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LTO at 22:23 PM on 6 January 2019CO2 effect is saturated
MA, Michael - thank you for this; very helpful, and it's tht first time Ive heard about the lapse rate as an explanation for how global warming works. There are a few things I'm still not following:
1. How much of a difference does the effective widening lf the bands actually makw at the concentrations werew talking about? Eg if the effective drop in radiance (ie area under thr curve) at 400 ppm co2 was 100, what would it be at 800 ppm?
2. I'm not following the black body radiation argument, because co2 excitation and subsequent emission of 15 um isn't a black body phenomena (correct me if I'm wrong here). A single co2 molecule in an excited state will release a 15 um photon, and this is separate to black body radiation.
3. I'm not sure I'm following why the temperature of the escape altitude increases. As indicated by MA earlier, there isn't necessarily energy transfer to the surrounding gas as excited co2 molecules increasing the temp of surrounding air through collision then in principle increases the number of co2 molecules excited through collisions with surrounding air, hence minimising net energy transfer. I'd thought thr main mechanism behind the greenhouse effect was re-radiation of 15 um photons back to the surface (or water vapour), not through heating of surrounding air. Is that wrong? Or are these minor secondary effects that are only really relevant once you get past the primary saturation point?
4. Even if the temperature of the escape altitude is increased, it's not clear to me why that is necessarily transmitted to the ground through the lapse rate. What is the mechanism? Presumably not convection. Given the existence of eg temperature inversions in the troposphere and the day-night temperature cycling, it isn't clear to me why that is necessarily the case.
Thanks!
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Feneley at 22:16 PM on 6 January 2019CO2 increase is natural, not human-caused
The arguments presented are helpful and fairly comprehensive, but I was surprised the author, dana1981, did not address what, in my view, is the most important scientific publication on this issue: “The phase relation between atmospheric carbon dioxide and global temperature” by Ole Humlum, Kjell Stordahl and Jan-Erik Solheim in Global and Planetary Change 100: 51-69, 2013. These authors showed, using published temperature time series from multiple sources and global CO2 and anthropogenic CO2 data that, for the years 1980 to 2011:
1. There was a good temporal correlation between global CO2 and ocean temp, land temp, global temp and lower troposphere temp BUT the global CO2 FOLLOWED the ocean temp, then the land temp, then the lower troposphere temp, in that order, with lags of 9-12 months.
2. In contrast, there was poor temporal correlation between anthropogenic CO2 emissions and both global CO2 and temperature.
3. While anthropogenic CO2 was emitted overwhelmingly from the northern hemisphere, the time sequence of ocean temperature variation commenced in the Southern Hemisphere, reasonably close to the equator, then spread north and south to the poles, always preceding the global CO2 time sequence.
These carefully determined temporal sequences and correlations, based squarely on the published temperature and CO2 data, clearly indicate a causal sequence in which global temperature changes PRECEDE global CO2 changes by 9-12 months, commencing with changes in the ocean surface temperature, then the land temperature, then the lower troposphere temperature. These observations are the complete OPPOSITE of what should be expected if anthropogenic CO2 emissions were driving both the global CO2 levels and then causing a secondary increase in temperatures.
So, while I appreciate the energy balance and other arguments advanced above, causality requires a demonstrated temporal sequence of changes that the data I describe here simply do not support. I would be very interested in your explanation for these observations.
Moderator Response:[TD] Humlum is wrong. Type "Humlum" into the Search field at the top left of this (or any) SkepticalScience page.
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Ari Jokimäki at 17:03 PM on 6 January 2019New research, December 24-31, 2018
Thank you, Jonas! :)
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nigelj at 10:37 AM on 6 January 20192019 SkS Weekly Climate Change & Global Warming News Roundup #1
Evan @3
I agree melwater pulse 1a is associated with 5 metres per century, but read the wikipedia article. Only half this is at most is attributed to destabilisation of the antarctic, the remainder to the melting of ice sheets over north america which do not exist anymore, so my conclusion is a destabilising antarctic as discussed in the article above would perhaps cause 2 metres of sea level rise per century. Which would be catastrophic.
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Evan at 09:55 AM on 6 January 20192019 SkS Weekly Climate Change & Global Warming News Roundup #1
nigelj, am I missing something. What I've read Meltware Pulse 1A was associated with about 5m/100 years for 4-500 years. Or are you saying that 2m/century is the amount associated with Meltwater Pulse 1A that was on top of the background declatiation rate top give a total of 5m/century?
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AFT17170 at 09:18 AM on 6 January 2019It's the sun
Hello Michael — indeed, as a layman observer, I perceive that the battle started at "it's not warming", moved to "it's warming but not us", and is indeed now at "it's not that bad" or "not worth the cost to mitigate".
No, I cannot point to any recent "stored up past solar activity" arguments, I was reacting to those arguments that appeared on this thread.
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Jonas at 08:41 AM on 6 January 2019New research, December 24-31, 2018
Hello Ari,
as already posted for Baerbel for this start of the year and from time to time to John Hartz, I want to thank you and all of the SkS team for your work: as a small multiplicator in my semi-private network, I depend on you ..
The science overview is mostly to specific for me, but I get a broad impression of what's going on in climate related research via the titles (very valuable background info) and view some 4-6 articles you link per post: enough to keep me going with Johns links ..
My saturday evening is devoted to SkS (you and John and other posts and as needed the general resources).
Best,
Jonas -
Jonas at 07:58 AM on 6 January 20192018 in Review: a recap of the Skeptical Science year
Hallo Bärbel,
ab und zu schreibe ich einen Dank an John Hartz, weil ich dessen Posts inzwischen am meisten nutze, aber zum Jahresanfang will ich auch Dir und SkS allgemein Danke für euer Engagement sagen.
Ich weiß nicht, wer die direkten Leser von SkS sind, aber ich vermute, die indirekten sind noch deutlich mehr .. Ich jedenfalls filtere SkS (und andere Quellen) und verlinke ein paar Posts oder Graphiken in einem kleinen Forum für die Bio-Selbsternte-Gärten in meiner Heimatstadt, das ich betreue und an anderen Stellen. Für Klein-Multiplikatoren wie mich sind Seiten wie SkS sehr wichtig (deshalb unterstütze ich das auch per Spende).
Angesichts der unguten Perspektiven (die ich als bedrohlich empfinde) sind insbesondere auch die Posts zur psychologisch sinnvollen Kommunikation hilfreich.
Viele Grüße,
Jonas.Moderator Response:Thanks for your feedback & donation, Jonas!
For those not able to read German, here is a quick translation of Jonas' comment
Hello, Bärbel,
every now and then I write thanks to John Hartz, because I use his posts the most, but at the beginning of the year I also want to thank you and SkS in general for your commitment.
I don't know who the direct readers of SkS are, but I guess the indirect ones are much more ... I filter SkS (and other sources) and link a few posts or graphics in a small forum for the organic self harvest gardens in my hometown, which I take care of and elsewhere. For small multiplicators like me, sites like SkS are very important (that's why I support it with a donation).
In view of the unpleasant perspectives (which I find threatening), the posts on psychologically meaningful communication are especially helpful.
Many greetings,
Jonas. -
One Planet Only Forever at 06:17 AM on 6 January 20192019 SkS Weekly Climate Change & Global Warming News Roundup #1
nigelj,
I agree. The Bold main title gets used without the important context.
It would have been better to reverse the two.
Experts continue to warn that our overall picture of sea-level rise looks far scarier today than it did even five years ago - However, a recent more terrifying sea-level prediction now appears to be far less likely.
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nigelj at 06:08 AM on 6 January 20192019 SkS Weekly Climate Change & Global Warming News Roundup #1
Regarding the article published in the magazine Science: "A Terrifying Sea-Level Prediction Now Looks Far Less Likely. But experts warn that our overall picture of sea-level rise looks far scarier today than it did even five years ago."
This is a very good article, but the title is so badly worded and immediately creates the impression sea level is not an issue. I know the second part of the title is a cavet that hints at problems, but the impression is made in the first sentence, that there's no problem. Please just stop this naive journalism.
It's only when you read half way through the article that you find they are still predicting about 5 metres of sea level rise by year 2300, which is huge, and not so far into the future. This is buried away and would be easily missed. Sigh.
Meltwater pulse 1a was 16,000 years ago and associated with destabilisation of the antarctic and about 2 metres of sea level rise per cenury is attributed to this, spread over several centuries. I often quote this because its an event that happened, so is particularly pertinent. Modelling the future is challenging, but we have this known information from our past to consider as well.
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Tom_S at 06:00 AM on 6 January 2019We're heading into cooling
I'm new to this site. After a quick read I have two initial observations:
(a) Evidentally only Climate Scientists are "real" scientists so input from other closely related fields of science e.g. meteorology, astronomy etc. can cheerfully be discounted or ignored
(b) I see several exhorations such as "Then prove it: do the analysis, write it up, publish it." but have to ask - since the Science is Settled, why bother?
Tom S.Moderator Response:[DB] Thank you for taking the time to share with us. Skeptical Science is a user forum wherein the science of climate change can be discussed from the standpoint of the science itself. Ideology and politics get checked at the keyboard.
Please take the time to review the Comments Policy and ensure future comments are in full compliance with it. Thanks for your understanding and compliance in this matter.
Off-topic snipped. -
One Planet Only Forever at 03:08 AM on 6 January 2019CO2 measurements are suspect
billev @89,
Your clarifying of what you are suggesting or asking about has been helpful.
As Eclectic has pointed out, politics related to climate science can be discussed on Weekly Digests.
I can add more science related points to what Eclectic mentioned.
All global leaders, in business and politics, have been increasingly informed about the constantly improving awareness and understanding of climate science through the collective global expertise evaluating the science and consolidating summaries of scientific understanding (with regular updates - because science by its nature is constantly increasing and improving awareness and understanding).
The IPCC is the global body that does that. Many IPCC Reports have been produced, starting with the AR1 series of reports that were published in 1990. The IPCC is currently working on the AR6 series of reports planned for publication starting in 2021 with the last document of the series planned to be published in 2022.
So there is very little 'climate science' awareness and understanding that the Governor of any state (or elected official at a Federal level) would be 'unaware of'.
Consider that understanding of history of availability of awareness and understanding of climate science the next time you read about some elected official questioning how much is really understood about climate science. You should seriously question, be skeptical of, the motives of such a questioner.
Climate science has confirmed that future negative climate change consequences are being caused by the continued increase of CO2 in the atmosphere due to human activity, mainly the burning of fossil fuels. And the scientifically understood solution is to stop increasing the CO2 in the atmosphere. So every regional leadership is tasked with the responsibility of figuring out how to get their portion of the global population to stop contributing in any way to the increase of CO2 or other human activity created GHGs.
That is as far as the science goes. And that understanding is not going to be changed by new research. All evidence indicates that the urgency to stop the creation of new CO2 is only going to increase as business and political leadership fail to effectively correct the problem that has been developed.
I hope that helps you understand this issue.
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michael sweet at 21:18 PM on 5 January 2019It's the sun
AFT,
My feeling is that the "skeptics" have given up. 10 years ago they argued that it was not warming. Now most of them say they have always said it was warming but the warming will not be bad. They also argue that it will crash the economy to take action even though all peer reviewed studies say it will be beneficial.
Not very many people argue that it is past solar activity stored up. Can you link an example of a serious argument? Scientists have identified the sources of heat. During El Nino some stored heat is released while more heat is stored during La Nina. Longer term storing of heat is global warming. Can you link an example of someone claiming a war of statistics?
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Eclectic at 13:52 PM on 5 January 2019CO2 measurements are suspect
Billev @ 85/89 , if you are talking about science ~ then the sources of atmospheric CO2 are already well-known (and have been, for decades).
If you are talking about politics (the best policies for abating the global warming problem, and the most speedy but economical & socially-advantageous ways of achieving zero nett carbon emission) ~ then this is not the right thread for such discussion [perhaps try one of the Weekly Digests?]. As always, you would need to give consideration to jobs lost versus jobs gained in advancing renewable-type industries & services . . . and put everything in perspective wrt past & present out-sourcing of jobs to China, Mexico, etcetera, in both the short term and longer term.
B. Your comment at #86 is bizarre. Please read Climate Myths 12 and 91.
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billev at 12:14 PM on 5 January 2019CO2 measurements are suspect
My point is this. The Governor of California is attempting to install laws to limit the use of fossil fuels in order to reduce GHG emissions. This may prove to be costly to the citizens of California in terms of higher operating costs and the departure of manufacturers and jobs. If a better understanding of the sources of GHG (particularly CO2) can demonstrate that the laws limiting human consumption of fossil fuels will not significantly diminish the growth of CO2 levels then unnecessary costs caused by those laws can be avoided. In other words if it is found that increasing vegetation due to a warming Earth is the only significant source of increased atmospheric CO2 then the futility of costly policies to limit fossil fuel use might be avoided. To this end it would be valuable to political leaders to have much more detailed measurement and analysis of the sources of atmospheric CO2 than is now available.
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AFT17170 at 11:29 AM on 5 January 2019It's the sun
I discovered this site about a month ago and have been working my way through several of the articles and thousands of comments. The comment traffic on this article has been quite light since mid 2017. Have the skeptics given up this argument?
My layman's absorption of all this is the following (expressed in my layman's language) — it seems that any argument along the lines of "it's current solar activity (of some variety)" is devastated by the broad array of evidence... less incoming radiation being measured, less outgoing radiation measured, nights warming faster than days, winters warming faster than summers. I think I get that, let me know if I missed or mistated something.
Does this array of evidence Is also work against the varieties of "it's past solar activity stored up and now being released", or could such forcings be consistent with the previously stated evidence? Or does that devolve into a war of statistics?
Thanks in advance.
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Eclectic at 10:08 AM on 5 January 2019CO2 effect is saturated
LTO @482 ,
forgive my bluntness, but your recent questions show that you are still floundering rather than "understanding the principles [behind the GHE]".
The GHEffect is multi-faceted, but straightforward. Take your time, think things through and put the pieces together in your mind. There is no trickery, no hidden or undiscovered "unknown unknown" factors . . . it is all simply very basic physics [high school level physics will be quite adequate].
Picture the Earth of 300 years ago, when things were very close to equilibrium [though to be more accurate, the Earth has been cooling very gradually for around 5 thousand years]. The air CO2 level was about 280ppm, and the "escape altitude" was at the appropriate level. Now look at today : CO2 level 410ppm, and the escape altitude has risen 100 or 200m higher and colder ~ fewer and slower molecular collisions. And therefore marginally less excitation and emission of 15um photons to space. And yet we still have about the same incoming heat energy from solar radiation. Result : imbalance.
Now jump 100 years into the future. Wise political leaders have (of course!) long ago brought "zero nett carbon emission" into being, and have fostered projects which incorporate carbon (dioxide) into the soil . . . bringing air CO2 levels down to the low 400's. Planetary surface temperature is 1 degreeC above 2019 levels [i.e. 2 degrees above pre-industrial levels] and is steady. The escape altitude is at (say) +300m, but the air at that point has [stabilized] become slightly warmer . . . enough for the 15um IR loss-to-space to have increased back to the pre-industrial amount ~ so the Earth is in thermal equilibrium again (solar radiational input and terrestrial radiational output are matched). But we on the surface here are 2 degrees warmer than pre-industrial.
The alternatives are rather worse, if we allow the GHE to push things up 3 or 4 or 5 degrees.
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michael sweet at 08:42 AM on 5 January 2019CO2 effect is saturated
MA Rodgers: Thanks for posting that graph.
LTO:
Black body radiation is the net of all the photon emitting events. When the temperature is higher more photons are emitted. According to the Boltzman equation, the number of photons emitted is proportional to T raised to the fourth power. A small change in T means a large change in photons emitted.
UV radiation not absorbed in the stratosphere passes through the Troposphere and is absorbed at the surface. There has to be an absorbing molecule, like ozone in the stratosphere, for the energy to be absorbed.
It appears to me that you are applying a double standard. Unknown "Global cycles" do not need evidence while scientific explainations require every T crossed and I dotted. Fortuantely, the T's and I's have all been done. Keep reading scientific sites and you will find out what you seek. Be careful of reading "Skeptic" sites as they traffic in nonsense which has to be unlearned.
1) Exact numbers are beyond my pay grade. Look at MARodgers graph.
2) The temperature at the escape altitude is essentially fixed because it must be high enough to allow all the energy incoming from the sun to be emitted. The lapse rate of the atmosphere (the decrease in temperature with increasing altitude) is a physical constant and is also fixed. When the escape altitude increases, the temperature at the new escape altitude also increases to ensure conservation of energy. When the temperature increases at the new escape altitude the increase propagates down to the surface to comply with the lapse rate.
While at the surface the 15 micron absorbtion is saturated at the escape altitude it is not. Therefore increasing CO2 increases temperature. People who do not understand the greenhouse effect think because absorbtion at the surface is saturated temperature cannot increase. The escape altitude is where the action is .
Someone else suggested that the temperature at the escape altitude did not change as much as I think it does. I think there is an issue of different simplifications of a complex subject.
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One Planet Only Forever at 08:01 AM on 5 January 2019CO2 measurements are suspect
Billev @85 and 85,
In addition to RickG's question I am curious about why you mention that the Governor of California would care about the atmospheric CO2 levels in that State.
Identifying sources of CO2 emissions or other GHGs by satellite survey could be helpful. But other than identifying concentrated human production sources of GHGs, the level of CO2 in a region is rather 'beside the point'.
Increased CO2 is happening globally (it is seen at every location that measures CO2 levels).
The Global Warming and resulting Global Climate Changes are the problem.
Please provide more detail regarding exactly what you are suggesting or asking about.
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RickG at 07:46 AM on 5 January 2019CO2 measurements are suspect
@Billev (86). I'm not quite sure what you are suggesting. Are you saying that gloal warming is causing a rise in CO2 and not the reason for global warming?
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billev at 03:31 AM on 5 January 2019CO2 measurements are suspect
My previous comment is based upon the idea that the current CO2 level in the atmosphere has an effect on global warming. In fact it is more likely an effect of global warming rather than a cause of it.
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billev at 03:19 AM on 5 January 2019CO2 measurements are suspect
From the comments above, I feel that the current capability for measuring atmospheric CO2 is grossly inadequate. For example, I would think that if the Governor of California wished to concentrate on levels of CO2 in his state that might be problematic then he should have access to CO2 measurements at a number of surface CO2 measuring sites scattered across the state. He could then better determine if actions to reduce human induced CO2 emissions would have any significant impact on the overall CO2 levels in the state. He might well discover that the CO2 output from the states areas of intense vegetation could not be significantly countered by reducing the level of human induced CO2 emissions. Then again, he could receive evidence that such measures might well reduce the CO2 level to an acceptable amount.
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MA Rodger at 00:52 AM on 5 January 2019CO2 effect is saturated
LTO @482,
An unsaturated GHG (like methane) does provide for stronger warming effects with rising concentrations, these being roughly linear increases in warming with rise concentrations, rather than the logarithmic relarionship found with CO2.
(1) What you mean by "bands of absorption" is not clear. The bendy wobble absorption band at 15 microns is made up of a set of wavelengths which are weaker the further away from the central part of the band. Thus the CO2 absorption appears as a wide dip at 15 microns as per this graph below.
Note the small spike in the centre of the dip. This is the strongest part of the CO2 bendy wobble absorption. Here at this precise wavelkength you would be up into the stratosphere before a photon has a clear shot at space. (It is an upward spike because the stratosphere is warmer at that altitude than the upper troposphere.
One of the effects of adding CO2 to the atmosphere is to widen the broad CO2 dip as there are weaker wavelengths at the edges that are not saturated and in dry air would allow a photon to be emitted by CO2 and have a clear shot at space from ground level.
If you mean by "band" an energy of photon that imparts a different wobble into CO2, there are none of consequence operating in the IR range, the closest being 4.3 microns.
(2) The impact of altitude-increase is that (and here your question up-thread was hidden by your additional comments on 'rate of collision') through the troposphere temperature drops with altitude and so the Stephan-Boltzmann relationship applies. A colder gas is unable to emit as much IR. See the contours on the graph above. Less photons emitted to space, more energy accumulating on the planet, a warming planet until the energy fluxes are balanced
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LTO at 23:57 PM on 4 January 2019CO2 effect is saturated
To clarify my query: I understand well enough the principles behind the greenhouse effect. However, what I recently only became aware of was that there is already a vast overabundance of co2 to absorb all the IR emitted at 15 um, so the effect of adding more co2 at current levels must have a vastly smaller effect than adding thse same amount of co2 at much lower levels. This seems to be common ground amongst those in the know, but I'd say unknown to 99% of people.
The explanation for why it matters nevertheless seems to be twofold, and here is where I'm struggling to understand quantitatively how significsnt the effects are.
1. CO2 also has other minor bands of absorption, which may depend on concentration amongst other factors, that arent saturated. My question here is just how much additional energy this actuslly captures and re-radiates back to the ground. Is it really significant in the grand scheme.
2. Increasing CO2 increases the altitude of emission (perfectly happy here), and because 15 um photons are being released at this higher altitude therefore global warming (this is where I'm getting lost).
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LTO at 23:40 PM on 4 January 2019CO2 effect is saturated
Michael: thanks for taking the time. Apologies on the collision point, i see it's a bit of a red herring. I'm still not getting the importance of temperature on the escape altitude. I understand black body radiation (kind of) but not how that relates to the discrete emission of a photon from an excited molecule. In other words, the collision between bulk property thermodynamics and a discrete quantum event. This may just be my own deficiencies.
What i don't follow is your point on UV and stratosphere. The article you linked to https://www.wunderground.com/resources/climate/strato_cooling.asp was clesr that tbe decrease in ozone layer was the main cause in a large decrease in stratosphere temperature through decreased UV absorption. It *must* therefoelre be the case that this energy was transferred to the troposphere instead. Given ozone depletion very simply predicts a decrease in stratosphere temps, the greenhouse effect prediction would seem to carry less weight: the two effects would need to be disambiguated, increasing uncertainty, particularly as according to that article the ozone effect is dominant.
I'd suggest its unfair to call explanations based on temperature cycles post hoc - this idea is obviously very well supported by the pre-industrial historical record. The weakness in that argument is of course that it predicts anything, amd therefore predicts nothing .NNevertheless, the challenge is to show something unusual is happening, which is difficult to do persuasively when we've only been measuring certain metrics for a short period. That's a very different topic to this one though!
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michael sweet at 22:59 PM on 4 January 2019CO2 effect is saturated
LTO,
Unfortunately I do not have much time.
1) The number of collisions at the surface is about 1 million times faster than the relaxation time. The change in temeprature to 10 kmn is about 40C. That is about a 20% change in speed and collision rate. The pressure change is about 40 kPa. About a 40% change which changes the collision rate a little more than 40%. Combined they change the collision rate less than a factor of 5. At the escape altitude there are 200,000 times as many collisions as emissions.
The atmosphere is a black body. At a lower temperature it emits less energy. Science of Doom will have a graph of energy emitted compared to temperature. Black body radiation changes relative to T to the fourth power so small changes are a much larger effect.
Complex models can exactly calculate the emission spectrum of the entire atmposphere at any level or all combined but are not needed to explain the greenhouse effect. They demonstrate that scientists know what they are talking about. (I do not have time to find a reference, sorry)
2) Most of the UV light is still absorbed. There is not that much energy in the UV remaining (it can be calculated and is considered by climate scientists).
The Stratosphere is a completely different situation than the Troposphere. The Troposphere is heated by energy coming up from the surface. CO2 blocks this energy from escaping (until it reaches the escape altitude) so the Troposphere warms.
The Stratosphere is warmed by UV light from the Sun. Increased CO2 causes increased emission of IR energy. Since the Stratosphere is above the escape altitude (as discussed above) the increased IR emission results in increased loss of energy and cools the Stratosphere. The key understanding is the escape altitude (which is very complicated but we simplify to 10 km for these discussions)
Scientists predicted this effect in advance. It is a key signature of the greenhouse effect. Post hoc explainations about unknown "global oscellations" do not hold the same weight as predictions made in advance. I know of no alternate explainations for how the Troposphere could warm as the Stratosphere cools.
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MA Rodger at 22:49 PM on 4 January 2019CO2 effect is saturated
LTO @472 &475,
I think I should add to the message from Tom Dayton @473.
You talk of "unknowns in the system" and "taking someone else's word for it."
I appreciate that getting a grasp of AGW can be frustrating. I remember when I first encountered the Greenhouse Effect and the idea that there could be some equivalent to a sheet of glass allowing light in but preventing IR escaping seemed a bit much to accept. What you tend not to find, even now, is convincing explanations as to why the Earth's atmosphere is more hermitically sealed than any greenhouse or blanket. So I'll say it here. The atmosphere is incredibly well balanced vertically. Outside hurricanes, volcanic eruptions and other relatively rare events, the day-to-day reality is the motion of the Hadley Cells, They are responsible for most of the up-down movement in the troposphere and they take about two weeks to rise from surface to tropopause. Yet this is not something you will readily learn if you start asking folk. I share with you here my own frustrations from a few decades ago.
Yet there are some (probably very many) apparent incongruities that can be expressed about AGW that are not readily answerable in a simple way using non-scientific argument. This SkS site addresses many but there are always different flavours of incongruity to consider in such a complex system.Yet such incongruities do in no way support the notion of potential "unknowns in the system" where we have to "tak(e) someone else's word for it." And in particular here we are discussing an aspect of AGW that is in no way in dispute as, despite the complexity, there are absolutely no "unknowns in the system."
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Eclectic at 22:30 PM on 4 January 2019CO2 effect is saturated
LTO @477 ,
we seem to have cross-posted at 21:54 PM.
Your first paragraph shows that you are still a long, long way from understanding the Greenhouse Effect.
The "complexity in escape altitude" does not require a "model" of mathematical ingenuity & tour-de-force. You can do a good approximation on the back of the proverbial envelope, using a blunt pencil. Basically, use the temperature lapse rate of around 6.5 degrees per 1000m altitude. (Of course, the escape altitude is not a razor-thin layer, but a fuzzy zone . . .but your can treat it as one particular altitude (as described in some of the comments upthread) . . . while always remembering that other Greenhouse gases have different escape altitudes.
The stratospheric cooling is interesting, in that it demonstrates that modern global warming is not of solar initiation. But in practical terms, the stratosphere is so low density, as to have minimal effect (and similarly with the thermosphere).
Better for now, to focus your thoughts on understanding the GHE. Think about the transient condition, where (as right now) there is a nett inflow of heat into our planet . . . compared with future condition, where the Greenhouse influence has stabilized at a higher surface temperature.
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LTO at 21:54 PM on 4 January 2019CO2 effect is saturated
Michael: fantastic thank you
1. I find this a little difficult to believe in its face (which isn't to say it isn't true!) for two reasons. First, while the number of collisions is high, the relaxation rate of an excited co2 molecule is presumably quite fast, and so the net effect could be considerably more than it appears from the raw collision rate itself. Second, and more importantly, if temperature and pressure don't make much of a difference then why is the increase in escape altitude so important? I'm still not clear on why the relatively small decrease in temperature as the escapeealtitude increases affects the emission of a discrete photon so significantly.
On the ppm point, difficulty isn't a great excuse in my view! The constancy of co2 in ppm is a bit of a red herring, if i'm understanding things correctly, because really it's the molar concentration combined with pressure that gives effect to the phenomena. For example, both venus and mars have comparable (very high) co2 ppm levels, but clearly completely different effects, at least in psrt because of the difference in atmospheric pressure (as I understand it).
2. That's really useful re the troposphere thanks. The complexity in escape altitude mustmmake things very difficult to model.
That link is really interesting for two reasons. First, it implies that actually the hole in the ozone layer should uave been responsible for a significant portion of troposphere warming, as opposed to CO2. Presumably the UV light that would otherwise have warmed the stratosphere warmed the troposphere instead. Do we know how much troposphere warming is attributable to this?
Second, the point on CO2 cooling the upper atmosphere really didn't make sense to me. The argument appeared based on an assertion that the earth is always radiating the same amount of heat so an increase in troposphere temp must lead to a decrease in upper atmosphere temp, but I thought the whole point was that the earth was retaining more heat. Why isn't the increasing CO2 conc in the stratosphere leading to increased heat retention of photons released by co2 in the troposphere and concomitant warming? Could be related to the pressure point above, but in that case why isn't it a relevant consideration for increasing escape altitude?
3. I will do! May take a while - hopefully will get answered here first.
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Eclectic at 21:54 PM on 4 January 2019CO2 effect is saturated
LTO @472 ,
I must say I am puzzled by your assessment of the Science of Doom website. The Greenhouse Effect is understood through observational studies combined with well-established basic physics. Any usage of models came much later, and is certainly not foundational to the science of it all.
Please do not be discouraged. The CO2/Greenhouse Effect is actually quite simple & straightforward ~ once you have gotten your head around it. But it is not immediately intuitive.
Just like the Galileo/Tower-of-Pisa/falling-weights tale . . . and like the concept of Gravity . . . and Newton's Laws of Motion. All these things can be "unsimple" to explain in a few paragraphs ~ but are quite simple and obvious, after you have grasped the concepts. But for previous thousands of years, they were not intuitive at all ! And still are not ~ until you take a scientific approach and think things through.
As Tom mentioned in #463 : in air, the molecular collisions occur at a rate many orders of magnitude above the "relaxation times" of a CO2 molecule (where a CO2 molecule accepts the energy of a 15um InfraRed photon, and later "relaxes" to emit an equivalent IR photon in a random direction). Even where you reduce that collision rate by a hundred-fold (by reducing density & temperature, e.g. in the upper troposphere), you still get the situation where the collision rate is still vastly greater than the IR relaxation rate. When you think it through, you see that the end result gives a negligible difference in the actual effect [ e.g. comparing the bulk difference between 99.99% and 99.9999% ].
** And LTO ~ a word in your ear. While I myself am sweetly naive and unsuspicious that you might be uttering some phrasing of words which is alas too often heard coming from the mouths/keyboards of trollish science-deniers . . . nevertheless you have managed to cause Tom's ears to vibrate, by your using terms of the type: "incredulity / hoax-like / too-complex-to-be-an-honest-description / etcetera [obviously I am harshly paraphrasing your comments]."
Those sorts of phrasings are common among science-deniers [= faux-skeptics] who subconsciously wish to reject reality ~ and who summon all their powers of distraction & rhetoric, in order to deceive themselves.
( I do read the WattsUpWithThat website, for entertainment. Half the posters commenting there, are angry-crazies & political-extremists who are still in complete denial that CO2 & other Greenhouse gases have any global warming effect at all . . . and many of the other half are intelligent but so deeply affected by their Motivated Reasoning, that they distract themselves by using rhetorical smoke & mirrors ~ basically for deceiving themselves into a viewpoint that "there's nothing really unusual going on, and there's little or no global warming happening . . . and even if it is happening, then it's gonna be good for us, and with no major downsides". )
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LTO at 20:38 PM on 4 January 2019CO2 effect is saturated
Tom: I'm not sure what I did to attract your ire, but I apologize. The point I was trying to express is that the actual theory behind co2-induced global warming is significantly more complicated than I'd thought for a long time. To the extent that I genuinely wonder how many people would really claim to fully understand it, scientists (of which I'm one, albeit not a physicist) included. Is there anyone on this site who would put themselves in that category?
The impression I get (which may not be accurate) from that science of doom website is that the theory is based on modelling of complex interrelated agonistic and antagonostic phenomena, which makes it somewhat different class of scientific theory. Models are necessarily simplifications, and in highly complex systems hidden variables can often lead to very unexpected effects in the real world, which therefore leaves room for reasonable skepticism and uncertainty. Anyway, I'm on a journey of discovery here and have already learnt a lot, in part thanks to you, so once again thank you for your help and I'm sorry you feel you wasted your time.
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michael sweet at 14:33 PM on 4 January 2019CO2 effect is saturated
LTO,
I thought I could chime in since the original question was about my post.
I think you want a lot of detail and Science of DOom and And Then Theres Physics are good sources of detailed information.
For your questions:
1) The number of collisions is so great that the temperature and pressure do not make much difference. (I found an on line calculator once and was amazed at how many collisions there were and how small the temperature and pressure affected the colision rate).
It is probably too difficult to specify the temperature and pressure since it varies so much in different places. The ppm of CO2 is relatively constant through most of the atmosphere.
2) 10 km is commonly used as the escape altitude. This is a simplification for a basic explaination. The actual escape altitude would be different for different wavelengths, different in the tropics and the Arctic, different in deserts than over water and different over storms versus calm weather. Think of how much warmer it is at night when it is cloudy. Only the temperatures in the troposphere matter to the surface temperature. Increasing CO2 causes the stratosphere and the mesosphere to cool at the same time the troposphere warms! source
3) I think the altitude of escape is the key figure but you should check at Science of Doom. Come back here and post if you find out exactly what the explaination is.
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Tom Dayton at 14:22 PM on 4 January 2019CO2 effect is saturated
LTO: Oh, so no one should ever believe or act on any science in any field unless one completely understands everything about it? I’m sorry I wasted the time to answer your questions, because I strongly suspect that you never had any genuine interest in the answers.
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LTO at 13:45 PM on 4 January 2019CO2 effect is saturated
Thanks Tom - that site looks good, but will take some time to work through before can divine anawrrs to those questions. This is clearly very complicated physics - complicated to the extent that I'm wondering how many people really understand it well enough to be completely confident they have taken account of all complexities given the unknowns in the system, as opposed to just taking someone else's word for it. MA may have the answers!
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Tom Dayton at 13:00 PM on 4 January 2019CO2 effect is saturated
LTO: ScienceOfDoom has excellent explanations of the greenhouse gas effect.
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Philippe Chantreau at 12:49 PM on 4 January 2019Arctic sea ice has recovered
https://www.nature.com/articles/s41467-017-00552-1 is where the acutal Stein paper is located.
I'll elaborate on the Stein et al (2017) paper since it is relevant to Arctic sea ice. Lowisss13 did not refer to the paper itself but to a blog post about the paper. A few things are surpsising in the blog post. There is a graph of sea ice that I could not locate anywhere in the paper. The blog post mentions solar activity but the paper has very little about that, only a mention of obliquity in the conclusion section. It uses a fairly novel proxy analysis and ther eare inconsitencies with already existing work. The authors are very careful to qualify the scope of the results. They point to summer sea ice coverage in conditions significantly warmer than today and ascribe it to major differences in the AMOC, not solar activity.
Here is part of their conclusion:
"Finally, we have compared the Arctic sea ice conditions of the LIG and simulated future climate projections for 2100 and 2300, based on two different IPCC scenarios2, the RCP4.5 (583 ppm CO2eq) and the RCP6 (808 ppm CO2eq) (Fig. 8). Both scenarios show a severe reduction in sea ice coverage in the late summer, i.e., summer sea ice concentrations are significantly lower than those of the LIG. With increasing atmospheric CO2, however, the reduction of sea ice in the central Arctic Ocean is more rapid and disproportionately high in comparison to its margin. Whereas the mid-LIG summer sea ice concentrations were still around 60 to 75% in the central Arctic Ocean, but only around 20% or less along the Atlantic-Water influenced Barents Sea continental margin, nearly ice-free conditions might be reached in the entire Arctic Ocean in 2300. The number of ice-free summer months is increasing with higher atmospheric CO2. Under these high CO2 concentrations, the winter sea ice may start to melt as well (Fig. 8). Furthermore, the higher obliquity during the LIG (Supplementary Table 6) may suggest an insolation forcing during the LIG, whereas for the climate scenarios RCP4.5 and RCP6 the additional heat fluxes are induced by increased greenhouse gas concentrations in the atmosphere."
Not much ground for optimism there.
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Tom Dayton at 12:21 PM on 4 January 2019CO2 effect is saturated
LTO: Sorry, i’m Not knowledgeable enough to answer those questions.
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LTO at 11:35 AM on 4 January 2019CO2 effect is saturated
Graph of temperature and pressure by atmospheric height here: https://imgur.com/a/juS7yVf
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LTO at 11:29 AM on 4 January 2019CO2 effect is saturated
MA, Tom: really appreciate your replies, explains some points but also raise a few things I don't quite follow.
1. How significant is the effect of temperature on the likelihood of excited CO2 photon release? At higher altitude the atmospheric pressure is also decreased, which means that the length of time between molecule collisions is also increased. Similarly lower temperatures will decrease the rates of collision. Part of the issue here is the reporting of CO2 in ppm only - given the changes in pressure and temperature I'd have thought you needed accompanying concentration /pressure / temp data to really makes sense of how the competing phenomena interact.
2. Do you know what altitude range the CO2 photon to space release currently happens, how its changed and how sensitive this is to CO2 concentration? As I understand it the temperature actually increases between the tropopause (~11 km) and stratopause (~50 km). It decreases again to the mesopause (~85 km) and then stays pretty constant. The pressure by contrast drops 10 fold every 15 km or so. (see attached)
3. Is it only the altitude of escape atmospheric layer that is the relevant metric here in determining warming, or is it the depth of the envelope from ground to the altitude throughout which warming occurs. I'm trying to understand where exactly in the atmosphere the warming actually happens, and how this is then reflected back at ground level.
Thanks!
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Philippe Chantreau at 11:23 AM on 4 January 2019Arctic sea ice has recovered
My remarks are entirely warranted. What's in your eyes is irrelevant, and most likely what you want to see. Proper statistical analysis is what allows to determine whether there is a stabilization, a recovery or a continued trend. There is no stabilization in the PIOMAS data, the period you are considering is too short to yield any trend without a margin of error so large that no information can be extracted. There are multiple periods in the data where there appears to be a stabilization, and even increases, but the trend remains, as it does in the temperature escalator. There is no sign of stabilization in the sea ice extent either. Having an open mind does not equate to fooling oneself with wishful thinking.
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Lowisss13 at 04:40 AM on 4 January 2019Arctic sea ice has recovered
WOW! You're all so agressive!!!
Please keep your mind open.
-Recovery is maybe not the right term to use at these point. In my eyes, the last decade is more a stabilisation on term of arctic sea ice extend. There is always an stabilisation before a change of slope in an oscillation.
You all seem to see a strait line in the graphic of ''Arctic sea ice volume anomaly from PIOMAS''. For me it's a curve or rather the 1/4 of an oscillation.
Here's one source of reflection:
-Yes, 30 is the ''magic'' number in term of statistic. But considering the long climatic history of earth, we should consider a sample of 30 years, 30 centuries, 30 milleniums, etc. If you study the climat of the last century, 30 years is effectively more than sufficient. But the point is to determine what's the best gap of time to consider for climate variability.
-Solar activity is slowing and sunspot # 24 was smaller than expected. Now they have made a prediction for the next sunspot:
www.nature.com/articles/s41467-018-07690-0
Small Solar Activity variation can have huge effect on earth climate.
To me it's sound logical considering the size of the sun vs the size of the earth.
arxiv.org/ftp/arxiv/papers/0706/0706.3621.pdf
Co2 is certainly part of the climate change. But at what level?
Moderator Response:[DB] Off-topic and baiting snipped. Note that Stein et al 2017 supports that the recent loss of Arctic sea ice extent is unusual in the context of the Holocene, and does not detract from the anthropogenic nature of the current warming and the ongoing losses from the Cryosphere.
If you wish to discuss other aspects of climate change, such as solar levels and/or CO2, numerous other, more appropriate threads exist here. Use the Search function to find a more appropriate thread to discuss those. Also, please review the Comments Policy and ensure that comments adhere to it. Thanks!
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MA Rodger at 02:17 AM on 4 January 2019CO2 effect is saturated
LTO @462,
Regarding the altitude issue, I think the explanations you see as being at variance is due to them being part-explanations.
To explain:- if atmospheric CO2 levels increase, the altitude at which CO2 can emit photons dirctly into space increases. This results in the temperature of the space-emitting CO2 being lower and this lower temperature reduces the number of photons emitted and thus the global energy being lost to space.
These CO2-emitted photons are all in a small part of the IR spectrum with ~15 microns wavelength.
As the global energy is now out-of-balance, global temperature will rise, this temperature rise increasing the photons lost to space over all of the IR spectrum. When the energy balance is restored through this warming, the CO2 emission altitude will still be cooler than the emissions altitude prior to the increase in atmospheric CO2 levels.And I feel your "other query" hasn't been fully addressed.
A photon at the right energy (ie wavelength) can be absorbed by a CO2 molecule and set it into a bendy wobble. In almost all these occurances, the CO2 molecule will then be involved in a collision with another air molecule and the photon's energy will be absorbed within the gas, it being transferred to other modes of gas energy. You ask what then happens to this energy. It will be passed around the gas, this constituting a temperature increase. But a temperature increase will also mean more CO2 molecules are being walloped by the air molecules about them and this will result in more of them being in that bendy wobble which allows them to emit a photon. So more temperature also means more photons emitted by CO2, this cooling the gas, this providing an energy balncing mechanism. And note that if the number of absorbed photons increases because of more CO2, there is also more CO2 to go into a bendy wobble and then to emit photons, which also balances out the energy equation.Of course, those are still much-simplified descriptions.
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MA Rodger at 21:57 PM on 3 January 2019CO2 effect is saturated
Eclectic @465,
I think your response to the trolling is appropriate. I would perhaps add that the fool cannot even provide the numbers in his first point correctly. The date since which peak monthly surface temperature anomalies exceeded later lower anomalies in duration and in temperature difference was 2008 not 1995. This should be no surprise given the 2010 El Nino wasn't as big as the 2016 or 1998 versoins.
Moderator Response:[DB] Inflammatory snipped.
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Eclectic at 21:26 PM on 3 January 2019CO2 effect is saturated
Geologist-for-a-change [of pseudonym? ] @464 ,
Attention !
# You have posted on the wrong date. It is not yet April 1st.
# You have posted in the wrong thread. This thread is for "CO2 Saturated"-related comments.
# You have posted on the wrong website. You should be on WattsUpWithThat ~ the home website for commenters who have the deluded belief that the scientists are all wrong about everything.
# And you appear to have posted 27 years prematurely. If you have (as you say) studied climate science full-time for 3 years, and have not yet disentangled yourself from (almost) every piece of climate crackpottery known to man . . . then it sounds like you have stepped out no more than 10% of your journey from ignorance to knowledge.
Please return in 2046, and let us know how your education succeeded.
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Geologist for a change at 20:43 PM on 3 January 2019CO2 effect is saturated
Goodbye man-made global warming? As an independent (i.e. impartial) consulting geologist (doctorate in sedimentary geology) with 35 years of experience, having conducted an unpaid (impartial) full-time 3-year (since Nov 2015; continuing) review of the literature from ALL scientific disciplines relevant to climate- and sea-level change (geology, archaeology, physics, astrophysics, oceanography, meterorology, etc, etc), here are my main conclusions:
(1) There's obviously no doubt that Earth has warmed since thermometer measurements began in the 1800s (HadCRUT data; and online NASA/GISS online charts [yearly, monthly, and others], updated every few weeks). However, Earth began COOLING in February 2016 (NASA/GISS monthly chart). This cooling already exceeds all other measured coolings since 1995, in both duration (nearly 3 years so far) and magnitude (0.5 degrees C, fully one-third of IPCCs dreaded '1.5 degrees C by 2100', but in the wrong direction) ...
(2) Warming was driven by increasing solar-MAGNETIC output (controlling cosmic rays, therefore cloudiness; Svensmark's breathtakingly elegant theory), nothing to do with mankind's CO2 emissions which just happened, by pure (bad) luck, to grow during a solar upswing (rather than downswing), a ghastly coincidence; the reverse was about equally likely, 50:50.
(3) Changes in temperature are lagging about 25 years behind changes in solar-magnetic output, due to ocean thermal inertia (google it), dismissed by IPCC.
(4) Sea level is about to rise about 3 metres (sic), before 2100, driven by the increase in solar-magnetic output (up until its 1996 peak), its effect on sea level delayed a further 20 years (approx.; i.e. total sea-level lag is about 45 years) due to ocean 'conveyor-belt' circulation (also ignored by IPCC) delaying the arrival at Antarctica of 'solar-overwarmed' Atlantic surface water, via downwelling and southward mid-depth flow (AMOC). The floating ice shelves buttressing Antarctic on-land glaciers are NOW disintegrating at an accelerating rate (led by Pine Island, Thwaites and Totten), so catastrophic glacier failure by MISI and/or MICI is likely to begin within a decade, raising sea level by at least 3m within about 50 years. It's unstoppable.
Am I right? We'll know very soon. Regarding solar control of global temperature, the next two years will tell: I predict continued cooling, so keep a close eye on that NASA temperature chart. Regarding sea level, we'll know within 10 years, possibly much sooner: I predict the rate of sea-level rise, currently a trivial 3mm/year, but already increasing exponentially, will be at least ten times higher (3cm/year) by 2030, if not 2025. Watch NASA's online sea-level chart, updated every few months.
See my 20 ResearchGate contributions, mostly one-page items or single figures, fully self explanatory ... https://www.researchgate.net/project/Imminent-metre-scale-non-anthropogenic-sea-level-rise
Moderator Response:[DB] "Earth began COOLING in February 2016"
Statistical significance testing shows that, for climate related changes, 17 years (Santer et al) are the bare minimum, with 30 years or more being typically used.
For ANY of the instrumental series, over ANY time span ending in the present:
• There is NO period where warming is invalidated, against a null hypothesis of no warming. NONE.
• Against a null hypothesis of the long term warming trend, there is NO period where a "no warming" hypothesis is validated. NONE.
• Over ANY period with enough data to show statistical significance, that data shows a statistically significant warming trend. ALWAYSErgo, the warming continues, unabated.
Note that commenting here at Skeptical Science adheres to the nature of the OP of the thread upon which you comment. Please follow that rule. Thousands of comment threads exist here upon virtually every topic related to climate change and the denial of it. Use the search function to find the most appropriate thread for your expansion of your knowledge of the science.
Off-topic snipped.
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One Planet Only Forever at 15:12 PM on 3 January 20192018 SkS Weekly Climate Change & Global Warming News Roundup #52
It has been almost 20 years since Mark Hertsgaard explained that a Global Green Deal would be required to achieve the corrections that climate science has exposed are required for humanity to develop a sustainable and improving future on this planet (more info in WP Opinion piece by Katrina vanden Heuvel "Why the time has come for a Green New Deal")
A recent update of that understanding is the USA Green New Deal. And the WP Opinion piece ends by stating that Green New Deals are required in every nation (it needs to be global).
I reviewed the Green Party's detailed presentation of their Green New Deal. The GP Green New Deal has many similarities to the Leap Manifesto that was developed in the spring of 2015 in Canada. So Global action is happening.
A significant problem is how easy it is for misleading marketing to convince people that the system corrections identified in the Leap Manifesto or Green New Deal would not be personally advantageous (compared to their incorrectly developed perceptions of prosperity and opportunity).
Through the past 30 years most of the supposedly more advanced nations, and supposedly most rapidly advancing nations, have developed in the incorrect direction. They have developed an increased requirement for correction (and more future climate change harm).
Too many people are easily tempted to try to get away with more incorrect activity while avoiding suffering negative consequences. And their exposure to potential negative consequences from the required correction has increased as they prolonged or increased their development in the wrong direction.
That is the insidious damaging result of the deliberate misleading marketing efforts of undeserving wealthy people. An increasing number of people incorrectly develop larger required corrections that they will have to suffer the consequences of. And their increased resistance to being corrected (to avoid those consequences), just makes things worse (except for a few craftier rich people who manage to evade suffering significant negative consequences for their incorrect harmful actions)
Correcting popular and profitable activities is very difficult. It is more difficult the more popular and profitable they have been allowed to become.
The Leap Manifesto and Green New Deal contain many elements that would substantially correct the systems that so incorrectly developed unsustainable and harmful activity.
But to get to that corrected system, the undeserving winners in the existing systems need to be exposed as being the harmful people they actually are with real potential negative consequences for how they have behaved (the threats of law suits by young people are a good start).
As Naomi Klein titled her book that was associated with the development of the Leap Manifesto "No is not Enough". It is necessary to do whatever is required to correct or limit the behaviour of the undeserving rich (and wanna be rich) likes of Trump, not just tell them No. Don't just explain that they are incorrect and hope they will behave better (because they won't change their mind unless they sense that they really need to behave better to avoid personally suffering a worse consequence as a result of stubbornly refusing to correct their thinking and actions).
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Tom Dayton at 14:59 PM on 3 January 2019CO2 effect is saturated
LTO: Contrary to your second sentence, the temperature at the altitude of escape decreases, not increases. That is not because the temperature at a given altitude (of the troposphere) decreases. Instead, it is because the altitude of escape increases, and higher altitudes have lower temperatures. Increase in temperature of a given altitude due to greater CO2 absorbing IR from below, is insufficient to counteract the lower temperature due to the higher altitude of escape. The altitude of escape increases because of the larger number of CO2 molecules between a given altitude and outer space.
Regarding your second query: A CO2 molecule collides with other molecules--CO2 or other--about 100,000 times more often than that CO2 molecule emits a photon. So the vast majority of the time, the energy a CO2 molecule acquires from absorbing a photon is transferred to other molecules. That is part of the reason why Mars is so cold despite having so much more CO2 than the Earth does. Mars has so few molecules of anything in its atmosphere, there are few transfers of energy to other molecules, so much more of the energy remains in the CO2 molecule until it is emitted as a photon.
Yes, photons are emitted from CO2 molecules in random directions.
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LTO at 13:20 PM on 3 January 2019CO2 effect is saturated
Hi all, i'd like to follow on from Arf @459 above. It doesn't seem his query on why the temperature of the upper atmosphere matters when we're talking about discrete emission of a photon has been adequately addressed. The comment at 461 seems contradictory, as if there is an increase in temperature at the altitude of escape then this will increase black body radiation to space...
My other query relates to how the co2-absorbed photons actually contribute to warming, if the re-emitted photons are of the same energy as the absorbed ones. Is it that through a kinetic effect where a proportion of high energy absorbed co2 molecules vibrate surrounding air molecules, losing the absorbed energy and therefore never re-emitting the photon? Or is it because a proportion of the re-emitted photons are absorbed by something else (water, the ground etc). Or both?
I assume the photons we're talking about make their way out pf the atmosphere through a random walk type process
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Philippe Chantreau at 12:43 PM on 3 January 2019Arctic sea ice has recovered
To substantiate my previous post, the trend for September Arctic sea ice, when the minimum extent takes place, is -12.8% per decade, plus/minus 2.3%. 2017 and 2018 were above the trend line but within, or very close to the margin, not significant. Not a single month has 5 or more consecutive years above the trend line, within the margin or not. The trends for summer months are the higest. There is no way to interpret any of this data as even a beginning recovery.
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Philippe Chantreau at 11:59 AM on 3 January 2019Arctic sea ice has recovered
Lowisss13 "Arctic sea ice should continue to recover." In order to continue, it would have to start. There is absolutely no sign of a recovery on the NSIDC data. The trend over the satellite record is down for every month of the year. No recognizable sign of a reversal is visble in the data. The trend in ice volume in PIOMAS is even more pronounced. See applicable sites for reference.
Right now, NSIDC is showing over 500,000 sq.km below median, far below the interdecile range and below 2012 levels; interestingly, Antarctic sea ice is also quite low, close to a million square kilometers below median, with enormous missing chunks in the Weddell, Amundsen and Ross seas. Someone facetious could use a typical denier method and draw a line between the beginning of the record and the latest data point to show a tremendous decrease in Antarctic sea ice.
Perhaps Lowisss13 wants to use only a few years of Arctic data following the 2012 record low summer Arctic ice, which would be ironic following his remark that 70 years is a blink of an eye. A funny variation on the defunct "no warming since 1998" nonsense.
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