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Comments 9801 to 9850:

  1. Water vapor is the most powerful greenhouse gas

    Wowzee , if you are talking about the "GreenHouse" Effect keeping the Earth's surface warmer than freezing point . . . then certainly the effective strength of H2O's GHEffect is larger than CO2's GHEffect.   This has been known for a very long time.  Yes, a very long time.

    It may be best if you stop thinking in terms of H2O being the "dominant" GHE gas.   It is not.   Or rather, in using dominant , you make a misleading & poor choice of words — if you are trying to mean that it is H2O which dominates or controls the situation.

    A horse is far stronger / heavier / more powerful than its human rider.   But it is the lightweight rider that dominates/controls what the horse does.

    So too, the CO2 controls the climate (along with control by changes in solar output & levels of reflective aerosols, of course).

  2. Water vapor is the most powerful greenhouse gas

    Water vapor absorbs more solar energy than CO2 per molecule.  There are many more molecules of H2O in the atmosphere than CO2.  If the amount of absorbed solar energy exceeds the amount of thermal infrared energy that escapes into space, temperatures will rise.

    Burning one molecule of methane produces one molecule of CO2 and two molecules of H2O.  Similar chemical product ratios for burning gasoline, coal, and deisel. 

  3. Water vapor is the most powerful greenhouse gas

    https://earthobservatory.nasa.gov/features/EnergyBalance/page7.php

     Please see the graph from the NASA graph, both H2O and CO2 absorb in the infrared (12 - 14 micrometer) range.  The water vapor window is only slightly affected. Also keep in mind that the concentration of CO2 in the atmosphere is only a fraction of H2O. 

    This is why water vapor is the dominant greenhouse gas. 

  4. Water vapor is the most powerful greenhouse gas

    Water vapor is the dominant greenhouse gas, not CO2. The reasons include 1.) water absorbs infrared light much better and across a broader spectrum than CO2 which prevent the Earth from cooling off and 2.) the density (i.e. percentage) of water vapor in the atmosphere is much greater than CO2.  Physics says that the higher the density a chemical in a medium the higher percentage of light it will absorb.  

  5. SkS Analogy 20 - The Tides of Earth

    swampfoxh @3 and 4. My only caution would be that you are using linear logic. That is, you are dividing 120,000 by 43 to estimate how long the 6th mass extinction will take. I would expect that extinction-level processes are highly non-linear. I would also expect that proceeding 43 times faster than a "well-understood" event means that it will likely happen much, much faster than 120,000/43 years. I am not an expert in this area, so I will stop here and hope that an expert will chime in.

  6. SkS Analogy 20 - The Tides of Earth

    Of course, we made a number of assumptions about how long it took for Earth to proceed from general "goldilocks" conditions to the climate hell of the End Permian, selected 120,000 years, then applied the current rate of GGEs and fudged to get our Sixth Extinction to mature to a 90/97% die off by the year 4880.

    How far off are we???

  7. SkS Analogy 20 - The Tides of Earth

    Thanks for bringing up Milankovitch Cycles. We talk about this in my climate class: Climate Change: Impact of an Outlaw Species. I'll just throw in the calculations we did to compare the current Sixth Extinction with the end Permian along with the effects of the M-cycles. Our best guess was that the Sixth is motoring along some 43 times faster than the End Permian. Anyone out there have a better number?

  8. It's cosmic rays

    unknownwallet @111,

    (I should point out that you do not address the bogus cosmic ray theory which is the actual subject of this comment thread.)

    You say "i'd really to ask someone to prove me wrong" so let's kick off with your statement number one (which is also illustrated top left in the collection of graphics in your third URL).

    By volume, the percentage of water vapour in the atmosphere is 0.4% (and roughly half that by weight), thus much lower than the 2% value you present. In a dry atmopshere, today's CO2 levels top 400ppm(v) or 0.04% (0.06% by weight). Again this is greatly different to your value of (0.02 x 0.0362 =) 0.072%.

    Today's CO2 levels are (1 - 280/400 =) 30% anthropogenic thus 0.012% of the total atmosphere by volume (0.018% by weight) where as you say 3.4% of CO2 is due to human activity and thus 0.0025% of the atmosphere.

    (I should also mention the graphic below top left on your third URL which gives different values again 1% for all GHGs, of which 4% CO2, of which 4% is anthropogenic.)

    The raw volumes/weights of GHGs in the atmosphere is not in a very good gauge of their impact on the climate. Water vapour, for instance, is only present at the levels we see because the long-lived GHGs (which are predominantly CO2) It is long-lived GHGs that raise global temperatures and it is only this increased temperature that to allow the atmosphere to hold such levels of water vapour. And despite there being ten-times-more water vapour (by volume) than CO2 in today's atmosphere, its contribution in boosting the GH-effect is far less than 10x (even when cloud is factored in).

    The one value you provide that is entirely a mystery but also fundamental to your argument is the percent of CO2 - "only 3.4% of CO2 is due to human activity." Where does that 3.4% value come from?

  9. It's cosmic rays

    i respectfully disagree. 

    1. Only 2% of the atmosphere is greenhouse gases, only 3.62% of that is CO2 and only 3.4% of CO2 is due to human activity
    2. CO2 lags temperature changes by 800 years
    3. Sea levels have already been rising for the past 8000 years
    4. Climate change model's predictions have all been overestimates
    5. There has been no global warming for 18 years
    6. There has been no increase in the frequency of storms since 1954
    7. There has been no increase in the frequency or severity of droughts in the US
    8. Warming in the past (before human history) has been far more drastic in the past indicating that current warming is not human caused

    check these infographics to understand more,

    #https://anonfile.com/N28bb553n0/1561633804542_gif

    #https://anonfile.com/P88eb85dnb/1561631378053_png

    #https://anonfile.com/Rc83b055n2/1561629956134_png

    i'd really to ask someone to prove me wrong. 

    human made global warming isn't a huge deal, and there are bigger threats than this. 

    Moderator Response:

    [DB]  Pretty much every point you make is disproven on other threads here. Use the Search function to find a more appropriate thread.  After you read them and the comment threads attached, if you still have concerns, place those concerns there, not here.

    Please stay on-topic.

  10. One Planet Only Forever at 13:11 PM on 6 September 2019
    Consensus on consensus hits half a million downloads

    markpitsusa@1,

    In addition to the points made by nigelj in the comment @2, I have replied to your related recent comment on the SkS OP "The true cost of fossil fuels (Response to the Climate Myth "Renewables are too expensive" (a comment that also referred to Nordhaus). My comment there is regarding the ethical considerations that the likes of Nordhaus seem to not consider, or not be aware of.
     
    Improving awareness and understanding of climate science is an essential part of the required ethical actions. The book "A Perfect Moral Storm: Climate Change, Intergenerational Ethics and the Problem of Moral Corruption.", by Stephen M. Gardener, provides a comprehensive explanation/evaluation of the ethical issues related to climate science, including providing reasons why improving awareness and understanding of climate science is challenged (some people have developed powerful motivations to not want to improve their awareness and understanding, and have developed powerful motivations to not want others to improve their awareness and understanding).
  11. One Planet Only Forever at 12:35 PM on 6 September 2019
    Renewable energy is too expensive

    Markpittsusa@20,

    Do some research into "Discount Rates" applied to evaluating how much harm it is OK for the current generation to cause because portions of the current generation do not want to give up on enjoying current-day (status quo) ways of living (that they have a perceived high status in), that are undeniably harmful to future generations.

    Discounting the future with a 'Discount Rate' basically declares the harm done to future generations to become irrelevant as long as it happens far enough in the future.

    Ethically (essentials of Ethics are Do No Harm to Others; Help the less fortunate), there is no acceptable amount of harm that can be done to Others, and future generations are Others (a massive pool of Others, almost infinite, unless their future numbers are discounted).

    So, ethically it is questionable to include a discount rate in evaluations of how much harm it is acceptable to do to future generations compared to the benefits the current generation would have to give up to not harm the future generations. And given the lack of knowledge (uncertainty regarding anticiated harm, or missed due to ignorance of a potential harm) regarding how much harm is actually going to be done to the future, an amplification of the expected future harms would be more appropriate in an evaluation of acceptability than a discount rate.

    With that understanding in mind, understand that Nordhaus and Stern both applied 'discount rates' in their evaluations. Stern uses a lower discount rate and determines that rapid reduction of fossil fuel use is the correct economic action (and that is still using a discount rate).

    Of course if the ethical unacceptability of harming Others was admitted then there would be no way to justify anything other than the immediate ending of the increase of harm being done to the future generations.

    The incorrectly developed economy of today puts current day humanity in an ethical bind. And the lack of responsible actions by the more fortunate through the past 30 years has made the ethical challenge worse.

    Ethically, the required action is immediate ending of the pursuit of benefit from fossil fuels by current day humans. Except that ethically it is also necessary to 'help the less fortunate'. So the ethical refinement of the required action would be that the most fortunate must lead the effort to end the use of fossil fuels and assist the less fortunate adapt to the harm already being done, and help the less fortunate develop in ways that minimize their use of fossil fuels (essentially the fundamental basis for the Kyoto Accord - read the Kyoto Accord and the understandings that were established as the basis for developing the Kyoto Accord).

  12. Medieval Warm Period was warmer

    Just noticed this paper which looks at global coherence of warm and cold periods over last 2000 years. Not only was MWP not globally coherent but also the LIA had similarly mixed global distribution. Unlike the current warming period...

  13. SkS Analogy 20 - The Tides of Earth

    ubrew12, the complete statement that you partially quoted is

    "On 100,000-year cycles the global average temperature varies by 5°C, which causes variation in sea level of 120 m (400 ft). That is a lot!"

    "That is a lot" refers to a change of sea level of 120 m, not to the temperature change alone. I think many people are unaware that the Earth, through regular, normal, recent cycles, experiences sea level changes of 120 m.

  14. Consensus on consensus hits half a million downloads

    markpittsusa @1

    As to your question on "what we should do now" to mitigate the climate problem I suggest read the IPCC reports here. Broadly speaking mitigating climate change comes down to adopting renewable energy solutions, which will resolve the majority of the problem, but not all of the problem.

    The remainder of the problem is solved with supporting strategies of adopting negative emissions technologies through both enhanced natural sinks and systems of carbon capture and storage, and a moderate reduction in per capita use of energy and carbon intensive products.

    Of course some warming is locked in, so adaptation to climate change is necessary.

    Moderator Response:

    [PS] This discussion is showing signs of heading offtopic rapidly. Discussions of political solutions belong elsewhere.

  15. Consensus on consensus hits half a million downloads

    markpittsusa @1

    "All these articles on concensus are a waste of time. Even most Republicans who oppose legislation believe there is global warming. "

    No the consensus articles are not a waste of time. While most republicans do indeed believe climate is changing, as you say, the more important issue is whether they think humans are causing it, because this will influence what responses they think are appropriate. It's very possible that only a minority of republicans think humans are causing climate change discussed here so its still important to better communicate the consensus studies to the public.

    "The real question is what should we do now, which in turn depends upon the target for warming. Should the target be 1C, i.e., the current level? 1.5C which is the political solution reached with island nations? Maybe 2C, the original UN target? Or higher as Nordhaus argues, more like 3.5C?

    Limiting warming to 1 degree is impossible because we have already passed this number (refer to the NASA Giss temperature record or Hadcrut). Getting warming back down to 1 degree would  be possible but would take time and would require amongst other things negative emissions technology on a vast scale at huge cost.

    Can you provide a link to some evidence that 1.5% is a political solution. According to the IPCC here the reasons are "Furthermore, the report finds that "limiting global warming to 1.5 °C compared with 2 °C would reduce challenging impacts on ecosystems, human health and well-being" and that a 2 °C temperature increase would exacerbate extreme weather, rising sea levels and diminishing Arctic sea ice, coral bleaching, and loss of ecosystems, among other impacts."

    In any event 1.5 degrees is what the IPCC are suggesting, and they are the expert panel appointed to review these things.

    Nordhaus number of 3.5 degrees has come in for a lot of compelling criticism for example here. He fails to consider a whole range of climate impacts and makes some overly optimistic economic assumptions.

  16. SkS Analogy 20 - The Tides of Earth

    "On 100,000-year cycles the global average temperature varies by 5°C... That is a lot!"  Is it 'a lot'?  5C in 50,000 years is 0.01C per century.  The temperature change over the last century is seventy times higher, i.e. 0.7C per century.  I got tired of hearing the phrase 'climate changes naturally' (implying the current change is also natural) so I did some digging.  Looking at the global average temperature over the last 22,000 years, I calculated the temperature change per century for each of the last 220 centuries (further back in time these were estimates).  The plot of those 220 centuries is a normal distribution with an average change of 0.014C per century, and a standard deviation of 0.077C per century.  By ordinary 3-sigma statistics, the claim that last centuries 0.7C change is 'natural' is easily disproven (3-sigma is 0.24C per century).  Since 1993 the atmosphere has warmed at a rate of 2.24C per century, approximately ten times the rate at which it no longer could be considered 'natural', using that 220-century bell curve as a guide.  Climate indeed changes naturally.  Ordinary statistics proves the current change is not even remotely natural.

  17. Consensus on consensus hits half a million downloads

    All these articles on concensus are a waste of time.  Even most Republicans who oppose legislation believe there is global warming.  

    The real question is what should we do now, which in turn depends upon the target for warming.  Should the target be 1C, i.e., the current level? 1.5C which is the political solution reached with island nations? Maybe 2C, the original UN target?  Or higher as Nordhaus argues, more like 3.5C?

  18. Renewable energy is too expensive

    This expose does not reflect careful analysis. Whether renewable energy is cheap or expensive depends upon the time table and extend to which it is to be employed.

    According to Nordhaus, who as you know just won the Noble Prize for his work in this area, 3.5C is the optimal target in terms of mitigation. He includes all the costs (and more) that are mentioned in this article.

    I will not try to repeat his arguments since there are readily accessible in his own words. The best place to start is, for most readers, will be his book “The Climate Casino.”

  19. The North Atlantic ocean current, which warms northern Europe, may be slowing

    Human 2932847 @23-25,

    The article you cite appears a bit odd. Riser & Lozier (2013) 'Rethinking the Gulf Sream' describes itself presenting "Three new climate studies [that] indicate that our long-held belief about the Gulf Stream’s role in tempering Europe’s winters may not be correct. Yet the studies themselves do not agree." Yet these three are hardily "new" dating from 2002, 2009 & 2011. (the 2002 paper being our old friend Seager et al).

    And such a finding wouldn't show "much sign of controversy"?

    Riser & Losier (2013) does set out the two sides of the Seager controversy before pointing to that recent detailed modelling suggests it unlikely that meltwaters will "shut down" the AMOC.

    I have tried to stress that the research is more interested in the fate of the AMOC and measuring the trends so far, rather than the effects of slowdown on Europe (such effects bring the issue we discuss here).  There is detailed modelling (more recent that Riser & Lozier 2013) desribed in this RealClimate OP by Rahmstorf. This work is all about identifiying a fingerprint of AMOC strength in SST data. It does demonstrate the AMOC fingerprint caused by slowing. And regarding the cooling of Europe, note the cooling ocean temperatures up-wind of Europe.

    And "where these questions are more settled"? This is an area of active research. To keep up with it, the "questions" of interest need some defining.

  20. More Carbon Dioxide is not necessarily good for plants.

    If we can successfully reduce CO2 we should be back to get back to the ice age. It can be done with regressive taxes on fuel food and the basics, might get the population down as a boonus.

    Moderator Response:

    [PS] Sloganeering, offtopic, and strawman arguments. You might like to learn difference between pigovian and regressive taxes.

    Please note that posting comments here at SkS is a privilege, not a right.  This privilege can be rescinded if the posting individual treats adherence to the Comments Policy as optional, rather than the mandatory condition of participating in this online forum.

    Please take the time to review the policy and ensure future comments are in full compliance with it.  Thanks for your understanding and compliance in this matter.

  21. Understanding adjustments to temperature data

    frankprice @63: I located Zeke's 2nd installment: Understanding Time of Observation Bias, but I'm not sure what/where the 3rd installment is. That post was supposed to be about "automated pairwise homogenization".

  22. Understanding adjustments to temperature data

    I don't see a Lessons from Predictions in the upper right–hand corner. Where are parts 2 & 3??

  23. UAH atmospheric temperatures prove climate models and/or surface temperature data sets are wrong

    Hi. Sorry for the heavy necromancing, but I find the "Major corrections to the UAH temperature trend over the years" tables shown at the bottom of both levels of explaination to be not very helpful, unless one already knows what they see. In the article linked right above them, it is properly explained what the highlighting is supposed to mean (red: suggested by outsiders, but not applied by UAH; blue: applied by UAH and makes up half the trend) and how the numbers are to be understood in context. I believe it could be helpful to either add a small explaining paragraph or remove the figure here altogether, but emphasize that more information on the messed up corrections can be found follwing the link.

    Thank you for this amazing resource on Climate Change!

  24. The North Atlantic ocean current, which warms northern Europe, may be slowing

    Neglected to link the Sci Am article - here http://fds.duke.edu/db/attachment/2372

  25. The North Atlantic ocean current, which warms northern Europe, may be slowing

    This Scientific American summary goes into the debate over Seager's stuff. It's from 2013 and so has it been superceded ? It says -

    "recent modeling studies with higher resolution of ocean currents suggest that fresh Arctic meltwater may pour mostly into currents that are more restricted to the coastlines and there-fore have less influence on the open ocean, where downwelling primarily occurs. Even if freshwater significantly affected the amount of waters downwelled in the North Atlantic, it turns out to be highly unlikely that this change would effectively shut down the Gulf Stream. A shutdown is unlikely because the path and the strength of the Gulf Stream depend largely on the speed and direction of the large-scale midlatitude winds."

    Which doesn't sound like much of a threat.

    What would be a good source for the latest theories about the Gulf Stream, AMOC etc where these questions are more settled ?

  26. The North Atlantic ocean current, which warms northern Europe, may be slowing

    I don't see much sign of controversy , though, apart from here.

  27. 2019 SkS Weekly Climate Change & Global Warming News Roundup #35

    @William

    1. "I seem to remember that Florida is where the well off; those that made their money ignoring climate change, have retired to."

    2. ""Sea level rise and monster storms couldn't happen to a more deserving people.""

    It appears you have never been to, much less lived in Florida. 

     People who saved and are able to afford a pleasant retirement did not do so by "ignoring climate change", they did so by a dozen different means. Some made retirement nest eggs from saving 7% every year from age 23, some had public sector retirement at age 55, then continue working in some other capacity while collecting a generous pension.  Some were the person who opened the town's best roti-roll joint and then 3 satellites, some developed an app that took off. Some were in  government or other forms of organized crime. 

    What they have in common is that they wasted no time being gloating over bad things happening to people more successful than themselves. 

  28. CO2 effect is saturated

    GwsB:

    You have received a rather negative reaction, because you have made some pretty strong claims based on some faulty reasoning. Regulars here can be pretty impatient with such proclamations from newcomers.

    Let me try to explain where your error lies. To begin, thanks for making it clear just what you think "CO2 effect is saturated" means - often people that make that argument are less than clear. You have based your argument on the (correct) observation that very little IR radiation can travel directly from the surface to space.

    The part where your argument breaks down is actually hinted at in your post. You state that IR radiation absorbed in the atmosphere can be re-radiated - sometimes up, sometimes down. Eventually, that energy will be emitted to space, but it is delayed. Let us look at the implications of that.

    Radiation absorption is a logarithmic function, expressed by Beer's Law. If  a certain thickness of the atmosphere can absorb 10% of the IR radiation,and transmit 90%, then the amount passing directly through is 0.9 of the original value. The next layer (same properties) then transmits 90% of 90%, or 09.*0.9=0.81. The third layer will allow 0.93 = 0.729, and so on.

    The figure below shows that decline. It also shows the same result for a case where each layer transmits 95%, instead of 90%. The layer-by-layer sequence for 0.95 is 0.95, 0.952, 0.953 etc. Note the following:

    • After 200 layers, both curves show essentially zero transmission, fitting your "saturated" argument.
    • In the middle, however, the two curves are clearly not the same.For a coefficient of 0.9, it takes almost 23 layers to reduce transmission to 0.1. For a coefficient of 0.95, it takes almost 46 layers. (Yes, the doubling of the distance is an exact mathematical result of Beer's Law, and the per-layer doubling of absorption from 0.05 to 0.1.)

    The "saturation" argument fails to include that intermediate difference, and that is where it goes very, very wrong. This difference in how much IR radiation is transmitted how far is essential to understanding the greenhouse effect. Adding CO2 has a neglible effect on how much IR radiation can pass directly from the surface to space in a single step, Adding CO2 does affect how far IR radiation gets in a single step, and this affects how many steps it will take before it can finally reach high enough in the atmosphere to escape to space.

     

    Beers Law decay

     

    You can see this in the figure I provide, if you read it from right to left - i.e., think of the right as the surface, and the left as space. IR radiation emitted upward (to the left) at layer 10 has a 39% chance of escaping to space for a coefficient of 0.9, but a 63% chance for a coefficient of 0.95.

    (Note: the values and layers in the diagram are purely illustrative. Radiation transfer in the atmosphere needs to be calculated at many different wavelengths, not a single number as shown above. The general principle is correct, though.)

    As CO2 or other greenhouse gases increase, the IR lost to space originates at a higher altitude, where the atmosphere is colder. This means less IR lost to space, until the atmosphere can warm to compensate.

    An analogy for your "saturation" argument would be a foggy night, where you can't see the building two blocks away, but you can see a building one block away. From the perspective of the distant building, visibility is "saturated" - no light from the distant building is reaching your eye. Does this mean that adding more fog has no effect? No, because additional fog will eventually make it impossible to see the building that is only one block away.

    Proper examiniation of the effects of adding CO2 to the atmosphere requires that the effects throughout the atmosphere be included, not just the direct transmission from the surface to space in a single step. And the calculation that include all those effects show clearly that adding CO2 leads to surface and tropospheric warming.

  29. 2019 SkS Weekly Climate Change & Global Warming News Roundup #35

    I seem to remember that Florida is where the well off; those that made their money ignoring climate change, have retired to.  Sea level rise and monster storms couldn't happen to a more deserving people. A nice twist is that the poorer people live on an inland ridge while the rich, retired are right down on the beach.

  30. CO2 effect is saturated

    GwsB @525 ,

    you have completely failed to understand the CO2 (and H2O) mechanism of "greenhouse".

    Before you embarrass yourself by making further comments about CO2 saturation, please read & think about Dana's OP, and check out RealClimate & other information above. 

    Moderator Response:

    [PS] Please watch tone.

  31. CO2 effect is saturated

    GwsB @525,

    You ask if that Wiki graph you show @525 is misleading. It certainly is!!

    That Wiki graph simply shows the chance of a photon travelling vertically through today's atmosphere without a particular species of GHG absorbing it en route. It shows nothing of how many such photons would be travelling at each wavelength or even in what direction. The CO2 absorption band at 2.7μm is stopping solar radiation coming in from the sun not IR going out. The CO2 absorption band at 4.3μm sits in the gap between incoming solar radiation and outgoing IR - there are effectively no photons to be absorbed so it has no relevance to climate. And the inability of a photon to travel un-absorbed by GHGs out through the atmosphere does not prevent the mechanisms of the greenhouse effect from gaining strength through additonal levels of GHG. And I should add that the Wiki page you took the graph from provides a woeful attempt to describe the mechanisms of the GH effect.

    You say "The basic physics is simple: A photon of light at a wavelength of 14 μm [15μm] is passed from one CO2 molecule to the next performing a kind of random walk until it exits the atmosphere. There are two exits, outer space and the earth. Saturation means that a photon starting from the earth has very little chance of exiting to outer space." The effect of this 'saturation' is solely that there will be a random walk as all photons will be absopbed. This does not of itself make the chances of IR resulting from that absorption exiting into space small.

    Interestingly, you cite Zhong & Haig (2013) 'The greenhouse effect and carbon dioxide' yet you fail to acknowledge the finding of that paper which is "We conclude that as the concentration of CO2 in the Earth’s atmosphere continues to rise there will be no saturation in its absorption of radiation and thus there can be no complacency with regards to its potential to further warm the climate."

    Instead you set out contradictory conclusions of your own - "The total negative impact is almost cancelled by the positive impact around 15 μm."

    The GH-effect works because the emission & re-emission of IR from the atmosphere containing GHGs will only occur at those same wavebands which subject to are absorption. But the rate of re-emission is set by air temperature. As the temperature drops through the troposphere, the point where emissions will get out into space through the thinner upper atmosphere; that point in the troposphere will be colder. Thus the GHG at that higher altitude will re-emit less IR because it is colder. The more the GHG in the atmosphere, the higher the altitude and the bit of troposphere which emits into space and thus the less IR is emited.

    Of course, as the graphics in Zhong & Haig show, that mechanism will go into reverse as the altitude becomes high enough to reach the stratosphere. In the stratosphere, temperature rises with altitude and so the more GHG the greater the IR emissions into space. This is the mechanism which you mention being apparent in their Fig5b which you say results in the increasing GH-effect being "almost cancelled." However, the extra GHG effect of CO2, although reduced with increasing CO2 concentrations in the well-konwn logathithmic relationship, does not peak even if the 15μm band is taken in isolation. It keeps on increasing. And at CO2 levels above 2500ppm(v), the 15μm band is boosted by a compound absorption band at 10μm.

    The climate forcing of CO2 does not hit an upper limit. In the words of Zong & Haig (2013), "as the concentration of CO2 in the Earth’s atmosphere continues to rise, there will be no saturation in its absorption of radiation."

  32. Philippe Chantreau at 23:26 PM on 3 September 2019
    CO2 effect is saturated

    GwsB "the wings have little effect"

    That is false.

    The links at the bottom of this page to RC's saturated gassy arguments threads explains it, as well as other sources.

  33. CO2 effect is saturated

    In the discussion about the effect of CO2 on the climate there are certain images which may be said to incorporate the essential part of the arguments. Such iconic graphs are the driving force in changing one's view of the world. A good example is the sun with the planets rotating around it. This stopped all phantasies about what happens at the edge of the (flat) earth. This iconic image made it possible to sail Westward in 1492 in order to reach India.

    For CO2 the iconic image is the rippled increasing graph of the CO2 concentration as measured at Mauna Loa from 1960 onwards, sometimes extended over the past thousand years by observations from tree rings and ice cores to obtain the "hockey stick". For the influence of CO2 on climate the iconic graph is given in Wikipedia https://en.wikipedia.org/wiki/Greenhouse_effect (last updated 23 August 2019)

    Caption: "Atmospheric gases only absorb some wavelengths of energy but are transparent to others. The absorption patterns of water vapor (blue peaks) and carbon dioxide (pink peaks) overlap in some wavelengths. Carbon dioxide is not as strong a greenhouse gas as water vapor, but it absorbs energy in longer wavelengths (12–15 micrometers) that water vapor does not, partially closing the "window" through which heat radiated by the surface would normally escape to space."

    The graph shows that the effect of water vapour, H2O, is much greater than the effect of CO2. It also shows the saturation of the absorption due to CO2. The first argument (about water vapour) is valid. We can't do anything about the concentration of H2O though, except perhaps by increasing the temperature. So we will just have to accept this effect. The second argument (about saturation) is also valid. The absorption at wavelength 4 - 4.4 μm is 100% over most of the region, and so too at 12-15 μm. In comparison with H2O the peaks of CO2 are very steep and the wings have little effect. It is only the thin peaks at 2 μm and at 4.9 μm which will grow significantly if the concentration of CO2 is increased.

    The basic physics is simple: A photon of light at a wavelength of 14 μm is passed from one CO2 molecule to the next performing a kind of random walk until it exits the atmosphere. There are two exits, outer space and the earth. Saturation means that a photon starting from the earth has very little chance of exiting to outer space. It is almost certain to exit the atmosphere to the earth, where like shortwave radiation it will be re-emitted at a different wavelength. Even if the new wavelength with probability a half lies in an absorption band of CO2 or H2O, this only means a stay of execution. In the end the photon will escape to outer space through one of the long wave gaps in our atmosphere.

    The graph in Figure 2 in Zhong & Haigh (2013) is perhaps more precise, but the vertical scale runs over twelve orders of magnitude, (twelve orders of magnitude is from one mm to a million km, or from one gram to a Megaton). The result of this scale is that I am not able to comprehend the significance of the graph. Figure 5b, bottom, gives the difference between the radiative flux for the present level of CO2 (389 ppmv) and a level increased by a factor 32 (12500 ppmv). The total negative impact is almost cancelled by the positive impact around 15 μm. This impression is reinforced by Figure 6a where the graph is practically horizontal beyond 400 ppmv. In Figure 6b we see an increase in the slope beyond ten thousand ppmv. In that graph the horizontal axis is logarithmic and runs up to a million ppmv, which is a pure CO2 atmosphere. These results are based on models and therefore should be taken with a pinch of salt.

    The conclusion is: The direct impact on the temperature of the earth of the increase in CO2 from the present level of around 400 ppmv is relatively small. This is due to saturation at the bands where CO2 absorbs long wave radiation.

    Is the graph above misleading? It is described as "(Illustration adapted from Robert Rohde.)". Clicking on Robert Rohde results in the message: www.globalwarmingart.com refused to connect.
    If anyone knows a better graph I would be very happy to obtain a link.

    There is a nice course on climate denial presented by the University of Queensland https://courses.edx.org/courses/course-v1:UQx+Denial101x+1T2019/course/ The course is free of charge and contains a huge amount of good information on climate change. Unfortunately the course does not address the topic of the absorption of CO2 at specific wavelengths. Neither does the basic rebuttal by dana 1981.

    The near saturation of CO2 at present levels makes it difficult to convince people to vote for a cut in CO2 emissions or for a tax on such emissions.

    Moderator Response:

    [RH] Your image was breaking the page formatting. I can add it back in but it needs to be smaller than 450 px wide, which for that image was going to render it unreadable.

  34. 2019 SkS Weekly Climate Change & Global Warming News Roundup #35

    Hurricane Dorian is another slow moving Hurricane thus potentially being more damaging. Slow moving hurricanes are associated with climate change and dump more rain.

  35. IPCC's land report showed we're entering an era of damage control

    OPOF @20

    "The 'high meat and fat diets' are often promoted as weight loss diets. The science indicates that people on such diets should be carefully monitored by medical professionals to ensure "

    Yes and I have generally promoted the same. The low carbs high meat and fat diets might make sense as a temporary thing to loose weight, but not as a permanent diet. People should eventually transition back to a sensible sort of balanced diet like the Mediterranean diet.

    The trouble is the low carbs high meat and high fat diets are being promoted as a permanent thing, certainly by at least some experts and many of the people who have tried them. I see this all over the internet. I had to loose weight last year hence my interest.

    This creates an awful mixed message for society where one group are saying reduce meat consumption and eat more plants (carbs) for the sake of the planet, and other groups are saying eat high meat low carb diets.  The health authorities need to give a much more resolved, consistent and clear message.

    Of course the problems of eating too many calories especially if they are mostly white carbs are well known. I would not advocate that. The answer looks like its about balance and keeping total calorie intake moderate within healthy guidlelines, and keeping the white carbs component of this sensible as well. Asians and Italians eat like this and do not have big diabetes or heart disease issues.

    And it has to be said that its not even that clear that such high meat diets loose more weight than other diets in the long run, however if someone is diabetic then a high meat low carbs diet does become pretty imperative.

    "The key is understanding that the high meat consumption diets liked by people who grew up being impressed by people who could afford to eat large amounts..."

    Yes absolutely. Adults only need 60 grams of protein a day which is not very much, and it can come from meat or plants. High meat consumption is indeed more about habit and displays of status. However some meat in the diet seems fine to me in moderation, and another reason is because much of our land only really suits cattle grazing and can't be easily converted to crops. 

    Finally humans evolved as omnivores, ie we eat quite a varied diet with a bit of everything, and it's also important to enjoy our food. I'm reluctant to change this towards extreme sorts of diets, unless theres very solid science based evidence.

  36. One Planet Only Forever at 01:38 AM on 3 September 2019
    IPCC's land report showed we're entering an era of damage control

    nigelj@19,

    The 'high meat and fat diets' are often promoted as weight loss diets.

    The science indicates that people on such diets should be carefully monitored by medical professionals to ensure that their health is not compromised by the strict temporary diet. In some cases, just a minor 'cheat' on the diet can cause major harm to internal organs because the body systems are not in an adaptive state that is able to respond to the 'cheat'. And the person on such a diet still has to learn how to eat a healthy diverse diet that will not return them to the condition they tried to correct.

    The key is understanding that the high meat consumption diets liked by people who grew up being impressed by people who could afford to eat large amounts of meat are not healthy (and the protein from 4 oz of meat is all that a body will process from a meal). And that 'perception of superiority of eating lots of meat' is an unsustainable impression (just as the impressions of over-sized, over-powered personal transportation or housing is unsustainable).

    There is a massive variety of healthier reduced meat diets that can be enjoyed that maximize the use of locally sustainably grown products (including appropriately limited amounts of locally produced meats). And those diets, combined with adding activity like walking and biking rather than 'powered transport' will result in sustainable healthier weight loss, it will just take longer than the 'crash diets'.

    Improving awareness and understanding is hard to do in societies that are flooded with misleading advertising that harmfully develops easily impressed people who want what they develop a liking for 'quicker, easier, and cheaper', people who declare that they cannot and will not give up something they have developed a liking for.

  37. IPCC's land report showed we're entering an era of damage control

    Driving By @14 was perhaps a bit snarky, but does raise a very interesting and pertinent  issue on diet. Dietary advice is indeed  very contradictory, with seemingly well qualified people promoting diets that are low in meat and fat consumption, like the Mediterranean diet, and vegean diets (no meat) and others promoting high meat and fat diets like Atkins, Ketosis, and the Paleo Diet (technically a high fat diet but people will achieve this with higher meat consumption).

    People must be utterly confused, and plenty express this on websites.

    The high meat diets are in total contradiction to advice to reduce meat consumption for the good of the planet.

    Personally I think moderately low meat mediterranean diet makes the most sense all things considered. Italians and Greeks apparently have good health and longevity. Humans are omnivores.

    While meat is an inefficient use of resources, many grasslands grazed by cattle dont really suit crop production, so this suggests to me the only practical answer is moderately low meat diet.

  38. IPCC's land report showed we're entering an era of damage control

    I want to clarify my point @10. I was responding briefly to wjohnallen @7 who it seemed to me made an odd sort of statement namely " it turns out that a cow consumes more CO2 than it belches out as CH4 (on a CO2eq basis at a GWP of 25).Who knew that ruminants on grass pastures are carbon negative? " That seems an impossibility as I explained. Tell me why I would be wrong.

    However I accept there is good evidence that cows can managed to encourage higher rates of grass growth and thus more sequestration of atmospheric carbon by that grass and its products of decomposition in the soil. I've said this before. This seems like a different issue to wjohnallen's point. This would make cows carbon negative, although its not all that clear to me just how carbon negative they would be.

    I think science of the methane cycle was being confused with mitigation by enhanced soil sinks.

  39. One Planet Only Forever at 04:31 AM on 2 September 2019
    IPCC's land report showed we're entering an era of damage control

    For the benefit of those who choose not to read the 1972 Stockholm Conference report, it includes the following in its opening statements:

    "3. Man has constantly to sum up experience and go on discovering, inventing, creating and advancing. In our time, man’s capability to transform his surroundings, if used wisely, can bring to all peoples the benefits of development and the opportunity to enhance the quality of life. Wrongly or heedlessly applied, the same power can do incalculable harm to human beings and the human environment. We see around us growing evidence of man-made harm in many regions of the earth: dangerous levels of pollution in water, air, earth and living beings; major and undesirable disturbances to the ecological balance of the biosphere; destruction and depletion of irreplaceable resources; and gross deficiences (sic), harmful to the physical, mental and social health of man, in the man-made environment, particularly in the living and working environment."

    That was understood by Global Leadership 47 years ago. How about today? What has been learned by many of the Winners of competition for personal benefit, popularity and profit? They appear to have learned how to fight against improving awareness and understanding, including influence on the stories that get told and believed, and abusing their power to 'bake correction resistance into the systems (including laws and their enforcement) that they can influence' (william's steady point that the people Paying the Piper powerfully influence the actions of Leadership).

  40. One Planet Only Forever at 02:07 AM on 2 September 2019
    IPCC's land report showed we're entering an era of damage control

    Note to all:

    At the end of my comment@15 (the end of the quote from the 1987 UN Commission Report "Our Common Future") the likes of today's Greta Thunberg come to mind - don't they.

    What has changed in the past 30 years? The youth today are becoming more noticed, and are more violently attacked (through dismissive condescending statements and the trigger of anger in the general population to threaten them) by unjustified Winners in the Status Quo.

    Also note the increased amount of generic unjustified attacks on "The UN" and "Global Government".

    History is tragically full of cases where things had to get unbearably worse before attempts are made to correct and recover from the harmful developments. And History is full of examples of powerful beneficiaries of harmful development harmfully resisting understood required corrections (including efforts to limit improving awareness and understanding in the general population). That is a tragic history of Human Development that needs to be Sustainably Corrected to Limit the Damage Done and Increase the rate of Sustainable Improvement of the Future of Humanity.

    Children should not have to be the ones who are 'pointing that out'. Perceived Winners who do not very publicly and very powerfully support such children are undeserving of their Status.

  41. One Planet Only Forever at 01:43 AM on 2 September 2019
    IPCC's land report showed we're entering an era of damage control

    DriveBy@14,

    There is little justification for such a snarky attack on the very challenging pursuits of an integrated understanding of all of the considerations related to sustainably feeding the entire global population. It is a far more complex issue than climate science and the related required corrections of developed human activity (which, by the way, also impact the food issue).

    I will start by stating that 'Green' needs to be replaced by 'Sustainable Development'. And that, like Climate Action, the improvement of awareness and understanding can be crippled by a lack of interest by Leadership (the winners in the Status Quo) in developing and acting responsibly on that improving understanding. The main barrier to action by leadership is the vested interests of Leadership in defending the Status Quo which includes rigging institutions and laws in favour of the Status Quo, to the detriment of pursuits of Sustainable Development. Many developed popular and profitable actions, sources of status in the Status Quo, cannot be continued if Sustainable Development is the Objective.

    Please read the UN-ESA 2012 "Back to Our Common Future Project - Summary for Policymakers" and then investigate the globally agreed 2015 Sustainable Development Goals that need to be achieved by 2030 and be improved on.

    There are better solutions than Soylent Green. They are the development of Governance of all human actions by things like Sustainable Institutions and Cultures, everything governed by the Combined Governing Objectives of 'Helping the less fortunate' and 'Doing no harm to Others, especially the future generations of Others - the largest group, almost infinite, therefore a group that is deserving of the most consideration'.

    There can be a vast diversity of ways to live Sustainably (not just the food part - all of the SDGs being achieved and improved on). But they will struggle to be Developed and Sustained if they have to compete for popularity or profitability with unSustainable and Harmful alternatives. That is a Key Understanding. And it was expressed well in the 1987 document "Our Common Future" which was developed by collaboration of global expertise based on the global agreement that in order for Humanity to have a future improved awareness and understanding must govern global leadership (established by the 1972 Stockholm Conference with the Report from that conference here). The following is one of Key Understandings expressed in 1987 (about the time that resistance to correction by powerful Status Quo people on a bunch of fronts can be seen to be ramping up):

    "25. Many present efforts to guard and maintain human progress, to meet human needs, and to realize human ambitions are simply unsustainable - in both the rich and poor nations. They draw too heavily, too quickly, on already overdrawn environmental resource accounts to be affordable far into the future without bankrupting those accounts. They may show profit on the balance sheets of our generation, but our children will inherit the losses. We borrow environmental capital from future generations with no intention or prospect of repaying. They may damn us for our spendthrift ways, but they can never collect on our debt to them. We act as we do because we can get away with it: future generations do not vote; they have no political or financial power; they cannot challenge our decisions.
    26. But the results of the present profligacy are rapidly closing the options for future generations. Most of today's decision makers will be dead before the planet feels; the heavier effects of acid precipitation, global warming, ozone depletion, or widespread desertification and species loss. Most of the young voters of today will still be alive. In the Commission's hearings it was the young, those who have the most to lose, who were the harshest critics of the planet's present management."

  42. IPCC's land report showed we're entering an era of damage control

    Eat this, no eat that, no, eat the first this that was stated. 

    May I in modesty propose that the only true way for people to eat Green is Soylent. 

  43. The North Atlantic ocean current, which warms northern Europe, may be slowing

    Thank you for going to this effort for me, I'll follow through and read up on what has been presented, and hope that it is useful for others too.

  44. IPCC's land report showed we're entering an era of damage control

    Red baron @11

    "Remove the cow and other ruminents and that grassland environment loses its sink properties. Plow it to produce plant crops instead of meat, and it becomes a net source for both CO2 and CH4."

    Please stop lecturing me and implying I said things I didnt say. I made no reference in my comment @10 to the relationship between cows and soil carbon sinks. You are completely mistaken about what I said, again.

    Moderator, I'm tired of Red Barons repeated false accusations against me comments, aggressive attitude, and strawman statements.

  45. The North Atlantic ocean current, which warms northern Europe, may be slowing

    Human 2932847 @20,

    Regarding Seager et al (2002), I think you were looking in the very short list within the 2007 weblog you linked-to @6 (& its associated presentation slide show). I failed to consider this list as I was not expecting a publication to precede the weblog/presentation. I was expecting such publication afterwards and was thus faced with a list over 200 papers long to trawl through.

    Regarding a high number of citations, do note that the last publication I can see with Seager as co-author addressing directly the AMOC is Delworth et al (2008) mentioned @12 and that does not cite Seager et al (2002), that being a rather strong message. (And ditto Hurrell et al 2010 which also considers the Atlantic MOC with Seager as co-author.)

    And of the four papers citating Seager et al (2002) which I mentioned @19, two of them did not accept the controversial aspect of Seager et al (2002) and the other two did make mention of the controversy but were in truth far from supportive. So can it be "really so controversial if 313 people cite it?"  Yes it can indeed!

    "If it's really been supeceded then that's what I really want to know."  Even as no-more-than a controversial alternative, there is no indication within post-2015 literature that it now hasn't been.

  46. The North Atlantic ocean current, which warms northern Europe, may be slowing

    Seager et al (2002) was easy enough to find, being in the reference list. I agree that having multiple authors isn't a guarantee of correctness, but it is a guarantee of multiple authorship, for sure, which was my point. Is it really so controversial if 313 people cite it ?

    My point about changing the Columbia website is more a question - if it's so bad, and it's purpose is probably educational, then why is it still there ? I thought this might indicate it's merit in the eyes of academics, and widespread dissemination of the idea to students.

    If it's really been supeceded then that's what I really want to know.

  47. The North Atlantic ocean current, which warms northern Europe, may be slowing

    Human 2932847,
    You ask that you "don't want to get bogged down in lonesomeness and reputations of the scientists" so let us ignore the denier K-K Tung.

    You have done well tracking down Seager et al (2002) 'Is the Gulf Stream responsible for Europe's mild winters?'. Note that multiple authors is not a mark of good findings. A more normal gauge of the importance of a paper (but again not always a mark of good findings) is the reported number of citations and Seager et al (2002) has gained a healthy 313.

    The findings of the paper are accepted in part (the cause of the E-W Atlantic temperature differential & the AMOC's impact on Arctic ice edge) but the controversial finding (the AMOC is not significant in warming W Europe) has had a remarkably long life (eg Buckley & Marsall 2015, Palter 2015) given the only up-date is Seager (2006) 'The Source of Europe’s Mild Climate:- The notion that the Gulf Stream is responsible for keeping Europe anomalously warm turns out to be a myth' which is more an opinion piece that a research paper.

    Generally, as Seager (2006) sets out, most ignore this controversial finding (eg Wood et al 2003, Rahmstorf 2003), is last paper saying:-

    "To what extent do Europe’s mild winters depend on the transport of heat by the Gulf Stream and North Atlantic Current? Simulations in which the ocean’s heat transport is switched off consistently show a large winter cooling over the northern Atlantic and adjacent landareas, reaching several degrees in inland Europe, up to 10ºC over Greenland and even exceeding 20ºC over the Nordic seas. This heat transport warms the climate on both sides of the Atlantic, and is therefore not the main reason that Europe is warmer than Newfoundland — this phenomenon is mainly due to the prevailing winds in the two regions. But ocean currents do make the northern Atlantic much warmer than at comparable latitudes in the northern Pacific."

    Generally, the controversial finding has been left behind, including by Richard Seager. But as it is a part of the science, it should not be purged from the records (perhaps the suggestion @15).

  48. The North Atlantic ocean current, which warms northern Europe, may be slowing

    I don't know anything about why Chen and Tung are supposed to be bad - I'd never heard of them. And Seager has co-authors signing off on his papers, I count five co-authors on, "Is the Gulf Stream responsible for Europe's mild winters?", why don't these count ?
    It may be a personal quirk, but if I'm told that someone should be ignored because they're on their own I just start to root for the underdog, which may be counterproductive to the resonable aim of eliminating unreliable outliers from consideration.
    I don't want to get bogged down in lonesomeness and reputations of the scientists, please.

  49. IPCC's land report showed we're entering an era of damage control

    RedBaron @11

    You just aren't making any sense, and I'm sick and tired of your personal attacks, hectoring attitude, and false accusations.

    "This has been explained to you multiple times. I am not sure why you keep making stuff up without references that sounds good to you, but it is nothing more than sloganeering."

    I haven't made stuff up. I said "However the methane from cattle breaks down into CO2 and is mostly absorbed by natural sinks, so cattle are largely carbon neutral as far as I can see. The exception is where there is huge overstocking, and over grazing." This is non controversial accepted science and it doesnt need a bibliography.

    "The cow properly managed is part of an ecosystem that is a very large net sink for BOTH CO2 and CH4."

    I didn't say or imply  it wasn't a net sink for both CO2 and methane.

    "Running out of Time | Documentary on Holistic Management" 

    I support regenerative farming in general terms, but I do question some of the huge claims made by yourself and the regenerative community as to how much CO2 grasslands can sequester because it doesn't square up with the published research taken as a whole, and I make no apologies for that. More research is needed. Nick Palmer has raised similar points.

     

  50. IPCC's land report showed we're entering an era of damage control

    @10 Nigel,

    This has been explained to you multiple times. I am not sure why you keep making stuff up without references that sounds good to you, but it is nothing more than sloganeering.

    The cow properly managed is part of an ecosystem that is a very large net sink for BOTH CO2 and CH4.

    Cenozoic Expansion of Grasslands and Climatic Cooling
    Gregory J. Retallack

    "Unidirectional, stepwise, long‐term climatic cooling, drying, and climatic instability may have been driven not by tectonic forcing but by the coevolution of grasses and grazers."

    Remove the cow and other ruminents and that grassland environment loses its sink properties. Plow it to produce plant crops instead of meat, and it becomes a net source for both CO2 and CH4.

    So no. You are wrong, again... for the upteenth time. Not sure why you keep getting a pass from moderation for just making stuff up, not science based, not referenced, but please stop.

    I have had to repeat this to you an a few others so many times that I have made set answers with full references.

    What reaction can you do to remove methane?

    Can we reverse global warming?

    The bottom line is that adding animals and plants cools the planet, while destroying plants and animals is currently warming the planet. You have it exactly backwards.

    Maybe this video will help you understand better.

    Running out of Time | Documentary on Holistic Management

    Moderator Response:

    [DB] "you keep making stuff up without references"

    In order to provide a positive stimulus to the conversation, it would be best if you were to provide examples of such claims.  Simply asserting the claims of another are sloganeering without providing supportive examples is itself sloganeering.  Note that the emphasis of this forum is peer-reviewed literature published in credible journals, something that videos fall far short of.

    Inflammatory rhetoric snipped.

     

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