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Unforced Variations: Dec 2015

Filed under: — group @ 13 December 2015

This is a belated open thread for this month, for anything non-COP21 and non-AGU related.

177 Responses to “Unforced Variations: Dec 2015”

  1. 51
    Greg Charles says:

    Re: Theo @45

    Surface temperatures are used as a proxy for total warming because a) there’s a lot of data and it goes back a long way making comparisons possible, and b) surface temperatures are most relevant to us since we live on the surface. What leads you to conclude no one is concerned about surface temperature accuracy? From all I can see, the opposite is true.

  2. 52
    Hank Roberts says:

    http://www.bbc.com/news/science-environment-35109198

    It has been noted that skies are brighter now than they were in the 1970s and 1980s.

    The change has been attributed to environmental legislation that has removed a lot of the pollution particles that used to be emitted into the air by vehicles, industry and power generation.

    These would have dimmed skies by reflecting or absorbing sunlight.

    But Dr Long and colleagues argue that the observed changes are not as simple as they first appear.

    Yes, the light reaching the surface has increased but not in the way expected, he said in his press conference here.

    Instead of seeing a simple increase in direct shortwave radiation, a more diffuse version of this light is being detected.

    This indicates something must be scattering the light as it falls on the Earth.

    Plant profit

    And Dr Long’s analysis suggests this “something” is high-altitude ice particles, and he links their production to the water and other emissions in aircraft contrails.

    “You have to have a mechanism to generate the ice crystals and there is nothing in nature up there necessarily that we can identify that would consistently produce these ice particles, except the very well correlated and well documented increase in the commercial air traffic over the continental United States,” he told BBC News.

    The team does not think the “sub-visual contrail-generated ice haze” has a major effect on global warming. It may, though, have some significant effects on biology, says Prof Martin Wild, from of the Swiss Federal Institute of Technology in Zurich, who commented on the work.

    Plants preferred diffuse light, he explained: “If you have a canopy structure, the direct light is absorbed by the uppermost leaves. Everything below is shaded and so misses out on that energy. But diffuse light can travel deeper into the canopy and can be absorbed by the plants lower down. So in that sense, if you have more diffuse light those lower plants will profit.

    And Dr Long said there were implications for solar power systems, too: “For solar renewable energy – they have two types. They have photovoltaic panels that they kind of slant to catch most of the direct sun; and then they have concentrator systems that use the actual sunlight – they track the Sun.

    “If you’re decreasing the direct light, then you’re decreasing the energy available for those concentrator systems.”

    Dr Long cautioned that more analysis was needed to close his hypothesis, but said the circumstantial evidence linking planes to the ice haze looked strong….

  3. 53
    MA Rodger says:

    NOAA have just posted the global anomaly for November as +0.97ºC, the second warmest anomaly on record and a little lower than October’s anomaly.
    The year to date averages +0.871ºC, with the last 12-month average +0.867ºC and the 2014 calendar year averaging +0.735ºC. The 2015 average will be possibly around +0.88ºC.
    With the exception of January (2nd) and April (3rd), all 2015 months are the hottest for their respective months.

    =13th …. 2014 . 12 …. +0.82ºC
    =15th …. 2015 . 1 …… +0.80ºC
    =6th …… 2015 . 2 …. +0.8º7C
    4th ……. 2015 . 3 …. +0.89ºC
    =24th …. 2015 . 4 …. +0.77ºC
    10th …… 2015 . 5 …. +0.85ºC
    =8th …… 2015 . 6 …. +0.86ºC
    =15th …. 2015 . 7 …. +0.80ºC
    =6th …… 2015 . 8 …. +0.87ºC
    3rd ……. 2015 . 9 …. +0.91ºC
    1st ……. 2015 . 10 …. +0.99ºC
    2nd …….. 2015 . 11 …. +0.97ºC

  4. 54
    MA Rodger says:

    Dick Newell @42.
    I appreciate this is likely difficult for you as I note you have a very poor grasp of maths, but mistakingly labelling ‘most times’ as being ‘invariably’ is quite a basic error of logic. And @42 you appear to see no problem with this error.
    Indeed, the spreadsheet test you describe @42 would not yield the result you describe – that is, it will not find “most times it departs from the start point by a lot more than the actual departure in the real data.” Rather, it is correct to say that a ‘large minority’ will depart from the start point a lot more than the temperature trend of the last century-&-a-half, but this is itself a further proof that your random walk theorising is nonsensical. If global temperature did vary in such a manner, a large minority of the 150-year periods of recent history (about 20% of them) would have experienced global temperature changes (+ or -) in excess of double that of the last 150 years. Yet we know from proxy reconstruction of the last millennium that such temperature swings have not occurred. (This is effectively a restatement of the second point I made @26.)

  5. 55
    Dick Newell says:

    In reply to 46 &49.
    I think this will be my last shot at this. I assure you, I hate the idea of wasting people’s time, but I would genuinely like to understand. Let me have one last try. I would first like to thank folk for their (mostly) courteous responses:

    Imagine a barrel containing some water, this is my simple model of the particular part of the planet whose temperature is measured. The level of the water in the barrel represents temperature. I repeatedly toss a coin. If it comes down heads I pour a cup of water into the barrel, if it is tails, I take one cup out. My coin is the null hypothesis model for all of the other influences changing the energy in the atmosphere, some understood, and some not so. It is an unbiassed coin. As time proceeds, the level of water in the barrel will move from the original level in the manner of a random walk.

    The amount the water level changes is surprisingly large, many times more than the equivalent of 1 cup of water.

    A more sophisticated model would be to place the barrel in a pond, so it is sitting on the bottom, and a small hole is made in the barrel below water level.
    The first thing to happen will be that the water level in the barrel becomes equal to the water level in the pond. One then starts tossing coins, and the water level in the barrel will again start to move from its start point, but the negative feedback caused by the hole will constrain the amount by which it will diverge. The larger the divergence, the faster the water flows through the hole.

    This model can produce fluctuations looking very like the actual historic trend over the last 150 years, so why is it not a plausible empirical model of what is happening in the atmosphere?

    One last thing, having read the Tamino links (thank you), then presumably it will be a doddle for someone to claim this $10,000 prize:
    http://www.informath.org/Contest1000.htm

  6. 56
    Theo van den Berg says:

    Thanks Hank, Chuck and Greg for your responses. First Hank for me your suggestion to “start here” makes me laugh. I am no climate scientist, but I have been living Global Warming since 2007. Like securing 2km of forest to make sure nobody takes it down and decking it out for me to survive climate extremes and over-population. Almost daily I do things to help the environment. Talking and blogging is fun, but what we need is action and we need it now. Since 2007 I am an almost daily visitor to Real Climate, specially after major climate events. Many other GW websites have fallen by the wayside, either nurds loving numbers or frequented by those who love to argue. Even deleted Tamino after his obsession with Watts.

    Mine was just a simple observation from the gallery as experienced here in my environment. More heat creates more cloud, more cloud during the day reduces heat and keep it warmer at night. Only needs one clear day in a month to create a very high/low max for the whole month. I think the term for that is Cherry Picking. “start here” doesn’t really go into that other than that CERN CLOUD experiment. Mine is not an experiment but reality from observation.

    Chuck we all agree that most things are market based. The coal and tobacco companies are only supplying what they think we need and if you had invested as much as they have, it is “fair” for you to attempt to continue your supply. In my teens it was considered not cool if you did not smoke and now at 64, I still have about 7 slightly augmented cigarettes each day and I will defend the right to do so till I die. Finally I do agree that we should leave some coal in the ground, so that the next itteration of humanity has a chance to make a start :)
    I will now try to shut up, but remain a regular watcher of Real Climate.

  7. 57

    42 ;”,i>Doubtless more CO2 in the atmosphere in the atmosphere has some, unmeasurable effect, but it beats me how you can distinguish it from the noise. I suppose the answer is that the unverified models tell us.

    You could always repeat Tyndall’s experiment — even with crude Victorian apparatus , Prince Albert FRS could distinguish the CO2 effect from the absorbtion of heat by air.

  8. 58
    Tom Adams says:

    Dick Newell,

    Scientists have 450,000 years of temperature and CO2 concentration data:

    http://courses.washington.edu/pcc588/readings/Sigman_Boyle-Glacial_CO2_Review-Na00.pdf

    You are looking at the last 150 years 0.03% of this data.

    If we had only 150 years of data, I guess you would insist on only looking at 0.03% of that, the most recent 18 days!

    Look at all the evidence.

  9. 59
    Robin Johnson says:

    The COS “stall” doesn’t mean a stall in the global PPM – it simply means a “stall” is the yearly amount of CO2 being emitted and it is based on REPORTED numbers rather than an objective MEASURE. In other words, according to a compilation of the national self-reported CO2 emission numbers, emissions have “leveled” off such that the amount of CO2 emitted over the last 12 months was the same as the previous 12 months. And this leveling off is almost entirely attributable to a ~3% DROP in reported emissions from China. This does NOT mean that the global PPM number has leveled off – it is definitely still increasing as the CO2 monitoring stations attest.

  10. 60
    Lawrence Coleman says:

    33: Theo Van den berg. I thought your comment was balanced. The west would not be the technological powerhouse it is today if it wasn’t for coal that’s for sure! Still anyone with half a brain should have realised all the gray smoke belching from chimneys since the industrial rev was going to bite us on the bum one day before too long. When it became obvious to scientists say in the 1970’s that fossil fuels were causing an environmental impact we should have taken stock of the situation and done something. But we were still besotted by all our creature comforts and loving the lifestyle that fossil fuels have brought us. As I have said over and over, our selfish brain far outweighs our spiritual sense, and that’s the problem. It’s practically too late now to start embracing our new found connectedness to everything..even though it was there all along. I’m also from Aust. and our Queensland premier still desperately wants the Carmichael coal mine to proceed (the world biggest proposed coal mine). Very few people actually understand how critical and tenuous our situation is. Less do they realise how extremely fragile the environment and atmosphere is. When they finally come to appreciate the stark gravity of what is imminently ahead for us and immediately throw out all stops to change the way they/family/occupation/town etc does it’s business of course it far far too late. Such is our morbid and terminal addiction to fossil fuels and coal in particular. We have to act this way – go cold turkey immediately, yes it’s going to be hell and quite a few levels but at the end of the tunnel we might have a sustainable world for our progeny’s progeny. Lets hope civilisation does not collapse before we have invented a practical global CO2 scrubber. Geo- engineering does look increasingly essential to secure a future.

  11. 61
    Chuck Hughes says:

    Theo van den Berg says:

    17 Dec 2015 at 4:53 PM

    “Thanks Hank, Chuck and Greg for your responses. First Hank for me your suggestion to “start here” makes me laugh. I am no climate scientist, but I have been living Global Warming since 2007. Like securing 2km of forest to make sure nobody takes it down and decking it out for me to survive climate extremes and over-population. Almost daily I do things to help the environment. Talking and blogging is fun, but what we need is action and we need it now. Since 2007 I am an almost daily visitor to Real Climate, specially after major climate events. Many other GW websites have fallen by the wayside, either nurds loving numbers or frequented by those who love to argue. Even deleted Tamino after his obsession with Watts.”

    Theo, what you’re doing is rejecting the information you don’t like and defending the information you do like with no regard for the effect it has on the general population.

    Smoke yourself to death if you want to but don’t sit there and try to defend it as being beneficial for the rest of us. There’s a lot you don’t understand about Climate change. You have no chance of learning anything if you don’t change your attitude towards those who care enough to try and help you.

  12. 62
    Hank Roberts says:

    “securing 2km of forest”

    2 square kilometers? almost 500 acres, 0.7 square miles American?
    That’s impressive.

    I managed about a tenth of that so far.

    Now finding someone who’d like to keep preserving it as I get old-for-a-human is the tough question. Loggers on all sides, slavering ….

  13. 63
    Ray Ladbury says:

    Dick Newell,

    I have got to hand it to you. I have never seen anyone so assiduously ignore physics.

    Dick: “I hate the idea of wasting people’s time, but I would genuinely like to understand.”

    Horse pucky! If you were interested in understanding, you’d at least look into the physics.

  14. 64
    chick keller says:

    can anyone explain why satellite and surface temps disagree on recent warming?

  15. 65
    Dick Newell says:

    In answer to 54. Maybe my grasp of English is as bad as my grasp of maths, but the pedantic semantic arguments you make about my use of words goes way over my head I am afraid.

    In answer to 58: does not the 450k year historical data show that CO2 changes lag temperature changes, so if you are trying to demonstrate CO2 driving temperature change it is a poor correlation. Now, I am not saying recent CO2 increases are caused by temperature increases (it requires a much longer lag time), and I am prepared to accept that these increases are largely human generated, but to then say that this will cause a dangerous temperature increase is not proven.
    I could argue that the irregular temperature profile of the last 100 years could be caused by internal random variation overlaid on a CO2 driven temperature increase, but is that any more likely than the whole thing being driven by internal variation?
    Why are you guys so sure you are right? and please don’t say the models prove it, or it is physics or some other put down.

  16. 66
    Silk says:

    “This model can produce fluctuations looking very like the actual historic trend over the last 150 years, so why is it not a plausible empirical model of what is happening in the atmosphere? ”

    No. It. Can’t.

    I beg you. Produce an algorithm that reproduces the year-to-year variability of the 150 year data series, then run it 1000 times, and tell me how many times it produces a statistically significant warming (or cooling) trend, over the entire time period.

    And while you’re at it, explain where the energy that has heated the atmosphere and oceans by whatever it is over the last 30 years came from.

  17. 67
    Theo van den Berg says:

    60: Lawrence Coleman. Coal could still have a future with Carbon Capture and AUS should offer a discount to countries that do.

    My ultimate pipe dream for AUS is to be the saviour of humanity by becoming an exporter of H (and O2). Lease$ our wastelands at the centre to investors (like Japan) to build and run Nuclear power stations. 5th gen is much cleaner and can consume any rubbish like nuclear waste and even terrorists :) Power used to desalinate sea water. Salt for cooling and water for farming and water for splitting. Tankers full of H can explode, but cause minimal environmental impact. Get the UN involved to police it all. For AUS this would provide a good wholesome business, extra water, free? electricity and be safest country in the world. Also humanity needs to get of its arse and conquer the stars to find more real estate, and that can hardly be done on a bunch solar panels.
    Oops and now I have really overdone it. Hope that at least you guys (and girls?) got some entertainment out of this.

  18. 68
    Brian says:

    Coleman – Svante Arrhenius observed in 1896, following the eruption of Krakatoa and its immediate effects on the climate, that the burning of coal would have potentially devastating effects on the world’s climate. He reasoned however that we would run out of coal before we did too much damage. What he could not anticipate was the extraction and burning of crude oil which would over shadow the effects of coal burning by many fold. Arrhenius by the way was the third Nobel laureate for his work in chemistry.

  19. 69
    Steve Fish says:

    Re- Comment by Dick Newell — 17 Dec 2015 @ 4:30 PM, ~#55

    Dick, arguing by analogy can be useful, but only if the analogy matches the real world. See a post about this here at Real Climate- http://www.realclimate.org/index.php/archives/2014/09/on-arguing-by-analogy/

    Consider that the temperature at noon can be very hot and then very cold at midnight. Temperatures at the surface can be warmer or cooler for a few months or years (think El Niño or volcanic eruption), but as soon as the forcing stops the temperature returns to the mean. For a long term change the forcing has to remain constant. For a constant increase, the forcing has to continually increase, and what do you think that might be? In a random walk each step is additive to the sum of previous steps, while short term climate variability is not. In the personal human timescale CO2 increases are additive.

    Steve

  20. 70
    Jim Eager says:

    Dick Newell: “does not the 450k year historical data show that CO2 changes lag temperature changes, so if you are trying to demonstrate CO2 driving temperature change it is a poor correlation.

    No, it is not at all a poor correlation, it is your own false logic and misunderstanding of the 450k year historical data that is poor. CO2 lags temperature in the ice core record because CO2 did not initiate the warming, Milankovitch orbital forcing did. Rising CO2 then added even more warming as a feedback.
    We know with certainty that CO2 is a greenhouse gas: that CO2 absorbs IR energy has been established physics since 1859. Since then it has been intensively studied and quantified in the lab and in the atmosphere. There are other forcings that can drive both warming and cooling, but we know for sure that adding more CO2 to the atmosphere will cause warming, full stop.

    I’m sorry that you feel that physics is a put down, but as long as you remain willfully ignorant of the physics you will remain confused and easy prey for the kind of nonsense you’ve been writing here.

  21. 71
    Neil White says:

    Chick Keller (#64)

    Firstly, they’re measuring different things – the satellites measure the average temperature over a layer of the lower atmosphere, not surface temperatures.

    Secondly, there are a number of issues with the satellite estimates, and even some of the people who work with the satellite data (e.g. Carl Mears) regard the thermometer-based surface temperature record as being more reliable.

    The satellite data has numerous problems, a couple of which are
    – they don’t measure temperature directly, they infer it from other variables
    – the longer time series are stitched together from of a number of short records from similar (but not identical) satellites, and the matching of one to the next is not straightforward, especially as they all suffer from (mostly negative) drifts related to orbital decay. There are also some empirical adjustments which do not appear to be well understood.

    Reading Roy Spencer’s description of his own data set on his own web site is ‘illuminating’!

    If you find one of these satellite ‘surface’ temperature data sets that has realistic error bars assigned to it I (and, I suspect, quite a few other people) would like to see it.

    Regards

    Neil

  22. 72
    Dick Newell says:

    In reply to 66:
    “I beg you. Produce an algorithm that reproduces the year-to-year variability of the 150 year data series, then run it 1000 times, and tell me how many times it produces a statistically significant warming (or cooling) trend, over the entire time period.”
    I did that back in 2007 (before climategate). I have lost the code now, but it would be trivially simple to recreate it. (I still have the thing I wrote up at the time though) Knowing how pedantic folk can be, one needs to be sure what one means by “statistically significant”, but it is easy to get statistically significant trends by doing a simple linear regression,

    I am not saying that any of the curves produced precisely matched what happened, but it emulates the main characteristics: you can get curves that trend upwards for 150 years, downward for 150 years, go up and down for 150 years and everything in between, and the magnitude of the changes is similar to what actually happened, depending on how you set the negative feedback. With no feedback, the changes are often (need to be careful what word I use here, as “invariably” and “most times” seem to confuse people) much larger than what happened.

    And your second question:
    “And while you’re at it, explain where the energy that has heated the atmosphere and oceans by whatever it is over the last 30 years came from.”
    There are many components of the climate system. The temperature record is of just one of those components (the lower atmosphere). Energy moves between the 1 component and the others. Perhaps the biggest uncertainty is cloud cover, which could be a positive or negative effect. So, I don’t know the answer to your question, but there are several candidates.

  23. 73
    Theo van den Berg says:

    62: Hank Roberts. btw I am not bragging being this big landowner. Unlike a Sydney house block, one square km of beautiful Aussie vacant bush in my area goes for about 50K USD. Whoever, I meet, I always entice them to do the same to help protect the forests. Between you guys, you could own half the Amazon. Me lucky, cause at my age I am happy to live in the middle of nowhere costing almost nothing. Spend most of my days tending to the forest, making sure it does not burn and removing invasive weeds. In my previous incarnation, I was an IT consultant for 45+ years and I definitely prefer this one. And I am sure that the family portfolio can handle this small investment forever.

  24. 74
    patrick says:

    Thank you, Dr. Kate Marvel and others:

    http://www.nature.com/nclimate/journal/vaop/ncurrent/full/nclimate2888.html

    I don’t mean thank you for stating a point or a position. I mean thank you
    for advancing our knowledge. Thank you.

  25. 75
    Silk says:

    #65 “Why are you guys so sure you are right?”

    Read Working Group 1 Report from the IPCC. http://www.ipcc.ch

    That explains why we are, broadly, right.

    It explains it with reference to 100s, if not 1000s, of scientific studies that are, in turn, backed up by 1000s more. A multitude of lifetimes of scientists.

    We are (broadly) right because all the evidence says we are right, and there isn’t an alternative physical explanation for what has been observed that can be shown to be consistent with the observations. No other theory even comes close.

  26. 76

    D: Why are you guys so sure you are right? and please don’t say the models prove it, or it is physics or some other put down.

    BPL: Citing the physics is not a put-down. This is why we’re sure we’re right: Carbon dioxide absorbs infrared light better than it absorbs sunlight. That’s a fact. John Tyndall showed that in lab work in 1858. Since then we’ve mapped something like 100,000 carbon dioxide absorption lines. We are sure, based on the physics (however much you don’t like physics), that CO2 is a greenhouse gas. Add more to an atmosphere, the atmosphere heats up. Since it has done so nearly in lock-step with the CO2 since 1850 (r = 0.91, N = 164), that’s pretty good evidence that we’re right.

    And don’t say “proved,” because science never deals in proof. Science can only disprove theories, never prove them. Proof is for mathematics or formal logic.

  27. 77
    Dick Newell says:

    Let me be clear, I believe in Physics, I believe that CO2 will have a warming influence, some of the recent warming must have been caused by CO2, but I don’t know how much and I don’t know how one can find out how much, especially as the models don’t seem to imitate what happens in reality very well.
    So I would like to hear a rational argument to refute my conjecture that the temperature trend could be a random walk.
    To this end, I have put a model online. It is a spreadsheet that you can download and play with. There are 4 worksheets:
    1 Readme that explains it all
    2 Differences which contains real and fabricated data
    3 Real and fabricated temperatures resulting from 2
    4 Same as 3 but with a feedback parameter that you can play with.

    Prod any cell to see my formulae
    Edit any blank cell to generate a new set of random numbers
    The spreadsheet is here:
    https://drive.google.com/file/d/0B_fx9kYNkQnleS1kaExkQXFnNFU/view?usp=sharing

  28. 78
    Victor says:

    #70 Jim Eager: “CO2 lags temperature in the ice core record because CO2 did not initiate the warming, Milankovitch orbital forcing did. Rising CO2 then added even more warming as a feedback.”

    If that were the case, then we’d see a reversal at some point, with rises in CO2 leading and atmospheric warming following. The data show no sign of that. CO2 consistently lags temperature, strongly suggesting that the latter was consistently causing the former.

  29. 79
    MA Rodger says:

    Dick Newell @72.
    You tell us “I am not saying that any of the curves produced precisely matched what happened, but it emulates the main characteristics” of the last 150 years of global temperature. Do those “main characteristics” emulate the absence of any signs of the feedback you employ in your emulation? Coz there ain’t no signs in the real world at interdecadal scales.
    And I’m feeling conscious that up-thread I introduced mathematical requirements for such modelling while neglecting mention physical requirements (which others had addressed). Do consider this – if I produced a model which used only random inputs but could still emulate faithfully the characteristic movements of a football on a football pitch: if I produced such a model, it doesn’t mean in any way that the footballers aren’t actually responsible for the football’s movements.

    You also mentioned Keenan’s little puzzle @55. Do note, the Keenan challenge is for $100,000 not $10,000. Keenan is presumably creating random trends of random length with added noise to create his little puzzle. Given how much his trends fly about, it is not difficult to hide such small trends within some of the data-series without showing any obvious sign of which series are trended and which are not. As with your random walk models, Keenan’s data-series mainly look nothing like the temperature record. For instance, his data contains 10-year periods with 1ºC temperature changes. But of course, lack of realism isn’t something Keenan sees as required. He only challenges folk to spot which of his data-series are hiding his +/-1ºC/century trend. As well as providing a badge of his deniaism, Keenan appears to put rather a lot on his little quiz. He actually says of it “the prize will be awarded to anyone who can demonstrate, via statistical analysis, that the increase in global temperatures is probably not due to random natural variation.” And he is probably daft enough to see the absence of a quiz winner (other than himself) as some form of proof of the opposite.

  30. 80
    Silk says:

    “Knowing how pedantic folk can be, one needs to be sure what one means by “statistically significant”, but it is easy to get statistically significant trends by doing a simple linear regression”

    If you plot 150 points varying randomly, you won’t get a statistically significant trend. You may see a trend, it won’t be significant.

    The trend in HadCRUT4 is 0.075 +/- 0.011 deg per decade over the last 100 years.

    http://www.ysbl.york.ac.uk/~cowtan/applets/trend/trend.html

    Would you like to try to calculate the probability that this trend arose ‘by accident’? You can calculate, given the data, and the null hypothesis (no warming) the probability of it being random. Why not try?

    “There are many components of the climate system. The temperature record is of just one of those components (the lower atmosphere). Energy moves between the 1 component and the others. Perhaps the biggest uncertainty is cloud cover, which could be a positive or negative effect. So, I don’t know the answer to your question, but there are several candidates.”

    Now I /know/ you are trolling.

    As you well know, the atmospheric component is small, compared to the ocean component. And the ocean component has also seen strong warming.

    So perhaps you could provide to me a dataset of cloud cover changes that would yield a strong warming of the ocean?

    Because I have a dataset of CO2 (and other climate forcings, some anthropogenic, some natural) that explain the warming extremely well.

    There are not “several candidates”. There is one candidate.

    All this stuff was established in the 80s or before.

    The really interesting thing is that science /predicted/ in the 80s that continued emissions would lead to warming. And lo! It has come to pass.

    So the answer to your original question “Why are you so sure you are right?” really comes back to the fact we understood the basic science 25 – 30 years ago, made predictions on the basis of that science and the predictions were broadly in line with the outcome.

    Meanwhile, despite blather from the ‘skeptic’ community no one has actually produced an alternative theory that can be destroyed by, well, the data.

  31. 81

    #72–Dick, you might like to look at this link. Seems a bunch of very, very smart and knowledgeable folks already got together to summarize what is known about the magnitudes of various climate forcings:

    http://www.ipcc.ch/report/ar5/wg1/mindex.shtml

  32. 82
    Erica Ackerman says:

    Has anyone calculated the contribution of anthropogenic warming to the strength of the current El Nino? I swear I saw something along those lines, but can’t find it anywhere.

  33. 83
    Theo van den Berg says:

    Re Jim Eager @ 70: Agreed but do I now dare to put the cat amongst the pigeons ? The Milankovitch cycles of obliquity, eccentricity of orbit and precession have been well understood for along time and it is generally agreed that these cycles have caused the switch between Glacial and Interglacial periods in the past. We also accept somewhat reluctantly from Ice core records that CO2 concentrations lag temperature changes, but we do agree that CO2 causes feedback and amplifies those temperature changes. Then along come us humans and we create even more CO2 and now we have the temperature bomb exploding. Surely, you all agree so far, but now for the hard bit. Is it possible with all this talk of Hiatus and finding it hard to truly rely on our random walk sloppy temperature records, is it possible that those Milankovitch cycles are now doing some forcing in the other direction and slowly eating away the warming effect ? The cycle is well overdue in the downwards direction and if your heater is turning down, you will need more blankets to stay warm.
    Haha , another good one for coal. Maybe we should leave some in the ground so that later we can do some deliberate Global Warming to keep warm :)
    ps. Milankovitch is no longer in the dictionary which shows we no longer write about that old topic.

  34. 84
    Richard Caldwell says:

    Chris Colose: so arbitrarily large departures for the equilibrium reference point simply can not happen in the absence of external forcing being applied.

    RC: Nope. The correct answer is, “so NO departures from the equilibrium point can happen in the absence of external forcing being applied, though internal swaps of energy can occur as long as NO net change occurs. Thus, by sampling only a portion of the internal system one could mistakenly conclude that the system has changed in totality.”

  35. 85
    Erica Ackerman says:

    URGENT: The realclimate.com site may have been hacked.

    Something very suspicious was happening around 8pm Eastern time on
    12/19/2015. It is not happening to me now, which I think may actually just
    be a matter of someone covering their tracks. I’m writing to warn you in
    the likely event that this will happen to other people, as well.

    Two times, when I clicked on the header image, instead of getting sent to
    the home page, I got sent to an ad. The ad had a Continue to Site button,
    which I clicked the first time. This led to some other spam site. I opened
    Chrome developer tools and clicked on the header image a second time. That
    time I just waited for the ad to complete. All that showed up was a blank
    page with “about:blank” in the address bar. In Developer Tools, however, it
    showed a red security message saying something along the lines of, a secure
    site was redirecting to content that was not secure. I tried to trigger the
    problem again, but the third time I clicked on the header image, everything
    seemed back to normal and I was taken to the normal RealClimate website.

    Looking at my history, the ad page URL starts with go.goadvs.com, followed
    by a query string containing a lot of stuff that looks very much like base
    64. I tried decoding it at an online site, and got a lot of non-ASCII
    characters.

    So, my suspicion is that clicking on the header loaded a trap, and clicking
    on the “Continue to Site” button/link ran some code on my computer.

    Let me know if you need any more information, or if you want to see the
    query string for the ad page URL.

  36. 86
    James McDonald says:

    Just a note about the site: often now when I try to access it I get some kind of ad that lasts for 10 seconds after which I’m transferred to a blank page, I think at some site that sells web locations. It can then take three or four more attempts to actually get here.

  37. 87
    mike says:

    WP has a solid piece of journalism by Annia Ciezlado about the Syrian conflict. The piece is about drought, depletion of groundwater, and political/military use of wheat stores and how the Syrian conflict might be more clearly understood.

    https://www.washingtonpost.com/opinions/the-most-unconventional-weapon-in-syria-wheat/2015/12/18/781a0ae0-9cf4-11e5-bce4-708fe33e3288_story.html?wpmm=1&wpisrc=nl_headlines

    This level of understanding will likely evade a large number of global citizens and policy makers who may be more willing to bomb an imaginary country with an arab-sounding name than to try to understand how global conflict and climate change are connected.

  38. 88
    Chuck Hughes says:

    Oops and now I have really overdone it. Hope that at least you guys (and girls?) got some entertainment out of this.

    Comment by Theo van den Berg — 18 Dec 2015 @

    Somebody can correct me on this but when things really start to heat up, nobody is going to want to live in Australia. Also you’re closer to the WAIS so I would think that when it begins to collapse Australia will be one of the first places to notice it. Having any sort of nuclear facility near the ocean is a really bad idea. You’re not in a great location any way you look at it.

  39. 89
  40. 90
    Edward Greisch says:

    “Historic Los Angeles methane leak puts natural gas emissions under scrutiny
    As SoCalGas works to plug a monster methane leak, warnings abound for the electricity sector”
    http://www.utilitydive.com/news/historic-los-angeles-methane-leak-puts-natural-gas-emissions-under-scrutiny/411060/
    Do you still think natural gas is safe?

  41. 91
    Tom Adams says:

    65 Dick Newell

    “In answer to 58: does not the 450k year historical data show that CO2 changes lag temperature changes, so if you are trying to demonstrate CO2 driving temperature change it is a poor correlation.”

    Not a single climate scientist is trying to demonstrate that CO2 drove the temperature change that initiated the exit from the glacial periods. You got that idea directly or indirectly from someone that is trying to deceive you.

    Actually, climate scientists all know that CO2 did not initiate the warming. Climate scientist know that the Milankovitch cycles initiated the warming, and this warming initiated the CO2 release causing so feedback loop of more warming and more CO2 released. The key issue is that the ultimate magnitude of the warming is involves the heat trapping characteristics the CO2. Here’s an analogy: if a car was at rest on top of a hill and you gave it a little push, then gravity did not cause the car to go down the hill, but gravity is the cause of most of it’s acceleration. Similarity CO2 played a role in most of the warming that took us out of the glacial periods.

    Learn the science and stop being deceived.

  42. 92

    Help support our environmental film and see YOUR NAME in the credits https://www.indiegogo.com/projects/the-velvet-abstract#/

  43. 93

    DN @77: some of the recent warming must have been caused by CO2, but I don’t know how much and I don’t know how one can find out how much

    BPL: You could try linear regression, like I did.

  44. 94
    Chuck Hughes says:

    I will now try to shut up, but remain a regular watcher of Real Climate.

    Oops and now I have really overdone it. Hope that at least you guys (and girls?) got some entertainment out of this.

    Comment by Theo van den Berg — 18 Dec 2015 @

    Theo, exactly when do you intend to make good on your pledge?

    It’s not fair to fill us with false hopes and empty promises. It’s Christmas!

  45. 95
    Theo van den Berg says:

    Chuck @ 88: Don’t take it personally. The (and girls?) is my observation that there are not many ladies participating in this debate.

    Yes, some places in AUS might be hit hard in any warming, but we are a country of extremes anyway. Have already enjoyed? 48 degrees centigrade. But AUS is definitely the best place during Glacials :)

    The ‘wastelands’ I suggest for Nuclear are hundreds of miles from any coast and have a very solid foundation. Very easy to police as well, cause there is nothing for hundreds of miles.
    Worse place to be if and when GW reaches a tipping point, is in populated areas (Civil War) and on the coast. I live in a deep (defendable) valley in the mountains in one of the wettest areas in AUS.

  46. 96
    Hank Roberts says:

    for Erica Ackerman and James McDonald
    — looks like you have malware, I ‘oogled the info from EA’s post and found:

    go.goadvs.com Virus Removal Tutorial – RemoveVirusNow …
    removevirusnow.com/go-goadvs-com-removal/
    Nov 11, 2015 – The website go.goadvs.com keeps popping up as my default browser page every time I open a tab. Does this mean I have some sort of …
    How to Remove go.goadvs.com Virus from My PC
    fixwindowspconline.com/go-goadvs-com-removal/
    Nov 11, 2015 – I picked up the go.goadvs.com hijacker virus and can’t seem to remove it. … go.goadvs.com is a notorious browser infection which can hijack your Google Chrome, Mozilla Firefox, Safari and Internet Explorer. … Once successfully installed, go.goadvs.com virus immediately hits …

    there’s more. If you’ve not been running malwarebytes, and an antivirus program, look into this carefully.

  47. 97
    Hank Roberts says:

    PS for the people with the ad malware infestation:
    https://malwaretips.com/blogs/remove-go-goadvs-com/

  48. 98
    sidd says:

    Agree with McDonald and Ackerman, there is aggressive adware infesting this site.

  49. 99
    Dick Newell says:

    In answer to a question by Silk in no 80:

    “If you plot 150 points varying randomly, you won’t get a statistically significant trend. You may see a trend, it won’t be significant.

    The trend in HadCRUT4 is 0.075 +/- 0.011 deg per decade over the last 100 years.

    http://www.ysbl.york.ac.uk/~cowtan/applets/trend/trend.html

    You are right, a set of randomly generated numbers will only seldom generate a statistically significant trend, but a random walk will often demonstrate a statistically significant trend.

    As an aside, if one generates a 2 dimensional random walk – say 500 points, it is amazing the number of times it will generate a recognisable thing – I have managed a wonderful looking wild boar, as well as other animals and even stuff which looks like it came out of the Kama Sutra!

  50. 100
    MA Rodger says:

    Dick Newell @77.
    So you don’t notice the massive wobbles that remain in your ‘feedback’ series? They are two to three times the size of the wobbles in the HadCRUT record and are thus become the major feature of your synthetic series. Is it allowable to have the major feature in such series absent from the record it attempts to emulate? I think not!!