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Prism at 13:22 PM on 18 May 2016Past 150,000 Years of Sea Level History Suggests High Rates of Future Sea Level Rise
For perspective, 7 billion people standing in close formation would fit within the boundries of Los Angeles. A very, very small space compared with the occupiable land area on the earth.
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Tom Curtis at 13:11 PM on 18 May 2016Breathing contributes to CO2 buildup
DailySledge @60, the industrial revolution started in 1750, not 1850. As a result, from 1750 to 1849, industrial emissions of CO2 from the burning of coal amounted to 1.25 billion metric tonnes of Carbon. While only, approximately, a sixth of current annual industrial emissions, it still represents a substantive contribution to global warming. The contribution from Land Use Change was approximately the same as that from fossil fuel consumption in 1850 (spreadsheet), and is likely to have exceeded it beforehand. Together, these contribute to an annual increase of 1.3 ppmv in CO2 concentration over the period 1750-1849. However, probably more significant was the significant reduction in volcanic activity over the period, combined with an increase in solar activity. So your quadratic fits retrodiction of a positive temperature trend prior to 1850 is accurate as far as that goes, but misleading in that there have been substantial changes in the importance of different forcings over various intervals within the quadratic fit.
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billev at 12:50 PM on 18 May 2016The things people ask about the scientific consensus on climate change
What I'm asking is what method has been used to measure CO2's contribution to global temperature rise?
Moderator Response:[PS] See here for direct measurement. See "There is no empirical evidence" for other papers measuring the effect. (Harries, Wang, Evans, Philipona, Grigg, Chen all on that page). The IPCC chapter on "Attribution" covers methods for working out contribution in excruciating detail.
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Bob Loblaw at 12:06 PM on 18 May 2016Breathing contributes to CO2 buildup
It doesn't look like DailySledge has read all the comments to this article. The comment that "An increasing population does by breathing incrementaly contribute more CO2 gas to the atmosphere" has already been addressed (e.g. here).
Long story short, as scaddenp points out: more people store more carbon, so an increasing population has to be a carbon sink, not a source.
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dvaytw at 11:54 AM on 18 May 2016Models are unreliable
Should we all be jumping for joy?
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scaddenp at 11:38 AM on 18 May 2016Breathing contributes to CO2 buildup
I dont see how we can "breath out more than we take in". We take C in via our food, and emit in breathing. While we live, we are carbon sink.
The contribution of changes in biomass since 1750 is detailed in the AR5 WG1, p486, table 6.1. The total land to atmosphere change is estimated at 30 PgC +/- 45. Compare that fossil fuel contribution of 375 PgC +/- 30.
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sauerj at 09:58 AM on 18 May 2016What Sir David King gets wrong about carbon pricing
I recently joined Citizen's Climate Lobby (CCL). This group is wonderful! They advocate for Fee & Dividend using a relationship-building, respectful, kind approach. They have great resources. There are CCL chapters all around the world and in about every congressional district in the US. If you are looking for an way to plug-into effective action, please take a serious look at CCL! Their cause (CFD) is the most effective way to really start reducing carbon emissions. Email the local chapter leader and they will quickly get you involved. You will be glad you did. PS: They don't hound you for money; but they will hound you for your time and talent.
Also, read 'The Case for a Carbon Tax' Dr. Shi-Ling Hsu. Great book!
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DailySledge at 09:21 AM on 18 May 2016Breathing contributes to CO2 buildup
'By breathing out, we are simply returning to the air the same CO2 that was there to begin with.'
As biological engines we consume energy and produce waste, given we live on a planet that has finite mass of elements with the only addition to the total mass coming from stellar objects the I think it's safe to say in it's simplest terms the statement is correct.
CO2 measurements have been taken for many years and have been rising in concert with rising global temps with records extend back to 1850 showing a dramatic increase. Taking those temp records and using quadratic equation to extrapilate the curve of incidence, it shows that temp increases began before 1850, although incremently slower the trend was upward and this is before fossil fuels became popular, increasing trend can be attributed to increasing carbon based energy usage, which is directly related to and attributed to the increase in population.
Dramatic increases in modern CO2 levels are directly or indirectly linked to man and his actions in most cases.
A reducing biomass that converts CO2 to stored carbon coupled with mankind's increased CO2 producing enviroment and life suggest's the balances that we assumed as constants no longer apply.
If we are producing more CO2 than the global environment can absorb then the outcome is obvious, if the environments that can absorb CO2 keeps reducing or slow's down uptake due to excess CO2 then problem further compounds global impact.
If we were to compare increasing CO2 levels with global population increases we see much the same trend and increases as we see with fossil fuel usage if looked at solely.
An increasing population does by breathing incrementaly contribute more CO2 gas to the atmosphere, which does contribute to global warming and rising temps, by the time CO2 is converted and stored as carbon it will added it's own impact which add's to rising temps.
CO2 is as a gas, a pollutant, we breath out more than we take in so we add to the combined total of CO2 increase, it is posionous or hazardous depending on it's concentrations to most living organism.......
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billev at 07:12 AM on 18 May 2016The things people ask about the scientific consensus on climate change
The current level of CO2 is 400 parts per million which means there is one cubic foot of CO2 for every 2500 cubic feet of air. What is the measure of how much temperature rise is caused by this amount of CO2?
Moderator Response:[PS] You might like to look at the myths "CO2 is just a trace gas" and "CO2 only causes 35% of warming". You might like to clarify your question. I assume you mean how much of the temperature rise since pre-Industrial is caused by increase of CO2 since then. With 0% CO2 in atmosphere, earth would be frigid ice ball. Do you mean how much temperature rise by direct radiative effect, or how much by radiative plus feedbacks? (decreased albedo, increased water vapour etc).
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villabolo at 04:14 AM on 18 May 2016Mars is warming
GPWayne, your link to Fred Thompson in the green box no longer works.
Moderator Response:[GT] Thanks, we will update the link.
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denisaf at 11:35 AM on 17 May 2016The things people ask about the scientific consensus on climate change
It is ironical that this discussion is misleading as it is the operation of technical systems that have contibuted to climate disruption and ocean acidification and warming. Human have only made the decisions that led to these unintended consequences of the technical systems using fossil fuels.
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JWRebel at 04:01 AM on 17 May 2016Explainer: 10 ways ‘negative emissions’ could slow climate change
Very interesting summary and links. I fear that many of us are rather to sanguine about the clock we are on. The carbon budget can easily be optimistic:
- Current temperature anomalies, even if outliers, bring us within striking distance of the 1.5° C.
- Equilibrium temperature would be for current CO² levels is also uncertain, but we are not there yet.
- If positive feedbacks (permafrost, methane) or other discontinuities appear, there will be less scope for further human manipulation of climate.
The modelling and especially the costs for NETs does not seem very far along yet. (e.g., between £15 and £361 per tonne: that would make quite a difference if you were buying steaks!) Personally I feel CCS and BECCS seem to be sexiest and getting the most attention, but confidence in costs and scale seems unwarranted. Accelerated olivine weathering is often skipped altogether, but it is a natural process, extremely scalable, and according to Schuiling possible at $10/ton of CO².
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MA Rodger at 20:41 PM on 16 May 2016CO2 is not the only driver of climate
Ken Kimura @24.
I find your comments curious, extending as they do initially beyond this thread. Note here @24 you say you intend a couteous enquiry and see nothing to suggest you are not doing so. This is followed by a set of questions that imply you consider the person you address to be, if not sincere, not to be trusted. "...this claim of yours." "How can you be sure..."
The science being discussed here is not anybody's personal property. Scientific knowledge is open access thus owned by all. That is what makes it so powerful. (Having written this, I am conscious that I now embark on addressing questions that do have ownership and with answers that have a single author and so could be wholly disowned elsewhere.)
Picking up a word in your questioning @24, "How did they measure the stratospheric aerosol density during the period?", you might find Sato et al 1993 a worthwhile read (PDF here). This paper predates the appearance of the ice core data which has allowed the record to be extended back before 1883 with far greater confidence and accuracy.
Further, I am mindful that there may be a not-uncommon misconception buried within your various questions. You perhaps are of the view that early indstrialistaion was entirely driven by fossil fuel use, initially exclusively coal, and if this were so would we not have had from its earlierst times CO2 emissions & SO2 emissions in a constant proportion (until SO2 pollution was reduced in the 1970s). However, the contribution of mankind's rising CO2 emissions from burgeoning coal use only overtook the mounting emissions from low SO2-emitting wood burning in the 1910s, apparently. (CDIAC FF data & CDIAC LOC data.)
Perhaps for completeness, I should add that the forcing from GHGs in those early decades is often dismissed as too small to have significantly affected global temperatures pre-1940. Yet, if you examine the rise of atmospheric CO2 since pre-industrial times (IPCC AR5 data to 2011here), 27% of today's atmospheric CO2 rise causing 31% of today's CO2 forcings were present by 1940. And with their slower increase, the temperature response would likely be closer to 40% of today's total. But saying that we should be sure not to forget "CO2 is not the only driver of climate."
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michael sweet at 20:36 PM on 16 May 2016CO2 effect is saturated
Tom,
I was hoping that if I made an error that you would step in and correct it. Your summary is correct.
As I understand it, there is a great deal of variation in how radiation gets into space Your post above at 412 shows a small atmospheric window where some IR gets through the atmosphere from the surface. Other wavelengths have different efective mean altitudes of emission depending on how efficiently they are absorbed/radiated by the active molecules. The tropics is different from the Arctic and desert is different from the ocean covered areas. Your post includes all these details.
I meant the "essentially" to summarize all that information and your post at 423 into a single sentence. For the most basic explaination of the greenhouse effect if we assume that all radiation is emitted at 6 km than the explaination of increasing emission height affecting surface temperature is simplified. After one uderstands the basics of how temperature increases due to increasing emission height than the additional details you relate in 423 can be added.
You may be correct that the details are required, but I think it helps to understand the basics by simplifing the complex details. I think here we only differ in what we think is the proper way to simply explain how the greenhouse effect works (and your posts have much better graphics than mine). For more advanced readers (who read but do not comment) your post gives them additional detail so that they understand the effect better than my simplification.
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Tom Curtis at 18:05 PM on 16 May 2016CO2 is not the only driver of climate
Ken Kimura @24, anthropogenic aerosols are well known because the types and quantities of fuels burnt in various countries are well known, and so the production levels are known. Similarly, for volcanic aerosols, the size, force and duration of volcanic activity is also known, given an approximate indication of volcanic aerosol production. More importantly, aerosols are found in ice cores from Greenland, Antarctica, the Rockies, Andes and Himalayas, and also from Mount Kilimanjaro and (I believe) Mount Kenya from tropical Africa. The aerosol density at different levels in the ice cores can be compared to equivalent density levels in recent cores, which are then correlated with satellite measurements of aerosol optical depth. Combined, these give a reasonable though not perfect measure of aerosol optical depth going back hundreds of years.
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Christian Moe at 16:49 PM on 16 May 20162016 SkS Weekly News Roundup #20
Please note: The title for Screen and Francis' piece at CarbonBrief is wrong (the link is right). It should be "How the Pacific Ocean alters the pace of Arctic warming". Nothing to do with ExxonMobil.
Moderator Response:[JH] Correct article title (headline) inserted. Thank you for bringing this glitch to our attention.
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Eclectic at 15:28 PM on 16 May 2016CO2 is not the only driver of climate
Ken Kimura @24 , let me be quick to assure you that Tom Curtis was not the only one to see your: ". . . started long before 1940" comment as insulting (or something very close to that).
Perhaps you didn't mean it that way . . . or only meant it at some subconscious level . . . or at another level, meant it disingenuously. Or all three ways at once [such is the complexity & inconsistency of the human mind] . But your comments had a general background context or "tenor" which would lead Tom to his conclusion quite naturally and automatically, I do believe.
Aerosol reflectivity can be measured from ground stations; and in more recent decades from satellite observations; and measured indirectly by correlation with the observed changes after each significant volcanic eruption. [Instrumental measurement or proxy measurement]
For the accuracy of the measurements & estimations, you might care to consult the original scientific papers that investigated such phenomena. But, unless you have good reason to doubt their bona fides [in which case you should declare your hand : and show the evidence you rely on for such opinion] . . . then your question is a side-issue, which need not distract us from the main thrust of your inquiry.
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MarcusGibson at 15:00 PM on 16 May 2016Alarming new study makes today’s climate change more comparable to Earth’s worst mass extinction
I often wonder whether we're really the first 'intelligent' life on Earth.
After all, we haven't been around long enough to leave any fossils of ourselves. Even if we had, all but Siberia will have been subducted by continental drift before 'intelligent' life evolves again another 250m yrs.
They'll never even know we were here, butt for one or two rare 'London Hammer' type relics in the Mongolian Steppes.
This would explain the (unexplained) drop in the 13C/12C isotope ratio before the Great Dying. Another lifeform - like us - might have madly burned fossil fuels for 200 years before triggering their own extinction.
It would also explain the Fermi paradox.
The reason we've never found evidence of intelligent life in the universe is that every 250m yrs or so, sentience springs up for the briefest moment - just a hundred thousand years. Then it discovers fire, and carbon-based fuels, and the acquisitive behaviours and superstitions that helped it thrive, wipe it out in a cosmic blink.
Over an over. Across the universe. Little flashes of thought that never manage to coincide.
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Ken Kimura at 14:34 PM on 16 May 2016CO2 is not the only driver of climate
Tom Curtis @23.
"For you to then turn around and ask "you know that the industrialization started long before 1940" looks like a calculated, and hypocritical insult."
I had no intention to insult you.
And I have no idea why you thought so."With regard to your former question, stratospheric aerosols are almost exclusively from volcanic erruptions."
I have at least 3 questions.
1) What are the evidences of this claim of yours?
2) How did they measure the stratospheric aerosol density during the period?
3) How can you be sure that their mesurement was accurate? -
bozzza at 14:16 PM on 16 May 20162016 SkS Weekly Digest #20
(.. as a get-out-of-jail-free clause can I appeal to the idea that science doesn't even understand what 'current conditons' are?)
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bozzza at 14:13 PM on 16 May 20162016 SkS Weekly Digest #20
Tom,
Of course I trust your words and will read your links but I just find it impossible to believe long term structural integrity is not at stake.
Of course, I shall read... (not that I like reading much- obviously!)..!
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Tom Curtis at 12:20 PM on 16 May 20162016 SkS Weekly Digest #20
bozza @2, studies with models show that under current conditions, complete removal of sea ice will not prevent its reformation in the next year. While sea ice models have problems, the rapid recovery to trend levels of sea ice after 2007 and particularly 2012 show that in this case the models are correct. Hysteresis is, therefore, not currently a factor in Arctic sea ice, and probably will not be until we reach near permanent absent of Arctic sea ice, even in winter (if then).
In this sea ice contrasts with land ice, where there is substantial evidence we have reached a point of hysteresis for parts of the West Antartic Ice Shelf, and possibly for Greenland.
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Tom Curtis at 12:14 PM on 16 May 2016CO2 effect is saturated
michael sweet @422, I strongly suspect your attempt to answer Concerned Citizen's question will be fruitless. The evidence strongly suggests he is interested in obfustication rather than learning. That is clear from his continuous changing of the question he asks, and he refusal to accept any response as accurate or relevant (despite the responses to his questions having been both).
In attempting to answer Concerned Citizen, however, you stated that "Essentially all the energy emitted by the Earth is at the 6.0 km altitude". That is not correct. The "effective mean altitude of radiation" is approximately 6 km, but the effective mean altitude of radiation is just that altitude in the troposphere at which the globally averaged temperature is the same as the brightness temperature of the IR radiation from Earth, averaged globally and across all frequencies. That that is not the same as the altitude from which essentially all radiation is radiated is most easilly seen by comparing the 6 km temperature to brightness radiation of emission from real observations (in this case averaged over April to June from the Central Pacific for two seperate years, see Harries et al, 2001)
Note that the spike at 1050 cm^-1 is from stratospheric ozone, and is at a much higher altitude than other emissions shown. The central spike from CO2 emissions at 667 cm^-1 is not shown as the graph cuts of at 700 cm^-1.
Just looking at brightness temperatures, unfortunately, will give a mistaken impression as to the effective mean altitude of radiation, as brightness temperatures do not show the intensity of radiation at different wave numbers. For that we need a more traditional emissions spectrum:
In this case we have two such spectra, a clear sky spectrum and one from a thunderstorm anvil. Many cloud spectra will be from lower altitudes. It can be seen, however, how the combination of maximum intensity of surface emission near the CO2 absorption band, combined with the effects of clouds result in an "effective mean altitude of radiation" at around 6 km.
I am fairly certain you knew all this already, but your choice of words leads to an easy misunderstanding, and IMO one that would create confusion if not clarrified.
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bozzza at 12:08 PM on 16 May 20162016 SkS Weekly Digest #20
The concept of Hysteresis means long felt multi-year ice melt remains the reality. The kids will read about it in the akashic record called NSIDC as if it were reality tv!
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villabolo at 09:51 AM on 16 May 20162016 SkS Weekly Digest #20
From NOAA:
La Niña is favored to develop during the Northern Hemisphere summer 2016, with about a 75% chance of La Nina during the fall and winter 2016-17.
Is this likely to have an impact on the Arctic icecap's Minima?
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michael sweet at 23:48 PM on 15 May 2016CO2 effect is saturated
Concerned Citizen,
The temperature lapse rate is the amount the temperature changes as you increase altitude. It is about 6C per kilometer. That means that if you increase in altitude by one kilometer the air is 6C cooler.
Essentially all the energy emitted by the Earth is at the 6.0 km altitude. This amount of energy equals the amount of energy that arrives each day from the sun. If you increase the amount of CO2 in the atmosphere than the CO2 absorbs more of the energy coming up from the surface. The emission height raises to 6.1 km. This we have agreed on.
Heat is emitted from all materials in amounts proportional to the temperature. When the emission height increases to 6.1 km, less energy is emitted because the air is colder. This is because of the temperature change, not the change in pressure. There is an imbalance between what is arriving from the sun and what is emitted. This imbalance causes the Earth to heat up.
In order to reach a new equilibrium where the heat emitted from the atmosphere is the same as the heat arriving from the sun the temperature at 6.1 km has to increase. Because the lapse rate remains the same, the temperatue of the entire air column under 6.1 km increases the same amount as it increases at 6.1 km. Since the lapse rate is 6C per km the temperature has to increase about 0.6 C if the emission altitude increases from 6.0 to 6.1 km. When the rest of the air column increases in temperature the surface is 0.6C warmer. This is the global warming caused by the increase in CO2.
Do you understand the way that the increase in the emitting altitude (caused by the increase in CO2) results in an increase in the surface temperature?
The atmospheric pressure does not increase measurably from the increase in CO2. This is well known and no-one has suggested that atmospheric pressure changes the temperature. This is an example of a basic misunderstanding that needs to be corrected.
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ConcernedCitizen at 19:19 PM on 15 May 2016CO2 effect is saturated
michael sweet @418 Yes, I know about the temperature lapse rate, didnt 'Air at 6,1 km is thinner, I now that, I already said its colder' make that self evident?
So far not one of you has been able to describe the physics, the mechanical process, whereby putting an additional CO2 mollecule at 6.1 km raisies temperature by interaction wioth the lapse rate.
The lapse rate is based on atmospheric pressure, so if you added enough CO2, yes, you would increase the atmorpheric pressure, but this isnt the suggestion here and certainly isnt hapening because atmopspheric pressure isnt increasing.
So again, in the absence of any logical and clear explanaiton the explanation given here holds no water.
Moderator Response:[JH] If you cannot be civil, you will forfeit your privilege of posting comments on this site.
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denisaf at 16:48 PM on 15 May 2016Skeptical Science wins 2016 NCSE Friend of the Planet award
I have seen a list somewhere of the cities that are likely to be hard hit by sean level rise and storm surges. London, New York and the Netherlands have massive works in progress to cope with this predicament.
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Tom Curtis at 10:40 AM on 15 May 2016CO2 is not the only driver of climate
Ken Kimura @22, I discuss the trend from 1940-1970 because you asked a question about the trend from 1940-1970, and for no other reason. For you to then turn around and ask "you know that the industrialization started long before 1940" looks like a calculated, and hypocritical insult.
With regard to your former question, stratospheric aerosols are almost exclusively from volcanic erruptions. Tropospheric aerosols are from a combination of wind born sea salt, refractory compounds from forest, desert sand and anthropogenic factors. Forcings, however, represent the change in a factor over time, and the vast majority of the change in tropospheric aerosol load is from anthropogenic factors - primarily from sulfur in coal and oil. As can be seen from this graph from the IPCC AR5, the combined anthropogenic effect (red line) from 1940-1970 results in a positive slope in forcing:
The combined anthropogenic plus natural forcing is flat or negative due to the lack of volcanic erruptions from about 1915 and the onset of a large eruption (Agung, 1963-4) along with a number of smaller eruptions.
Note that the above graph sets the zero point for forcings at 1750 rather than the 1880 used in the GISS forcing graph you pointed to, and the Meinhausen 2011 forcings displayed in the model to which I linked.
With regard to the relation between anthropogenic GHG forcings and anthropogenic aerosol forcings, initially the aerosol forcing from oil and (particularly) coal dominate in the short term, but with steady state use the GHG forcing comes to dominate very quickly. That is because the initially dominant aerosol load is quickly washed out of the atmosphere by rain, while the GHG concentration (particularly CO2) accumulates. With accelerating coal combustion, these factors can approximately balance for a while, as can be seen from 1750-1860 above, but in the 20th century the GHG forcing has been stronger both because of the accumulation of CO2 in the atmosphere and a gradual switch to cleaner (ie, less sulphur content) fuels.
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Eclectic at 22:47 PM on 14 May 2016There's no correlation between CO2 and temperature
Ken @53 , there is something in what you say ~ yet you misunderstand the basic Modus Operandi of this SkepticalScience website.
When you ask a question or dispute a point, then your post will show in the Recent Comments page . . . where everyone will see it, and those who wish to reply will have the opportunity to go to your chosen thread. As a matter of course, the replies will also be funnelled through the Recent Comments page too. This way everyone can see them conveniently, and those who wish to add to / correct / or dispute those replies, will be able to do so.
So you see, that way you will get the best range of views / opinions / controversy / facts / useful links ~ all in the shortest time. And most conveniently all round.
It is a sensible & efficient arrangement ~ which is why I recommended that you keep your particular cluster of questions in one thread only. If you develop entirely unrelated questions as the discussion progresses . . . then it's best to get the first question(s) sorted out, before going on to another topic / another thread. It is best to progress step-by-step, reather than throwing up a large number of questions.
( Simultaneous multiple-pellet "shotgun" questioning is viewed poorly . . . since it's usually a sign of lack of sincerity in the poster ).
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Ken Kimura at 15:22 PM on 14 May 2016There's no correlation between CO2 and temperature
Eclectic @52,
This thread and the other thread(and many others) are closely related.
And many members post their opinions into these threads.
So it is inevitable their opinions overlap.
Hence, it is also inevitable that questions to them overlap.
I don't see why asking similar questions to different members is discouraged.
People have different opinions so that their answers may differ. Knowing different answers(some may be right, some may be wrong) is usually useful for most people. -
Eclectic at 13:33 PM on 14 May 2016There's no correlation between CO2 and temperature
Ken Kimura @51 , it would be best if your questions about aerosols & other drivers of climate, were kept on the one thread i.e. "CO2 is not the only driver of climate". That seems the most approriate thread; and it has the most approriate discussions in its comments column e.g. @20 and @21.
Running the same/similar questions in parallel (in different threads) is not good policy on your part. It gives the impression [ wrongly, I'm sure! ] that you may be more interested in "sloganeering" (as the moderators call it) . . . rather than in showing your genuine interest in finding information.
Similarly, your comment in the above-mentioned thread, that [your quote:] "you know that the industrialization started long before 1940" . . . does suggest [ wrongly, I'm sure! ] that you think in binary terms of industrialization being entirely absent and then on a particular date, being suddenly present at a high level of activity. Such comments by you, give the impression [ wrongly, I'm sure! ] that you prefer word games rather than science.
Good luck with your search for information & wisdom. There are some very knowledgeable people on this forum, who can help you.
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Ken Kimura at 11:12 AM on 14 May 2016CO2 is not the only driver of climate
Tom Curtis@21,
According to the figure 5 of the following page, stratospheric and reflective tropospheric aerosols were major negative forces during the period.
What do you think the main cause of those aerosols was?
If it was due to the industrialization, you know that the industrialization started long before 1940.
http://www.skepticalscience.com/co2-temperature-correlation-intermediate.htm -
Ken Kimura at 09:45 AM on 14 May 2016There's no correlation between CO2 and temperature
Eclectic @50,
I have at least two questions.
1) How did they measure the aerosol density?
2) If the aerosols were created by the industrialization and they counterbalanced the CO2 effect,
how do you explain that the global temerature had been increasing from 1910 to 1940?
See figure 1 of the following thread.
http://www.skepticalscience.com/ivar-giaever-nobel-physicist-climate-pseudoscientist.html -
Tom Curtis at 09:06 AM on 14 May 2016CO2 effect is saturated
braintic @419, thankyou for your clear, and accurate exposition of the band saturation effect. That is a genuine effect that is described very clearly by David Archer in Chapter 4 of his book, Climate Change: Understanding the Forecast (available online here); and also by Riccardo in the advanced version of the rebutal to the myth. The reason band saturation is presented as the advanced rebutal, while increased effective altitude of radiation is presented as the rebutal of the "CO2 is saturated" myth is that band saturation is a subtle consequence of the fundamental effect of the increasing altitude of radiation in an atmosphere in which the stratosphere warms with altitude (something I will explain in more detail below). In an atmosphere with a cooling stratosphere with altitude, there would be no band saturation - and the greenhouse effect would be stronger as a result.
You are clear that increasing CO2 causes increasing warming, but you appear to miss the fact that the myth is not about band saturation, but rather the myth is a claim that CO2 is saturated across all bands, and that this means increasing CO2 concentration will cause no warming. Given that Skeptical Science targets its basic explanations to those who have studied no science since their 10th year of education, you will understand that a basic rebutal saying that "CO2 is band saturated, but not saturated" is likely to generate confusion. Hence, the basic rebutal concentrates on the fundamental mechanism, while more advanced rebutals deal with the more subtle effects and refer those who are interested to more detailed explanations.
In any event, the theory of the greenhouse effect is fundamentally a theory about the energy balance between the Earth and space (including radiation from the Sun). It follows that the relevant altitude at which to determine "saturation" is not from the surface, but from space (effectively 70 km altitude). At 70 km, the mean free path for the resonant frequency of CO2 is not just over 30 cm, but effectively infinite in a tangent to the Earth, or approximately 35 Km vertically towards the Earth's surface. Adding more CO2 to the atmosphere decreases that downward, vertical mean free path, and hence the distance IR radiation from the Sun can penetrate the atmosphere from space. In more standard terms for climate science, adding CO2 reduces the optical depth of the atmosphere. (Note that I am not saying "mean free path" and "optical depth" are the same thing. They are not. But they are related concepts, and the later is most commonly used in discussing the issue in climate science.)
Because the mean free path downward from space has decreased at the resonant frequency, by Kirchoff's Law the mean altitude of radiation to space increases. That is because, altitude determined by mean free path downward is also the mean altitude of radiation to space, but while the former is measured from the notional boundary to space, the later is measured from the surface. Further, the same effect will be experienced at all frequencies in which CO2 absorbs IR radiation, and therefore also over the average of all thermal IR frequencies. Thus, when speaking of the effect of adding CO2, a simpler way of saying what happens is to say:
"So if we add more greenhouse gases the air needs to be thinner before heat radiation is able to escape to space. So this can only happen higher in the atmosphere. Where it is colder. So the amount of heat escaping is reduced."
Of course, while it is generally true that as we get higher in Earth's atmosphere, it gets cooler, it is not true in either the tropopause or the stratosphere:
That means that for those frequencies of CO2 absorption where the mean free path from the nominal edge of space places the mean level of radiation to space in the tropopause, increasing CO2 will not change the temperature of the gas radiating to space, and therefore not change the energy radiated to space at that frequency. At the resonant frequency of CO2, the mean altitude of radiation to space is in the stratosphere, so that increasing CO2, all else being equal, would result in more radiation to space. As it happens, not all else is equal and that excess CO2 cools the stratosphere on a very short time scale (hours) so in practise the effect is minimal change in the radiation to space. At the wings of the CO2 absorption band, however, the mean altitude of radiation to space is in the troposphere. Consequently raising the mean altitude of radiation to space decreases IR energy transmitted to space at that frequency until the mean altitude of radiation to space reaches the tropopause.
It follows from this that the band saturation effect represents a saturation of the energy radiated to space as the mean altitude of radiation to space enters the tropopause for given frequencies. It does not represent optical saturation (as it would need to be relevant to the myth). Rather, it represents a stable level of radiation to space due to the mean altitude of radiation to space at a given frequency being in the tropopause.
It should be noted that H2O (due to precipitating out rapidly with increased altitude) and other greenhouse gases (due to relatively low concentration) do not have this effect. Their mean altitude of radiation is firmly in the troposphere and increasing concentrations do not lead to band saturation for that reason. The one exception is stratospheric ozone, and stratospheric H2O (introduced by jet fuel). Because both are in the stratosphere, increased altitude increases thermal radiation to space.
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bjchip at 08:15 AM on 14 May 2016The things people ask about the scientific consensus on climate change
This also relates well to the fact of the consilience of the science, as discussed by Michael Shermer - here...
http://www.scientificamerican.com/article/why-climate-skeptics-are-wrong/
I hope that guy/gal is on good terms with their boss. I would be steering clear of such discussions unless I got a clear idea that it was possible to discuss them.
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villabolo at 04:48 AM on 14 May 2016Volcanoes emit more CO2 than humans
Hi John C, you might want to use this quote from the United States Geological Survey as regards the amount of CO2 released by volcanoes compared to human emmissions:
Gas studies at volcanoes worldwide have helped volcanologists tally up a global volcanic CO2 budget in the same way that nations around the globe have cooperated to determine how much CO2 is released by human activity through the burning of fossil fuels. Our studies show that globally, volcanoes on land and under the sea release a total of about 200 million tonnes of CO2 annually.
This seems like a huge amount of CO2, but a visit to the U.S. Department of Energy's Carbon Dioxide Information Analysis Center (CDIAC) website (http://cdiac.ornl.gov/) helps anyone armed with a handheld calculator and a high school chemistry text put the volcanic CO2 tally into perspective. Because while 200 million tonnes of CO2 is large, the global fossil fuel CO2 emissions for 2003 tipped the scales at 26.8 billion tonnes. Thus, not only does volcanic CO2 not dwarf that of human activity, it actually comprises less than 1 percent of that value.
This might be a more digestible reference for a basic level audience compared to a quote from two scientific papers.
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citizenschallenge at 23:51 PM on 13 May 2016Medieval project gone wrong
Hoskibui, thank you for a valuable article, you do a nice of explaining. It's come in very handy for a recent blog post regarding the misdeeds of CO2Science.org - and I've copied long sections to share.
"Is CO2Science.org 'criminally negligent'? Why not consider it?"
http://whatsupwiththatwatts.blogspot.com/2016/05/co2scienceorg-criminally-negligent.html
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jgnfld at 23:50 PM on 13 May 2016Coal made its best case against climate change, and lost
A number of people here are misunderstanding the nature of the proceedings. An adminstrative court hears evidence, takes submissions, takes testimony and cross examination, etc. but is not a "case" in the TV sense. In this case, the hearing is prescribed by legislation to write a legal opinion on evidence provided about a specific point (the social cost of coal) for the consideration of a higher body which will make the final decision.
It is an important step. But in no way was coal found "guilty". The finding is that on the preponderance of evidence (a criterion much lower than beyond a reasonable doubt) the evidence provided by the high social cost side is correct and that the evidence provided by the deniers was not correct. It's a beginning, but there is a very, very long way to go on the legal front.
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William Leslie at 23:25 PM on 13 May 2016The things people ask about the scientific consensus on climate change
I especially like the first point. Newton didn't need to replicate Kepler's observations before formulating his famous laws. He also readily acknowledged that he "stood on the shoulders of giants."
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braintic at 21:37 PM on 13 May 2016CO2 effect is saturated
This is NOT the correct explanation of the saturation of CO2 absorption of IR radiation. The fact is that the effect IS saturated at the resonant frequency of bending of a CO2 molecule (wave number 667).
However molecules CAN absorb radiation at frequencies that don't match the resonant frequency, albeit with a lower probability of absorption.
IR radiation at the resonant frequency has a mean free path of just over 30 cm with the current CO2 concentration. So almost all of that radiation makes it back to the ground. In fact that frequency becomes saturated at only a couple of parts per million.
A rough rule of thumb is that the probability of absorption reduces to about 10% for every 5% change in IR frequency. So the mean free path is multiplied by 10. So IR radiation which differs in frequency from the resonant frequency by 20% has a mean free path of about 3 km. At these altitudes the calculation is complicated by the thinning atmosphere, so the mean free path would actually be somewhat longer than that.
The effect of adding more CO2 is to reduce the mean free path of IR radiation at ALL frequencies. This has the effect of widening the band of frequencies that attain absorption saturation.
This is called BAND SATURATION. It is the widening of the band of frequencies that achieve saturation that causes the greenhouse effect to increase as more CO2 is added. And mathematically, it explains why the temperature effect increases logarithmically with CO2 concentration (ie. a constant temperature increase for every doubling of CO2 concentration).
I strongly suggest you change your article to reflect this science.
Moderator Response:[RH] All caps is against policy. Please take the time to read our commenting policies before you continue.
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michael sweet at 20:19 PM on 13 May 2016CO2 effect is saturated
Concerned Citizen,
It is too bad that you have alienated Tom Curtis. He generally is patient with learners and provides lots of data to support the consensus.
You need to step back and address one of your misconceptions at a time. When you list 5 or 6 misconceptions in a single post it is difficult to respond without a major post. You need to read the OP again and see what you misunderstand.
The increase in the radiation altitude causes the Earth to warm because of the temperature lapse rate. As you go higher in the atmosphere it gets colder. When the emission altitude is increased, less energy is emitted because it is colder. In order to reach equilibrium, the temperature must increase at 6.1 km so that the emitted energy equals the energy incoming from the Sun. Because the temperature lapse rate in the atmosphere stays the same, in order for the temperature to increase at 6.1 km, the surface has to warm also.
If you still do not understand why increasing emission altitude causes the surface to warm post again here. Do not add additional questions until we establish this description of the increase in temperature.
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ubrew12 at 19:55 PM on 13 May 2016The things people ask about the scientific consensus on climate change
I tell people that Scientific consensus is important less for Scientists, and more for Policymakers. And in lay discussions, the Policy is actually what is being discussed. The 'Do Nothing' alternative is promoted on the basis that the Science isn't 'proven' or 'complete' (which is an odd thing to promote, since logically an 'incomplete Science' should call us to 'Do twice as much of Something' if we were true conservatives). But if Policymakers admit that they aren't Scientists, then Scientific Consensus is the justification for action. On this topic, Policymakers of the last 30 years have taken the 'Do Nothing' alternative based on a 'whopping' 3-10% consensus of expert opinion. It's hard not to conclude they simply ignored the Scientists and made policy on the basis of intuition. We shall see how that goes.
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ConcernedCitizen at 19:33 PM on 13 May 2016CO2 effect is saturated
@Moderator: Right, so when I point out that I accept that CO2s GH effect isnt saturated but question the proposed explanation I am going to be blocked am I?
Tom Curtis@416
Air at 6,1 km is thinner, I now that, I already said its colder. How does putting an additional CO2 mollecule there cause warming? By changing kinetic into radiative energy and radiating it downwards.
The suggestion that there is a kind of 'CO2 lapse rate' just doesnt fit.
Moderator Response:[JH] Moderation complaint snipped.
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ubrew12 at 19:29 PM on 13 May 2016Coal made its best case against climate change, and lost
For 30 years, Richard Lindzen has been criticizing the Climate Models under apparently no pressure to offer a prediction alternative. Imagine Opthalmologist Lindzen ordering a patch on your one good eye because it wasn't seeing 20/20: "Trust me! You're better off blind!"
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DrivingBy at 12:35 PM on 13 May 2016Coal made its best case against climate change, and lost
@ OPOF
We can easily agree here: "There is an even less popular point regarding population."
I think you'll find that the rest is not a new idea, and is a hard sell. I was a bit off topic in my post, so I'll not pull the it further OT.
Moderator Response:[PS] Thank you. This thread is indeed drifting offtopic.
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One Planet Only Forever at 11:31 AM on 13 May 2016Coal made its best case against climate change, and lost
DrivingBy@4,
There is an even less popular point regarding population.
The highest consuming and highest impacting portion of the population is what needs to be reduced.
My preference would be for the most fortunate among humanity to be expected and required to be leaders of the advancement of humanity to a lasting better future for all. Anyone uninterested in being that kind of person, preferring to live life as a partying spectator, would choose to give up the opportunity for the life of a leader (and find the wealthier life opportunity unavailable to them no matter how tricky or secretive they tried to be).
The current system that excuses (and encourages) known to be unacceptable behaviour if it can be gotten away with, especially if it can be popular and profitable, clearly fails the needs of the future of humanity (as it focuses on meeting the desires of the most callous among us).
Total global wealth and food production has grown more rapidly than the population yet a significant portion of the global population still live short horrible existences. That clearly needs to change.
The elimination of the ability of the already most fortunate to continue to enjoy their undeserved perceptions of prosperity is a step in the right direction. It is a step that will need to be taken affirmatively by humanity in spite of the potential reactions from those who would try to fight against losing their ability to win rewards by behaving unacceptably.
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Digby Scorgie at 10:50 AM on 13 May 2016Skeptical Science wins 2016 NCSE Friend of the Planet award
mancan18 @9
For deniers to say that "correlation does not imply causality" dodges the fact that high levels of carbon dioxide are "associated" with high temperatures, and vice versa. Since CO2 levels are now high, the deniers have to admit that high temperatures are therefore to be expected — in other words, global warming has to be real.
To put it another way, the deniers can't have their cake and eat it. To use the correlation-causation argument they have to admit the reality of global warming. (This treats as a separate issue the adding of more CO2 to the atmosphere from burning fossil fuel.)
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DrivingBy at 23:04 PM on 12 May 2016Coal made its best case against climate change, and lost
Coal was a great step forward, 200 years ago, it brought us out of the era of wiping out forests for fuel, 12 hour workdays and travel by horse for the wealthy or by foot for the rest. Today's problems are mosqito bites compared to the harshness of life then, and fossil fuel provided the physical energy undelying that change.
Coal's time has now passed, we need to move away from carbon fuels (unless some clever soul figures out how to economically capture C02 emissions). We also need to reduce the world population unless we are willing to live with conflicts and poorer lives, but that is not a popular thought and probably never will be.
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CBDunkerson at 23:02 PM on 12 May 2016Coal made its best case against climate change, and lost
I'm surprised the contrarians were even allowed to testify given the rules of evidence. Possibly Minnesota is less strict than the federal court system, but generally only well established science can be presented.
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