incompetence on the subject was revealed.
Instead, you moved on to what you thought were new things, bringing in something you considered to be paleo data evidence. Once again, there is far more about this than you suspected and that was pointed to you but, once again, you could not acknowledge how weak your argument was.
You are free to have whatever opinion you choose. Considering the level of ignorance and lack of understanding that you have shown in this thread post after post, it is obvious that your opinion is worthless and I am also free to point that out. Opinions do not have validity by virtue of their existence. Some people hold the opinion that the Earth is flat; their opinion has no value.
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Sunspot at 06:19 AM on 7 October 20182018 SkS Weekly Climate Change & Global Warming News Roundup #40
My first reaction is, why are we suddenly taking climate information from the NHTSA as gospel? 4 degrees C by 2100 is a little high for most current "official" estimates I believe. And because one agency makes a statement like that, how is this suddenly the official position of the entire administration? But, as I will point out again, we already know that enough feedbacks have kicked in that it is likely pointless to mitigate what we are doing, it doesn't matter anymore. Not that we are trying anyway! I'm afraid 4 degrees C by 2100 is still too optimistic. Here in Concord NH it has averaged 4-5 degrees F above average since at least July, and it going to stay way above average for at least a few more weeks. At what point do we recognize that Abrupt Climate Change is here? (just wondering)
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michael sweet at 06:13 AM on 7 October 2018Venus doesn't have a runaway greenhouse effect
JC,
Can you provide a citation for your claim that "Georg Beck compiled data on the 19th century". What is your point?
If you do not provide a citation to support your claims they have little meaning.
Your claim about the GIEC has been addressed upthread. To summarize:
- 15 years is too short a time period to determine a trend.
- The "hiatus" trend was never statistically significant.
- The data has been updated which increased the trend over the time period you specified.
- The four hottest years in the record are 2014, 2015, 2016 and 2017. Adding these points to the data show that there was no "hiatus" in the trend.
- 2018 is currently the 4th hottest year in the record. The most recent 5 years are the hottest 5 years in the record.
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JC16932 at 05:33 AM on 7 October 2018Venus doesn't have a runaway greenhouse effect
I am French and I have very bad english. Concerning the hiatus, we do not have the same references, I understood that there are two groups that do not have the same reading of the data. Anyway the Giec says in chapter 9 page 769:
"The observed global mean surface temperature (GMST) has been shown to increase in popularity over the past 15 years over the past 30 to 60 years (Section 2.4.3, Figure 2.20, Table 2.7, Figure 9.8, Box 9.2 Figure 1a, c). Depending on the observational
data set, the GMST trend over 1998-2012 is estimated to be one-third to one-half of the trend over 1951-2012 (Section 2.4.3, Table 2.7; Box 9.2 Figure 1a, c). For example, in HadCRUT4 the trend is 0.04ºC per decade over 1998-2012, compared to 0.11ºC per
decade over 1951-2012 ".As for the current catastrophism, I find it exaggerated.
For the greenhouse effect, I understand the principle, the problem is to measure the impact of CO2 on temperature (and in particular the amount of CO2 released by humans). Georg Beck compiled data on the 19th century with high CO2 levels measured during the early ice age !
Moderator Response:[DB] "Concerning the hiatus"
Please understand that the "hiatus" was a discussion of the seeming slowdown in the rate of warming in a small portion of where the Earth stores energy, in its surface. In reality, the vast majority of energy stored in the Earth system is found in the oceans. The oceans continue to warm, unabated, unpaused and unhiatused (2017 was the warmest year on record for the ocean):
And surface warming also continues unabated, as shown by NASA (132-month smooth applied to reduce the noise, allowing the underlying signal to be more readily shown):
"Georg Beck compiled data on the 19th century with high CO2 levels measured during the early ice age !"
Beck's work has been amply shown to be in error, as has been pointed out to you (but which you have ignored). Future references to such will be deleted unless you can furnish credible evidence to support your contentions.
Atmospheric CO2 levels have been extensively studied and numerous converging lines of evidence show the recent rise in atmospheric concentrations of such to be anomalous over every timescale relevant to humans, whether the last 1,000 years, the last 10,000 years or even the last 800,000 years.
Please stay on-topic.
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nigelj at 04:58 AM on 7 October 20182018 SkS Weekly Climate Change & Global Warming News Roundup #40
Perhaps the reason for complacency in the Trump Administration over climate change is the corporate sector have convinced them that geo engineering or direct carbon capture would fix the problem, (probably with the costs dumped on the population, and the profits going to the corporate sector). The costs and risks of such schemes are huge, and its a disastrous solution especially as we will run out of fossil fuels anyway.
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Philippe Chantreau at 04:23 AM on 7 October 2018Venus doesn't have a runaway greenhouse effect
Proper statistical analysis in the following paper:
That paper predates the multi year streak or record setting from 2014 on. The idea that there is a slow down in warming is unsupported by any data, even the satellite series that include a large stratospheric influence.
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Philippe Chantreau at 23:38 PM on 6 October 2018Venus doesn't have a runaway greenhouse effect
There isn't and never was a hiatus. This has become a point because you attempted to make an argument about it, argument that was completely debunked right away because no part of it had any validity. "Visible" means nothing in the absence of real statistical analysis. Such analysis has been done and shows that there is no significant change in the long term trend. There is no current drop in temperature either. If you are trying to suggest that every year should be higher than the previous one in order to show a upward trend you are going to reveal that you are arguing in bad faith and should be ignored. What is happening now is similar to what happened after the massive El-Nino of 1998, when temperatures settled toward a baseline that was nowhere near where they were before the El-Nino, then continued increasing through natural variability.
I am not climate scientist or physicist either but I can read. The greenhouse effect is not that difficult to understand at all on its principle:
https://en.wikipedia.org/wiki/Greenhouse_effect
As fas as I know, Ladurie is not a prominent voice in paleo climate circles. The weight of the evidence in that area suggests that we were in a long term cooling trend that was interrupted by the massive injection of radiatively active gasses in the atmosphere. There is plenty of info on that, do your homework yourself.
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MA Rodger at 22:40 PM on 6 October 2018Venus doesn't have a runaway greenhouse effect
JC @241,
I appreciate you have a language barrier to leap with your contributions here. Yet you should appreciate that presenting a link to an illustration of unknown origin on a scientific web-site is not the done thing. Do we assume this diagram (pasted below) is somehow from historian Emmanuel Le Roy Ladurie? Is it just based on snow & ice or does it also involve the analysis of Grape Harvest Dates which ELR Ladurie has analysed for French regional harvests & more widely? (It is interesting that using Grape Harvest Dates as proxies for temperature has suffered correlation issues as "climate change has fundamentally altered the climatic drivers of early wine grape harvests in France", a bit like the famous "decline" problem faced by proxy tree ring reconstructions.)
Perhaps with the language barrier, your problems understanding why there is no simple relationship between levels of CO2 and the resulting GH-effects could stand further description of the workings of CO2.
CO2 does not provide a planet with a full suit of winter clothes. On its own, CO2 provides only hat and gloves. And if you venture out into the "neiges hivemales" wearing only hat and gloves, you will likely freeze to death by morning. It doesn't matter how thick and woolly the hat and gloves are: you will freeze. Venus without its H2O & SO2 would be very-much colder than it actually is. Likewise Earth without its H2O, but on Earth it is the CO2 that raises temperatures to the point where H2O melts and evapourates into the atmosphere. No CO2, then no atmospheric H2O and the Earth freezes.
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JC16932 at 17:55 PM on 6 October 2018Venus doesn't have a runaway greenhouse effect
I seek explanations figures on the 3 planets from a universal law of the greenhouse effect. For the moment I only read studies for each planet as if we could isolate the greenhouse effect of CO2 and unify its effects. However, CO2 must react well to energy wherever it is and heat accordingly.
I am also a scientist (but not a climatologist or physicist) and the greenhouse effect does not seem clear to me at all, moreover no one can explain it simply. We are dealing with vague explanations.
As for the hiatus, it is visible, as is the current drop in global T °. But that's not the subject of this discussion.
As far as I am concerned, and in agreement with the studies of Leroy Ladurie, I realize that the current phase of warming follows the regularity of the last four thousand years.
Thank you for all the documents on the greenhouse effect, that's what I'm looking for. I would read them carefully. Thanks again.
Moderator Response:[DB] Activated image link. It works easiest to use the insert image tool instead of using html.
"the current drop in global T °"
There is no current change in the upward trend in global temperatures:
"the current phase of warming follows the regularity of the last four thousand years"
Multiple studies have shown the recent warming to be anomalous, regardless of the context of the time period involved, whether over the past 1,700 years, the past 10,000 years or even the past 22,000 years (below).
Thousands of posts on this site exist to edify the reader. Of particular relevance to your statements made in this comment can be found here, here, here and here.
A breakdown of skeptic arguments and the subsequent evaluation of them can be found here.
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Philippe Chantreau at 03:50 AM on 6 October 2018Venus doesn't have a runaway greenhouse effect
JC @ 230:
I don't see anything to add to MA Rodger's remarks, which also link to appropriate litterature. The pause-that-never-was is the only way to call this imaginary phenomenon. Who in their right mind would have expected a neutral/La Nina year to be warmer than a major El-Nino year after less than 20 years? That's the kind of warming we're seeing. and the answer is: scientists who study this stuff would have expected that, they even projected it in scientific papers.
The same kind of people who published the studies that have been linked in this thread to try to point you in the right direction, the kind that really knows what they're talking about. Perhaps you should accept the fact that there is nore to this body of knowledge than your back of the enveloppe calculations.
JC @ 237 "It would require a greenhouse effect theory that takes into account the exact amount of molecules and the available IR energy supported by these molecules."
As with the water vapor thing, it's only your ignorance that makes you think it is not the case. If you had any interest in learning about what's out there before trying to make a point, you would have started here: http://modtran.spectral.com/
And would have found this: http://web.gps.caltech.edu/~vijay/pdf/modrept.pdf
And, since you were concerned about water vapor, you could also have looked at this: http://climatemodels.uchicago.edu/modtran/
All of which are far more interesting than your "calculations." MODTRAN models atmospheric IR radiation at all altitudes quite well, and has been validated against measurements in multiple studies. In case you hold ideological or tribal hang outs that prevent you from trusting the "other camp" sources, be aware than the US Air Force is a major developper of these models, has copyrighted the name and holds several patents on it.
"Reality is that which exists whether we believe in it or not."
Moderator Response:[PS] "Quite well" would be more accurately stated as "with exquisite accuracy". As to accounting for all molecules, then please see Ramanathan and Coakley 1978 . Arguments from personal incredulity dont cut it here, especially where the real science is confirmed by experimental evidence.
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knaugle at 03:06 AM on 6 October 2018New research shows the world’s ice is doing something not seen before
#1
"The Arctic" as well is not just the Arctic Ocean. If one includes only that part of the Earth above the Arctic Circle, it also includes most of Greenland as well as the large Islands of Northern Canada, Victoria, Baffin and others. There is a LOT of land ice there.
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MA Rodger at 00:54 AM on 6 October 2018Venus doesn't have a runaway greenhouse effect
JC @236/237,
I concur with michael sweet @238.
Do note that the calculations required to determine GH-effects are complex. See for instance Postawko & Kuhn (1986) 'Effect of the greenhouse gases (CO 2 , H 2 O, SO 2 ) on Martian paleoclimate' which is a reasonably simple example of such analyses.
Also note Fig2 in that paper which represents today's Mars and Fig3 which sows the effect of having a 1,000mbar CO2 atmosphere instead of today's 6mbar CO2 atmosphere. The result is a warming of some 30K requiring an additional GH-effect of some 80Wm^-2 (additional to today's GH-effect which is some 12Wm^-2), the increased CO2 requiring the atmospheric CO2 content to rise from 2e16kg to 361e16kg.
Are you happy with these figures? If not we can perhaps try a different approach.
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michael sweet at 00:07 AM on 6 October 2018Venus doesn't have a runaway greenhouse effect
JC,
But greenhouse theory does take into account the exact amount of molecules and the IR energy uspported by those molecules.
On Mars there is a smaller greenhouse effect because the atmosphere is so thin. Even so, Mars is about 10C higher in temperature from the greenhouse effect. Because the atmosphere is so thin and there is no water vapor, the height in the atmsophere where the IR energy can escape is much lower than it is on Earth. That makes the greenhouse effect less on Mars.
Just because you do not understand the greenhouse effect that does not mean that scientists do not understand it. Greenhouse models describe the temperature of Earth, Mars and Venus with great accuracy. You have just not looked for the data.
You have provided only your own error filled calculations to support your wild claims. Why should I believe a person whyo cannot even keep track of obvious errors like saying the CO2 in the Mars atmosphere weighs more than the entire atmosphere?
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JC16932 at 23:10 PM on 5 October 2018Venus doesn't have a runaway greenhouse effect
It would require a greenhouse effect theory that takes into account the exact amount of molecules and the available IR energy supported by these molecules.
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JC16932 at 23:00 PM on 5 October 2018Venus doesn't have a runaway greenhouse effect
I correct. I made a unit error at the end of my calculation. Thank you :
The mass of the atmosphere of March = 25.10 ^ 15 Kg
865.87 g of CO2 for 1 kg of atmosphere
So 865.87 x 25.10 ^ 15 = 2.165.10 ^ 19 g of CO2 in the atmosphere of Mars = 2.165.10 ^ 16 kgTo summarize: The amount of CO2 (Kg) in the total atmosphere of each planet and its greenhouse effect (GHE) :
Venus : 4.72.10 ^ 20 Kg - GHE : 13870.15 W/m2 (+430°C)
Earth : 3.128.10 ^ 15 Kg - GHE : 26 W/m2
Mars : 2.165.10 ^ 16 kg - GHE : 0 W/m2 !!!!!!!!!
But there is always more amount of CO2 in the matter atmosphere (x 6.9) than in the Earth.
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MA Rodger at 22:47 PM on 5 October 2018Venus doesn't have a runaway greenhouse effect
JC @234,
I think you demonstrate the problem we face with the discussion you bring here. How can a substance comprising 97.8% by weight of the Martian atmosphere weigh 2.165e19kg/2.5e16kg = 3800% of that atmosphere? To throw your own incredulity back in your face (and unlike yours, mine is well founded incredulity) "Where is the logic ?"
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JC16932 at 22:03 PM on 5 October 2018Venus doesn't have a runaway greenhouse effect
Ma Rodger : "NASA give the total weight of the Martian atmosphere as ~2.5e16kg suggesting a CO2 content of ~2.4e16kg, a ration of 7.7 to 1.0"
2.5e16kg That's the value I use.
But you made a miscalculation : 96% is the proportion in volume and not in mass. I want the real amount of CO2 (in kg or in mole) which explains my calculation :In 2.5e16kg of Martian atmosphere, there is 2.165.10 ^ 19 Kg of CO2 (or 7000 times more kg of CO2 than in the atmosphere of the Earth).
The greenhouse effect of Mars is close to zero.
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MA Rodger at 21:24 PM on 5 October 2018Venus doesn't have a runaway greenhouse effect
JC @232,
You appear to be using misconceptions of the operation of GHG on other planets to argue that CO2 is not driving climate change. I think that makes you commenting off-topic.
But to continue awhile here, there is no disagreement that Mars has a higher pressure of CO2 in its atmosphere (6.0mbar) than there is in Earth's atmosphere (0.6mbar) although you calculation is overly-complicated and wrong to suggest the atmospheric CO2 content on Mars is 2.165e19kg or 7,000-times greater than the value for Earth. The ratio will be less than the 10:1 ratio of CO2 pressures as Mars is a smaller planet. (NASA give the total weight of the Martian atmosphere as ~2.5e16kg suggesting a CO2 content of ~2.4e16kg, a ration of 7.7 to 1.0.)
Also, the impact of GHGs on the Martian surface temperature is small but it is not zero as your "GHE : 0 W/m2 !!!!!!!!!" implies. How do you obtain the zero value?
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JC16932 at 19:55 PM on 5 October 2018Venus doesn't have a runaway greenhouse effect
On Mars :
95.32 m3 of CO2 in 100 m3 of atmosphere.
PV = nRT
n = (685.4 Pa x 95.32 m3) / (8.314 x 210.15 ° K)
n = 37.39 mol of CO2 in 100 m3 of atmosphere44 g of CO2 per 1 mol
So 37.39 mol = 1645.16 g of CO2 in 100 m3 of atmosphereThe density of Mars atmosphere = 1.9 Kg / 100 m3
We have 1645.16 g of CO2 for 1.9 kg of atmosphere
So 1645.16 / 1.9 = 865.87 g of CO2 per 1 kg of atmosphereThe mass of the atmosphere of March = 25.10 ^ 15 Kg
865.87 g of CO2 for 1 kg of atmosphere
So 865.87 x 25.10 ^ 15 = 2.165.10 ^ 19 Kg of CO2 in the atmosphere of Mars.To summarize: The amount of CO2 (Kg) in the total atmosphere of each planet and its greenhouse effect (GHE) :
Venus : 4.72.10 ^ 20 Kg - GHE : 13870.15 W/m2 (+430°C)
Earth : 3.128.10 ^ 15 Kg - GHE : 26 W/m2
Mars : 2.165.10 ^ 19 Kg - GHE : 0 W/m2 !!!!!!!!!
Where is the logic ?
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MA Rodger at 18:59 PM on 5 October 2018Venus doesn't have a runaway greenhouse effect
JC @230.
"The giec" is usually known by its English acronym 'IPCC' and indeed the IPCC AR5 Technical Summary does include Box TS.3 'Climate Models and the Hiatus in Global Mean Surface Warming of the Past 15 Years.' This analysis dates to 2013 and thus predates Karl et al (2015) which rattled a number of 'artifacts' from the global surface temperature record and with it became an undeniable 'pause-buster' in the eyes of AGW-denying contrarians. And Box TS.3 will obviously not have been able to include in its analysis the last five years of global surface temperature (2014-18) which will soon become shown to comprise each of the warmest five years on record. Thus, if there were (as asserted by JC @222) some "stagnation of steam from 2000 to presently," it would not provide a "correlation" with global surface temperature which has been far from stagnant since 2000.
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JC16932 at 18:24 PM on 5 October 2018Venus doesn't have a runaway greenhouse effect
Philippe Chantreau : "Once again, I note that JC does not dispute the fact that, unlike what his (her)previous claim suggested, global temperatures have not been stagnant since 2000".
Yet this is called hiatus in the last report of the giec !
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nigelj at 12:45 PM on 5 October 20182018 SkS Weekly Climate Change & Global Warming News Roundup #39
scaddenp @28, yes Geoff Robinson was commendably neutral, another recent example might be Patrick Gower.
I think whats happened in America is climate change has been identified as a left wing thing, possibly due to Al Gores book and so has become rather tribal.
But it also looks like conservatives in business are particularly sceptical so lets explore this. I think MFT is pretty convincing but only part of the story. I've read plenty of articles in reputable magazines that conservatives and liberals are born that way and have different characteristics that go beyond MFT although the evidence suggests characteristics are not rigidly fixed either. Conservatives are more sceptical of change and big government (because it represents change in some ways?) and this is unfortunate because it's hard to effectively resolve the climate problem without some government input.
The climate problem is basically a consumption problem, and tragedy of the commons problem. I would contend to solve this on the basis of individual initiative alone would be far too slow, if it would work at all, hence the need for things like carbon tax and dividend, or regulations etcetera, yet these are an anathema to conservatives who prefer private sector initiatives. But they are simply wrong on this one, and I guess the thing is to convince them without telling them they are wrong as such or demonising them or playing the blame game That has been my position.
A lot of this comes back to Democrats. They are not perfect and need to own the climate issue more, and this will propel Republicans to make a response, a point argued some time back.
It's a complicated beast of an issue with a lot of things going on. Government can help change behaviour and build electricity grids but they can't make individuals completely change their behaviour in democratic societies. The issue is in all of our hands.
A few people in power like the Koch Brothers have far too much influence and are just plain destructive and self centred, lets call it for what it is, but its important not to demonise all wealthy people or conservative wealthy people. Many are the complete opposite. And even if their influence was removed it would not completely resolve the climate issue.
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scaddenp at 08:58 AM on 5 October 20182018 SkS Weekly Climate Change & Global Warming News Roundup #39
And a further thought, how effective do think lecturing someone on their lack of altruism is going to be when in fact climate denial is rooted in identity ("that is what my tribe believes") and authority ("the authorities I trust says its a hoax")?
I value crusading for climate change and have no doubt about your intellectual grunt in advocating for the planet. I do however think you are operating from misconceptions about motivations and which is limiting your ability to communicate effectively.
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scaddenp at 08:16 AM on 5 October 20182018 SkS Weekly Climate Change & Global Warming News Roundup #39
"The 'polarization' of political opinion can be understood to be largely due to a portion of the population choosing not to engage in, being able to avoid or evade, altruistically evaluating their intuitive desires and beliefs and correcting their opinions accordingly."
I strongly disagree - this is just demonizing the opposition and completely at odds with published literature on causes of political polarization. Even a cursory glance at the literature will supply better models.
Altruism is alive and well in Trump-supporting, climate-denying citizens often to degrees much higher than in liberal climate-change action supporters. I do not think your model has empirical support whereas better models (eg MFT) do.
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Philippe Chantreau at 06:51 AM on 5 October 2018Venus doesn't have a runaway greenhouse effect
Once again, I note that JC does not dispute the fact that, unlike what his (her)previous claim suggested, global temperatures have not been stagnant since 2000.
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michael sweet at 06:42 AM on 5 October 2018Venus doesn't have a runaway greenhouse effect
JC,
Reading the OP I noticed this sentence:
"In the dense Venusian CO2 atmosphere, pressure broadening from collisions and the presence of a large number of absorption features unimportant on modern Earth can come into play (figure 1b), which means quick and dirty attempts by Goddard to extrapolate the logarithmic dependence between CO2 and radiative forcing make little sense."
This states that both our calculations cannnot be made because the atmosphere on Venus to too different from that of Earth for this simple extrapolation. It apears that Goddard is the originator of this malarky. Since the OP was written in 2011, it has been known since at least then that your source of information is incorrect.
I suggest that you read more background information and come back when you have questions. If you continue to read Goddard you will never understand what is happening. Read more of the posts here at Skeptical Science and you will begin to understand the process of AGW.
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michael sweet at 06:33 AM on 5 October 2018Venus doesn't have a runaway greenhouse effect
JC,
I am sorry, I do not have enough time to search the internet to find the correct calculation for you. It is your responsibility to cite correct calculations to support your claims. As I stated, the most likely error in my calculations is that your unsupported value for Venus is too high.
I have shown that your calculation of the forcing from CO2 on Earth, using data from Venus, is incorrect. Now you have provided the value of 26 W/m2 which seems reasonable to me. You challange that value without providing any supporting data. The value you originally calculated at comment 219 of 0.092 W/m2 is clearly completely incorrect. My estimate of 322 W/m2 is closer to the value of 26 W/m2 you now propose, and I pointed out that my estimate had an error in it. The albeido must be considered. If the albeido was 100% the surface would be frozen no matter how much CO2 there was.
If you do not know how to do the calculation you must withdraw your wild claims. You have provided no citation of someone who knows how to do this calculation and you do not know how to do it. You are making an argument from ignorance. Scientists figured this out over 100 years ago. Try to catch up.
Where did you find this false information so I can read what the original person wrote?
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william5331 at 05:29 AM on 5 October 2018How Arctic lakes accelerate permafrost carbon losses
The amount of organic material accumulated in the permafrost is indeed a threat but there may be an even more dangerous source of carbon that could be vented into the atmosphere. Permafrost varies from a few feet in the south of it's range to a few thousands of feet at it's most extreme. Undoubtedly, there are areas below the permafrost with deposits of shale, coal and liquid hydrocarbons. With the depression of the land due to ice sheets and the subsequent rebound cracking the layers of overburden, it is likely that they will be able to vent their methane upward. Unde normal circumstances, this would vent into the atmosphere, be oxidized and make it's contribution to the atmospheric Carbon dioxide. However if it hits a ceiling of permafrost the methane will combine with the water in the soil and form clathrates. The methane of thousands of years will be accumulating, ready to be released in a huge outpouring. The trouble will come when these thermokarst lakes melt through the permafrost layer and release the methane in the clathrates.
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JC16932 at 04:43 AM on 5 October 2018Venus doesn't have a runaway greenhouse effect
Michael Sweet : "Since the base 2 log of 150,000 is 17.2, you must divide the forcing on Vensus (13870 W.m2 according to you) by 17.2, not 150,000. That yields an estimated forcing on Earth of 806 w/m2. It does not take into accoount the vastly different albeido's of Venus and Earth (Earth has a much lower albeido than Venus about 0.3 and 0.75)".
But 806 W/m2 is not at all the value of the greenhouse effect of CO2 in the Earth's atmosphere (officially estimated at 26 W / m2 for 300 ppmv), so your calculation is not suitable ! In addition albedo does not intervene in the calculation of the greenhouse effect.
Science seems to be unable to have a universal theory of the greenhouse effect that is capable of explaining the T ° of Venus and the Earth. . As long as this point is not resolved how can one claim to predict radiative forcing ?
The amounts of CO2 (4.72.10 ^ 20 Kg of CO2 in the atmosphere of Venus, and 3.128.10 ^ 15 Kg for the Earth) were calculated taking into account the pressure and the temperature of each planet.
I do not see anywhere calculations taking into account the actual amount of CO2, which is still surprising because it is still the number of CO2 molecule that play a role in the power of the greenhouse effect.
Moderator Response:[DB] Sloganeering snipped. You cannot simply ignore the rebuttals of your argument. You have to use the math, physics and citations to credible sources to support your position. That's how things work in science-based venues such as this.
Failure to do so means you concede the points.
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One Planet Only Forever at 02:24 AM on 5 October 20182018 SkS Weekly Climate Change & Global Warming News Roundup #39
scaddenp,
The claims made and actions taken by people regarding climate science, including what type of political leadership they will vote for, are 'what they are'. Raising awareness and improving understanding regarding those behaviours, particularly focusing on the acceptability of the behaviours, is not 'polarizing'.
My commenting here is motivated by the evidence of the behaviour of people and the claims they make regarding climate science and the related corrections of developed human activity and fundamental beliefs regarding the acceptability of human activities.
The information on this site improves my awareness and understanding. And the feedback I get here helps me develop a more robust improved awareness and understanding.
Every human has the ability to altruistically examine reasons and use the result to change their mind about intuitive preferences they may have developed. The developed socioeconomic-political environment they are in can be understood to significantly influence how they develop their thinking.
The 'polarization' of political opinion can be understood to be largely due to a portion of the population choosing not to engage in, being able to avoid or evade, altruistically evaluating their intuitive desires and beliefs and correcting their opinions accordingly. That can happen on the left or the right. But the history of behaviour regarding climate science leaves little doubt which side is most resistant to altruistically improving their awareness and understanding of the corrections of developed human behaviour that are required to have a sustainable improving future for humanity.
I believe it is important to improve the awareness and understanding of the ability of everyone's modern human mind to make altruistic helpful larger worldview reasoning govern over primitive intuitive limited worldview self-interested temptations (How to be helpful, or at least not be harmful). I understand how much easier it is to appeal to Intuitive selfish perceptions that can be harmful or unhelpful.
My professional engineering career was based on constantly improving my awareness and understanding to be more helpful and less harmful, and never allowing popularity or profitability considerations to compromise the minimum standard of acceptability and encourage the achievement of higher than minimum levels of safety (risk of harm) and reduction of harm. (a related point: making it harder or more expensive to benefit from burning fossil fuels changes how people live or profit which 'disappoints' some people but does not 'harm' anyone. The less fortunate people still need assistance from the more fortunate. And assistance to poorer people that is contingent on more fortunate people getting away with burning more fossil fuel cheaper is not a sustainable way of helping the less fortunate.)
A major point made in “The Enigma of Reason” is that arguing (reason based discussion regarding an issue) is how we learn, because it requires reasoning to justify/confirm an Intuitive belief.
The evidence of behaviour regarding climate science indicates that many people will not engage in an argument/discussion to improve their awareness and understanding if they sense that they will likely be proven to have to change their mind, correct their Intuition based beliefs. To help the future of humanity it will almost certainly be necessary to externally govern and limit the freedom of those people until they learn to change their minds. A related example of resistance to behaving responsibly is the undeniable need to correct the thinking of people who Intuitively believe that their ability to be a safe driver is not compromised by driving faster, drinking alcohol, smoking pot, texting or similar compromises of their best effort to focus on helpfully driving responsibly safely. Those people need to be 'made to change their mind' to reduce the harm or risk of harm to others. And they may even need to have their permission to drive removed until they learn to correct their understanding and behave according to that improved corrected understanding.
I admit that pushing for everyone to be helpful can be 'too much for some people to take'. And being helpful is an aspiration not a minimum requirement. So the limit on acceptability is really the 'minimum' requirement regarding behaviour that 'no one should personally benefit from or enjoy an action that harms others or creates a risk of harm to others'. That is the fundamental ethical and moral basis for Professional Engineering (and medical professionals). It is also the basis for the creation and enforcement of laws. Any laws created that are contrary to that understanding (like the undoing of EPA restrictions related to fossil fuel activity) can be understood to be incorrect legal actions (the rule of law often requires correction, especially when popularity and profitability have been able to influence the making-up, or enforcement of the law).
The pursuers of benefit from burning fossil fuels have a long history of resisting limits on the harm done by their pursuits. The USA did not implement reduced sulphur content in diesel in step with the European improvements, and that lack of corrective action was popular. The technology to do it was not the issue. The issue was the relative competitive advantage of not doing it. Economic politics compromised the implementation of a technically viable reduction of harm from activity in the USA, and it was popular. (a related point is that the Europeans have resisted implementing recent stricter requirements to reduce NOx from diesels, including major car makers deliberately cheating the testing of their vehicles because they wanted to give the buyers the higher power and performance that can be achieved by not reducing the NOx, while appearing to be behaving better).
Applying the above stated minimum measure of acceptability to the human activities related to climate science awareness and understanding means that the burning of fossil fuels is simply unacceptable because it causes harmful consequences for others, particularly for future generations, no matter how regionally and temporarily popular or profitable other beliefs may be. And there are many other harmful consequences of the activity. It is also an activity that cannot be continued by future generations. The non-renewable resource gets more difficult to obtain benefit from. Even if it was simply a matter of the unsustainable consumption of a non-renewable it could be argued that it was harmful to future generations because it reduces the amount of resources, or makes it harder to access remaining resources they may be able to develop a sustainable benefit from (or use in a real emergency like an impending ice age that can have its impacts reduced by the deliberate burning of fossil fuels to create a helpful CO2 blanket).
Sticking with the minimum requirement to not harm others, the aspiration to limit the accumulated human impacts to 1.5C can be understood to already be a compromise of the minimum acceptable principle. And 2.0C impact is an even larger compromise of that understood minimum evaluation of acceptability.
Without an alignment of understanding regarding the minimum measure of acceptability, and the related understanding of the aspiration of the activity of all humans (to help develop a sustainable better future for a robust diversity of humanity), there is no way to discuss or debate or argue about the required actions. The people who do not accept the undeniable understanding of the measure of minimum acceptability of human actions will not understand why their unacceptable proposals are not being allowed to compromise the minimum threshold of acceptability.
I have tried to stick to the facts in the political portion of this comment. What is undeniable that altruism will align with acceptance of the minimum requirement of acceptable human behaviour and pursue the aspiration of helpfulness, and selfishness will do the opposite. And the evidence of which political groups most strongly resist improving awareness and understanding of the undeniable minimum and aspiration regarding acceptable human actions is becoming harder to deny because of the behaviours exhibited related to climate science. The facts of the matter show that people perceived to be on the Right are typically very wrong regarding climate science and the required corrections of what has developed. The required corrections include correcting undeniably unsustainable beliefs about what is acceptable.
Changing minds is hard work, especially when others can get away with misleading appeals to selfish interests. It is not helped by 'compromising improved awareness and understanding' with the preferred beliefs that some people have developed an unjustifiable liking for, no matter how popular or profitable such unjustifiable beliefs have become.
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michael sweet at 02:18 AM on 5 October 2018Venus doesn't have a runaway greenhouse effect
JC,
As MA Rodger pointed out, the relationship between CO2 concentration and climate forcing is logarithmic. Since the base 2 log of 150,000 is 17.2, you must divide the forcing on Vensus (13870 W.m2 according to you) by 17.2, not 150,000. That yields an estimated forcing on Earth of 806 w/m2. It does not take into accoount the vastly different albeido's of Venus and Earth (Earth has a much lower albeido than Venus about 0.3 and 0.75). Adjusting for albeido I get a CO2 forcing on Earth of 322 W/m2 which is a little high but much closer to the actual value than your number. Probably your value for Venus is too high.
There are obviously several gross errors in your calculations since you did not account for the logarithmic relationship to forcing or the albeido. There may be an error in my calculations, but it is better than yours. To eliminate errors we should only use peer reviewed data. Please cite a peer reivewed source to support your wild claim.
It appears to me that you have simply copied the analysis of some denier who does not know how to do the calculations. Can you tell us where you obtained this argument?
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MA Rodger at 19:11 PM on 4 October 2018Venus doesn't have a runaway greenhouse effect
JC @222,
I concur with both the Response@222 and Philippe Chantreau @223. The data you suggest demonstrates water vapour being "the cause" of changing global temperature shows solely stratospheric water vapour. Thus the SkS page "What is the role of stratospheric water vapor in global warming?" is relevant as it puts in context the climate forcing from changing stratospheric water vapour levels.
The second point you make concerns there being 150,000 more CO2 in the Venusian atmosphere. Such a massive difference in CO2 levels would only result in a similar massive difference in radiative forcing if the relationship between CO2 levels and CO2 forcing were linear. It is not. Increases in atmospheric CO2 levels on Earth yield a linear forcing for each doubling of the CO2 level. While such a logarithmic relationship would not hold for 150,000 times the level of CO2, such a rise does represent seventeen doublings. And Venus isn't the Earth in that a temperature of Venusian levels on Earth would presumably see Earth's oceans evaporate resulting in 270 bar of water vapour in the atmosphere, that being about 150,000 times the level of water vapour in the Venusian atmosphere.
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Philippe Chantreau at 10:39 AM on 4 October 2018Venus doesn't have a runaway greenhouse effect
I note that JC does not dispute the fact that the statement "nobody follows the evolution of the global humidity of the atmosphere" has no grounding whatsoever in reality. There is so much wrong with the following post #222 that I won't have the patience to address it all. It reflects ignorance more than anything else. Among other things, it seems to suggest that global temperatures have been stagnant since 2000. This is obviously not the case since all 4 warmest years on record have happened since 2014. In fact, 2017 holds the dubious distinction of being the warmest non El Nino year in the instrumental record, beating the massive El Nino year of 1998.
https://www.climate.gov/news-features/understanding-climate/climate-change-global-temperature
There is no statistical analysis or link from JC to substantiate any "correlation." The long term trend on the higher tropospheric/stratospheric water vapor is undoubtedly up, per the NOAA link I provided above.
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JC16932 at 04:28 AM on 4 October 2018Venus doesn't have a runaway greenhouse effect
Here, on your link, https://www.esrl.noaa.gov/gmd/ozwv/wvap/, we see the increase in water vapor from 1980 to 2000 then the stagnation of steam from 2000 to presently . There is therefore a correlation with the T ° of the globe much better than the correlation CO2 / T °.
We thus see that the atmospheric variations of the water vapor is the cause of the variations of T °!As for the amount of CO2 in the Earth's atmosphere (150,000 times less molecules than in the Venus atmosphere), the energy retained is also 150,000 times less since a CO2 molecule acts in the same way on Venus and on earth.
Moderator Response:[PS] A lot of misconceptions here. Please see the Water Vapour argument to understand the processes better. You might like to look up the clausius-clapeyron equation too.
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Philippe Chantreau at 03:34 AM on 4 October 2018Venus doesn't have a runaway greenhouse effect
JC, your post does not seem to make any sense. Simulations of the GH effect take into account not only CO2 but H2O, CH4 and numerous other gasses. Water vapor is well studied and monitored by NASA's Aqua satellite, through the MODIS instrument:
https://earthobservatory.nasa.gov/global-maps/MYDAL2_M_SKY_WV
NOAA's Earth System Research Laboratory has an Ozone and Water Vapor group whose focus is more specifically on stratospheric water vapor:
https://www.esrl.noaa.gov/gmd/ozwv/wvap/
These took me less than a minute each to find. There is a considerable amount of litterature on the climate effects of increasing global water vapor content, too much to link here.
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