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Unforced variations: Mar 2018

Filed under: — group @ 28 February 2018

This month’s open thread for climate science related items. The open thread for responses to climate change is here.

408 Responses to “Unforced variations: Mar 2018”

  1. 301
    CCHolley says:

    Victor @291

    Some examples:

    Yawn. Same old same old.

    If a steady increase of CO2 levels causes global temps. to rise, then how do we explain the lowering and/or leveling off of global temps. during the period ca. 1940-ca. 1979? This is roughly 40 years without significant warming, surely not a short-term bit of random “noise.” Yet AGW advocates claim that the doubling of CO2 levels will invariably, due to iron clad physical laws, result in 2 degrees (or more) of global warming. Since this is the period during which the burning of fossil fuels really took off, it’s hard to see any evidence of such a relationship. This in itself strikes me as strong evidence for falsification. Not to mention that the strong upward trend in temperatures at the end of the 20th century leveled off considerably during the first 15 or 16 years of the 21st, a period when CO2 levels were soaring.

    This is an oft repeated tired meme. Victor has been told countless times that the heat content of the earth system is dependent on the net effect of all of the radiative forcings, i.e. energy in versus energy out. The war period and rapid economic growth that followed resulted in very high levels of heat blocking aerosols in the atmosphere. Significant enough to block enough solar energy to offset the CO2 signal. This is not disputed. The clean air act of 1970 followed by similar measures in Europe greatly reduced these aerosols allowing the CO2 forcing to re-imerge. The ignoring of the effect of the aerosols by Victor shows a complete lack of interest in understanding the truth of the science or a purposeful desire to deflect reality.

    Likewise for the early period of the 21st century after an extreme El Nino that was followed by an ENSO negative phase dominated by La Nina events. Although the period appears to be a slowdown, it was not statistically significant. The long term 30 year plus trend shows significant warming.

    It is Victor doing the denial by creating a false *problem* with the science.

    When we compare the steady rise in sea levels over the 20th century with the steady rise in CO2 levels, it does look like a pretty convincing correlation, yes. However, and regardless of what caused it, the lowering/leveling of global temps. during the same 40 year period cited above apparently had no effect on sea levels, which continued to rise regardless. How then can we infer an effect on sea levels produced by a much briefer and far less intense cooling period caused by the Pinatubo eruption? And what about all the other major eruptions during the 20th century?

    LOL. Victor is so clueless he does not get the point. The problems he states with sea level rise have nothing to do with the cause of the temperature rise.

    Regardless of that point, sea level measurement and analysis is highly complex and problematic. Sea levels are effected by movement of land masses both upward and downward, changes in gravitational pulls on the water due to changes in ice masses. Changes in currents and winds, salinity, and so on. Tide gauges are located close to land, thus not giving a complete picture. Not only that, different tide gauge sites use different technologies. Different analysis of the data give different results.

    The most commonly used sea level rise reconstruct is Church & White and the one likely used by Victor to make his pointless claims about correlation of sea level rise to CO2 or even temperatures. Correlation becomes greater once the data shifts to satellite measurements, hence the revealing of the Pinatubo eruption.

    But Church & White is not the only analysis. Jevrejeva et al and Hay et al reconstructs both are more closely aligned with temperature changes. Hay et al of 2015 shows steady rise from 1900 to 1940 with a plateau with almost no rise until about 1980, then a continuation of the earlier trend until 1993 when sharp acceleration begins. Hay et al is likely more accurate due to the statistical approach used. Victor’s questions are based on outdated information. Not a surprise.

    CC Holley has attempted to downplay the importance of sea level acceleration, but the fear of precisely this sort of event being caused by continued CO2 emissions is one of the principal “selling points” of the climate change paradigm.

    Victor misconstrues my point. The point was that the evidence for or against acceleration does nothing to our understanding of the role of CO2 in warming the planet. What Victor fails to understand or accept is that the question of acceleration only has to do with our understanding of the response of sea levels to warming. ANY WARMING.

    Regardless, the evidence is that sea levels are accelerating and that it is a serious problem even today.

  2. 302

    Here are my answers, in response to which Victor will allegedly change his mind:

    1. Demonstrate that the recent increases in global temperature represent a true long term trend, despite significant hiatuses both in the 20th and 21st centuries.

    BPL: A trend is present if the linear regression of a time series against elapsed time is significantly different from zero. Using the Hadley CRU time series, I find the slope to be 0.00507173 with a standard error of 0.000266163, which gives it a t-statistic of 19.05490182. With a sample size of N = 167, this means this slope is significant at p < 1.22429 x 10^-43. Thus it is both a true trend (highly significant) and long term (167 years).

    2. Demonstrate that warming in the past tells us that warming will continue into the future, despite the fact that a very similar trend in the opposite direction during the middle of the 20th century convinced so many that we were headed for another ice age.

    BPL: Counterfactual question. Rasool and Schneider (1971) decided a mini-ice-age might be coming on the basis of aerosol pollution, given a CO2 warming power many times less than we now know it to be. The trend was not the reason for the projection, which they later admitted to be wrong.

    3. Demonstrate that the warming we are now experiencing is in fact caused by CO2 emissions and not the result of natural variation. Since the steep rise in CO2 during the middle of the 20th century did not heat the earth in any significant manner during that period, it’s hard to see how “the physics” in itself can be used to make such an argument.

    BPL: We know from radiation physics that CO2 is a greenhouse gas, therefore putting more in the atmosphere should cause warming. As confirmation, the correlation between CO2 levels and CRU temperature anomalies (see above) is r = 0.912, p < 1.43 x 10^-64. Since 83.2% of variance is accounted for, "natural variation" can only account for, at most, the other 16.8% in that time period.

    4. Demonstrate that the relatively modest increase in global warming that is now anticipated by AGW alarmists is necessarily harmful.

    BPL: http://www.ajournal.co.uk/pdfs/BSvolume13(1)/BSVol.13%20(1)%20Article%202.pdf

    Of course, Victor won't actually change his mind just because his questions have been answered. Watch.

  3. 303
    CCHolley says:

    Victor @291

    Bottom line:

    In order to make a case for the sort of drastic reduction in the burning of fossil fuels or any other human causes of CO2 emission, one would have to:

    Ridiculous.

    Victor continues to ignore reality and facts and science and evidence and, did I say reality?

    1. Demonstrate that the recent increases in global temperature represent a true long term trend, despite significant hiatuses both in the 20th and 21st centuries.

    Done. Victor just ignores reality. The long term trend since 1900 is unprecedented in the paleo history of temperatures. Why Victor thinks hiatuses cast any doubt on the effect of CO2 to warming is beyond comprehension, other than he is attempting to deflect. The warming is well correlated to increases in CO2. Victor ignores our understanding of climate forcings and that aerosols have a strong negative effect by blocking sunlight. And aerosols were high from about 1940 until legislation eliminated it. I lived through it. Again, what drives temperatures is well understood. Again, Victor ignores scientific reality. No surprise, he admits he is not qualified to judge physics.

    2. Demonstrate that warming in the past tells us that warming will continue into the future, despite the fact that a very similar trend in the opposite direction during the middle of the 20th century convinced so many that we were headed for another ice age.

    LOL. Victor invokes the tired ice age cometh meme. Only 7 papers over that 15 year period discussed the possibility of an ice age coming, while about 45 papers discussed CO2 induced warming. The well understood aerosol forcing caused the pause in warming. PERIOD. But Victor the denier ignores this well known reality. Also, it is indisputable through physics that CO2 causes warming. Victor, nor anyone has provided evidence to the contrary. Victor can only deflect. blah, blah, blah is all Victor can do. CO2 causes warming and there is nothing to indicate that as CO2 continues to rise, the warming won’t continue. That’s physics. Physics Victor ignores.

    3. Demonstrate that the warming we are now experiencing is in fact caused by CO2 emissions and not the result of natural variation. Since the steep rise in CO2 during the middle of the 20th century did not heat the earth in any significant manner during that period, it’s hard to see how “the physics” in itself can be used to make such an argument

    Victor ignores that the warming experienced requires a change in forcing. There are no natural changes in forcing that could possibly cause the warming. NONE. This inconvenient truth is ignored by Victor. Claiming natural variation as a possible alternative is a specious claim not backed by science or evidence. The possibility does not exist. Yet CO2 forcing is clear and backed by physics. Victor’s inability, ‘hard to see how “the physics” in itself can be used to make such an argument’, to understand the science is simply an argument from incredulousness. Victor’s proclamation does not change the reality of the science. The physics of aerosol cooling is well understood and ignored by Victor. blah, blah, blah, Victor can only argue by ignoring reality and science.

    4. Demonstrate that the relatively modest increase in global warming that is now anticipated by AGW alarmists is necessarily harmful.

    False premise. No one with any credibility believes that warming will be modest. As shown by the physics and not disputed by anyone, the minimum sensitivity to CO2 doubling is 2 degrees celsius. Again, this not disputed. This will not result in modest heating. The possibility of net feedbacks reducing this sensitivity has not been demonstrated and is not supported by evidence. It is highly likely to be higher due to feedbacks. Certainly Victor has not provided any evidence to the contrary yet he has been provided clear evidence of the physics behind CO2 forcing. Victor can only argue through unfounded and unsupported assertions.

    Victor cannot show that climate sensitivity to CO2 is low.
    Not a surprise since no scientists have been able to show such.

    Victor cannot show how natural causes can be responsible for the warming.
    Not a surprise since no scientists have been able to do so.

    Victor has nothing but continued obfuscation and deflection. blah, blah, blah, blah. It is all Victor’s got.
    Over and over again he ignores the science and the evidence. Over and over again, he repeats the same old tired refuted talking points.

    It is tiresome.

  4. 304
    Climate State says:

    We’re planning a new narrated production on unknowns. What do you guys think might surprise us when it comes to climate?

    Gavin recently gave an interview in those regards (where he mentions the Antarctic ozone hole discovery) https://www.smh.com.au/environment/climate-change/expect-more-complete-surprises-from-climate-change-nasa-s-schmidt-20180212-p4z035.html

    And recently, Surprised Researchers find Ozone Loss at Populated Areas https://www.youtube.com/watch?v=zCEL84JpjEA

  5. 305
    Victor says:

    293 MARodger: “Or do you have a reason for disputing the 28% pre-1940 AGW forcing (relative to 2011) as set out in IPCC AR5 AII Table1.2? (And note the pre-1940 CO2 forcing is given as 32% of the 2011 value.)”

    No — but YOU do. If you want to assume that aerosols resulting from pollution produced by the burning of fossil fuels were responsible for the cooling evident from 1940 through the late 70’s, then you have no reason to claim ANY degree of warming due to CO2 forcing during any earlier period.

    [Response: Ok this is enough. Further pointless repetitions of ridiculous points are just going to get boreholed. Try harder to be interesting. – gavin]

  6. 306
    Climate State says:

    #290 Are there efforts to add heterotrophic feedbacks to climate models?

    There is now.

    The Arctic’s carbon bomb might be even more potent than we thought
    https://www.washingtonpost.com/news/energy-environment/wp/2018/03/19/the-arctics-carbon-bomb-might-be-even-more-potent-than-we-thought/

  7. 307
    CCHolley says:

    Victor @borehole

    Victor is willfully ignorant.
    The arrogance of the ignorance is unsurpassed.

    Not being able to accept reality, Victor responds to the aerosol question with:

    Yes, this is the standard excuse. I find it laughable. What you fail to recognize is the fact, well known in all branches of science, that it is always possible to come up with some explanation for the failure of an hypothesis to stand up under evidence-based testing by introducing some additional factor or factors that serve to complicate/obfuscate the issue.

    and:

    The only “necessity” prompting the introduction of the aerosol pollution hypothesis is the necessity of rescuing a failing theory from falsification

    Since, Victor cannot dispute the science, he simply responds that the science is made up.

    He then somehow tries to invoke Occam’s Razor, implying that the inclusion of aerosols is just adding unnecessary complexity. He seems to miss that it is a real part of the drivers of temperatures by scattering incoming sunlight. His supposed *evidence* that it does not contribute to cooling is that China and India are now heavy emitters of aerosols and it is not cooling. dah. At least apparently he accepts that it is warming. So, yes, China and India are emitting aerosols, of course, but over a much stronger CO2 signal.

    But when it comes to Occam, Victor seems to ignore that:

    1. CO2 is a greenhouse gas that restricts energy loss to space. Physics tells us that the minimum sensitivity to increases in CO2 is a minimum of 2 degrees celsius and likely more.

    2. There is no known alternative possible cause of the warming experienced. There are no known natural drivers currently increasing the radiative imbalance. And none that would cause the arctic to warm faster than lower latitudes, nights faster than days, and winters faster than summers.

    Nope, Victor only selectively (and improperly) invokes Occam’s Razor.

    I guess scientists should never attempt to understand complex systems, because that would be against Occam’s Razor. Occam’s Razor must somehow rule out the possibly of systems being complex.

    Unbelievable.

  8. 308
    Victor Grauer says:

    305: “Try harder to be interesting. – gavin”

    Sorry if I’m not interesting enough for you, gavin. Perhaps these videos will prove more entertaining:

    https://youtu.be/HEbNOSNAsm0

    https://youtu.be/17aNU9fKzho

    https://youtu.be/BiKfWdXXfIs?t=2m58s

    https://youtu.be/vro-yn59uso

    https://youtu.be/gJwayalLpYY

  9. 309
    Lepeee says:

    Advertencia: no invertir en el HYIPP de Antonio Meseguer, alias Carpetilla en Forobeta, con su socio Carlos Arreola. Ambos estafadores se montaron a más de 400 personas y dejaron a muchos en la calle. El esquema Ponzi se comió los ahorros de cientos de personas, mientras que el dueño de Forobeta encubrió durante todo este tiempo una MEGA ESTAFA sin precedentes en el marketing digital hispano. Los señores Antonio Meseguer y Carlos Arreola deberán dar sus correspondientes explicaciones.

  10. 310
    Russell Seitz says:

    304

    “We’re planning a new narrated production on unknowns. What do you guys think might surprise us when it comes to climate?”

    For openers, there’s this article in Earth’s Future:

    Its abstract notes :
    The Earth’s atmosphere is not the only source of radiative forcing and anthropogenic climate change. As surely as people and civilizations have carbon footprints, they have albedo footprints as well. By altering the reflectivity of roughly half the land surface of the Earth in the past, mankind has made inadvertent geoengineering a part of the landscape of history. This worldwide alteration of reflectivity raises questions about the future of climate change, for albedo is a first‐order determinant of the Earth’s radiative equilibrium. As surfaces absorb roughly 100 times more solar energy than the CO2 in the atmosphere, future anthropogenic changes in both land and water albedo may figure significantly in climate policy outcomes.

    https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2013EF000151

  11. 311
    MA Rodger says:

    It appears Voctor the Troll @305 feels his grasp of climate forcing is sharp as occam’s razor. His argument runs something like ‘If YOU are stupid enough to plead there was CO2 forcing pre-1940 causing the pre-1940 warming, how can there not have been ANY warming 1940-70 when CO2 emissions continued to increase, smarty-pants?’ Golly!! That’s a tricky question!!!
    Of course it is only ‘tricky’ in as much as Victor the Troll is asking it. So the answer need to be couched in a way that he will find understandable. As the man is stricken with chronic denialism, that is not easy.

    Victor the Troll @305.
    The level “pollution produced by the burning of fossil fuels” is not determined by the amount of FF you burn but by what sort of FF you burn and how you burn it. And additional to that consideration, FF is not the only contributor to anthropogenic CO2 emissions which in turn are not the only contributor to anthropogenic climate forcing.
    Your Grand Theory seems to rest on the idea that FF-use produces CO2, a GHG which is warming the planet but that, in some bizarre balance, a commensurate quantity of SO2 aerosols must also be produced cooling the planet. We seemingly cannot have the one without the other so what is ‘source’ for the pre-1940’s goose is also ‘source’ for the 1940-70 gander. Either both show warming or both show cooling. We cannot have one warming while the other does not. ‘Simples’!!!
    The following is overly-simplistic, but I feel explains your problem, Victor.
    While IPCC AR5 AII Table 1.2 shows AGW racked up 33% of its 2011 CO2-forcing-level by 1940 and a further 13% 1940-70, SO2 emissions had a bit of a hiatus 1910-40 (roughly 30% of 2010 levels throughout the period) followed by a period of sky-rocketry 1940-70 (something like a further 90% of the 2010 level achieved by 1970). There is no linkage between FF CO2 emissions & SO2 emissions, a linkage you assume and without which your Grand Theory very rapidly splash-lands and gurgles round the U-bend.
    So, Victor the Troll, do you have any other Grand Theories that yo wish to share with us?

  12. 312
    Killian says:

    CH4 and Permafrost

    This new study seems to take us back to where I thought we were in 2007 with this issue, before some studies started suggesting less dangerous possibilities and certain researchers started getting some pretty serious, and I thought unfair, heat.

    I hope someone with some chops will explicate this in plainer English in case I am misunderstanding the gist.

    https://www.nature.com/articles/s41558-018-0095-z.epdf?referrer_access_token=QimruZqY0uQyvJhlxat8ItRgN0jAjWel9jnR3ZoTv0N8I-MYIYWzKL_kSfxnCJqK5MhEqa1ECTKGMkwkdtwwdRBnpqZb1-iie3xj4GeIn_ATzYOYZ_qH4owg6tA5W_yYLypIP2SUN5-B1T5yexwNadXdwCZt3wyAarxCPC0Nv3lXljO2n4dUQQDimyNua3Tnd21O6bRqgq5YEXModik7bKXZTRVCsXL5btzFCn1ue-c-ltsrUkl1ZlWfKJ4h4XiaA6qEcw5474V3V54ossVOcVqoW3t1_ow7xF60nqcgwrNXk5mNIEx9Z6M48j2ZmaN7wOxfwaQ5BDzgkO51tABEDT710d1AeRsMA44IH8haLVAGf3Z3T9_HC0MLnAaJfWJo&tracking_referrer=www.washingtonpost.com

  13. 313

    Killian, #312–

    My take on Knoblauch et al (2018) [https://doi.org/10.1038/s41558-018-0095-z], FWIW:

    1) Anoxic soil conditions are shown to produce more methane than thought over multi-annual time scales.

    2) Since permafrost terrain tends toward anoxic conditions, improved modeling of CO2e emissions will require accurate mapping of the relevant hydrology, and of soil and vegetative conditions.

    3) Uncertainties in the present study are quite high, therefore more work will also be needed to try and narrow the ranges, if improved emissions modeling is to be achieved as per point #2.

    In a nutshell, things are worse than thought with regard to a terrestrial permafrost CO2e feedback, but it’s still pretty hard to say by how much.

  14. 314
    Victor Grauer says:

    311 MARodger: “The level “pollution produced by the burning of fossil fuels” is not determined by the amount of FF you burn but by what sort of FF you burn and how you burn it.”

    Precisely. And the sort of FF burned during the first half of the 20th century was produced by the fuel most likely to generate sulfate aerosols: coal. During that period, moreover, there were no constraints on the burning of coal whatsoever, thus no constraints on the production of the sort of aerosols currently claimed to have a cooling effect on the atmosphere strong enough to offset the effect of CO2 emission.

    MA: “There is no linkage between FF CO2 emissions & SO2 emissions, a linkage you assume and without which your Grand Theory very rapidly splash-lands and gurgles round the U-bend.”

    Excuse me? How can there be no linkage when both have the same source, the burning of fossil fuels? Talk about denial. Sheesh.

  15. 315
    Victor says:

    307 CCHolley says:

    CC: Since, Victor cannot dispute the science, he simply responds that the science is made up.

    He then somehow tries to invoke Occam’s Razor, implying that the inclusion of aerosols is just adding unnecessary complexity. He seems to miss that it is a real part of the drivers of temperatures by scattering incoming sunlight. His supposed *evidence* that it does not contribute to cooling is that China and India are now heavy emitters of aerosols and it is not cooling. dah. At least apparently he accepts that it is warming. So, yes, China and India are emitting aerosols, of course, but over a much stronger CO2 signal.”

    V: The unconstrained burning of highly polluting coal throughout Asia did not begin, “now,” CC, but has been going on ever since so many of these countries first became industrialized. It was certainly going on during the last 20 years of the 20th century, and was certainly a major contributor to both CO2 emissions AND sulfate aerosols during this period — a period that saw the ONLY major runup of global temperatures that could possibly be attributed to CO2 emissions. The notion that the atmosphere cooled mid-century due to the emission of such aerosols and then drastically heated up thanks to the clean air act is myopic. When we pull back to consider the larger picture we see that pollution due to sulfate aerosols continued unabated in the great majority of coal burning plants worldwide, regardless of constraints imposed in the US and Europe.

    CC: There is no known alternative possible cause of the warming experienced. There are no known natural drivers currently increasing the radiative imbalance. And none that would cause the arctic to warm faster than lower latitudes, nights faster than days, and winters faster than summers.

    V: Argument from ignorance. Various possible causes have been proposed, no more, or less, convincing than the AGW hypothesis. Bottom line: though it’s not clear what caused the dramatic runup in temps. between the late 70’s and late 90’s, there are a great many precedents for such events in the past, notably the 1910-1940 runup, which no one has been able to explain either.

    CC: I guess scientists should never attempt to understand complex systems, because that would be against Occam’s Razor. Occam’s Razor must somehow rule out the possibly of systems being complex.

    V: Your comment reveals a serious misunderstanding of Occam’s Razor. General Relativity is far more complex than anything devised by Newton, but it very elegantly accounts for much more of the evidence than Newton’s theories. Since it is the simplest explanation that accounts for so much (if not all) of the evidence, it is perfectly consistent with Occam’s Razor. Arguments put forth by advocates of AGW are based on portions of the evidence carefully selected to support a pre-conceived view and as such account for very little.

  16. 316
    MA Rodger says:

    NOAA have posted for February with an anomaly of +0.65ºC, a small drop on January’s +0.71ºC but the lowest monthly anomaly since February 2014. 2018 is the 11th warmest February on record (=6th in GISTEMP), the top eleven being 2016, 2017, 2015, 1998, 2002, 2004, 2010, 1995, 1999, 2007, 2018.
    Feb 2018 sits as =112nd highest NOAA anomaly (=42nd highest in GISTEMP, the difference from NOAA mainly down to the full arctic coverage).
    The various monthly global surface & TLT records 2010-to-date graphed out here (usually 2 clicks to ‘download your attachment).

  17. 317
    Dan says:

    re:308
    It is certain that Victor has reached a new level of scientific ignorance and arrogance. It has been long established here that he has no clue about the scientific method. And now in desperation (which he won’t admit of course) he resorts to videos on a scientific blog run by peer reviewed climate scientists? How vile and insulting. Clue for you Victor: Science is not conducted by videos or TV debates.It is done via research, data analysis, peer review and scientific conference debate. You are become the poster child of intellectual laziness vis a vis scientific ignorance. There is no excuse for failing to try to learn. But you take it another level: You are now trying (and utterly failing) to be condescending to peer reviewed scientists while you have no clue. I am still waiting for you to explain why the stratosphere has been cooling (it should be warming if the sun/natural causes are the cause of global warming) without violating the 1st Law of Thermodynamics (look it up and learn). I asked you this quite a while back and you conveniently ignored it. Of course the reason you did is that you have not read the peer-reviewed science. And the scientific method has been the cornerstone of all science for centuries. The idea that somehow you think you know something that literally thousands of climate scientists do not is the absolute height of scientific arrogance. And ignorance.

  18. 318
    prokaryotes says:

    #313

    Some quick thoughts (first draft)

    There is possibly a chain mechanism underlying climate system feedbacks. From a natural system perspective the first principle is planetary albedo (the sum of landscapes, water bodies and clouds).

    If we start out with a balanced system which contains frozen water at the poles, the mid to high latitudes begin to thaw, triggering soil greenhouse gas feedbacks (permafrost thaw and following oxic and anoxic sources add to the greenhouse gas budget), a chronic linear process (which helps to accelerate changes of the equilibrium state, reduces the ability of the atmosphere to break down greenhouse gases – less hydroxide radicals). Weather gets more erratic (more heat, drought, fires, flash floods).

    Now we have to consider anthropogenic feedbacks – which are positive and negative. Negative are ofc the actions to reduce emissions, which at the same time make societies more resilient, since renewable’s are per design more decentralized. Positive can continue to dominate due to aspects related to psychological handling, and more heat has been shown to increase conflict potential, increased disruptions means increased rebuilding efforts, by all means (using wood and coal for burning if someone lacks technological advancements).

    Then if a warming trend continues, overtime the oceans get warm enough and release continental margin located hydrates from shallow regions. With even further warmth over time coastal waters become more stratified, less perturbation reduces the amount of CO2 absorption (less water is transported into the deep, less carbon is transported to the deep, most is consumed again). More feedbacks develop (serious algae, dead zones, acidification, and cloud cover changes). Very stormy background due to chaotic distribution of cold and hot regions (icebergs from disintegrated ice sheets, and high levels of atmospheric CO2), due to global deglaciation. At this stage extinction of high magnitude.

    With even further warming more hydrates are released, additional global soil feedback (extreme soil respiration rates, compost bomb instability) and weathering becomes a driver, now Ocean very stratified, maybe things like permanent El Nino, weather systems probably move very slow – everything gets stuck due to lack of perturbed ocean, no or very little frozen water at the poles. Oxygen decline in ocean and atmosphere gets so little that only very few species can adapt or survive at all. If this state continues the planet could get the Venus syndrome.

  19. 319
    nigelj says:

    Victor says

    “If YOU are stupid enough to plead there was CO2 forcing pre-1940 causing the pre-1940 warming, how can there not have been ANY warming 1940-70 when CO2 emissions continued to increase, smarty-pants?’ Golly!! That’s a tricky question!!!”

    Its not a question of belief. CO2 levels increased from approximately 1900 – 1940 so indisputably had some role in that warming period. And Victor levels of coal burning prior to 1940 were comparatively small. Remember we have evidence of three drivers of warming over the pre 1940 period, CO2 emissions, increased solar activity and an unusually reduced period of volcanic activity. This could easily explain the warming, and overwhelm any effect of coal burning during the same period.

    After 1940 there were very high sulphate aerosols from the boom in industrial activity in western countries and the consumer revolution and increase in population really taking off. This only really started in earnest during WW2 and after then. Remember the industrial revolution of the Victorian age was mostly confined to Europe, and the industrial boom after WW2 was much wider globally.

    From the 1940’s to 1970s approximately, the particulates and sulphates reflected sunlight, with the net effect that temperatures were stable despite increasing CO2 levels then controls on these pollutants were introduced around the 1960s to 1970s (using a cap and trade scheme in some countries). This is not unlike the principle behind proposals to introduce geoengineering reflectors in space (not good proposals however), to counter the effect of the greenhouse effect by reflecting solar radiation.

    The issue is not all about agw theory. Its about observing changes in temperature up and down, and finding logical reasons. It so happens that climate is rather sensitive to sulphate aerosols.

    And yes China is burning coal in recent decades, but many of the sulphates are filtered out, so its not enough to supress global temperatures. And quantities of atmospheric CO2 are also higher.

    Its just not that hard to explain the flat periods in temperatures, and its not trickery, its just looking carefully for possible explanations like with any field of science or exploration.

  20. 320
    nigelj says:

    Victor think’s that Occams Razor says that the simplest explanation is the correct explanation. It doesnt, it only says the simplest explanation is “usually” the correct explanation.

    And the term simplest is only relative to available explanations.

    Clearly atmospheric warming has multiple causes, including CO2 and solar changes, geothermal energy and forest fires etc and all can be at the same time, but research shows solar changes have limited effect, and CO2 is dominating in recent decades and will continue to dominate.

  21. 321
    Hank Roberts says:

    https://www.washingtonpost.com/graphics/2018/national/early-spring/

    Spring is springing earlier and earlier

    Higher temperatures for much of the country are popping first blooms ahead of schedule in recent years.
    … in large expanses of the continental United States, spring is actually arriving earlier than in past years.


    Change in first leaf date between 1951–1960 and 2006–2015

    The USA National Phenology Network monitors the status of spring in the form of first-leaf and first-bloom indexes.

    https://www.usanpn.org/home

  22. 322
    CCHolley says:

    Victor @315

    Victor continues his tired tripe.

    The unconstrained burning of highly polluting coal throughout Asia did not begin, “now,” CC, but has been going on ever since so many of these countries first became industrialized. It was certainly going on during the last 20 years of the 20th century, and was certainly a major contributor to both CO2 emissions AND sulfate aerosols during this period — a period that saw the ONLY major runup of global temperatures that could possibly be attributed to CO2 emissions. The notion that the atmosphere cooled mid-century due to the emission of such aerosols and then drastically heated up thanks to the clean air act is myopic. When we pull back to consider the larger picture we see that pollution due to sulfate aerosols continued unabated in the great majority of coal burning plants worldwide, regardless of constraints imposed in the US and Europe.

    Never said it began now.

    Not myopic at all. Try looking at what the evidence actually says. CO2 forcing has far outpaced aerosol dimming since the late 1970s. The use of scrubbers (yes China and India installed scrubbers although not used consistently) to remove SO2 along with the shift to natural gas means the amount of aerosols has not kept up with CO2 forcing.

    Sun-blocking aerosols around the world steadily declined (red line) since the 1991 eruption of Mount Pinatubo, according to satellite estimates. Credit: Michael Mishchenko, NASA

    http://www.wikiwand.com/en/Global_dimming

    Wild et al., using measurements over land, report brightening since 1990,[13][32][33] and Pinker et al.[34] found that slight dimming continued over land while brightening occurred over the ocean.[35] Hence, over the land surface, Wild et al. and Pinker et al. disagree. A 2007 NASA sponsored satellite-based study sheds light on the puzzling observations by other scientists that the amount of sunlight reaching Earth’s surface had been steadily declining in recent decades, began to reverse around 1990. This switch from a “global dimming” trend to a “brightening” trend happened just as global aerosol levels started to decline.[31][36]

    http://www.wikiwand.com/en/Global_dimming

    Argument from ignorance. Various possible causes have been proposed, no more, or less, convincing than the AGW hypothesis. Bottom line: though it’s not clear what caused the dramatic runup in temps. between the late 70’s and late 90’s, there are a great many precedents for such events in the past, notably the 1910-1940 runup, which no one has been able to explain either.

    Baloney. Argument by assertion. No plausible alternatives have been put forth supported by evidence. No evidence of increased solar, in fact, solar has been declining. Natural variation cannot create heat and account for the amount of warming. Any alternative explanation must support the fact that nights are warming faster than days, winters faster than summers, and the arctic warming faster than lower latitudes. No natural cause nor increased solar can account for these observations. Victor has had multiple chances to provide evidence of alternatives, but has failed to do so. Not a surprise because neither has his heroes Curry, Lindzen, or any contrarians. It is Victor who repeatedly shows ignorance.

    Your comment reveals a serious misunderstanding of Occam’s Razor. General Relativity is far more complex than anything devised by Newton, but it very elegantly accounts for much more of the evidence than Newton’s theories. Since it is the simplest explanation that accounts for so much (if not all) of the evidence, it is perfectly consistent with Occam’s Razor. Arguments put forth by advocates of AGW are based on portions of the evidence carefully selected to support a pre-conceived view and as such account for very little.

    LOL. Victor selectively applies Occam’s Razor to suit his delusionment and denial. It is Victor that claims that the complexity of climate is not possible due to Occam’s. For Victor to claim superiority in understanding anything related to science is a joke and supreme arrogance.

    CO2 is the simplest explanation for the warming. CO2 is a greenhouse gas and physics tells us that the minimum sensitivity to a doubling of CO2 with water vapor feedback is 2 degrees celsius. There is zero evidence that net feedbacks are negative, in fact the evidence says they are significantly positive. When is Victor going to supply evidence contrary to this basic truth? Never, because it is not possible. In addition, there is NO plausible alternative possibility for the warming despite Victor’s false proclamations without supporting evidence. Denying AGW is contrary to the obvious as postulated by Occam.

    Victor’s assertion that mainstream science is selective is not supported by evidence. Climate is complex and multiple forcings drive climate and these forcings are all identified. There are no magical *natural* unknown possible alternatives of the warming. Occam’s Razor must include adherence to the laws of physics.

    Back to the basics that Victor deflects over and over again:

    1. CO2 is a greenhouse gas that restricts energy loss to space. Physics tells us that the minimum sensitivity to increases in CO2 is a minimum of 2 degrees celsius and likely more. This is a basic truth.

    2. There is no known alternative possible cause of the warming experienced supported by evidence conforming to the laws of physics. There are no known natural drivers currently increasing the radiative imbalance. And none that would cause the arctic to warm faster than lower latitudes, nights faster than days, and winters faster than summers.

  23. 323
    Victor says:

    319 nigelj: “Victor says”

    nj: “If YOU are stupid enough to plead there was CO2 forcing pre-1940 causing the pre-1940 warming, how can there not have been ANY warming 1940-70 when CO2 emissions continued to increase, smarty-pants?’ Golly!! That’s a tricky question!!!”

    No, that’s not what I said. That’s Mr. Rodgers’ sarcastic paraphrase of what I said. I don’t recall ever calling anyone stupid on this or any other forum. (Though I’ve been sorely tempted at times.)

    nj: CO2 levels increased from approximately 1900 – 1940 so indisputably had some role in that warming period. And Victor levels of coal burning prior to 1940 were comparatively small. Remember we have evidence of three drivers of warming over the pre 1940 period, CO2 emissions, increased solar activity and an unusually reduced period of volcanic activity. This could easily explain the warming, and overwhelm any effect of coal burning during the same period.

    V: The logic behind the claim that lowered temperatures mid-century were due largely to the emission of industrial aerosols from the unconstrained burning of fossil fuels depends on the assumption that the warming to be expected from the release of CO2 was somehow neutralized by the release of those aerosols. If you subscribe to this hypothesis, then it’s hypocritical to insist that this was an effect that occurred only when convenient for your purposes and deny that the same logic, based on the same process of neutralization, can then be applied to any other period.

    It doesn’t matter if levels of coal burning were comparatively small prior to 1940. If you expect your hypothesis to be taken seriously then you must be willing to apply it across the board, not only when it’s convenient for you. If those aerosols canceled the warming effect of fossil fuel emissions from 1940-1979, as has been claimed, then they would have had the same effect prior to 1940, regardless of whether the volume of both CO2 emissions and aerosol emissions were smaller. The fact that neither you nor Rodger nor apparently anyone else posting here is willing to accept that very simple logic says a lot about the confirmation bias that appears to dominate mainstream climate science generally.

    You can, of course, argue that other factors were at work in the early 20th century warming phase, but if you want to argue that the mid-century cooling was largely due to the neutralizing effect of industrial aerosol pollutants, then you cannot, as did Rodgers, claim that any part of that earlier warmup was due to the burning of fossil fuels.

  24. 324
    SystemicCausation says:

    Hayhoe vehemently advises against engaging with the “smokescreens” skeptics tend to offer as the reasons they couldn’t possibly agree with or act on the issue of climate change. “There’ll be no progress that way,” she insists.

    https://www.ecowatch.com/katharine-hayhoe-climate-change-2550366098.html

    Systemic Causation is like being caught in an endless loop heading to no where.

  25. 325
    MA Rodger says:

    Victor the Troll Grauer @314.
    Thank you, because that is a good answer in an ‘argumentation’ sense. That is, I am not saying the crap you provided @314 was in any way correct. Rather, your answer allows your denialist fallacies to be identified with some clarity.

    You are obviously convinced that there is linkage between CO2 forcing & SO2 forcing, that the two remain proportionate between 1910 and 1970. Yet your conviction in this matter is pure fantasy. Allow me to demonstrate with data that shows none of the proportionality you assume.

    (Note, I did write “There is no linkage between FF emissions & SO2 emissions which is evidently not what the more detailed argument that sentence summated was presenting. There is, of course, a weak linkage between FF emissions & SO2 emissions rather than no linkage. Goodness – a bit of an own-goal allowing the troll to cherry-pick a mistake.)

    If there were a goosey-goosey-gander linkage such that the periods 1910-40 and 1940-70 should (bar other factors) both show the same global temperature trend, the various CO2 & SO2 factors should be proportional. For simplicity, considering the full period 1910-70, we see the following relative levels at the start and end of that period.

    Increase1970 relative to 1910 … … … var from SO2
    SO2 emissions/yr ………+3.4x … … … … … …0
    CO2 FF emissions/yr …..+3.9x … … … … .. +15%
    All CO2 emissions/yr …..+1.6x … … … … … -46%
    CO2 forcing ……… …….+1.1x … … … … .. –68%
    All AGW +ve forcing .. …+1.4x … … … … … -59%

    SO2 emissions from Richie & Roser (2018)
    CO2 emissions from Global Carbon Project
    Forcings from IPCC AR5 AII Table 1.2.

    Of course Victor it is not impossible that the crap you spout has some sort of evidential basis. If that is the case, now is the time for you to demonstrate such a basis.

  26. 326

    Victor said:

    “Arguments put forth by advocates of AGW are based on portions of the evidence carefully selected to support a pre-conceived view…”

    An unsupported assertion, much less probable, on the evidence, than the mirroring assertion that denialist argumentation is carefully selected to support a pre-conceived view.

    https://soundcloud.com/doc-snow/laughing-fool-blues-2

  27. 327
    MartinJB says:

    Of course, a climate model that didn’t include aerosols would be incomplete. I think there’s pretty strong evidence that aerosols are important (if short-lived) drivers of temperatures. Rather than adding unneeded complexity, including aerosols makes climate models more representative of the actual climate.

  28. 328
    Victor says:

    317 Dan sez: “I am still waiting for you to explain why the stratosphere has been cooling (it should be warming if the sun/natural causes are the cause of global warming) without violating the 1st Law of Thermodynamics (look it up and learn). I asked you this quite a while back and you conveniently ignored it.”

    Sorry if I ignored you, Dan. It’s probably because the temperature of the stratosphere contributes little to the AGW hypothesis if the troposphere refuses to cooperate. Consider the following graph, courtesy of Skeptical Science: https://static.skepticalscience.com/images/Cooling_Stratosphere.gif

    The upper segment does indeed appear to reveal a steady cooling of the stratosphere, so far so good. But the lower segment, titled “Warming in the mid to upper troposphere,” is more than just a little misleading. No warming is evident until about halfway through, beginning with the late 1970’s. Prior to that point, we see cooling — consistent with what we already know, that global temperatures appear to have either declined or held steady from ca. 1940 through the late 70’s.

    It might sound convincing to argue that steadily declining stratospheric temps coordinated with steadily rising tropospheric temps are a sure sign of significant CO2 involvement, but unfortunately for you the temperature of the troposphere has not steadily risen as expected — in fact, the negative correlation you want to see occurred only during a relatively brief 20 year period, from ca. 1979-ca. 1998. And since it’s the troposphere that’s far more influential in determining global temperatures, the temperature of the stratosphere can safely be ignored.

  29. 329
    Hank Roberts says:

    I wish we could convince Victor to adopt statistics rather than his eyeball, to determine where a trend can be claimed.

    Consider the following graph, courtesy of Skeptical Science: https://static.skepticalscience.com/images/Cooling_Stratosphere.gif

    The upper segment does indeed appear to reveal ….. But the lower segment …. No warming is evident until about halfway through …

    Sorry, V, but you’ve been making claims for a long time now asserting what you think you see in pictures.
    You’ve known better all along.

    The source data for the charts there is available and you can use woodfortrees to test whether there’s a trend.

    But you’ve known for, well, years now that what you claim you see, and what the statistical tests return, don’t agree.
    And we know your take on that:

    “Who ya gonna believe, me or your own eyes?”
    — Duck Soup

  30. 330
    Hank Roberts says:

    For anyone new here, you can look this stuff up for yourself.

    http://www.woodfortrees.org/plot/uah5/trend

  31. 331

    V 315: it’s not clear what caused the dramatic runup in temps. between the late 70’s and late 90’s, there are a great many precedents for such events in the past, notably the 1910-1940 runup, which no one has been able to explain either.

    BPL: Increasing greenhouse effect. Explained a long time ago.

  32. 332

    V 323: The logic behind the claim that lowered temperatures mid-century were due largely to the emission of industrial aerosols from the unconstrained burning of fossil fuels depends on the assumption that the warming to be expected from the release of CO2 was somehow neutralized by the release of those aerosols. If you subscribe to this hypothesis, then it’s hypocritical to insist that this was an effect that occurred only when convenient for your purposes and deny that the same logic, based on the same process of neutralization, can then be applied to any other period.

    BPL: Has it ever occurred to you that the relative amounts of aerosols and CO2 are known for these periods, and the relative amounts of cooling and heating from each is also known? Sure it’s convenient–it’s convenient because it matches the facts. What alternative have you got? Unexplained “natural variation?” Color me not impressed.

  33. 333

    V 323: If those aerosols canceled the warming effect of fossil fuel emissions from 1940-1979, as has been claimed, then they would have had the same effect prior to 1940, regardless of whether the volume of both CO2 emissions and aerosol emissions were smaller.

    BPL: Only if they were smaller in exactly the same ratio, Victor. You’re stuck on the idea that they have to have been produced in equal amounts. Doesn’t follow.

    V: The fact that neither you nor Rodger nor apparently anyone else posting here is willing to accept that very simple logic…

    BPL: It’s not what I would call “logic.”

  34. 334

    Does anyone have a time series for aerosols or aerosol forcing? I’d like to try CO2 + aerosols on temperature as a time series multiple regression.

  35. 335
    nigelj says:

    Victor @323

    “V: The logic behind the claim that lowered temperatures mid-century were due largely to the emission of industrial aerosols from the unconstrained burning of fossil fuels depends on the assumption that the warming to be expected from the release of CO2 was somehow neutralized by the release of those aerosols. If you subscribe to this hypothesis, then it’s hypocritical to insist that this was an effect that occurred only when convenient for your purposes and deny that the same logic, based on the same process of neutralization, can then be applied to any other period.”

    With respect this is nonsense. The cooling effect of aerosols is not an assumption or a hypothesis. It has been demonstrated time and time again, particularly with volcanic eruptions where the atmosphere cools for a year or so. They emit similar aerosols to coal burning industry etc. The effect has been accurately quantified. The effect was strong after WW2 because of the large scale, and rather weaker before that period, its that simple.

    In fact the increase in coal burning by China from 2002 – 2012 is implicated as one contributory factor in the so called temperature pause, but not a huge one.

    “It doesn’t matter if levels of coal burning were comparatively small prior to 1940. If you expect your hypothesis to be taken seriously then you must be willing to apply it across the board, not only when it’s convenient for you. . If those aerosols canceled the warming effect of fossil fuel emissions from 1940-1979, as has been claimed, then they would have had the same effect prior to 1940, regardless of whether the volume of both CO2 emissions and aerosol emissions were smaller. The fact that neither you nor Rodger nor apparently anyone else posting here is willing to accept that very simple logic says a lot about the confirmation bias that appears to dominate mainstream climate science generally.”

    Nonsense. Of course it matters that the levels of coal burning were lower globally before 1940. Science is all about different quantities operating at different times. You simply have to take these into account.

    “You can, of course, argue that other factors were at work in the early 20th century warming phase, but if you want to argue that the mid-century cooling was largely due to the neutralizing effect of industrial aerosol pollutants, then you cannot, as did Rodgers, claim that any part of that earlier warmup was due to the burning of fossil fuels.”

    Nonsense and utterly illogical. Theres no direct relationship between mid century aerosol cooling and CO2 levels prior to 1940. They are different things with different effects at different times. Higher levels of CO2 prior to 1940 had some role in warming at that period, because of the greenhouse effect, but are insufficient when calculated to explain all the warming. The other factors I mentioned fill the gap quite well when the calculations are done. This is simple logic.

  36. 336
    nigelj says:

    Victor @328

    “Sorry if I ignored you, Dan. It’s probably because the temperature of the stratosphere contributes little to the AGW hypothesis if the troposphere refuses to cooperate. ”

    With respect this is patent nonsense. We are talking two separate issues that can be explained independently. Your lack of logical analysis is apparent.A cooling stratosphere is well demonstrated and clearly implicates CO2 regardless of any other trend anywhere else and explanations for the same whatever they might be.

    ““Warming in the mid to upper troposphere,” is more than just a little misleading. No warming is evident until about halfway through, beginning with the late 1970’s. Prior to that point, we see cooling — consistent with what we already know, that global temperatures appear to have either declined or held steady from ca. 1940 through the late 70’s.”

    Nonsense. The article made no claim that tropospheric temperatures increased in a linear fashion right through the 20th century and early 21st century. We also dont have any data from weather baloons until the mid 1950s, and that data is limited. Anyway tropospheric temperature trends and surface trends are broadly consistent with a flat period after WW2.

    “It might sound convincing to argue that steadily declining stratospheric temps coordinated with steadily rising tropospheric temps are a sure sign of significant CO2 involvement, but unfortunately for you the temperature of the troposphere has not steadily risen as expected — in fact, the negative correlation you want to see occurred only during a relatively brief 20 year period, from ca. 1979-ca. 1998. And since it’s the troposphere that’s far more influential in determining global temperatures, the temperature of the stratosphere can safely be ignored.”

    Nonsense. Nobody has argued anything about some combination of statospheric and tropospheric trends, this is a pure strawman.

    And nobody has ever claimed the temperatures of the tropsphere or the surface would increase in a linear fashion. The IPCC stated right back in the 1990s there will be flat temperature periods of roughly a decade within a longer term rising trend. The so called ‘pause’ was only a 6-8 year slowdown in temperatures.

    The following is surface data from NASA GISS, showing how global temperatures have increased from the 1970s to 2017 and how small the pause was being about 6 – 8 years around 2002 – 2008.

    https://en.wikipedia.org/wiki/Global_temperature_record#/media/File:Global_Temperature_Anomaly.svg

    The following is tropospheric data from RSS, and shows an increase in global tempertaures from 1970 to 2017 and again a relatively small pause which is only a slight slowdown in the trend in this particular graph.

    http://www.remss.com/measurements/upper-air-temperature/

    (Please note the surface data looks steeper only because the vertical scale is different. They arent much different if you use the same scales and if overlaid the graps are pretty similar.)

    The flat period of temperatures after WW2 has been sufficiently explained by an extended period of industrial aerosols, and is before the modern global warming period anyway. Nobody was making detailed predictions prior to the 1940s! Do you not realise that?

    Your statement on negative correlations doesnt make sense, and doesn’t apply to 1979 – 1998. We have a longer term trend of decreasing stratospheric temperatures well beyond this period. And trophopheric and surface temperatures have undeniably increased from the 1970s through to 2017, the last year of full data, with only short slowdowns of a few years, as in the graphs I posted.

  37. 337
    MartinJB says:

    Victor Grauer / Docgee / Polar Vortex @ 323 makes what strikes me as a strange statement:

    “It doesn’t matter if levels of coal burning were comparatively small prior to 1940. If you expect your hypothesis to be taken seriously then you must be willing to apply it across the board, not only when it’s convenient for you. If those aerosols canceled the warming effect of fossil fuel emissions from 1940-1979, as has been claimed, then they would have had the same effect prior to 1940, regardless of whether the volume of both CO2 emissions and aerosol emissions were smaller.”

    Surely the relative amounts of aerosols and greenhouse gas emissions is of the utmost importance when evaluating the total forcing. To be simplistic about it, if the ratio of aerosols (from all sources) to greenhouse gasses (from all sources) increased, then surely the net forcing would decline. Am I missing something?

  38. 338
    Killian says:

    #324 SystemicCausation said Hayhoe vehemently advises against engaging with the “smokescreens” skeptics tend to offer as the reasons they couldn’t possibly agree with or act on the issue of climate change. “There’ll be no progress that way,” she insists.

    https://www.ecowatch.com/katharine-hayhoe-climate-change-2550366098.html

    Systemic Causation is like being caught in an endless loop heading to no where.

    Heading nowhere, yes. One of the advantages Hayhoe has is she is not pushing a hard-to-swallow agenda, but a BAU Lite agenda. She’s not a systems designer, and I never hear her, or hear of her, talking resources or collapse or extinction. So of course she can be successful. I honestly don’t think she fully sees the picture for what it is, so she is content with her LEDs and her EV. Great. But what she is touting will get us nowhere near sustainability.

    What then, the long-term value of half a story? At least she’s raising awareness? What would the response be if she were telling people the full long tail risk?

    And, yes, I have raised these issues with her.

  39. 339
    Killian says:

    #313 Kevin McKinney said Killian, #312–

    My take on Knoblauch et al (2018) [https://doi.org/10.1038/s41558-018-0095-z], FWIW:

    …In a nutshell, things are worse than thought with regard to a terrestrial permafrost CO2e feedback, but it’s still pretty hard to say by how much.

    Yes, got all that. I was looking for more technical quantification, which I did not make clear.

    Cheers

  40. 340
    Victor says:

    329 Hank Roberts says:

    “I wish we could convince Victor to adopt statistics rather than his eyeball, to determine where a trend can be claimed. . .

    But you’ve known for, well, years now that what you claim you see, and what the statistical tests return, don’t agree.”

    V: from the “Statistical Analysis Handbook” – (c) 2015 by Dr M J de Smith:

    “Whatever the form of the trend it is usually preferable to remove and/or specify the trend explicitly prior to further analysis and modeling. There are several ways in which this may be carried out. The first step is usually to examine the graph of the time series visually, to see if any trend-line behavior can be observed. It may be that a series has no observable trend, has a trend across its range, or exhibits a trend in part of its range. In the latter case it would be sensible to separate the time series into a number of subsets, each of which could be modeled separately. Autocorrelation analysis is a very useful technique for identifying trends and periodicities in the data, in a manner that is often more precise than can be obtained with simple visual inspection.

    Having identified that a trend exists, one can then consider procedures for identifying and managing trends. . .”

    In other words, prior to applying a statistical analysis to any set of data it is important to determine whether any trend actually exists. And according to Dr. Smith, who presumably knows what he is talking about, it makes sense to “examine the graph of the time series visually, to see if any trend-line behavior can be observed.” Thus identification of the trend must come first and only if one can be identified does it make sense to proceed to a statistical analysis. To put it bluntly, statistics per se is NOT sufficient to identify a trend while, according to the good doctor, eyeballing a graph is.

    Also note what he says about data that “exhibits a trend in part of its range,” which is precisely what we see the troposphere graph: “In the latter case it would be sensible to separate the time series into a number of subsets, each of which could be modeled separately.”

  41. 341
    Victor says:

    Oops, I forgot to include the link to the Handbook referenced in my previous post. Here it is: http://www.statsref.com/HTML/index.html?trend_analysis2.html

  42. 342
    CCHolley says:

    Victor @323

    It doesn’t matter if levels of coal burning were comparatively small prior to 1940. If you expect your hypothesis to be taken seriously then you must be willing to apply it across the board, not only when it’s convenient for you. If those aerosols canceled the warming effect of fossil fuel emissions from 1940-1979, as has been claimed, then they would have had the same effect prior to 1940, regardless of whether the volume of both CO2 emissions and aerosol emissions were smaller.

    NO they don’t have to have the same effect. Science does not work that way. You can never be assumptive, you need to understand all the evidence and the mechanisms before you assume that what applies in one situation applies in another. In this case, the evidence says it does not. The rate of aerosol cooling is not necessarily equal to the amount of CO2 warming as there are other factors that come into play. Both CO2 emissions and aerosols are dependent on the fuel source. The rate of CO2 emission from combustion per BTU is dependent on the fossil fuel burned as is the sulfur content. In addition, CO2 is well mixed in the atmosphere changing the radiative forcing over the entire earth while aerosols are short lived with a very localized effect relative to the emission source. So to logically conclude that the effect is the same prior to 1940 would imply all things are equal. They are not.

    We know there was a large increase in aerosols after 1940. Since sulfates in the atmosphere are quickly precipitated out, the sulfur can be found in ice core record thus providing a historical indication of aerosols present up wind from the ice. For example, the sulfur trapped in ice cores in Greenland is indicative of the presence of sulfate aerosols downwind of the United States and Canada (McConnell et al., 2007). These data show an increase of sulfur in Greenland ice cores from the 1940’s to the 1980’s and a decrease thereafter, in line with northern American emission inventories.

    We also know that the cooling from the 1940’s to the 1980’s was mostly in the northern hemisphere. This can be seen in the temperature records. Except for the temperature spike anomaly around 1940 due to the biased warm change in war time ocean temperature measurement methodology, there was little or no slow down in temperature rise in the southern hemisphere. Of course the rapid industrialization occurred mostly in the northern hemisphere and most of the aerosols were emitted there and thus this is where you would expect the cooling to have occurred.

    So why not a similar cancelling effect prior to the 1940s? To answer this we need to look at where the increases in fossil fuel burning actually came from. When we look at the record, coal consumption rose exponentially from about 1850 to the beginning of the great depression when it took a significant drop, but then rose rapidly during the war years falling off again after the war, but then about 1950 it began to sharply rise again. But the real culprit here was the explosion in the number of automobiles and the meteoric increase in consumption of gasoline after the war along with a significant rise in the use of natural gas, mostly for new home heating. Both of these factors likely highly changed the spatial profile of the aerosol coverage. i.e. we had smog where there previously was no prior pollution to block sunlight. Aerosol cooling is far more dependent on the amount of geography covered by aerosols rather than the exact amount of aerosols themselves. So for the cooling period the growth in spacial coverage likely far outpaced the amount of increase in total aerosols unlike the prior period and the make-up of the source was significantly different.

    This is what science is all about, using all the evidence rather than assumptive reasoning which can easily fool us. Aerosols absolutely cause cooling, that’s not a hypothesis it is scientific truth supported by evidence.

    But it is complicated. Victor has problems with complexity.

  43. 343
    Victor says:

    335 nigelj: “Nonsense. Of course it matters that the levels of coal burning were lower globally before 1940. Science is all about different quantities operating at different times. You simply have to take these into account.”

    Let me try to be more explicit: if you want to assume (or, if you prefer, conclude) that aerosols produced by the increased burning of fossil fuels after WWII had a cooling effect that essentially cancelled out the warming that would be expected as a result of the release of CO2 produced by that burning, then it’s only logical to conclude that there exists a certain ratio between the warming and cooling effects produced by that same burning. This makes sense because, according to your interpretation, both the warming and cooling effects stemmed from the same source.

    Now once this ratio (whatever it might be) has been established, I see no reason why more or less the same ratio cannot be applied to all cases of fossil fuel burning prior to that period, especially since there were no controls over the emission of such aerosols during either period. If you want to argue otherwise, then please specify how the burning of coal and oil differed in such a manner as to produce a greater degree of warming vs. cooling in the earlier era.

    If the warming effects of CO2 emission from ff were essentially neutralized after the 1940s, then one would expect that a similar neutralization would have been in effect prior to 1940. Unless of course you can provide some reason why the ratios would have differed. Since it’s the ratios we’re talking about and not the absolute levels of either CO2 or aerosols release, then the burning of ff would have produced the same cooling effect during both periods.

    Sorry, but I can’t put it any more simply than that. If you can see the flaw in my logic then please by all means explain. Ad hominems and insults don’t count.

    [Response: The ratio is not constant in time, because aerosols have a much shorter perturbation time on atmospheric composition than CO2. Effectively, aerosols depend on current emissions, CO2 levels depend on accumulated emissions. So to match CO2, aerosols would have to increase exponentially, and they don’t. – gavin]

  44. 344
    nigelj says:

    Victor @340

    “And according to Dr. Smith, who presumably knows what he is talking about, it makes sense to “examine the graph of the time series visually, to see if any trend-line behavior can be observed.” Thus identification of the trend must come first and only if one can be identified does it make sense to proceed to a statistical analysis.” Then do a statistical test etc.

    Yes, and everyone here except you looks at graphs of temperature and see an increasing trend from 1970 – 2017, and we look at temperature versus CO2 since 1900 and see a rough correlation. Maybe you just dont understand how to read a graph, or have a sort of subconscious denial. Perhaps you should look into that.

    Hint: when 2 trends on a graph are roughly in visual synchronisation, there likes a statistical correlation. And since 1900 – 2017 CO2 and temperature are in a rough visual correlation.

  45. 345
    nigelj says:

    Victor @343

    “If the warming effects of CO2 emission from ff were essentially neutralized after the 1940s, then one would expect that a similar neutralization would have been in effect prior to 1940”

    I hear you, but only “all things being equal” and they aren’t.

    Gavin has mostly answered the issue about the ratio of warming to cooling regarding CO2 and sulphates. I found that comment pretty interesting.

    And I think the period before 1940 was complicated. Temperatures were driven upwards by CO2 and also solar changes and low volcanic activity. This is another reason why the effects of aerosols from coal burning were overwhelmed in this period.

    Im not a climate scientist, and I have a design related degree, so others above explain it in better detail and have more knowledge, however I grasp the basics easily enough. Its just a case of thinking about multiple factors interracting simultaneously and changing over time. Its like solving a murder mystery.

    Im a naural born sceptic, my parents nicknamed me “doubting thomas”, however the pieces of the puzzle are all consistent with agw theory.

  46. 346

    V 340: prior to applying a statistical analysis to any set of data it is important to determine whether any trend actually exists.

    BPL: But you determine whether any trend actually exists by applying a statistical analysis. I’ve explained this before, in detail.

  47. 347
    Killian says:

    5 billion facing water shortages by 2050? 32 years. And will anyone be surprised if it’s significantly sooner?

    https://www.theguardian.com/environment/2018/mar/19/water-shortages-could-affect-5bn-people-by-2050-un-report-warns

  48. 348

    Okay, I managed to accumulate a bunch of climate time series thought to be connected to temperature. I got CRUTEM4 for 1850-2017, CO2 for the same period (Mauna Loa + Law Dome ice cores), aerosol optical depth for 1850-2012, annual sunspot number for 1700-2014, and multivariate ENSO index for 1950-2017. Unfortunately, that left me with only N = 63 contiguous data points (1950-2012). On that basis, I got R^2 = 0.858 and p < 7.28 x 10^-24. All X-variables were significant except for sunspot number. The temperatures (real and modeled) were:

    Year T Tmodel
    1950 -0.173 -0.187
    1951 -0.052 -0.098
    1952 0.028 -0.109
    1953 0.097 -0.077
    1954 -0.129 -0.171
    1955 -0.19 -0.212
    1956 -0.267 -0.169
    1957 -0.007 -0.012
    1958 0.046 0.007
    1959 0.017 -0.038
    1960 -0.049 -0.077
    1961 0.038 -0.092
    1962 0.014 -0.130
    1963 0.048 -0.137
    1964 -0.223 -0.255
    1965 -0.14 -0.075
    1966 -0.068 -0.051
    1967 -0.074 -0.086
    1968 -0.113 -0.085
    1969 0.032 -0.022
    1970 -0.027 -0.057
    1971 -0.186 -0.102
    1972 -0.065 0.088
    1973 0.062 -0.008
    1974 -0.214 -0.071
    1975 -0.149 -0.114
    1976 -0.241 0.020
    1977 0.047 0.111
    1978 -0.062 0.085
    1979 0.057 0.130
    1980 0.092 0.158
    1981 0.14 0.129
    1982 0.011 0.110
    1983 0.194 0.106
    1984 -0.014 0.083
    1985 -0.03 0.109
    1986 0.045 0.181
    1987 0.192 0.297
    1988 0.198 0.163
    1989 0.118 0.181
    1990 0.296 0.262
    1991 0.254 0.195
    1992 0.105 0.087
    1993 0.148 0.232
    1994 0.208 0.279
    1995 0.325 0.275
    1996 0.183 0.254
    1997 0.39 0.411
    1998 0.539 0.392
    1999 0.306 0.274
    2000 0.294 0.315
    2001 0.441 0.354
    2002 0.496 0.429
    2003 0.505 0.431
    2004 0.447 0.440
    2005 0.545 0.445
    2006 0.506 0.457
    2007 0.491 0.421
    2008 0.395 0.408
    2009 0.506 0.500
    2010 0.56 0.466
    2011 0.425 0.438
    2012 0.47 0.542

    If you graph it out, it's quite a nice match.

    One point of interest: AOD had very little effect. Most of the jogging up and down is due to ENSO. We (the good guys) were right about aerosols qualitatively, but not quantitatively. Score one for Victor.

  49. 349
    Hank Roberts says:

    Victor says: “… Having identified that a trend exists, one can then consider procedures for identifying and managing trends. . .”
    In other words, prior to applying a statistical analysis to any set of data it is important to determine whether any trend actually exists.

    Nope. Victor, you’ve misread a description of how one decdes whether to use a one-tail or a two-tail statistical test.

    You have consistently shown quite a genius for self-justification, proclaiming your eyeballs superior to the arithmetic, as you keep claiming no trend exists in multiple data sets where you could easily do the math and find out you are wrong.

    That’s wrong. Wrong, wrong, wrong.

    Go to woodfortrees. Read the Notes section on how easy it is to misuse the trend analysis tool to fool yourself.
    Then try using it on the entire data sets, any of the complete data sets available there. You’d probably prefer BEST.

  50. 350
    Hank Roberts says:

    For Victor, let’s pick a chunk out of a data set most likely to fit your preconceptions:

    1) I’d bet you see no trend here: http://www.woodfortrees.org/plot/best/from:1840/to:1920

    got that? Got the old Mark One Eyeball tuned up and looked at the graph? did you see anything there?

    Now try doing the arithmetic (or letting woodfortrees do it for you).

    2) http://www.woodfortrees.org/plot/best/from:1840/to:1920/trend