Discussion thread: reactions to House Hearing

by Judith Curry

Climate Feedback has interviewed a number of scientists regarding the recent House Hearing on climate science.

The article:  Scientists reactions to the US House Science Committee hearing on climate science.

The scientists that were interviewed:  James Renwick, Gavin Schmidt, Tim Osborn, Retto Knutti, Victor Venema, Mark Zelinka, Matt King, Andrea Dutton, Lauren Simkins, Valerie Trouet, Kerry Emanuel, James Elsner.

I am familiar with about half of these scientists.

Let’s look at the statements they were asked to respond to:

“It is an empirical fact that the Earth’s climate has warmed overall for at least the past century. However, we do not know how much humans have contributed to this warming and there is disagreement among scientists as to whether human-caused emissions of greenhouse gases is the dominant cause of recent warming, relative to natural causes” – Judith Curry

The responses say that there are a lot of studies that use climate models and focus on the period since 1950 that say human causes dominate.  Ok, but I don’t find those studies convincing, and the HOW MUCH question has still not been quantified in a precise way.  There is DISAGREEMENT about HOW MUCH.  How can they argue that there is NOT disagreement over this issue, when two reputable, widely published scientists that have received external recognition (e.g. myself and Christy) clearly disagree?

And even the IPCC says more than half. That’s from 51 percent to 99 percent. That is a big interval… I just don’t know how much is human vs. how much is natural and I think there is a great deal of uncertainty and it is very difficult to untangle it” -Judith Curry

Yawn.  ‘But human causes are more than 100%’.  Get a dictionary and see how  ‘HALF’ is defined.  And yes, lets criticize my statement  using  climate model results, which are tuned to the recent warming as per several published papers and a blog post from Isaac Held.  Their methodology for detection-attribution analysis is flawed.  I have a draft post on this, but no time to complete.  Get back to me with your attribution studies once you understand multi-decadal variability in the oceans and your climate models get the linkages, amplitudes and phasing correct. Head over to SOD, including his latest post.

[…] I demonstrate that the consensus of the models fails the test to match the real-world observations by a significant margin.” -John Christy

The responders argue that climate models shouldn’t be expected to predict short term (e.g. 20 years) temperature variations correctly.  Well, that is a good argument since they don’t get multidecadal ocean variability correct.  But if you accept this argument, then why should we believe the attribution studies using these models for warming since 1976?

Indeed, I am a co-author of a report in which we used a statistical model to reproduce, to a large degree, the atmospheric temperature trends without the need for extra greenhouse gases. In other words, it seems that Mother Nature can cause such temperature trends on her own, which should be of no surprise.” -John Christy

Mother nature can indeed cause substantial temperature trends on its own.  The ‘detection’ part of ‘detection and attribution’ seems to have gotten lost during the past 10 years.

“the models tend to be too sensitive to greenhouse gases, likely related to the fact the models tend to shrink clouds more than in reality, so that more sunlight gets in and heats up the Earth more. […] The Earth has a way to release the heat that greenhouse gases try to build up.” -John Christy

Well even the IPCC AR5 seemed to be heading in this direction with its conclusion about ECS. Zelinka cites recent papers that use arguments related to low level clouds to argue for higher climate sensitivity.  Many posts at CE argue for lower sensitivity.  But more significantly, leading cloud expert and IPCC author Bjorn Stevens has argued for lower sensitivity (upper limit at 3.5C)

Everyone seems to agree that climate models are running to hot for the past ~20 years.  There are a lot of possible reasons.  But ignoring the evidence of Nic Lewis sensitivity analysis (and related studies) is not helpful in this regard.  This is clearly an unresolved issue, and arguments for lower ECS are at least as valid as arguments for higher ECS.

“Climate models have a large amplifying effect from clouds and water vapor. The magnitude of this amplifying effect, and even the sign, are in dispute. A lot about the oceans that we don’t understand, how the ocean transports heat and carbon in the vertical is not well represented in the climate models. We also have these very large-scale, long-term ocean oscillations, which play a huge role in determining our climate. These are not well simulated and we don’t have good documentation of the really long time period oscillations. The effects of the Sun on climate, particularly the indirect solar effects.” -Judith Curry

The only responses to this one were about water vapor: “The large amplifying effect of water vapor is real and is well simulated by climate models.”   There is little empirical evidence for a large long-term trend in water vapor path. The climate models have sloppy thermodynamics.  The odds of climate models doing this correctly are slim.

The other points that I made were not rebutted.

“It’s been warming for hundreds of years! And we can’t explain all of that due to human causes..” -Judith Curry

Valerie Trouet argues that it has only been warming since 1850.  I will leave it to Steve McIntyre to critique PAGES2K.  But the IPCC has no explanation for warming between 1850 and 1950 – only a minuscule amount of this warming can be attributed to humans.  This warming is natural, and the processes producing warming from natural causes did not stop in 1950.

“I have demonstrated that we cannot predict the behavior of climate.” -John Christy

Osborn responds that we can predict the annual cycle and response to volcanoes.  Christy is correct that there is no evidence that we can predict the behavior climate on decadal to century time scales.

There is little scientific basis in support of claims that extreme weather events – specifically, hurricanes, floods, drought, tornadoes – and their economic damage have increased in recent decades due to the emission of greenhouse gases. In fact, since 2013 the world and the United States have had a remarkable stretch of good fortune with respect to extreme weather, as compared to the past.” -Roger Pielke, Jr.

Elsner and Emanuel respond that there is some evidence of hurricane intensity increase since 1987.  However, this increase is only in certain ocean basins, and there is no way to determine whether this increase is caused by AGW or natural variability. Emanuel states an AGW caused increase should not be detectable until mid 21st century.

The rest of Pielke’s statements were not contested.

JC reflections

Well, I think of this as sort of a red team exercise.  The IPCC report is the original blue team.  Think of Christy, Curry, Pielke as the Red Team.  The scientists providing responses in the Climate Feedback article are defending the  Blue Team against critiques by the Red Team.  And then this blog post responds to defenders of the Blue Team.

I think this kind of back and forth is very useful.  The Goliath Blue Team didn’t manage to score any meaningful points against the Red Team in the Climate Feedback article, as far as I can tell.  Obviously the selection of the individuals by Climate Feedback and the limited topics each individual chose to respond to does not necessarily cover all the bases or present the best possible arguments.

The Blue Team has its work cut out for it in defending their assertions.  Even the small Red Team of Christy, Curry, Pielke scored some major points in this Hearing.

This kind of exchange is very illuminating, and I am strongly supportive of a more formal Red Team/Blue Team exercise.

 

461 responses to “Discussion thread: reactions to House Hearing

  1. I like how I did not see one single attack on someone being anti Science or having a bad hair day. It was an honest debate and such should continue. And I did learn a couple of new things which is always good.

    • agreed. the attacks were not personal. and they did not make the 97% argument. This is constructive.

      • Within the confines of the hearing this is true, but several terse moments.. not least the denier in oral/written testimony differences; and for the non-constructive out-of-hearing related material, anyone visiting RP Jr or Snr twitter accounts will see the hurt that has been launched to Jr and Dr Curry.
        The publication & promotion of this calculated insult attack is deplorable. Childish sniggering at the entendre is hurtful. Public responses are mandatory; and one of the respondents in the Article being reviewed here is well up to his eyeballs in this matter.

  2. Judith,
    I followed your entry into the blog discussions and slow conversion from a supporter of the CAGW position to an open mind on the issue and gradual understanding that the reasonable skeptics actually were trying to get at the actual facts, not being “deniers”. A skeptical mind set is actually a necessary condition for a real scientific issue, even when the evidence is strong for a conclusion. Being a skeptic is not denying the evidence, just making an effort to be as sure as possible, especially on an issue that profoundly affect all of humanity. I just wish other so called scientists that maintain the CAGW position were as reasonable as you. They have proven to me that the fear of losing funding and or acceptance of their fellows dominates having true open minds, and this gives me a bad feeling for the future. The rejection of conservative and even moderate speakers at collages (by teachers and “snowflakes”) is another sign of the problem. This is a very disturbing trend- the rejection of discussion of topics by the very institutions that are supposedly the foundations of open minded learning. I am pleased for your conversion, and so sorry it impacted your teaching, and this will be a loss to the students.

    • They have proven to me that the fear of losing funding and or acceptance of their fellows dominates having true open minds, … is a preporterous conclusion.

      • Roger Knights

        I agree. I think it’s mostly an ingrained greenie mindset plus noble cause corruption plus groupthink that are the problem, not selfishness or virtue signaling.

      • Someone said something about childish sniggering.

      • I think it’s mostly an ingrained greenie mindset plus noble cause corruption plus groupthink that are the problem, not selfishness or virtue signaling.

        And somebody else pointed out the PAWS made fools of a lot of very smart people, and it continues to do so… because they have their own little set of reasons for remaining completely fooled.

      • So you never heard the phrase publish or perish?

        You do understand the meaning of the word perish, huh JCH?

        So it’s not a preposterous proposition after all is it? That people whose livelihood depends heavily on bringing in grant money might have concerns of losing it.

      • russellseitz

        Who could watch he Committee’s overlords kowtow to three of the less than three dozen talking heads they’ve heard say the same words a dozen times before at as many Heartland & GWPF conferences, and fail to snigger.

        The script is an endless loop of Groundhog Day and Thank You For Not Smoking. Give it a rest Judith- you’re making life far too easy for the march organizing classes .

    • Thanks Leonard, I agree 100%
      You have neatly summarised almost exactly my own position.

  3. The scientists that were interviewed: James Renwick, Gavin Schmidt, Tim Osborn, Retto Knutti, Victor Venema, Mark Zelinka, Matt King, Andrea Dutton, Lauren Simkins, Valerie Trouet, Kerry Emanuel, James Elsner.

    As I understand it, they are all part of the Climate Feedback community, any of whom can choose to comment on an article that is being reviewed. They weren’t specifically interviewed, I think.

    The IPCC report is the original blue team. Think of Christy, Curry, Pielke as the Red Team.

    Roger appears (happy to be corrected if my impression is wrong) to object to being labelled as anything other than as part of the IPCC/mainstream. Interesting that you seem to perceive him as part of a “Red Team”, which is distinct from what you perceive as the IPCC/Blue Team.

    • All three of us are in the 97% consensus — its warming, and humans contribute to it. Since the Blue Team doesn’t admit for disagreement and seems to be going beyond the IPCC AR5, there’s not much to differentiate RP Jr from myself and Christy in context of the climate debate. Also, RP Jr focuses on observations, rather than theory and climate modeling results.

      • I think that depends on how you define the 97% consensus. Do you, for example, agree that “humans are causing global warming”?

        there’s not much to differentiate RP Jr from myself and Christy in context of the climate debate.

        Would be interesting to know if Roger agrees with this.

      • The zillion dollar question is how much of the warming is caused by humans. IPCC says more than half (usually interpreted as >50%, but in Gavin math, i have no idea how to interpret ‘half’). Gavin says 110%. Every scientist who is not senile and has considered this problem says human contribution is > 0. So yes, humans cause global warming. So do natural processes. How much warming is caused by humans is THE key issue of debate.

        At the hearing, both Christy and RP Jr responded to a question: Do you agree that it it is more likely than not that humans are the dominant cause of recent warming? Both responded yes. I would respond yes to this, but with low confidence. I think ‘as likely as not’ is a characterization I would have more confidence in, which was how i responded to the question in the Hearing.

      • Sorry, messed up the blockquote above. The last sentence is mine.

      • and Then There’s Physics: I think that depends on how you define the 97% consensus.

        97% agree with the statement that: climate is warming and human activities are contributing to the change.

        Here is one reference: https://www.wunderground.com/resources/climate/928.asp


        Question #1: When compared with pre-1800s levels, do you think that mean global temperatures have generally risen, fallen, or remained relatively constant?

        About 90% of all the scientists and 97% of the climate scientists said temperatures had risen.
        Question #2: Do you think human activity is a significant contributing factor in changing mean global temperatures?

        About 82% of all the scientists and 97% climate scientists agreed that human activity is a significant contributing factor.

        It gets paraphrased a lot.

        But what counts as “significant”? Is the urban heat island effect “significant”? Deforestation?

        It is hard to find someone who does not agree with the 97% on those statements. Even Christopher Monckton agrees (or so he posted multiple times at WUWT).

      • Curryja: “its warming, and humans contribute to it.”
        Shouldn’t a distinction be made between human contributions from CO2, albedo, aerosols, etc.?
        In the context of the discussion, the statement assumed CO2 is the dominant cause of human induced warming. Do we know that to be true?

      • Judith

        As it appears that we have not as yet exceeded natural variability in the Holocene, it becomes very difficult to know how much of the current warm era is caused by man.

        It could be none at all (which defies physics unless the warming effect ceases at around 300ppm i.e. that is the top of the co2 logarithmic curve) Or it could be ALL of it and if it wasn’t for mans efforts it would currently be much cooler.

        As the rise in co2 is supposed to be accompanied by severe weather events, which clearly are as yet not out of the ordinary) co2 may not be the climate trigger claimed. The ‘Uncertainty’ and the ‘I don’t know’ monsters are the two largest ones in the zoo. It would be good to be able to capture them both and carry out forensic tests on their true capabilities.

        tonyb

      • Pmhinsc

        Yours is a good question. There is far more co2 locked up in the soil than there is in the oceans or atmosphere

        http://e360.yale.edu/features/soil_as_carbon_storehouse_new_weapon_in_climate_fight

        Man has had a profound effect on his environment. In Britain virtually the entire landscape has been shaped ny thousands of years of tilling, cutting down trees, building etc. in America the great grass plains were virtually destroyed in the 19th century.

        I would suspect that this all caused more co2 to be released than ever the burning of fossil fuels has. Man can’t help having an impact on this planet by our sheer numbers and our evolving technology and life styles. It is pointless to pretend we can ever get back to pre industrial 300ppm.

        Mind you there were many periods of considerable warmth pre industrial so whether there is a direct relationship between co2 and warming has yet to be proven and if it can be proven, which aspect of our existence has caused it is the next debate.

        Tonyb

      • Judith,

        IPCC says more than half (usually interpreted as >50%, but in Gavin math, i have no idea how to interpret ‘half’).

        It’s more than half of the observed warming (since 1950 in the case of the IPCC attribution statement). Why is this difficult to interpret?

      • yes, this is my interpretation. But Gavin disagrees.

      • yes, this is my interpretation. But Gavin disagrees.

        In what way does Gavin disagree? (I don’t think that he does)

      • But are you in the 110% consensus?

        In Gavin maths 110% is the correct number, because there are 10% more climate scientists that agree than the number of climate scientists there would be had it not been for anthropogenic global warming.

      • Steinar,
        Umm, no. The analysis suggests that natural influences have probably had a net cooling effect and – hence – that the best estimate for the anthropogenic contribution (since 1950) is slightly more than all of it.

      • Judith’s quote is “And even the IPCC says more than half. That’s from 51 percent to 99 percent. ”
        To the uninformed (Republican congressman), this reads as equally likely 51% and 99%, when in fact it isn’t. It was carefully designed to mislead about what the IPCC said. In fact the 100% part of the probability curve is many times higher than at 51% which is at the tail, as noted in the response.

      • “…and Then There’s Physics”,

        Did you miss the joke? Few should have problems in understanding what Gavin means by 110% when he explains it. But does his answer make sense given how the question was framed: how much of the observed increase in global surface temperatures is caused by anthropogenic forcings? A better reply may be “all of it, because without these forcings it would be cooler”. The question was “how much of the observed increase”, not “how much anthropogenic warming compared to observed warming”.

      • The problem all along has been that the 97% consensus statement was designed for a political purpose, namely, to blur the important distinctions between Judith Curry for example and someone like Mann. Arguing about such consensus statements is really a waste of time. Real diversity on the issue of warming is everywhere and the climate science community should embrace it. It’s another example of politically motivated attempts to narrow the range of opinion that will avoid public shaming and smearing. I would like very much to know if ATTP is still clinging to the fiction that such completely vague consensus statements are meaningful or interesting.

      • ATTP,
        “Why is this difficult to interpret?”
        Yes, I can’t see why this causes difficulty. At the time they wrote, warming probably seemed to be about 0.7°C. What they are saying is that natural variation could have generated an increase of at most 0.35°C. But that amount is uncertain; it could have been less or negative. Their best estimate is that the effect was slightly negative, so anthropogenic effect was slightly more than 0.7.

        And I don’t think Gavin has trouble with that either.

      • More than 100%.
        An airplane cruises at 100 mph. It flies with a 20 mph direct tailwind. It is responsible for for 100 / 120 83% of the ground speed. When it turns 180 degrees, it is now responsible for 100 / 80 125% of the ground speed.
        Increase the wind speed to 50 mph.
        100 / 150 or 67%
        100 / 50 or 200%
        Now reduce the airplane’s cruise speed to 75 mph and wind speed of 50 mph.
        75 / 125 or 60%
        75 / 25 or 300%
        The weaker the engine and the greater the wind speed the more outrageous the flying into a head wind claim is.
        Cruise speed of 50 mph and wind speed of 50 mph.
        50 / 100 or 50%
        50 / 0 or a really big number.
        The power of CO2 to warm is the engine power.
        The wind speed is naturally occurring things.
        An under powered plane and strong winds leads to this over 100% claim as far as I know. If this is deceitful accounting and it may be, please object.

      • Jim D: In fact the 100% part of the probability curve is many times higher than at 51% which is at the tail, as noted in the response.

        and Then There’s Physics: that the best estimate for the anthropogenic contribution (since 1950) is slightly more than all of it.

        Nick Stokes: Their best estimate is that the effect was slightly negative, so anthropogenic effect was slightly more than 0.7.

        How many scientists agree with the statement that at least 90% of the warming since 1885 was caused by anthropogenic CO2?

      • How many? I would say nearly all that study it, know what forcings are, and calculate sensitivities. The reason being that the positive imbalance means that the forcing accounts for all the warming so far with more in the pipeline, and people who study this are aware of that, while many skeptics don’t fully understand this critical part of the information.

      • “How many scientists agree with the statement that at least 90% of the warming since 1885 was caused by anthropogenic CO2?”
        Beats me. Who said that?

      • Throughout the comments a discernible difference of perceptions is revealing itself…it has over many posts, but here neatly captured. I am seeing a ready acknowledgement of human activities generally, or in the confines of CO2 emmissions, contributing to the development of climate, that is “significant”, or as RPJr says, “discernible” -see https://twitter.com/RogerPielkeJr/status/852937882629263366

        But what context is this contribution referred to?
        Again we can refer to IPCC’s definition of Uncertainty
        https://www.ipcc.ch/pdf/special-reports/srex/SREX-Annex_Glossary.pdf
        “Uncertainty may originate from many sources, such as …ambiguously defined concepts or terminology” . There is ambiguity in what different people mean whenthey say they agree with the concept.

        UNFCCC’s defined “change of climate which is attributed directly or indirectly to human activity that alters the composition of the global atmosphere and which is in addition to natural climate variability observed over comparable time periods.”

        There seems to be a group that conceive of the significant human contribution to be a thing that is not only in addition to natural variation, but in fact over-riding and dominating it.

        And there seems to be a group that conceive it to be an influence that affects by contributing to the several and many factors that have always come together to yield a climate.

        And so let’s say the Arctic has a lesser extent “because of climate change” and “humans significantly contribute” to this.
        How different the two conceived ways impact on the meaning of this!

        Model ensemble system scientists appear to be dismissive of the short- and long-term oceanic systems, “a 60-year period that averages out a lot of the ocean-cycle stuff” “Ocean cycles don’t increase the ocean heat content according to any theory out there.” examples illustrated by JimD

        But the model ensemble scientists are highly dependent on an approximate match of their ensemble results of the oceanic systems.

        As Dr Curry pointed out in Climate Models for the Layman http://www.thegwpf.org/content/uploads/2017/02/Curry-2017.pdf p14 “El Niño helps improve the agreement between models and observations, but not by very much”;
        Gavin Schmidt proffered a model:observation graph in the Article being discussed here, commenting “This is not to say that there are no discrepancies”

        Simply relying on forcings to generate model ensembles, tuned to the warming period following the late 70’s climate shift, and looking at the various outcomes of parameter changes and fusing them as a ill-defined ensemble to compare with observations is not describing the world, and is therefore not a model of the world, for climate.

        In 1994, the first obvious first step toward understanding was shown in:
        Miller et el THE 1976-77 CLIMATE SHIFT OF THE PACIFIC OCEAN http://horizon.ucsd.edu/miller/download/climateshift/climate_shift.pdf
        “To advance our understanding of mankind’s potential influence on climate,
        the study of various natural climate variations is of paramount importance.”

        By doing this, understanding distribution of heat and what it can do when pooled and pooling increases, or when warmer waters are directed at the Arctic, or what happens in periods of sustained ENSO states, then we can see how the development of Warm Periods or Cool Periods can arise. We can consider our understanding of climate shifts – punctuated equilibrium in climate, also unaccounted for by the model ensemble systems.

        https://pbs.twimg.com/media/C8Xw7ffVYAAD23F.jpg:large
        http://onlinelibrary.wiley.com/doi/10.1029/2009GL038777/full
        https://pbs.twimg.com/media/C9BRDjiUMAATk8N.jpg:large

        And then we can look also for a human contribution to these systems.
        It will be significant, but 1.5degreesC is significant.

        Happy Easter to all.
        John

      • Nick Stokes: Who said that?

        No one I know of. I put the question that way, hoping to clarify the “greater than half” wording.

        How many believe that more than 60% of warming since 1885 has been caused by anthropogenic CO2? 70% … 90%. So far, I think we have 3 takers: Gavin Schmidt (though he may reference 1950 as the appropriate start), Jim D, and (my inference) aTTP. (again the reference may be 1950). Note that in the case of Jim D, he did not this time constrain his attention to warming since 1950.

        In pp 45 – 49 of “Atmosphere, Clouds, and Climate”, David Randall calculates that a doubling of CO2 concentration will increase surface temperature by 1.2K. Granted that it is only an approximation, I am guessing he would cast his vote way short of 90%. In “Principles of Planetary Climate”, Raymond Pierrehumbert endorses a figure of 2C per doubling, which I think implies he also would vote way short of 90%. There are of course lots of different reported transient and long-term sensitivities.

      • Judith wrote: “All three of us are in the 97% consensus — its warming, and humans contribute to it.”

        However, if I remember correctly, none of you EXPLICITLY said this during the hearing. I really wish one of you had said this when the Democrats constantly lambasted you for being out of the mainstream.

        When you have been personally attacked during a hearing and not been given time to reply by your attacker, I believe you can appeal to the chairman for an opportunity to reply – especially when the attacker uses all their time talking and doesn’t leave time for a reply.

      • Matthew,

        It is hard to find someone who does not agree with the 97% on those statements. Even Christopher Monckton agrees (or so he posted multiple times at WUWT).

        Here is a consensus meta-study (on which I am an author). It says

        Climate scientists overwhelmingly agree that humans are causing recent global warming. The consensus position is articulated by the Intergovernmental Panel on Climate Change (IPCC) statement that ‘human influence has been the dominant cause of the observed warming since the mid-20th century’ (Qin et al 2014, p 17).

        So, the consensus position is not that humans have contributed to some global warming, but that humans are the dominant cause. Given this, it seems quite easy to find people who do not agree with this.

      • Judith wrote above: “The zillion dollar question is how much of the warming is caused by humans. IPCC says more than half (usually interpreted as >50%, but in Gavin math, i have no idea how to interpret ‘half’). Gavin says 110%. Every scientist who is not senile and has considered this problem says human contribution is > 0. So yes, humans cause global warming. So do natural processes. How much warming is caused by humans is THE key issue of debate.

        At the hearing, both Christy and RP Jr responded to a question: Do you agree that it it is more likely than not that humans are the dominant cause of recent warming? Both responded yes. I would respond yes to this, but with low confidence. I think ‘as likely as not’ is a characterization I would have more confidence in, which was how i responded to the question in the Hearing.”

        For both strategic and scientific reasons, I think you are falling into a trap by discussing the attribution issue in terms of above 50% or below 50%. If ABOUT 50% of warming might be due to man, then the IPCC’s projected warming might be 2X too big. Meeting the 2 degC limit won’t require drastic and immediate cuts in emissions. Many scientists are concerned that the IPCC’s models are running hot, so 50% is a viable possibility policymakers need to consider. “About 50%” is good enough!

        Scientifically, I find it difficult to accept that ECS could be 1 K or lower. You and Nic used energy balance models to calculate a central estimate for ECS of 1.6 K – while ASSUMING that 100% of warming IS anthropogenic. If only 50% of warming were anthropogenic, that central estimate would be 0.8 K. Your 95% confidence interval would then extend up to 2.0 K, but not if Nic’s arguments for a lower limit for aerosol cooling is accepted. So, in some ways, an argument for less than 50% anthropogenic warming is also an argument for an ECS of 1 K or less.

        Yes, warming from the 1920s to 1940s parallels warming from 1975-1998 and that argument was valid during the Pause. However, the Pause is dead. Due to the recent El Nino, the rate of surface warming for the 19 years since 1998 is essentially the same as the two decades preceding it. The length and magnitude of warming over the last 40 years is at least double that seen anywhere else in the instrumental record.

      • For the timescales of relevance here, TCR is what should be used.

      • “Every scientist who is not senile and has considered this problem says human contribution is > 0”

        Um, no. First, have you questioned every scientist? Second, is there real evidence that it is >0? Certainly CO2 is a contributor, but so are many other human activities. Humans put an awful lot of steam into the atmosphere that may well be cooling, etc.

        Absolute statements like this degrade your credibility.

      • and Then There’s Physics: Here is a consensus meta-study (on which I am an author). It says … The consensus position is articulated by the Intergovernmental Panel on Climate Change (IPCC) statement that ‘human influence has been the dominant cause of the observed warming since the mid-20th century’ (Qin et al 2014, p 17).

        That is not the source of the 97% figure that was quoted. Even the consensus meta-study does not say what percent of scientists agree that anthropogenic CO2 is the dominant driver of the warming.

        It remains silent on what caused the warming of the first half of the 20th century. Whatever it was, did it end? Whatever it was, will a strong effort to reduce CO2 emissions reverse it?

        Humans caused urbanization, deforestation, increased water consumption, increased agricultural productivity, and increased CO2, concomitantly, and persistently since the middle of the 19th century.

        Hence my questions: what fraction of scientists believe that anthropogenic CO2 has caused more than 60% of the warming since 1885? 70%.

        I am among those who agree that the Earth surface [has warmed] (cf ) and that humans have contributed to the warming. Getting from there to policy is a road full of deep holes.

      • > I have no idea how to interpret ‘half’

        Try NG:

        http://climatechangenationalforum.org/your-logic-escapes-me-by-john-nielsen-gammon/

        It’s not as if we’ve never been there before.

      • So the blue team’s a one size fits all kind of bunch.

      • “How much warming is caused by humans is THE key issue of debate.”

        Why does it matter if warming is on account of humans or not?
        I think the problem should be framed as:

        “How much are temperatures rising”
        “What is the root cause of temperatures rising”
        “Is it desirable/undesirable”
        “Is there anything ‘we’ can do about it?”

        I don’t see whether it matters if we fry by mother nature vs. anthro if there is nothing anyone can do about it, for instance.

        So, I wonder what extra information from a science perspective one gets if it’s anthro vs. natural?

      • What natural sources of warming are operating?

        If up to 50% of the warming since 1950 could be natural, what are the suspected sources?

        The Sun? Don’t think so.
        The Oceans, are they not warming?
        Cosmic Rays? That one is funny!
        Multi-decadal and centennial oscillations? Please show workings.

        There isn’t any natural sources of warming so If I missed anything please supply sources.

      • Bob Droege:

        You asked what other natural source of warming could be operating.

        The warming is caused by EPA (and similar agencies abroad) driven reductions in SO2 aerosol emissions, which allows sunshine to strike the earth’s surface with greater intensity.

        Current cooling is being caused increasing SO2 emissions from the Far East, and possibly some volcanic SO2 emissions.. It will only be temporary.

      • For a detailed explanation of my preceding post, use the DuckDuckgo search engine for “Climate Change Deciphered”.

      • What natural sources of warming are operating?

        If up to 50% of the warming since 1950 could be natural, what are the suspected sources?

        The Sun? Don’t think so.
        The Oceans, are they not warming?
        Cosmic Rays? That one is funny!
        Multi-decadal and centennial oscillations? Please show workings.

        There isn’t any natural sources of warming so If I missed anything please supply sources.

        The fact that the IPCC sez “more than half” should be a pretty good clue that there isn’t actual science behind the statement, otherwise it wouldn’t likely be a nice integer fraction ( 1/2 ). Though 1/2 is possible, it also represents digit bias. An actual number based on measurement would probably be some specific value (52.98%) +/- an error estimate ( 47.34% ). So this is just a made up statement, of which there are many in the IPCC reports.

        Now, Judith, from what I’ve gathered, doesn’t say the observed warming isn’t from GHG forcing, only that there is a lot of uncertainty because some of could easily be from natural variability. The warming from 1910 through 1945 and the record warm years of 2015-2016 are good examples. 2015-2016 were very high temperature years, but not because of GHGs as a departure from the longer term trend – GHG forcing increased by some hundreths of W/m^2, which is not enough to explain the big departure. Rather, albedo changed for 2015-2016:

        In addition, the oceans lost a lot of heat to the atmosphere. So 2015-2016 were warm because of internal variation – more solar absorbed and more heat from the oceans. Such things occur on longer time scales as well.

      • @ Bobdroege

        “What natural sources of warming are operating?”

        H20 in the atmosphere.

        Contributions of Stratospheric Water Vapor to Decadal Changes in the Rate of Global Warming
        “Stratospheric water vapor concentrations decreased by about 10% after the year 2000. Here we show that this acted to slow the rate of increase in global surface temperature over 2000-2009 by about 25% compared to that which would have occurred due only to carbon dioxide and other greenhouse gases. More limited data suggest that stratospheric water vapor probably increased between 1980 and 2000, which would have enhanced the decadal rate of surface warming during the 1990s by about 30% compared to estimates neglecting this change. These findings show that stratospheric water vapor represents an important driver of decadal global surface climate change.”

        That article was about Stratospheric water vapor concentrations. How about the rest of the atmosphere?

        Also, remember that the cloud feedback effect hypothesized by IPCC is an effect that responds to any change in surface temperature and atmospheric temperature. Hence, anything that cause a temperature variation will then also cause the cloud feedback effect that enhances the original effect.
        Ref. e.g: IPCC;AR5;WGI; Figure 7.10 | Cloud feedback parameters.

      • Burl, unmasking the cooling effects of aerosols that are emitted with the warming CO2 don’t count, as natural warming effects.

        That should be implicitly obvious.

      • Bob:

        Precisely. They are man made warming events, but are NOT included in the IPCC diagram of radiative forcings–except as being mislabeled as CO2 forcing (which doesn’t exist, as my model shows).

      • Science or Fiction,

        The stratospheric decrease in water vapor is also not a natural effect, it is due to the increased greenhouse effect due to the burning of fossil fuels.

        nice try though

      • Bob

        What natural sources of warming are operating?

        You might want to start this investigative journey by understanding what natural sources were involved in the non-Minoan Warm Period, the non-Roman Warm Period and the non-Medieval Warm Period.

        That should get you in the ball park.

      • @ bobdroege | April 17, 2017 at 2:52 pm |

        “The stratospheric decrease in water vapor is also not a natural effect, it is due to the increased greenhouse effect due to the burning of fossil fuels.”

        To repeat: “Stratospheric water vapor concentrations decreased by about 10% after the year 2000. … More limited data suggest that stratospheric water vapor probably increased between 1980 and 2000.”

        That must be some peculiar relationship between burning fossil fuel and the amount of stratospheric water vapor.

        Looks like inductive reasoning to me. Is it based on the premise that variation got to be caused by humans since climate itself is hypothesized to be stable with minimal variation?

        Anyhow, your claim that variation in stratospheric is caused by humans is something I would like to see proved. At least I would expect that you identified the source for that claim.

      • Science or Fiction,

        Glad to oblige, but this is not a proof

        http://www.xplora.org/downloads/Knoppix/ESPERE/ESPEREdez05/ESPEREde/www.atmosphere.mpg.de/enid/0,55a304092d09/2__Ozone/-_Cooling_nd.html

        CerescoKid,

        First you will have to provide evidence that these previous warm periods were as warm or warmer than today, haven’t seen any.

        Lack of volcanos and solar effects may cause a little warming, but nothing like we are seeing now. And I’m not buying any indirect solar effects or multi-centennial ocean oscillations.

      • @ bobdroege | April 18, 2017 at 9:28 am |

        Thanks for the reply.

        However, I can not find any support for your claim: «The stratospheric decrease in water vapor is also not a natural effect, it is due to the increased greenhouse effect due to the burning of fossil fuels.» at the page you linked to.

        Maybe you would be so kind to quote the statements that you think provide support for your claim?

      • Science or Fiction,

        I had the sign wrong, I though that stratospheric water vapor was decreasing because CO2 was cooling the stratosphere, that’s wrong.

        The stratosphere is cooling and increasing in water vapor both due to the greenhouse effect.

        “Tropospheric water
        vapor increases in close association with warming (6) and this
        represents a major climate feedback that is well simulated in
        global climate models (7).”

        From the Soloman cite you posted.

        It’s still a feedback and not a natural source of warming.

      • @ bobdroege | April 18, 2017 at 5:23 pm |

        You claim that:
        «The stratosphere is cooling and increasing in water vapor both due to the greenhouse effect.»

        And refer to the following statement in support of your claim:
        «Tropospheric water vapor increases in close association with warming (6)»

        That looks like incoherent babble to me.

  4. The responses say that there are a lot of studies that use climate models and focus on the period since 1950 that say human causes dominate. Ok, but I don’t find those studies convincing, and the HOW MUCH question has still not been quantified in a precise way. There is DISAGREEMENT about HOW MUCH. How can they argue that there is NOT disagreement over this issue, when two reputable, widely published scientists that have received external recognition (e.g. myself and Christy) clearly disagree?

    ##########
    1. Your disagreement is not informed. It’s confused and doesn’t count.
    2. Neither of you is published in that corner of the
    Market.
    3. Disagreement basically makes you a denier so they are just being polite.
    4. Your position is fringe science and they are following your guidance and ignoring fringe science.

    • You clearly need to reread my (published) paper on Climate Science and the Uncertainty Monster
      http://journals.ametsoc.org/doi/pdf/10.1175/2011BAMS3139.1

      You also need to reread all my blog posts under the attribution tag
      https://judithcurry.com/category/attribution/

      • Steven Mosher

        Judith. You asked a question. ..How can they argue…
        I gave you four ways…I answered your question. ..

        I red teamed what you wrote before.not convincing. No real arguments presented. All four arguments i list still apply. You still don’t get the attribution argument and basically ran away from the last discussion you had with gavin.

        Merely pointing to your prior failed attempts doesn’t really help.

      • David Springer

        @M0sher. I don’t know if you’re being sarcastic or not. That’s not good.

        Without a winking smiley or other blatant display of humor, it is utterly impossible to parody a warmist in such a way that someone won’t mistake for the genuine article.

        https://en.wikipedia.org/wiki/Poe%27s_law

    • There was a time I would have smiled at this as sardonic ridicule of those making this type of statement.

      • Steven Mosher

        She has not learned that you can argue a point by merely asking questions. …how can they argue? Easy peasy ways to argue…

      • Steven Mosher

        Edit can’t argue by asling questions.

      • Sure you can. If someone makes a highly confident statement, and you ask a question about relevant causal relations that they can’t answer, well then this weakens their argument and reduces confidence in it.

      • David Springer

        Sure you can argue by questions.

        Here’s an example:

        Should people without a science degree be considered experts in a field of science?

        Is Steven M0sher still posing as an expert in science when he has no degree in any field of math or science?

      • A degree is not the magic potion you portray it as Springer. I have 3, in three different disciplines. Yet worked as an engineer at a nuclear power plant without having a degree in any of the fields of engineering.

    • The worst part here is that I’ve lost track of the playe, and I can’t tell if this is intended to satirize the Gavinesque warmers or simply a demonstration that they’re impossible to satirize.

      • Judith asked a rhetorical question about how people can argue that there is not disagreement. Mosshher the Great and Powerful responded with inane ways irrational people could argue. Judith’s mistake was to omit the word “rational”.

        And of course that neatly returns to your point. I agree.

    • Steven Mosher: 1. Your disagreement is not informed. It’s confused and doesn’t count.
      2. Neither of you is published in that corner of the
      Market.
      3. Disagreement basically makes you a denier so they are just being polite.
      4. Your position is fringe science and they are following your guidance and ignoring fringe science.

      I conjecture that those are hypothetical answers to the question, none that you endorse.

    • That’s my point: How does this pass a group of accomplished attorneys in the Senate? How does one not differentiate the various arguments in the 97%?

      • I mean, how does this highly qualified group of scientists leave a Senate hearing full of highly qualified attorneys and ……there is no resolution as to what the differences are?? Are the Senators incompetent? The scientists? How does this happen?

  5. …How can they argue that there is NOT disagreement over this issue, when two reputable, widely published scientists that have received external recognition (e.g. myself and Christy) clearly disagree?

    True, true and that is why, for example, we have a Supreme Court comprised of nine justices who are charged with responsibility to resolve conflicts between circuit courts — also comprised of judges — and, to that end, the justices of the Supreme Court oftentimes disagree.

  6. Regarding the >50% issue, I would simply ask “Is a 1°C increase over 100yrs unusual in the context of the past few thousand years?”. If this question can’t be answered, then an “extremely likely >50%” opinion is unwarranted.

    • It is highly unusual and unprecedented in the last few thousand years. On geological time scales this would appear as a large vertical step.

      • Very little evidence to support your assertion. No high resolution temperature record over that period.

      • Thank you. We are looking at 30-50 year periods of warming, this is not resolved in most paleoclimatic data sets, especially the further back you go.

      • You only need an accuracy of 100 years to see this step and paleoclimate methods have that. If any other such steps existed or were even hinted at, we would have seen a lot of study of those periods. The 21st century average is going to be a degree or two warmer than the 20th century, and no precedent exists for that in thousands of years. It would have been seen.

      • Paleo studies have large error bars / course resolution. Structural uncertainties with data and methods likely mean error bars are under estimated.

      • The error bars are nowhere near a degree for century averaged temperatures in the last few millennia. Temperature variations are very coherent and a downward trend is detected prior to the recent warming.

      • Many practitioners of statistics disagree.

      • You seem determined to see nothing unusual here.

      • Not at all. I would merely use more cautious language.

      • …but even for you the weight of evidence points to unprecedented warming rates, no?

      • There are several studies that suggest that climate changes in terms of decades or even years are as fast or faster than today. “As the world slid into and out of the last ice age, the general cooling and warming trends were punctuated by abrupt changes. Climate shifts up to half as large as the entire difference between ice age and modern conditions occurred over hemispheric or broader regions in mere years to decades.”
        http://www.pnas.org/content/97/4/1331.full
        “Researchers at Friedrich-Alexander-Universität Erlangen-Nürnberg have shown in the latest edition of the journal Nature Communications that the temperature changes millions of years ago probably happened no more slowly than they are happening today.”
        https://phys.org/news/2015-11-global-fast-today.html

        Also their is the question whether apparent glacial change that is frequently proposed is in fact an artifact of the measuring technique.
        https://phys.org/news/2015-11-ancient-climate-underestimated.html

      • The AMOC has been fairly reliable for the last few millennia, bringing warmer conditions to Europe, but now we are putting it in jeopardy for another one of these abrupt changes you refer to. It’s a documented tipping point that is susceptible to melting phases in the climate history, such as the one we are embarking on again. No comfort to be gained there.

      • Jim D

        Let’s focus just on the MWP to see if present warming is unprecedented. The usual discredited attempts to discredit the MWP involve amplitude, lack of synchronicity and that it has only been found in one part of the globe. Since there are numerous studies indicating warm periods in NA, SA, Asia and Africa we can dispense with that as a reason to dispense with the MWP.. With differences in warming by hemisphere and region in the current warming, then apparently that criticism should not hold up against the MWP. So, we have amplitude. I agree with comments above about error bars, but lets assume there is a higher temperature today. What does that prove? The overall environment is different today than it was 1000 years ago.

        During the MWP had millions of acres of concrete and pavement been laid? Were there millions of acres of deforestation? Had millions of acres of wetlands been destroyed? Had major metropolitan areas across the globe been built adding to UHI? Per Tony, had millions of acres of soil been disturbed? Were there 7 billion humans and billions of domestic animals with whatever unknown impacts they could have on the temperature. Were there governmental agencies available to cool the historical temperature record?

        Even if the current temperatures don’t rise up to those suggested in the MWP, so what? There are too many other variables adding to the potential for increased temperatures having nothing to do with fossil fuels.

      • The MWP was during a long slow decline in temperature from the even warmer Holocene Optimum, and that was likely the precessional part of the Milankovitch effect that favors northern ice more now than back 10k years ago. However, now the trend has reversed and hockey-sticked up again, and northern ice is melting despite the orbital effects favoring it. Mysterious, no?

      • And when the oscillations and natural variability that caused the low Arctic Sea Ice 100 years ago finally return and the trend goes up again then your entire argument will be toast.

      • It may go up because of an AMOC slowdown or stopping in response to increased melting of Greenland. This would not be good news for Europe. Such a reversal would be consistent with previous warming episodes because the ocean and cryosphere don’t respond to warming very linearly. So if that happens, refer to Hansen’s interesting ACP paper for where that path takes us.

      • Jim D: It is highly unusual and unprecedented in the last few thousand years.

        Is that about the warming since 1885? Or is that about the warming since 1950 about which the consensus statement says that humans are the dominant influence?

        Do the warming of the first half of the 20th century and the second half of the 20th century have the same cause?

      • You may or may not accept that the sun increased in activity between 1910 and 1940 and contributed to about half of that warming with the rest from CO2. What we have had since the 1970’s is about double that and still continuing in the 30-year temperature, but the skeptics insist these are equal, and I don’t know why.
        http://woodfortrees.org/plot/gistemp/mean:120/mean:240/plot/gistemp/from:1985/trend

    • Climateadj

      Temperature goes up and down like a yo yo. It is certainly not at all unusual in the past few thousand years. Ask the bronze age dwellers, the Greeks, the Romans, the Vikings…….
      Tonyb

      • They don’t go up by two to several degrees unless you are coming out of an Ice Age, and even that is a comparatively slow process.

      • Jim D, there is no data from ice age transitions that has enough temporal resolution to make your slow rate of emergence assertion. We do not have any idea of what the temperature rate of change is during glacial period termination. It could be gradual, it could be chaotic having relatively large temperature changes in relatively short time frames with what looks like a slow changing average. Why should smoothness in natural climate change be assumed?

        Be careful of making assertions when using data that is derived from sources that have poor temporal resolution, and as such represent highly temporally averaged phenomena.

      • The Ice Age transition is an example of a rapid forcing change from the albedo feedback. There were periods where sea level rose by many meters in a century. Abrupt forcing changes have been absent in the last 10k years during which civilization arose. Until the last century. We are now seeing rapid forcing changes and rapid responses. Tipping points may be tipped for the first time since civilization. It’s not a good thing.

    • David Springer

      Why should the context be just the past few thousand years?

      Non-human causes of warming have been operational on the earth for close to 4.5 billion years if the consensus age of the earth is correct.

      Shouldn’t we examine a bigger stretch than 0.0001% of the earth’s history to see what she’s capable of doing without human influence?

      • I will settle for late Holocene, past 8000 years.

      • Judy Curry Wrote: I will settle for late Holocene, past 8000 years.

        Mother earth nailed it in both the NH and SH while milankovitch moved energy in from the sun out of the NH and into the SH. Both hemispheres are regulated by the ice cycles that promote more snowfall when polar oceans are warm and thawed and less snowfall when polar oceans are cold and frozen. Look at ice core data, the best proxies for the most recent 800 thousand years in Antarctica and 150 thousand years in Greenland.
        http://popesclimatetheory.com/page85.html

  7. It appears to be a step in the direction of real progress longer term towards a real consensus. Bring Goliath down to earth with real data where possible and acknowledge where real data does or does not support conclusions for policy making. Goliath was said to be four cubits and a span tall (which corresponds to around 6’9″), but the shadows (propaganda?) made him appear much larger than life.

  8. Climate Feedback was basically the Red Team this time for numerous dubious statements made in the House hearing. Skeptics need to be prepared for Red Teaming sometimes, and should welcome the pointed rebuttals, rather than greet it with comments like “yawn” and “ha ha”. They used no such language.

    • Can you please articulate the ‘dubious’ statements made by witnesses in the Hearing? The statements in Climate Feedback article are clearly not dubious, as per my arguments in the post.

      • There were many that the Climate Feedback group simply labeled ‘incorrect’, and others were labeled ‘misleading’.

      • Labeled but not shown to be so. This comment made after having read the whole thing. You cannot take those assertions at face value without checking. Fallacious Argument from authority, from those with clear vested interests in CAGW and known biases.

      • The Osborn rebuttal went on to say “assessments of the cause of recent warming consistently find that greenhouse gases are the dominant cause of recent warming. These assessments consider other climate forcings, including natural effects (the most important ones on timescales of decades are variations in solar and volcanic activity) and human-caused aerosols, but the most likely effect of these other forcing would have been to cause global cooling in recent decades. Thus, there is agreement between scientists that the observed warming is due to human-caused emissions of greenhouse gases.”
        That is where the ball is now in your court to rebut this. The argument from Judith was weak on this because no other forcing as yet unaccounted for has been put forwards, nor any arguments that those listed have not been accounted for properly in their quantification.

      • I’ve rebutted this many times. They use models that are tuned to the period of interest, which should disqualify them from be used in attribution study for the same period (circular reasoning, and all that). The attribution studies fail to account for the large multi-decadal (and longer) oscillations in the ocean, which have been estimated to account for 20% to 40% to 50% to 100% of the recent warming. The models fail to account for solar indirect effects that have been hypothesized to be important. And finally, the CMIP5 climate models used values of aerosol forcing that are now thought to be far too large.

      • I would like to see studies that show the oceans can account for much of the warming since 1950. This is a 60-year period that averages out a lot of the ocean-cycle stuff I have seen so far. Plus oceans aren’t forcing and the OHC change cannot be forced by the ocean itself. It is a response, not a forcing.

      • There are many, read my posts on the attribution tag, and also week in review (where I cite many of these).

      • Studies relate to cycles that cancel out over 60 years, not secular trends that they make a point of not discussing.

      • there are ocean oscillations on the time scales of millennia, there is a whole spectrum. And then external forcing projects onto this whole spectrum decadal to millennial modes.

      • Ocean cycles don’t increase the ocean heat content according to any theory out there.

      • Its about redistribution of heat in the earth-atmosphere system, and changes to atmospheric circulations resulting in regional cloudiness changes does alter the total amount of heat in the system. All this with no external forcing.

      • Papers on this are missing. It is just imagination. Why does it decide to redistribute now when the forcing is at record strengths? Coincidence? I think not. Record forcing = record warming is far more rational.

      • JimD, “Ocean cycles don’t increase the ocean heat content according to any theory out there.”

        You should jump right on that so you can explain it to deniers like Toggweiler.

      • JimD, btw, the ocean mixing time is much greater than the atmospheric response time some you can have weakly dampen ocean oscillations that take several centuries to become fully dampened. Believe it or not, there are people that actually study such things that might not be on your preferred reading list.

        http://journals.ametsoc.org/doi/pdf/10.1175/1520-0442%281996%29009%3C2821%3AOCDAIO%3E2.0.CO%3B2

      • captd, as far as I can tell even Toggweiler does it via CO2 changes, but go ahead and explain. Is this going to be one of those Salbyist ideas where emitted CO2 doesn’t count?

      • JimD, “captd, as far as I can tell even Toggweiler does it via CO2 changes, but go ahead and explain.”

        Toggweiler had a great line in his Shifting Westerlies piece in science, ” The magnitude of the shift seems to have been very large. If there was a response to higher CO2 back then, it paled in comparison. Changes in the north-south temperature contrast today are not going to be as large as they were at the end of the last ice age, but even small changes could be an additional source of modern climate variability.” Only cited 99 times so I guess it isn’t a big deal.

        https://www.gfdl.noaa.gov/bibliography/related_files/jrt0901.pdf

      • ocean circulation? We are messing with that with Arctic warming, so it could become important again before you know it, and it could be because of us this time.

      • JimD, “ocean circulation?” Yes Jimmy, it takes time for ocean overturning circulations to take up or give off heat energy and you have weakly damped oscillations while that is going on. Since the oceans and atmosphere are tightly coupled, you can have shifting of “westerlies” or north-south swing in the “thermal equator” and ITCZ. It is just like the hemispheric seesaw on shorter time scales. Right now the majority of heat uptake is in the southern hemisphere because there is more ocean volume to mix. The northern Atlantic, northern Pacific and southern hemisphere oceans all have different time constants so you get pseudo-cyclic oscillations.

      • I claim that the solar influence on our climate is poorly understood, and has been highly discounted. The heat content in the northern and southern polar regions of the oceans are much more influenced by solar induced geomagnetic power dissipation than other regions of the oceans. The magnitude of this additionally induced heat and its temporal characteristics is unknown.

        This means that there is a completely unknown heat source in the oceans that is not accounted for in any climate model, or for that matter anywhere else. It could be big or small; we just don’t know anything about it.

        I assert that anyone that claims that they have accounted for and understand all dominant climate forcings are simply incorrect, and noone has thoroughly evaluated this effect.

      • captd, yes, the ocean changes slowly except when it doesn’t. It can slow, but can’t stop the warming from a forcing change, which takes place on land anyway as that has much less damping.

      • JimD, “captd, yes, the ocean changes slowly except when it doesn’t. It can slow, but can’t stop the warming from a forcing change, which takes place on land anyway as that has much less damping.”

        Most of the land warming is in the 30N to 60N region which is easily related to a ITCZ shift plus the usual anthro suspects. For some reason people like to look at AMO, PDO and grand pacific climate shift, but there has just been a northward shift since around 1976/77. Since the land mass tends to amplify warming form any cause more, it is naive to assume the ocean shift has little impact.

        As the southern oceans catch up, the ITCZ should shift downward, reducing the northward flow of energy. There will still be anthro related warming, but less internal internal energy being amplified by the northern dominate land masses.

        That is the thing, everything gets amplified, even inconvenient stuff not just CO2.

        Even some of the die hard warmistas are setting up their end game.

        https://phys.org/news/2017-01-rapid-arctic-shifted-southern-ocean.html

      • Judith, you might have more effect explaining to Jim D that the Easter bunny is not real. He believes in global warming in the same manner I believe in Jesus having risen from his tomb.

      • “Papers on this are missing. It is just imagination. Why does it decide to redistribute now when the forcing is at record strengths? Coincidence? I think not. Record forcing = record warming is far more rational.”

        The NULL hypothesis should be the given. AGW theory should be suspect until it is proven with high confidence against it. Why bother with paleo reconstructions if this isn’t important?

    • As usual Jim D your premise inverts reality.

  9. Climatefeedback.org, About—fact checking mdia climate reports. Looks more like a consensua enforcer site than anything else. Read all the comments. If that is the best they have got, they are in trouble.
    IPCC AR4 WG1 SPM figure 8.2 says the warming from ~1920-1945 could not have been mainly AGW; not enough change in CO2. Yet it is essentially indistinguishable from the warming ~1975-2000. Shoots down their attribution claims.
    Christy’s point about models /observations cannot be responded to with ‘models not expected to work over 20 year periods’. Wrong on two counts. In 2011, Santer published that they should. And TAR pointed out climate is nnlinear chaotic, so the further out you go the WORSE things get.
    They are losing, and perhaps beginning to realize it.

    • I think the “skeptics” have somehow ruled out a solar contribution to the warming between 1910 and 1940, and its reversal thereafter. The trends are consistent with the sum of solar and CO2 forcing with other components like aerosols also adding in after 1950, and the occasional volcano. The solar change between 1910 and now nets about zero, so the near degree of warming since 1910 is non-solar. Try to think of a reason for that. It focuses the mind.

      • The potent argument about comparing the two periods (Lindzen’s initially) does not require knowing what caused the earlier warming. It only requires knowing it was not AGW. And the logical presumption that whatever it was, it did not cease to exist in 1975.

      • It was the sum of CO2 and solar, maybe about half each. The solar part since declined, while the CO2 part got stronger and now dominates anything the sun can do.

      • You don’t know how much absorbed solar changed.
        Look at the CERES data for 2015 and 2016.

        Evidently, absorbing more solar radiance can yield record global mean temperatures.

      • OK, how much of that is from a positive cloud and albedo feedback to CO2 forcing? Many would say this is not unexpected because there appear to be cloudiness and albedo trends that occur as we warm. Note also that greening is a positive albedo feedback.

      • I’m glad to know that CO2 dominates anything the sun can do. I was staying awake at night worried that if the sun goes out we’d all freeze, but since that’s not the case, I feel relieved.

      • Sure, those extra 33 C from the greenhouse effect keep things cosy for you too. The sun can’t do it alone, and with just the net solar radiation, the global average temperature would be a chilly minus 18 C instead of plus 15 C.

      • OK, how much of that is from a positive cloud and albedo feedback to CO2 forcing?

        Exactly – how much is natural – you don’t know and you can’t even guess because there were no consistent measurements even from 1979.

      • Cloud changes are feedbacks, as is albedo. The 2 W/m2 forcing change from CO2 is driving all this. Nothing else comes close to 2 W/m2 over the last century, but maybe you can suggest otherwise.

      • Cloud changes are feedbacks

        No, there’s no clear reason to believe a change of cloud cover follows from global average temperature.

        Clouds vary from circulation changes of which there are an infinite variety possible .

      • I didn’t say that. They can only be due to regional changes. Global average cloud has no particular meaning because there are so many different kinds. It is unlikely they have much coherent feedback, but some affect the energy budget more than others, especially low clouds.

      • Cloud feedbacks are strongly negative or the radiative balance between the northern and southern hemispheres wouldn’t be just 1 W/m^2, instead of something like 10 W/m^2.

    • They are losing, and perhaps beginning to realize it. …

      No, they’re winning.

      Heatwave. First 1/4 mean of 2017 is well above the 2016 annual mean, and 2017 is positioning itself to become the 4th record warmest year in a row, and, whenever an El Niño, which is forecast, starts mid NH summer, the El Niño usually last well into the subsequent year… and of the two years the El Niño spans, the 2nd of the two is usually the warmest. Think 97-98, 05-06, 09-10, 15-16. That means 2018 could be even warmer than 2017… if an El Niño forms in the NH summer. We’ll soon know. It remains the forecast.

      And those who actually looked 1940 to 1975 as a question instead of a political talking point figured out the current heatwave could happen.

      By 2020 the landscape for skeptics will be completely barren.

  10. It’s not sure that this kind of ping-pong is useful.
    An impossible debate (reason vs. dogma) is taking place, with the dogmatics not even wanting to listen to simple questions:
    – where are evidences of signals attributable to greenhouse gases?
    – If ECS is very likely between 1.5 and 4.5 °C (to which the contribution of other GHGs must be added), it is then quite likely that natural cooling is already underway, thus compensating the alleged GHG induced warming. Are statistically significant cooling signals observed?
    – are there validation protocols for CMIP models that allow using them to calculate future scenarios over one or more centuries?
    – What are the natural phenomena that are not yet integrated (or are integrated with simple summary formula) in the CMIP models, why?
    – Who knows what unknown unknowns could be?

    As no valid answers are given to such questions one can only conclude that anthropogenic warming is no theory but just a belief. It’s useless to discuss beliefs.

    • Reason versus dogma debate, dogma loses. That is why most dogmatics won’t allow it. Deleted reason comments at RealClimate is but one example of many. Banned from following on twitter is another.

    • Michel:

      You wrote: “As no valid answers are given to such questions one can only conclude that anthropogenic warming is no theory but just a belief”

      No, man made global warming IS real but it has NOTHING to do with greenhouse gasses.

      Proof of this can be found by googling “Climate Change Deciphered”.

      The model presented there has been empirically tested (and validated) multiple times, unlike the greenhouse gas hypothesis. And it projects ever-increasing temperatures, if no action is taken.

      Anyone, with an open mind, please respond with any objections.

      • @Burl Henry
        The existence of a phenomenon does not prove anything. In particular not the attribution of almost all warming to GHGs.
        And it is a tautology to demonstrate a theory with a model that makes use of the undertying hypothesis: you get a confirmation, but it is formally wrong.

      • Michel:

        My model is very simple. It simply states that a reduction in the net global amount of SO2 aerosol emissions in the atmosphere will cause average global temperatures to rise, because of the cleaner, more transparent air, which allows sunshine to strike the earth’s surface with greater intensity.

        Examination of the temperature record over the past 150+ years shows that this is true for every instance where it happens, with the temperature rise being approx. .02 deg. C. for each net Megatonne of reduction in SO2 aerosol emissions.

        The temperature record also shows that every El Nino, over the same time period, is coincident with a decrease in SO2 aerosol emissions.

        And you are using tautology to dismiss all of these facts ?

      • @Butl Henry
        Fine ! You have a plausible hypothesis. How do you validate it ? Observed evidences ?
        Is this included in CMIP models?
        Coïncidence or even some correlation don’t constitue proof.

      • Michel:

        The model has been empirically tested and validated at least 3 dozen times, without an exception. Read my post by Googling Climate Change Deciphered for an explanation.

        With respect to temporary warming periods due to a business recession or a depression, the correlation is 100%.

        No coincidence here, it always happens.

        .

      • @Burl Henry
        It would have been easier if you had given the link to your article.
        Not wanting to enter into a SO2 discussion which is not the subject matter of this blog post, I only note that you establish a mere correlation linking SO2 emissions peaking in the 70’s and warming following it.
        How to explain the ± stagnation during 1940-1970 and over the past 19 years ?
        In a multi-parameter regression analysis I can correlate to r2=99% Temperature with CO2, and also to r2=99% Temperature without CO2 but with e.g. declination angle of the Earth’s magnetic field. This does not constitute any proof. See http://wp.me/P4uV7N-Xr (in French, a better language for me).
        Only it tells that attribution and quantitation of it cannot be assigned to one only pet parameter. In this sense, such claims are refuted (falsified).

      • > Proof of this can be found by googling “Climate Change Deciphered”.

        Second hit:

        The Madhouse Effect is a breezy, engaging read, interspersed with wry illustrations courtesy of cartoonist Tom Toles of The Washington Post. It offers many excellent insights into life on the front line battling US climate-science obfuscation. We learn about the cadre of contrarian scientists routinely rolled out to cast doubt on issues such as ozone depletion and anthropogenic climate change (as well as second-hand smoke and the dangers of pesticides). We read of the television, radio and Internet ‘shock jocks’ who chase ratings by giving equal weight to scientific consensus and denialist rhetoric. The power of vested interests in US politics and implications for state and federal action on climate change are made abundantly clear, with Mann an amiable, if rather despairing, guide.

        http://www.nature.com/nature/journal/v538/n7623/full/538034a.html

        I doubt that’s what you had in mind, BurlH.

        Please advise.

        PS: Kidding. Please look under “sulphur dioxides” –

        https://contrarianmatrix.wordpress.com/lots-of-theories/

      • Willard:

        You are right. Googling it no longer brings up my essay???.

        However, if you use the DuckDuckgo search engine, it is the first item on the page.

        But I see that you found it. Any comments?

      • > Googling it no longer brings up my essay???.

        I quoted the second hit, BurlH. Guess the first one.

        ***

        > I see that you found it.

        I already did. I thought I told you already.

        ***

        > Any comments?

        I hope your correlations skills aren’t used to manage other people’s assets.

      • Willard:

        You wrote “I hope your correlation skills aren’t used to manage other people’s assets”

        You obviously did not understand what I was pointing out.

        Temporary increases in average global temperatures coincided 100% of the time with business slowdowns (recessions, depressions) over the past 150+ years, due to reduced SO2 aerosol emissions resulting from decreased industrial activity.

        These were unintentional reductions in SO2 emissions.

        It follows that the intentional reductions beginning circa 1975 would also cause temperatures to increase, and the warming expected from their removal matches actual average Jan-Dec global temperatures to within .02 deg. C, or less.

        Please explain where you feel that my correlations are faulty..

      • > Temporary increases in average global temperatures coincided 100% of the time with business slowdowns

        Your “coincided 100%” looks a bit farfetched considering that you’re just eyeballing a graph., BurlH.

        Also please bear in mind that the absence of a thing can’t be a cause. It must be something else. So you’ll need to rework on your

        Since the unintentional reduction of SO2 aerosol emissions in the troposphere causes temporary increases in average global temperatures, it follows that the intentional reduction of SO2 aerosols from the troposphere due to Clean Air efforts will also cause temperatures to rise.

        What you say seems to only be true in the sense that anything can follow from falsity.

        Comparing your results with what is being reported in the relevant AR5 chapter might be needed. If you prefer to start with something more classical:

        You might also like:

        http://www.yaleclimateconnections.org/2008/06/common-climate-misconceptions-why-reducing-sulfate-aerosol-emissions-complicates-efforts-to-moderate-climate-change/

        Hope this helps.

      • Willard:

        You wrote “Your “coincided 100%” looks a bit far fetched considering that you’re just eyeballing a graph”.

        Nothing far fetched at all. I simply noted that each business slowdown over the past 150+ years coincided with a temporary increase in average global temperatures, with no exceptions, a 100% correlation.

        You also wrote “please bear in mind that the absence of a thing can’t be a cause”

        With respect to climate, it absolutely can be a cause. Today is a bright, sunny day, warmer than yesterday. The cause is that yesterday had a cloudy sky, and the ABSENCE of any clouds today results in more warming.

        The same applies to dimming SO2 aerosols. Fewer aerosols = less dimming and therefore warmer temperatures. Surely you can understand this.

        No rework needed on my cited statement.

        Thank you for the link to the Yale SO2 paper. I was unaware of it.

        However, their conclusion “The data suggest an urgency for the world to take immediate and effective action to begin reducing emissions if a mean temperature increase of 2.0 deg. C. is to be avoided” is completely wrong. (Was this paper peer reviewed?)

        Continued reductions in SO2 emissions will GUARANTEE that an INCREASE of 2.0 deg. C. will occur (and probably within 25 years, or less, as noted in my essay)

      • > With respect to climate, it absolutely can be a cause.

        Not really, BurlH. You miss the active ingredient. The A in AGW is positive, whether you like it or not. Forcing, feedback. Learn the difference.

        Zeke provides the details. His calcs should show you where to find your misstep. Have you noticed how he uses parts of your argument to reach a conclusion that is opposite to yours?

      • “The A in AGW is positive”

        No, the A is for anthropogenic, with a positive connotation. And the reduction in SO2 aerosols is an anthropogenic action, resulting in AGW.

        Yes, Zeke’s conclusion is opposite to mine, but it is scientifically incorrect. You can’t prevent more warming by decreasing dimming SO2 aerosol emissions.

      • > the reduction in SO2 aerosols is an anthropogenic action, resulting in AGW.

        One does not simply warm the world by removing a negative feedback, BurlH. Causation does not exactly work like that. There’s something that humans dump in the atmosphere like there’s no tomorrow that causes AGW.

        Maybe it’s a vocabulary thing. Please ask Zeke. He has a Twitter account.

      • Uh, SO2 aerosols are not feedbacks, Willard. They act independently by reducing solar inputs.

      • Start here, Charlie:

        https://en.m.wikipedia.org/wiki/Climate_change_feedback

        You might also like this piece:

        https://www.wired.com/2008/06/ff-geoengineering/

        Published two years before JC.

      • Willard, both of your links support my statement. The first, by not mentioning SO2 as a feedback. The second, by showing SO2 as a primary actor on solar energy.

        Your inane comments are the reason I quit taking you seriously a long time ago.

      • Oh, I see, Charlie. I should have written “the difference between negative and positive feedback earlier.” My mistake.

        Negative cooling doesn’t explain warming at all. It’d be like saying that Joe Plumber could make a profit simply by cutting on his expenses. If he makes no money, his bank account will never increase.

        Your first comments show you never took me seriously.

      • Reduction of a cooling agent means: 1) The system won’t cool as much; or 2) the system will warm less.

        Your inanities are manifest, Willard.

      • > the system will warm [more]

        The absence of a cooling source can’t warming the system, Charlie. Think credit and debit. Better yet, think hockey: a good defence wins championships if and only if offence scores at least one goal each game.

        (Anthropogenic) negative forcings ain’t ain’t enough to account for the balance we got. It’s not even close.

      • The absence of a primary (non-feedback) cooling source says nothing about the system.

        Minor warming in a generally cooling Holocene doesn’t seem to be alarming.

      • > Minor warming in a generally cooling Holocene doesn’t seem to be alarming.

        Minimizing impacts is different than denying CO2 as AGW’s main driver, Charlie. It another level of the Contrarian Matrix:

        https://contrarianmatrix.wordpress.com/do-not-panic/

        That’ll have to wait. Too much Zamboni.

      • I don’t deny minor past GW recovery from the Little Ice age. I deny that IPCC climate models are capable of supporting fundamental changes to our societies, economies and energy systems. They are shown to exaggerate CO2 warming by factors of 2 to 3.

        Additionally, there is NO evidence that minor warming, coupled with increased CO2, will harm any aspect of man’s existence on this planet. Simply bruiting “CO2 leads to AGW” is meaningless to any discussion of climate change.

      • IPCC continued malfeasance about forcings and feedbacks leaves one with no alternative except to deny any accuracy to assertions of “CO2-equivalents” and their supposed impacts on our stable climate.

      • Oops! The system will warm more.

      • > “the difference between negative and positive feedback earlier.”

        Or rather negative and positive forcing.

        Damn SwiftKey.

      • Willard:

        You say that “one does not simply warm the world by removing a negative feedback”

        And yet it happens every time there is a large volcanic eruption.

        Its SO2 aerosol emissions into the stratosphere provide a negative feedback, temporarily cooling the earth, and a positive feedback, as it warms back up to pre-eruption levels, as the SO2 aerosols settle out.

        And the same positive feedback occurs whenever global SO2 emissions are reduced by Clean Air efforts, warming the Earth by removing a negative feedback.

        This is a scientific fact, empirically tested and validated dozens of times. And it explains all of the anomalous warming that has occurred
        the last 40+ years.
        with no hypothetical warming from “greenhouse gasses” needed.

      • > yet it happens every time there is a large volcanic eruption

        Volcanoes’ aerosols are a source of cooling, BurlH. The source of warming ain’t the absence of aerosols. It needs to come from elsewhere. Basic double entry bookkeeping.

        It’s a forcing, BTW. My mistake.

        ***

        > it explains all of the anomalous warming that has occurred the last 40+ years.

        You haven’t read Zeke’s article, have you?

      • Willard:

        I find it incredible that you cannot grasp the simple fact that, if cooling aerosols are present, their removal will cause average global temperatures to rise.

        But you apparently have a lot of company.

      • BurkH,

        Facts are not conditionals and causation aren’t based on negative facts. Aerosols cause cooling. Something else than the absence of aerosols cause warming. That warming is anomalous. As Zeke puts it,
        aerosols pretty much cancel out the warming from all the non-CO2 greenhouse gases.

        This should tell you that the main culprit is CO2.

      • Willard:

        You insist that the main culprit is CO2.

        However, this is just an unproven hypothesis, and I have shown in my essay that THERE CAN NEVER HAVE BEEN ANY WARMING DUE TO CO2, because the amount of warming from the reduction in SO2 aerosols perfectly matches the rise in anomalous global temperatures, 1975-2011.

        And yes, I have read Zeke’s paper, and he confirms that the removal of SO2 aerosols will cause global temperatures to increase.

        He does make the mistake, however, of not recognizing that the anomalous warming present at the time of his paper (2008) was actually caused by earlier reductions in SO2 emissions, and was not due to greenhouse gasses.

      • > This is just an unproven hypothesis

        I too prefer my hypotheses proven, BurlH.

        AFAIK, this is an accounting problem:

        The major positive forcings include CO2 at 1.66 watts per meter squared (W m-2), methane (CH4) at 0.46 W m-2, nitrous oxide (N2O) at 0.16 W m-2, and various halocarbons (CFCs, HCFCs, etc.) at 0.34 W m-2. Aerosol direct effects account for -0.5 ± 0.4 W m-2 negative forcing, with SO2 comprising -0.4 W m-2. Indirect effects are around -0.7 W m-2, with a large uncertainty range of -1.8 to -0.3 W m-2.

        http://www.yaleclimateconnections.org/2008/06/common-climate-misconceptions-why-reducing-sulfate-aerosol-emissions-complicates-efforts-to-moderate-climate-change/

        I don’t know exactly how you came to the conclusion that SO2’s cooling can cancel CO2’s overall warming. I have no idea why you think the absence of SO2 would bring any warming without any positive forcings of the scale of CO2.

        One last try. Were it not for aerosols, we’d be at around 460 ppm right now. These are CO2 equivalents. They aren’t SO2 absences. Less SO2 means more CO2. Even you should agree with that, BurlH.

        Best of luck.

      • Willard:

        I would simply quote from Zeke’s paper: “Figure three below shows the practical implications of a REDUCTION of aerosols in the next century .
        If CURRENT greenhouse gas concentrations remain CONSTANT at current levels, scientists project about 1.34 degrees C warming relative to pre-industrial temperatures by the end of the century………A REDUCTION of anthropogenic atmospheric sulfate aerosols by 50 percent means that 1,34 degrees C. warming suddenly becomes 1.70 degrees C”.

        Note that WITHOUT any change in CO2 levels, he states that simply reducing SO2 levels will cause temperatures to rise.

        Which is exactly what I have been saying.

        And, again, he is trying to have it both ways, implying that all of the warming up to 2008 was due to increasing CO2 levels, and also implying that all of the reductions in SO2 levels since 1975 (about 30 Megatonnes) had zero warming effect, but will cause warming from 2008, and on. An utter impossibility!

      • > also implying that all of the reductions in SO2 levels since 1975 (about 30 Megatonnes) had zero warming effect

        This implication runs against the basic fact that SO2 aerosols have a cooling effect. Zeke acknowledged that fact. It’s in the first part of your quote. He even gave a numerical estimate of that negative forcing elsewhere in the text. See my quote above.

        There’s no such implication and your still stuck with an accounting problem. The 1.7 C of warming when we abstract aerosols away can’t come from aerosols. It cannot come from the absence of aerosols either.

        Perhaps it’s a grammar thing.

      • Again, Willard: Explain the about 1915 to about 1945 “anomalous” warming.

      • SO2 aerosols are not feedback. They are a primary driver of cooling independent of any other “forcings.”

      • David Fair:

        David:
        You wrote “SO2 aerosols are not feedback”

        I agree.

        “They are a primary cause of cooling independent of any other forcings”

        And a primary cause of warming when their concentration in the
        atmosphere is reduced.

      • By definition, Burl.

        Willard is a twit.

      • “as well as second-hand smoke and the dangers of pesticides.”

        Yep, there were quite a few people that criticized the methods used to produce “dangers” from sparse data and there still are since science “activists” tend to use similar questionable methods as political tools.

        Overstating potential danger has grown into more than a science cottage industry. Might be part of that ethical double bind situation, noble cause corruption and headline grabbing mentality.

        I seem to recall comparing the impact of Chinese Herbal Tea consumption with second hand smoke and that killer tea should have been banned years ago.

        Slate has a decent article on the second hand smoke situation. Of course, “Real Climate Scientists” would never fall into such a trap.
        http://www.slate.com/articles/health_and_science/medical_examiner/2017/02/secondhand_smoke_isn_t_as_bad_as_we_thought.html

      • I guess I am one of the alarmists.

        My model shows increased warming whenever anthropogenic SO2 aerosol emissions are reduced, and there are probably 85 Megatonnes of emissions still in the atmosphere.

        With about .02 deg. C. of warming for each net Megatonne of reduction in global emissions, we could have an additional 1.7 deg. C of warming coming our way, unless emission reductions are halted (which will never happen because of China and India eventually cleaning up their pollution).

      • Another thing I found interesting is the “projected” number of asthma attacks that would be avoided with the clean power plan. Since the shale boom, emissions are down but asthma cases are rising. It is almost like there is a negative correlation between asthma and centralized coal power plants, but a positive correlation between asthma and vehicular emissions. Damnedest thing.

      • > Yep, there were quite a few people that criticized the methods used to produce “dangers” from sparse data and there still are since science “activists” tend to use similar questionable methods as political tools.

        On the one hand, people.

        On the other, activitsts.

        Srsly, Cap’n?

      • “Srsly, Cap’n?” Unfortunately, yes. Banning and overselling potential dangers tend to motivate response. The self described “activists” politicize, “People” are inclined to question the political process.

        Since the topic is reactions to a political hearing, “people” and “activists” are important concepts to grasp. When the motivation is poorly done “science” and assertion of “facts” that aren’t, things get messy.

      • > The self described “activists” politicize, “People” are inclined to question the political process.

        We’ve got years of blog posts and comments that contradict this self-serving dichotomy, Cap’n. Start here:

        https://judithcurry.com/2010/

        As if activists would not be inclined to question the political process or that people like you would never politicize.

        Junior calls what you’re suggesting stealth advocacy, BTW.

      • Willard, bad science is bad science, when you defend bad science you are …. what’s is a polite term?

      • Hmmm….

        I had to search, and sure enough, metabolic syndrome appears to be a risk factor for asthma.

        “Obesity appears to be a predisposing factor for the asthma onset, both in adults and in children.”

        So consider that. The insane want to implicate global warming while being responsible for their own poor health.

        Here’s a criteria. If you:
        * smoke
        * know how much a bag of Oreos cost
        * drink more than an IPA a day
        * have more sexual partners than wedding rings

        you cannot worry or betch about global warming.

      • Cap’n,

        I’m sure there’s also a word for Freedom fighters portraying themselves as “people” and whining about “activists”.

        How would you describe the political affinities of someone who’d brandish the World government strawman in an interview with a radio show conspiracist or retweet Quillette’s crap?

      • Willard, so many wrongs to right, must keep you busy.

        “On the one hand, as scientists we are ethically bound to the scientific method, in effect promising to tell the truth, the whole truth, and nothing but — which means that we must include all the doubts, the caveats, the ifs, ands, and buts. On the other hand, we are not just scientists but human beings as well. And like most people we’d like to see the world a better place, which in this context translates into our working to reduce the risk of potentially disastrous climatic change. To do that we need to get some broad based support, to capture the public’s imagination. That, of course, entails getting loads of media coverage. So we have to offer up scary scenarios, make simplified, dramatic statements, and make little mention of any doubts we might have. This ‘double ethical bind’ we frequently find ourselves in cannot be solved by any formula. Each of us has to decide what the right balance is between being effective and being honest. I hope that means being both.” Schneider.

        That “broad based support” would be “people” some of which self describe as “activists.” Lots more activists on the warm and fuzzy liberal side of the aisle. Highlighting the “dangers” would be using the dramatic.

        Now if you can collect yourself, the second hand smoke initial studies were crap that grossly over sold the “dangers.” Ditto with “pesticides” since there are 100s to chose from including “organic.”

        Are there right wing extremists? Without a doubt, but science is supposed to above the fray.

      • Turbulent “I had to search, and sure enough, metabolic syndrome appears to be a risk factor for asthma..”

        There was a recent study that linked diabetes with global warming because there is a correlation between the two :) Science at its bestest.

      • Willard, this blog isn’t doing that great of a job catering to angry white males, unless the stereotypical angry white male has a background in engineering, health or meteorology.

        The more alarmist type websites appear to cater to the angry at angry white male set. Such is life.

        Neither have squat to do with bad science and over selling the “dangers” to promote science policy. Have you compared the correlation between asthma and electric power production? I would think an unbiased science type would be willing to call out some of the BS instead of defending every blurb someone has to pay in order to get published. Perhaps the stellar paper that discovered that warming causes diabetes is what you consider sound science?

        http://www.latimes.com/science/sciencenow/la-sci-sn-global-warming-diabetes-20170320-story.html

        This has inspired future leader of the free world Chelsea Clinton to take action.

      • I think what Burl Henry is saying is that the clean air acts are so effective that they have not only removed industrial age SO2, but also some purported pre-industrial SO2, so the SO2 level is now even below the pre-industrial level to account for his warming effect in the last couple of centuries. Whether there really was so much pre-industrial SO2 and, if so, who was emitting it, and how we removed that, are beyond his explanation.

      • Jim D:

        No. I am not saying that clean air efforts have removed all of the industrial age SO2.

        Global levels peaked in 1972-1975 at approx. 131 Megatonnes, and, so far, clean air efforts have only reduced them to about 85 Megatonnes Lots of room for more warming as reductions continue.

        Enjoy..

      • Why is it so much warmer than 200 years ago then? So2 levels are probably higher now because we have industry. Did the SO2 cause the warming or what?

      • Jim D.

        Any reduction in the global inventory of SO2 aerosol emissions will permanently raise temperatures by approx. .02 deg. C. for each net Megatonne of reductions in the emissions. As a result, average global temperatures have been climbing since 1975 when they were about one deg. C. lower than now.

        SO2 levels were supposedly much lower in the 19th century, but there is evidence that they were actually rather high, which would cause a cooler environment.

        The evidence is the temporary spike in average global temperatures that occurred during the “long depression” of Oct. 1873-March 1879, when temperatures soared to the same levels seen in the 1930’s (see the Met Office HADCRUT4 plot of of average global temperature anomalies, 1850 – present).

        The only known cause of temporary increases in average global temperatures is the reduction in the amount of SO2 aerosol emissions, and the long depression would have provided ample time for most of them to have settled out.

        Does anyone else have another explanation for the temperature spike?

      • So you really are saying preindustrial aerosols are so much greater than now they account for it being up to 1 C cooler through most of the millennium. It’s the CO2 that changed, of course.

      • Jim D, why was it so much warmer during the various historical climate optima than it was 200 years ago?

        Is the CO2, SO2, methane, etc. forcings manifest in climate science the whole story? They don’t seem to do so well outside the late 20th Century tuning period.

      • Milankovitch is why it became cooler after the Holocene Optimum. We are currently in a Milankovitch period that favors northern ice believe it or not.
        There are some misconceptions about tuning addressed in a new realclimate post on the hearing by Gavin Schmidt that you should look at.

      • Burl Henry or Jimd

        I hold no opinion either way of the cooling effect of SO2.

        How long lived is it in the atmosphere and typically what would have been its prime uses in the 19th century? As far as I can see it is used in wine making and in bleaching paper. For it to build up to significant levels that could affect the atmosphere, presumably there were other uses.

        Tonyb

      • Tonyb:

        The wide-spread use of coal for heating, manufacturing, and coking would probably have been the major source of SO2 emissions into the atmosphere during the 19th century. Much of the coal would have been high in sulfur content.

      • tonyb, it doesn’t last long. To keep it sustained means sustained emission, and the content depends mostly on the emission rate than on any integration over time like CO2. This is why high values 200 years ago are so dubious, plus factoring how little of the world was civilized then and the low population. It’s a non-starter.

      • Burl and jim

        As you may be aware western European cities suffered massive air pollution during the 19th century. Artists such as Monet came to Britain to paint the scenes caused by the pollution.

        This article is about Turner and the likely levels of pollution during his time as an artist

        http://www.ibtimes.co.uk/great-masters-19th-century-paintings-build-timeline-earths-past-pollution-levels-1441775

        The amount of coal being burnt should not be underestimated, in everything from domestic grates to massive furnaces, steam engines for every purpose to creating gas and electricity.

        What with a string of volcanoes to mans own efforts it may well be there were spikes in SO2 beyond what we currently believe.

        However, key to this would be how long it remains in the atmosphere. I stil have no idea how long it stayed around for and whether it could build up over the decades

        Tonyb

      • Tonyb:

        For intermittent sources of anthropogenic SO2 emissions, they generally settle out within a few days

        However, most sources of anthropogenic SO2 emissions are relatively constant, since they are constantly being renewed. As such, they have an effectively ” infinite” lifetime, ending only when the emitting sources are either modified to reduce emissions, or are permanently shut down.

        The aerosols, however, don’t build up in the atmosphere.

    • Santer showed that the warming since 1993 is natural
      http://www.nature.com/ngeo/journal/v7/n3/fig_tab/ngeo2098_F1.html
      (Volcanic contribution to decadal changes in tropospheric temperature)

  11. If there is a red team, it has bloomed in the last few years. I would count MH England, M Zelinka, SP Xie, RN Jones, C. Zhou as a small number of examples of its membership.

    Instead being politically biased against one side or the other, they have simply tried to expand understanding of the physics of the system… and are scoring points.

  12. “Yawn. ‘But human causes are more than 100%’. Get a dictionary and see how ‘HALF’ is defined.”

    This is true if you take 100% to be a whole. You can get >100% when it’s presented as a % increase. So it appears the usage is in reference to % increase in which half of the % increase could be a percentage greater than 50%. I.e. If the % increase is 110%, then half of that would be 55%, not 50%.

    • without the context that that the whole is 110% or whatever, the only rational interpretation of ‘more than half’ is > 50% but < 100%

      • Judith, surely the more than 100% thing is an assertion that without human activity the world would now be cooling. On that basis not only is human activity responsible for all warming (100%) it is also offsetting the cooling.

        Note that I do not disagree with your rational interpretation but you are not dealing with rational people.

  13. The second sentence of the IPCC AR5 attribution statement is often not quoted here, but it is important for putting the first sentence into context.
    “It is extremely likely that more than half of the observed increase in global average surface temperature from 1951 to 2010 was caused by the anthropogenic increase in greenhouse gas concentrations and other anthropogenic forcings together. The best estimate of the human-induced contribution to warming is similar to the observed warming over this period.”
    This means that the center of the distribution is at 100%.

    • Yes, climate models say all of the warming was caused by humans. But climate models were tuned to the period in question, and do not adequately account for multidecadal ocean circulations and indirect solar effects. So, low confidence at best in the climate model result.

      • Attribution is mostly from observations and physics. The ongoing positive imbalance, measured by OHC changes, is a key part that says the warming is trying to keep up with a forcing change. The main forcing change is GHGs, and that is just physics.

      • Actually, no. AR4 WG1 SPM fig 8.2 makes it clear that attribution is based on climate models, and that ismillogical. For AR5 CMIP5 the tuning period was expressly fromYE 2005 back 3 decades fo 1975. So the AGW model parameters were tuned to best fit most of the second period of warming. They ‘tuned in’ whatever natural variation was also in that period like in the previous one 1920-1945. That is why CMIP5 are running grossly hot as Christy showed; the natural variation turned ‘cold’ like from ~1946-1975 and the models don’t have it.

      • The fingerprint strategy is even worse. the fingerprints are not specific to CO2 induced warming (just to warming in general), and do not account for fingerprints associated with multidecadal ocean oscillations. And people wonder why I am unconvinced.

      • The attribution is from fingerprinting. Cooling in the stratosphere, measured radiative changes, increases in ocean heat content, point not only to the increase in forcing, but also the cause of that increase. Models can back that up with physics. It is very inconvenient for skeptics that they have to allow that the observed degree of warming from only half a doubling of CO2 is consistent with AGW being right while also asserting, for some reason, that it can’t possibly be the case that CO2 dominates.

      • yes, and how are those fingerprints different from solar heating and warming associated with internal variability?

      • OHC doesn’t increase from internal variability. The stratosphere doesn’t cool from solar strengthening or internal variability. The radiative flux does increase from CO2 in a very particular way that is observed, and consistent with the same radiative transfer theory that underpins and quantifies the forcing associated with AGW.

      • Jim D, your seemingly compelling last statement fails for several reasons.
        1. OHC is an estimate, only ‘reasonable’ since Argo. Argo only samples the upper half of the oceans (200 meters, estimated average depth ~ 3800 meters, max ~12000 meters); else Trenberth’s missing heat could not have gone missing below. Paper cites in essay Missing Heat (yea, get my cheap ebook and educate yourself).
        2. iPCC AR5 itself could not find a central estimate of ECS since models were 2x observations. Uncertianty Monster bites.
        3. Attribution is NOT from fingerprinting per IPCC. And the fingerprinting papers are by and large laughably poor climate science. One example. Stratosphere stuff depends a lot on solar indirects(e.g. Ozone), not well understood, not well measured, very not well modeled.
        Your confidently asserted claims simply to not withstand de minimus scrutiny. Show the science behind them with challengable references, please. Else we contest a mere bloviation.
        BTW, I have complete copies of AR4 and AR5? Plus copies of about 800 of,the most seminal papers they use. So at least start by trying to support your confident assertions using IPCC. You failed there, already, here.

      • The IPCC may not have a central estimate, but they do have a best estimate in their attribution. ” The best estimate of the human-induced contribution to warming is similar to the observed warming over this
        period. ” While skeptics are usually happy to quote the IPCC, they do so selectively, hoping no one will notice, and, yes, it works because the congressional Republicans are none the wiser when these IPCC statements are not put in context. Pulling the wool over their eyes is easy, as the skeptics on that panel were able to prove, but doesn’t pass muster with the scientific audience who are aware of the full statements and what is actually said about attribution in the AR5.

      • The ‘more than half’ statement, whatever its ambiguity and lack of precisions, is much less likely to be wrong than the 100% statement.

      • That’s an assertion that looks contrary to the IPCC statement that 100% is the most likely value.

      • “OHC doesn’t increase from internal variability”

        Sure it does.
        Reduce cloudiness over an area of ocean and the OHC increases.

      • Since we are talking about climate, you have to look at decadal, or 30-year trends of OHC, not the variations you get with the ENSO cycle that self-cancel on decadal scales.

      • Since we are talking about climate, you have to look at decadal, or 30-year trends of OHC, not the variations you get with the ENSO cycle that self-cancel on decadal scales.

        And clouds can’t vary on 30-year trends?

        Of course they can.

      • not the variations you get with the ENSO cycle that self-cancel on decadal scales.

        Oh, yeah, on the basis of ENSO alone, you would expect a warming trend from 1975 to date ( more EN, fewer LN ):

        In fact, using the extended MVEI, ENSO corresponds pretty well with 1910-1945 warming, 1945-1975 cooling, and 1975 to date warming.

      • Turbulent Eddie:

        You may have missed my earlier comments that all ENSO warmings and subsequent El Ninos over the past 150+ years are coincident with reductions in SO2 aerosol emissions. Definitely man made.

      • Clouds don’t have a memory, and don’t spontaneously change except in response to other changes where they may act as feedbacks.

      • Cloud responds coherently to changes in ocean and atmosphere circulation. e.g.

        Just like precipitation – cloud is ephemeral but is recreated in accordance with climate processes. Not everything is global warming feedbacks.

        The global energy budget is constantly varying as the climate system varies. Global energy content is the system memory of net changes in outgoing energy – mostly – which are mainly cloud changes in the short term.

        The data is quite clear. Net up is warming by convention.

        “The top-of-atmosphere (TOA) Earth radiation budget (ERB) is determined from the difference between how much energy is absorbed and emitted by the planet. Climate forcing results in an imbalance in the TOA radiation budget that has direct implications for global climate, but the large natural variability in the Earth’s radiation budget due to fluctuations in atmospheric and ocean dynamics complicates this picture.” Loeb, N.G., Kato, S., Su, W. et al. Surv Geophys (2012) 33: 359. doi:10.1007/s10712-012-9175-1

        Complications is wot Jimmy don’t like.

      • RIE, “Cloud responds coherently to changes in ocean and atmosphere circulation”. Exactly. They don’t cause changes, they respond, and if you get less clouds as it gets warmer, that is a positive feedback, and that is what the data shows for the 1990’s.

      • Ocean and atmospheric regimes – such as the IPO – change independently of whatever global warming there is. The cloud changes in the Amy Clements et al graph is associated with the PDO – in the climate4you graph ENSO. The tropical cloud radiative effect in the 90’s was an order of magnitude greater than the change in greenhouse gas forcing. Not everything is global warming.

        But you are an extremist Jimmy – and I can’t quite get my head around your thought processes. What I do know is that it is not worth arguing verbiage with you.

      • I think clouds do respond to ocean changes too, as I said. El Nino is a good example of that. Is that too extreme for you?

  14. O/T but important!
    Apparently according to NYTimes today the Trump Administration will make a decision about the Paris Agreement on Tuesday. Pruitt came out yesterday against it. But with Bannon in decline, the Tillerson Cohn Ivanka Jared team will probably outweigh him. Is there any way we can influence this decision in the next couple of days? Maybe an Open Letter with multiple signatories?

    Paris Agreement—pros and cons
    CONS
    1. Entire basis of agreement depends on unvalidated models showing CO2 will lead to serious warming—but recent results show the models are overestimating the effect of CO2 (Christie, Congressional testimony).
    2. Agreement commits US to reducing fossil fuel use (i.e., closing coal mining operations by adopting the Clean Power Plan) while allowing China to continue until 2030.
    3. Agreement will cause electricity costs to “skyrocket” (Obama’s words) mainly hurting the workers who voted for Trump.
    4. Agreement commits US to contributing heavily to $100B fund to go to other nations (including China!) Obama already contributed $1B, the last $500M illegal, since the Green Climate Fund of the UNFCCC includes a terrorist organization (PLF).
    5. Agreement is actually a treaty and requires approval by the Senate, which has not occurred.
    PROS
    1. Sorry, can’t think of any. What does a “seat at the table” get for us? What do Ivanka and Jared know about CO2?

    POLICY OPTIONS
    1. Get out cleanly by denouncing it as one of the worst deals ever. Deal was made by previous Administration and election of Trump suggests people were not fooled. Trump keeps his promise to his voters. Win-win.
    2. Identify Agreement as a Treaty and submit to the Senate for approval. Senate turned down Kyoto about 95-0 and will do the same with Paris. Advantage is that future Democratic Administration cannot just re-enter the Agreement without convincing the Senate to go along.
    3. Ignore Agreement but start process of withdrawing from UNFCCC, which will probably make Agreement moot.

    • I think you need Lamar Smith and his fossil fuel buddies like the Kochs to weigh in. Appearance of self-interest seems not to matter for this lot, Trump included.

      • Roger Knights

        IIRC, the Kochs were initially warmists. (Or was that the senator from Oklahoma?)

      • I have been following this discussion for about 10 years. The truth is that the argument hasn’t changed very much in spite of the army of scientists and hangers-on and billions of dollars spent. The IPCC sensitivity remains at 1.5-4.5 per doubling, the physics is the same, and the measurements are so messed up that “adjustments” can literally account for total observed temperature change. The models still spew out a garbled mess of spaghetti – and always have. Billions of dollars and we still get projections instead of predictions. Time for some paradigm shifts? I sometimes think we way over-think the whole issue. Maybe it is as simple as we can think we have moved outside the range of normal climate change when the descendants of the vikings can once again sustain agriculture in Greenland. The whole debate is keeping a lot of folks employed. Whether or not it is productive employment may be another question. And in this corner – wearing the red trunks……..

      • Projections instead of predictions for the reason we can’t predict emission rates because we can’t predict human behavior, so they have to project based on different emission/behavior scenarios. In fact they can be fairly precise about temperature change per emission being in the range 1 C per 1500 GtCO2 emitted, but those emissions could be anywhere from 1000 GtCO2 to 10,000 GtCO2 going forwards with the highest probability somewhere in the middle or the lower end depending on the effectiveness of action.

      • Don’t forget: also can’t predict solar variability, volcanic eruptions, and multi-decadal and longer ocean oscillations

      • The main uncertainty is human behavior, but yes major volcanoes, glacial tipping points, you can throw this all into why this is not called a prediction.

    • Yes Lance O/T, but (extremely) important.

      I don’t entirely agree with your analysis of the Paris Agreement – see my post here: https://judithcurry.com/2016/08/16/cop21-developing-countries/. And I would add a fifth option:

      Initiate the process of withdrawal thereby triggering an international crisis/furore. Respond by putting the notice on hold pending the outcome of a US/China summit the main topic of which would be the determination of each country’s position on climate science – something that’s never seriously discussed at top level UN climate negotiations (and about which China is remarkably coy). The key questions would be these: is mankind responsible for recent increases in atmospheric temperatures and, if so, should/can anything be done about it – and by whom? I believe the outcome of such a meeting would open a lot of eyes.

      My thinking is spelled out in more detail here: https://ipccreport.files.wordpress.com/2017/03/note-on-paris-agreement.pdf

    • No way of predicting what will happen due to the sheer unpredictability of Trump. Like the mule he would have driven Hari Seldon wild.
      The message seems to be that he does not want to commit America to putting in Billions without similar action from all other sides. In this context he has 3 options of repudiating the Paris Climate Agreement.
      He can simply refuse to engage with or give any money to the UN. This seems to be his current strategy and one which is working. Very hard to attack him when he is not doing anything.
      The second is to actually put an embargo out in the open, to make an announcement that there will be no further funding and that he would like the UN to respect this. This can be attacked but is still in keeping with the Treaty.
      The third is to actually rescind the Paris Agreement, either through the Houses being asked to formally approve or deny it or by Presidential fief. The former would be more preferable but the number of green Republicans makes it very dangerous.
      My feeling is number 2 first and if Americans get upset at the World reaction and unite against it in opinion polls loudly then to put it to the houses with popular support.

    • Decision meeting canceled.

  15. “Well, I think of this as sort of a red team exercise. The IPCC report is the original blue team. Think of Christy, Curry, Pielke as the Red Team. The scientists providing responses in the Climate Feedback article are defending the Blue Team against critiques by the Red Team. And then this blog post responds to defenders of the Blue Team.

    I think this kind of back and forth is very useful. The Goliath Blue Team didn’t manage to score any meaningful points against the Red Team in the Climate Feedback article, as far as I can tell.”

    ##################

    well you show that you dont understand how Red Team and Blue team work

    Guess what YOU DONT GET TO SCORE THE GAME.

    As Red team you dont get to say or even try to judge who scored points or who is winning.

    you DONT get to play the Referee or Judge. As a Team member you basically have to step back from the whole process and let others judge
    or disqualify yourself.

    The biggest fail of the “Red” team is Christy’s continual use of a grey chart.
    A chart that he has never supplied the underlying data for.
    a Chart that he has never supplied the code for.

    Major infraction. As a Red team member you dont get to defend him. You get to tell him to Observe best practices and cough up his data and code.

    ALL of it.

    I award you zero points.

    • Sorry, everybody gets to assess the exchange, including red and blue team members to decide if further iterations are worthwhile.

      • Gaia is the referee and score keeper.
        Many of the rules secret.
        Fault her for dropping standards and producing such unholy and ‘unnatural” creatures such as us.

        I deny my fig leaf.

      • No. calling your own fight while you are still in the ring,
        raising your own hand in victory, just looks silly.
        I’ll accept your surrender on line.

        See how silly that looks?

      • Mosher – You seem to take the position that your team enters the100 game season with 50 wins. Then you retain the option to “move the goalposts”. Your team was even given the “nobel” gold metals half way through the season.

    • Mossshhher the Great and Powerful says “Guess what YOU DONT GET TO SCORE THE GAME.”

      And you do? Wow!

      • Generally speaking, when you run a blue team red team exercise you have outside observers who then Inform the Blue team of areas they need to work on.

        Based on what the Red team presented at Congress …

        The Blue team Wins. 2/3

        A) Christy Presented undocumented work. His work is out of date.
        His work has have never been documented.
        His work has never been replicated.
        THIS IS SAD, because there actually IS and interesting issue
        here, just NOT the one that Christy thinks.
        B) Curry. Presented nothing new. Her arguments basically come down
        to she doesnt understand what they did, and also an argument
        from incredulity. Again, there is a good argument here, She just
        hasnt presented it.

        Peilke is the only one who comes close to making points.
        Peilke 1, blue team 0

        There is no consensus on Climate extremes.

        So. advice to red team.

        1. Document your work… CDRs Please
        2. Pielke Glad to see you back, lose the chip on your shoulder and get back to work

      • Roger Knights

        Steven Mosher: Generally speaking, when you run a blue team red team exercise you have outside observers who then Inform the Blue team of areas they need to work on.

        That’s true of intra-organizational red/blue exercises. When there is no overarching hierarchy in place, a formal structure from the outside is needed for evaluations, such as a science court.

      • In this case, the people outside would be an organization like NAS, RS or APS (or even Apple and Google) who don’t have a dog in the fight, and they have spoken in no uncertain terms repeatedly over the last decade or so. The blue corner wins.

      • Jim D, generally speaking you don’t get to nominate the decision maker and the decision as you have done here.

        Oh, and this is not a boxing match.

      • Oh Mossshhher the Great and Powerful, your hubris is exceeded only by your proclamation that you are a scientist.

        What ever happened to you?

    • Only Stephen gets to score the game, clearly.

    • The biggest fail of the “Red” team is Christy’s continual use of a grey chart.

      Christy’s point – that the Hot Spot has been a no show since ’79 – is a point brought to us by the “Blue” team (IPCC). So, confirmation?

      While Christy has been a part of the UAH analysis, the fact that similar published and peer reviewed findings from other MSU analyses, the RAOB data, and the Reanalyses, kinda point out the obvious.

      • It is interesting that the tropical Pacific has net cooled between 1979 and 2010, possibly owing to starting in an El Nino dominated period in the early years, and ending with la Ninas. This would be a challenge for a hot spot to develop. End points matter. Christy did not show this, and perhaps doesn’t realize.

      • As published, the CMIP5 models create too much tropical precipitation when modeling the past, a problem which got worse from CMIP3 to CMIP5.

        That is why the models think there should be a hot spot. Now, that jibes with ENSO cycles, but remember up above where you wrote things like ENSO didn’t matter for thirty years because they average out?

      • While ENSO averages out globally over 30 years, it doesn’t if you are just looking at the ENSO region. It seems it would take longer to average out for smaller regions. The GCMs average it out by using an ensemble.

    • Steve Mosher, I commented below that in fact Cristy’s graphic had been replicated by Steve McIntyre and even at Real Climate with some small differences in baselines and averaging methods.

  16. David L. Hagen

    curryja
    Include The Right Climate Stuff ex NASA engineers & scientists in a broader “Red Team”.

    We, a group of retired and highly experienced engineers and scientists from the Apollo, Skylab, Space Shuttle and International Space Station eras, have volunteered our time and effort conducting an objective, independent assessment of the AGW alarm and reality of the actual threat. We have reviewed hundreds of reports and technical papers relevant to the subject matter, and discussed key issues with experts on both sides of this controversy.

    THE TRCS CLIMATE MODEL – 1 Hour Video HAROLD DOIRON, PH.D. – 18JAN2017

    The presentation explains why, after 5 years of independent, objective study, our TRCS research team has challenged the climate science consensus and recommended to the Trump Administration why climate science used at the EPA to justify CO2 and other Greenhouse Gas regulations, needs an in-depth scientific review by a broad panel of scientists, engineers and mathematicians, selected for their competence and lack of conflicts of interests.

    See TRCS Reports

    • As a retired engineer, I’m impressed by the video THE TRCS CLIMATE MODEL, linked above. By approaching Transient Climate Sensitivity an engineering problem, rather than a scientific one, Harold Doiron makes the “wickedness” of the broader climate simulation problem irrelevant, and arrives at a meaningful conclusion that focuses on the impact of atmospheric CO2 concentration alone.

      This is exactly what policymakers ought to want, if they’re serious about making decisions that reflect both empirical knowledge AND the values and priorities of the citizens whom they serve. Too bad Doiron’s answer isn’t one that the climate alarmists will want to hear.

      • David L. Hagen

        silvertomster TRCS has the crafted the only climate model that has been validated that I know of. That is critical for policy decisions.

  17. After watching this and many previous congressional hearings, I’m struck by the number of members who seem to believe: 1) the climate only changes because of human activities; and 2) somehow, humans can stop the climate from changing. Furthermore, these same members don’t listen, they don’t understand, and they use ad hominem tactics to discredit and silence those who don’t submit to their authority on the subject. It’s impossible to reason with people like this.

    • DC is an industrial town.
      The product is stark political division.
      ‘Climate Change’ is one of their grandest creations.
      April 29
      Climate Jobs, and Justice
      I mean …
      Climate, Jobs and Justice
      It’s a package deal.
      Reason has nothing to do with it.

    • Dr. Curry quite helpfully describes climate change, and its human influence, as a wicked problem. Just how wicked is it? Consider the number of variables, dependent, independent, and interdependent and you begin to appreciate the delusion of those who believe the science is settled, or that there is any kind of consensus. Politicians love these eternal problems. No matter what the opposition says or does, the problem persists as a worthy cause, to save the planet from some evil. They tar and feather anyone who argues against their cause. They condescend, they belittle, and they silence all who oppose their cause. This really has very little to do with climate science, a discipline they do not appreciate.

  18. If you read the ice core charts you will see man has no effect on the four previous ice ages and the fifth ice age began around 2,000 years ago because he was insignicant. The CO2 level was around 280ppm at the end of each ice age. A little after the beginning oif this ice age, man began adding CO2 at a greater level than photosynthesis could remove it, thus the rapid increase in the level. The level is now about 383ppm.As the oceans drop Nature will make more green foliage and the CO2 level hopefully will drop. The ocean will continue to drop until the land area is large enough to turn natrure to melting the ice.

  19. Some tips based in my summary on climate held in: drive.google.com/file/d/0B4r_7eooq1u2ZlIwZFcxQ2ZWaHc
    Why models fail the test to match the reality?. In my 2.5 it is shown that models are built to account for the wished effects of greenhouse gases; but IPCC explains these failures very well: read just beside my diagram 9. On another hand, linear statistics say that in order to have models capable of predicting decades of climate behavior we need to collect hundreds of years of accurate measurements (see 1.1.3).
    ECS has not been properly estimated despite almost 50 years of climatic research. In 2.2 I show many ways on how not to appropriately estimate this ECS. All those ways, instead of answering which is the actual ECS range, seem that have been built to answer: how can we justify an ECS range between 1.5 and 4.5.
    Curry is right: all warming cannot be explained as due to human causes. First of all because of ECS uncertainties (see 2.2), secondly due to that adjustable radiative forcing list (see 2.3).
    It is difficult to hold Emanuel statement (an increase in hurricane activity due to AGW will be detectable by 2050-2075) in any statistical approach. In Extreme Value Statistics there is a huge room for having many extremes and not to attribute them to AGW. And in linear statistics we will require hundreds of years of measurements.
    Other climatic issues: acidification at present is not a problem (see 2.4; but, just in case, I hope we could keep measuring oceanic variables); sea level rise (see 2.1.4) seems to be no problem (coastal cities would not have to build walls on their coasts) because ice melting is slow enough (see 2.1.3).
    The last and probably the most important issue is not about the global temperature measurement but about the global temperature uncertainty measurement (see 2.1.1 and 2.1.2). Mr. Christy told me that the statistical uncertainties in their global temperature measurements were correctly achieved; but I keep disagreeing (see 2.1.2 (iv) counterexample).

  20. Valerie Trouet, Associate Professor, University of Arizona:, refutes “warming for hundreds of years” with the Pages2K graph, which oddly shows just that. It clearly shows temperatures from 4500 to 800 at the same level as current temps. It shows the Little Ice Age from about 1600 to 1825/50 or so, then warming from there. It is a quibble to say that the rise from 1625 to 1775, followed by a dip to the coldest part of the LIA, then warming again to present, cannot be represented as warming for hundreds of years. Perhaps one would better say “warming for almost two hundred years”….to be more strictly correct — but Trouet, like many Consensus Champions, is quibbling rather than making a scientificly correct statement.

    • Well, 450 to 800……

    • “It clearly shows temperatures from 4500 to 800 at the same level as current temps.”
      No, the graph is in 30 year bins ending in 2000. So what it shows is that those years are comparable to the 1970-2000 average. But we’re currently more than half a degree above that.

      • Stokes ==> Yet another quibble…..the record of 450-800 is probably only accurate/precise on the order of plus or minus 2 degrees certainly more than 1 degree. Picking the “now” end of a time series, especially one of 30 year averages, is not valid, as you know well.

      • “Picking the “now” end of a time series, especially one of 30 year averages, is not valid”
        Well, you did it. But of course it’s valid; if not, then what part is? It’s true that the now end is not so well covered by proxies. But this is a silly misuse of uncertainty. “It was warmer in 450”. “The data says no”. “OK, but the data might be wrong”. You don’t have anything. What we know is that a rise in temperature is expected if air CO2 increases. It has increased, and so has the temperature – a lot. And where still pumping out CO2, and the uptrend shows no signs of diminishing.

    • “But we’re currently more than half a degree above that.”

      By currently are you referring to the last 30 year bin or a much shorter period? Wouldn’t want to mix apples and oranges.

    • “Valerie Trouet, Associate Professor, University of Arizona:, refutes “warming for hundreds of years” with the Pages2K graph,”
      Successfully. Here is the plot:

      It’s very clear there that there was no “warming for hundreds of years” before 1900, as the House was told. And it’s no good just saying Steve McI has complaints about Pages2K. If you’re making a statement to the House, you should have evidence, not just doubts about contrary evidence.

      • Stokes ==> The graph speaks for itself. The temps were the same in 450 as today. The LIA tanked at around 1600, started rising to about 1775, tok another 50 year dip, then rises from then.

        It is a silly quibble to thrash against the “warming for hundreds of years”. It has been warming, more or less continuously (with decades stalls) for “almost” 200 years, if one starts in 600/625, then hundreds of years is clearly straightforwardly true.

        And denying that the 450-800 period was as warm as 2000s is beyond silliness.

      • On that right-hand scale, today’s temperature would be ~0.6 C.

      • Nick

        And others have suggested that the warming began in the 1600s and 1700s. Complete with graphs. You should know there is no gold standard in any of this. Results from studies can infer just about anything. I just read one regarding the LIA and Antarctica. The author found no evidence of the MWP or the LIA. Suggesting they were not global events. But with delicious irony he also found no evidence of the current warming event either, to my great relief. So, I guess we can call the whole thing off.

  21. I think the best response is my recent article:
    School of Scepticism (http://scottishsceptic.co.uk/2017/04/15/school-of-scepticism/)

    We need to combat the groupthink that has developed in Universities as shown in the area of climate

    Sceptics from years outside Universities show great diversity of views – and encouraging older experienced people could restore the “genetic diversity” of ideas.

    Academics are likely to strongly resist any move and/or attempt to enforce conformity to the existing group-think and thereby nullifying any benefits

    Subject to a small number of constraints, there appears no legal way to stop such a venture and it could proceed without the consent of group-think academia.

    Such a venture could offer three levels of awards equivalent to “honour’s years”, masters and doctorate.

  22. If Salby, Humlum, Harde, and Hertzberg are right Our CO2 is not even controlling atmospheric content and the net AGW due to CO2 has to be small enough to make it indecipherable from the noise in the measurements. With CO2 following the integral of temperature (Salby) and temperature leading CO2 on short time scales (Humlum) I find the model based attribution statements of over 50% unconvincing. The IPCC position that all the increase in CO2 since the industrial age is from anthropogenic causes is not based on very convincing evidence. A very small variation in natural carbon sinks could completely mask the fossil fuel source.
    I think that attribution studies need,at a minimum, to seriously consider these claims .

    • “The IPCC position that all the increase in CO2 since the industrial age is from anthropogenic causes is not based on very convincing evidence.”
      Here (from here) is a plot of the actual mass of C in the air, vs the amount we have added.

      Not convincing?

      • More made up data – we don’t have accurate figures for early CO2 – so why do you show a false hockeystick graph?

      • “More made up data – we don’t have accurate figures for early CO2”
        We have ice core samples, actual gas, and dated to the year. Made up?

      • Not really. If you could plot natural emissions they would be about 30 times the fossil fuel emissions. It wouldn’t take a very big change in them to hide the human part and the resulting concentration tracks integral of temp and not human emissions. When emisions went up in 2000 concentration rate of change was unchanged. When emissions leveled out three years ago concentration rate of change did not change.

      • “If you could plot natural emissions they would be about 30 times the fossil fuel emissions.”
        That’s nonsense. “Natural emissions” can only really be volcanic, and that is tiny. There are natural annual movements of CO2 within the environment, but they do not create new CO2. Some is from respiration/decay, but that only returns CO2 to the air whence it came. And some is the seasonal exchange of CO2 with the sea as it warms and cools. As the above plot shows, none of this created any trend before 1850. The reason is that it is just the same CO2 moving around.

      • “That’s nonsense. “Natural emissions” can only really be volcanic, and that is tiny.”
        Can the plants that use CO2 in photosynthesis tell the difference between a molecule that was released from a warming ocean and one released by burning gas? Do you think the CO2 released by decaying plants is somehow intrinsically different from CO2 released from coal burning? The CO2 in the coal came from the atmosphere too. I don’t think you can just look at fossil fuel CO2. You need to consider all the well mixed CO2 in the atmosphere from all of its sources and sinks when you study the carbon cycle for this planet.

      • “Do you think the CO2 released by decaying plants is somehow intrinsically different from CO2 released from coal burning?”
        It’s not different. But burning makes more of it. There has basically been about 1500 Gt C bouncing around for millions of years, between air and biosphere, with some exchange with ocean. That’s why past CO2 ppm were so stable. Now we’ve dug up, burnt and added nearly 500Gt. That is why CO2 ppm went up post 1850.

    • > If Salby, Humlum, Harde, and Hertzberg are right […]

      That’s a big if.

      At least one part of this big if is Harde to believe.

  23. Most of this discussion has centered on the attribution question which I think is really a difficult question and relies on AOGCM’s that are probably largely incapable of saying much on the subject.

    The question of tropospheric warming particularly in the tropics is very interesting because it affects the basic assumptions in AOGCM’s and the lapse rate theory. Mann appears to have been wrong on the absence of a tropical hot spot implying higher ECS as Nic Lewis showed.

    Mosher I fear is quite wrong about Cristy’s graph. It’s generated a lot of “vetting” by Steve Mcintyre, Real Climate, and a lot of strong denial, a sure sign there is something important here. It appears to me that with small differences in baselining and averaging, both McIntyre and Schmidt have replicated Cristy’s graph.

    • “Mosher I fear is quite wrong about Cristy’s graph. It’s generated a lot of “vetting” by Steve Mcintyre, Real Climate, and a lot of strong denial, a sure sign there is something important here. It appears to me that with small differences in baselining and averaging, both McIntyre and Schmidt have replicated Cristy’s graph.”

      No. Christy has not produced.

      A) the code required to get the GCM data from the Original source
      Its NOT Trivial.
      B) He hasnt published the Data.
      C) he hasnt published the code to do the chart.

      Neither has Mcintyre ( he;s done C)
      Neither has Real Climate.

      Now read what I wrote carefully. The Original data Deposited to the Archive for GCM data… Not some secondary copy… not some copy passed to them by Christy… But the ACTUAL Code that downloads the actual data from the actual official archive.

      The minute any one of those three ( Christy, McIntyre, Gavin) Publishes that code… the code to get that data.. Then I’ll know they grabbed the correct data. Until then you are TRUSTING that they gt the right data and downloaded it properly.

  24. From the very recent Real Climate page on comparison of AOGCM’s to data, you will find the following trend chart.

    https://niclewis.files.wordpress.com/2016/03/briefing-note-on-climate-sensitivity-etc_nic-lewis_mar2016.pdf

    This is a more quantitative statement that essentially replicates Christy’s graphics but with more data sets.

  25. David Springer

    Might as well be a foreign language.

  26. You had mentioned in your written testimony using multiple narratives to address issues of plausible likelihood narratives in a venue of uncertainty. Instead you have used the Red Team and Blue Team approach which, in my opinion leads to the realm of winners and losers rather than the stories that may be close to an plausible explanation.

    Why did you choose the Red/Blue team approach?

  27. stevefitzpatrick

    Hi Judith,
    The different reactions to a policy issue with vast scientific uncertainty are mostly an indication of differences in priorities and politics. Conservatives value the wealth and wellbeing that fossile fuels have brought about much more than the potential future problems/costs from warming. Liberals and (even more!) greens are just the opposite. From the Charney report until now, it has always been primarily a disagreement about goals, values, and priorities. That kind of disagreement has no real resolution except at the ballot box, meaning the losers are not going to at all happy. The appoplexia among the climate alarmed, so evident since early November, will continue unabated for as long as their preferred policies are rejected (so for sure as long as Trump is in office). Honestly held beliefs about what makes moral public policy are not usually subject to compromise or revision.

    • Steve, I largely agree with your statement. The real problem here is that people generally care a lot more about the next 10 years than what will happen 100 years from now. That’s just human nature. Thus, the alarm has to be justified by various fictions such as that extreme events are increasing now.

      • stevefitzpatrick

        Of course any fiction which can be used to advance the desired political outcome will be so used. Increased frequency/intensity of hurricanes, tournedos, rain storms and even snow storms, most all outright fictions or gross misrepresentations have already been used. It is a political disagreement about right and wrong, and so a zero-sum game. Which is why the disagreement is so bitter.

  28. From the article:

    Climate Scientists Spread Panic: ‘Ten Years’ to Save the Earth

    In their report, titled “Pathways for balancing CO2 emissions and sinks,” a team of eight scientists warns that “anthropogenic emissions need to peak within the next 10 years, to maintain realistic pathways to meeting the COP21 emissions and warming targets.”

    The statement was immediately repackaged by environmentalists to read: “Scientists say we have ten years to save the earth.”

    http://www.breitbart.com/big-government/2017/04/15/climate-scientists-spread-panic-ten-years-to-save-earth/

    • Dr. Duane Thresher, a climate scientist with a Ph.D. from Columbia University and NASA GISS, has stated bluntly that it is “mathematically impossible for climate models to predict climate.”

  29. Back in the day, as a young physics/chem teacher,(in the 1970’s) every science body in the world, every mainstream magazine as well as every science magazine had dire predictions of famine, pestilence, mass starvation and more due to the coming ice age. I saw graphs, I saw members of the entertainment field pleading for the world to recognize the coming disaster. I read of suggestions that carbon (soot) should be put on the polar ice cap to melt it. I have dozens upon dozens of articles from those days saved.
    I understand the homogenization process and I have looked at what Tom Karl has done. But that much!!!!! I tried to check where his work has been peer-reviewed, but I was not equal to the task. I do not understand how when a temperature has been once homogenized and the present warmed or more so the past cooled, that the same can happen again and again and again. It is interesting to look at temperature records at one period in time, and then look at them again at various periods of time later.

    Locally, in So MN, raw summer highs were between 10 and 15 deg F higher in the thirties than at present (five year periods) and mean summer temps were about 8 deg F higher.
    Some winters were a bit colder in the 30’s. I expect that all of this may have been due, in part, to then being the dust bowl years, the lakes were quite dry and the humidity lower. Many farmers tried to farm what a few years before was a lake, but in general the areas were too alkaline, They were then used as pastures.
    Nevertheless, when I am able to look at Raw US temps from all over, and from those who are willing to send me records, the raw temps indicate there was in fact cooling from after the 40’s, when I expect the industrial revolution accelerated, to at least the 70’s.
    Maybe someone can enlighten me. Anyone?

    • Darryl:

      You are correct that the temperature increases were related to the acceleration of the industrial revolution, up to the 1970’s.

      Sulfur Dioxide aerosol emissions have a very strong dimming effect, and they continuously increased up to about 1972, peaking in the troposphere at about 131 Megatonnes.

      Thereafter, Clean Air efforts reduced their amount (and cooling effect), causing the anomalous temperature increases observed since then.

    • > Back in the day, as a young physics/chem teacher,(in the 1970’s) every science body in the world, every mainstream magazine as well as every science magazine had dire predictions of famine, pestilence, mass starvation and more due to the coming ice age.

      Back in my days, the Ice Age myth did not extend to every science body, every mainstream magazing, and every science magazine.

      Retro-alarmism sounds cool.

  30. Good grief.

    Fires create heat, by burning stuff. They also create CO2. There tends to be a fairly strong correlation between the amount of heat and the quantity of CO2.

    Thermometers have recorded increases in the U.K. since the Industrial Revolution. Ditto in Japan, but later onset. Their Industrial Revolution occurred somewhat later.

    The atmosphere does not trap, store, or accumulate heat. It slightly slows the escape of heat from the surface to the cold depths of space.

    Even after your fire has gone out, the fireplace still radiates heat – even at night. So do roads, buildings, rocks and so on. Hence higher temperatures for a while, even when the original heat source vanishes.

    No need for any magical GHGs. Just Feynmanesque physics. Climatologists seemingly refuse to accept the normal definition of climate, but can’t actually define what it is they supposedly study. There doesn’t even seem to be a testable hypothesis of the mad idea that CO2 somehow generates additional heat to increase the temperature of thermometers.

    Just a bunch of ever vaguer and obfuscatory assertions which seem to boil down to “I say I’m a scientist, so you have to hear, believe, and obey!”

    What a load of rubbish! Gavin Schmidt a scientist? The man who thinks that 38% probability is support for “The hottest year EVAH”? His grip of statistics and probability seems tenuous, at best. If he’s the best example of a mathematician than the Warmists can produce, it’s surprising that the farce has endured so long.

    Oh well, H L Mencken wrote “No one ever went broke underestimating the intelligence of the American public.” And of course, American politicians tend to be members of the American public.

    Cheers.

  31. Judith,

    Mother nature can indeed cause substantial temperature trends on its own.

    Christy is correct that there is no evidence that we can predict the behavior climate on decadal to century time scales.

    I think you missed the most important issue: Can the planet rise much above its current temperature (i.e. unusually cold) while the present arrangement of the tectonic plates, ocean gateways and ocean currents exists?

    Put another way, is there a limit on how much the planet can warm until the tectonic plates realign so as to redirect ocean currents to move more heat from the tropics to the poles?

    Scotese (2016) – Figure 15

    Scotese (2016) https://www.researchgate.net/publication/275277369_Some_Thoughts_on_Global_Climate_Change_The_Transition_for_Icehouse_to_Hothouse_Conditions

    Points to note: Earth’s GMST is rarely this cold. Last time was 300 Ma ago. Rarely ice at the poles. Average surface temperature was 7C warmer than now for the past 650 Ma (and life thrived during most of this time).

    When the planet is warmer the temperature of the tropics is little changed. Warming at mid and high latitudes in beneficial, while little change in the tropics. What’s the evidence for the perceived threat?

    Eric J. Barron, Climate Variations in Earth History – Figure 9

    Source: https://www.ucar.edu/communications/gcip/m10histclimvar/m10overview.html

    • I should have pointed out in the Barron Figure 9 the coldest Cretaceous curve shows the average annual temperature of the poles is above freezing and the tropics are little warmer than now (currently about 26C)

  32. Reblogged this on Tallbloke's Talkshop and commented:
    The more open discussion of actual climate issues, the better for everyone.

  33. Andrea Dutton, Assistant Professor, University of Florida: quotes Michael Mann.
    This was the most disappointing of the responses from the Red Team
    He said
    “We have widespread measurements now from satellites, direct measurements of the total ice mass contained in the ice sheet, and there is no question that the 2 main potential contributors to global sea level rise, the Greenland ice sheet and the west Antarctic Ice sheet are losing ice..”
    The fact that the Antarctic ice shelf as a whole has increased considerably in the last decades and the total ice gain [GRACE] exceeds the ice lost from both small parts of Antarctica and from Greenland were allowed to go begging.

    • angech,

      The fact that the Antarctic ice shelf as a whole has increased considerably in the last decades and the total ice gain [GRACE] exceeds the ice lost from both small parts of Antarctica

      Not everyone agrees. In fact

      The Zwally 2015 conclusion is clearly an outlier among recent studies of Antarctic mass balance.

      I also don’t know where you’re getting your claim for Greenland from as – as far as I’m aware – it is pretty well accepted that Greenland is losing ice mass.

      • ATTP
        “Not everyone agrees. In fact The Zwally 2015 conclusion is clearly an outlier among recent studies of Antarctic mass balance.”
        Saying this does not make it so ATTP.
        This study was by the blue team.Zwally was/is one of the good guys.
        It is the latest and most up to date hence the most accurate of the studies that we have to hand.
        You should not dismiss it as an outlier.
        It is a Blue team result.
        No Christy’s, no Curry’s just good, honest warmists pointing out that their previous calculations were wrong.You seem to be following Victors point that observations are wrong is the first response rather than the models may be wrong, his second step.
        Michael Mann’s complete omission of this fact in his answer said more for his honesty and truthfulness than anything else on that fateful day.
        At least I hope it will be a fateful day.

      • Saying this does not make it so ATTP.

        Depends what you mean. It seems that Zwally is indeed an outlier. Being an outlier doesn’t mean that it’s wrong. Claiming it as a fact though would seem rather strong, given this.

      • Zwally is close to the REVISED GRACE estimate for Antarctica. The estimate depends critically on GIA correction. The 2011 loss estimate was based on a GIA model. Actual differential GPS observational estimates became available in 2013. Plugging them in shows slight or essentially no loss, while Zwally’s 2015 analysis based on IceSat shows a slight gain. The earlier Gia model was way off. Mcintyre did a long post on the Grace revision and Zwally a ways back. Well worth a read or reread.

      • Zwally’s number also makes the sea-level rise rate hard to account for. He needs to find lots of melting glaciers elsewhere to compensate for what is not lost by Antarctica. His estimate in 2005 was that Greenland contributes to a small loss in sea-level while Antarctica gives a small gain netting 0.05 mm/yr. These fall far short of what is needed to account for sea-level rise.

      • Spatial and temporal Antarctic Ice Sheet mass trends, glacio-isostatic adjustment, and surface processes from a joint inversion of satellite altimeter, gravity, and GPS data

        Their comment on Zwally 15:

        A recent study using ICESat measurements estimates a net mass gain of 82 ± 25 Gt yr−1 between October 2003 and October 2008 [Zwally et al., 2015]. This estimate strongly contrasts with previous mass balance estimates and in particular with our solution. For a similar period, we obtain a mass anomaly of −31 ± 22 Gt yr−1. The dominant process driving their positive mass balance is the dynamic thickening of EAIS (136 ± 50 Gt yr−1). Our estimate of the ice dynamics component in this region is an order of magnitude smaller that their estimates (12 ± 10 Gt yr−1 ). …

  34. Victor Venema, Scientist, University of Bonn, Germany:
    “Climate models inform us about long-term warming and have not been developed for short-term predictions, which are strongly influenced by fluctuations from, for example, El Niño. The timing of El Nino is not predictable more than a year in advance.
    The beauty of climate models is that they have an El Nino effect [and La Nina] built into them which Victor knows but chooses to ignore so that he can amplify his grievance.
    The basic effect of this is that over 30 plus years the effect of both even out and the models should/could approach the natural observations they are trying to predict. He knows this.
    The models don’t succeed.
    Instead of acknowledging this blemish on the face of climate science he doubles down saying,
    “The uncertainty of climate models results for short-term prediction is expected to be about twice the model spread of the CMIP models.”
    Is just shorthand for saying that natural variability occurs in large doses in small time periods.
    This completely negates his following comment that
    “John Christy provides no evidence that the discrepancy is due to the models and not due to errors in his dataset”.
    Perhaps John should have asked Victor to give this evidence “The uncertainty of climate models results for short-term prediction is expected to be about twice the model spread” in support of the fact that models are prone to discrepancy. Thanks Victor.

  35. Gavin Schmidt, Director, NASA Goddard Institute for Space Studies:
    There is indeed overwhelming evidence for warming in the last century. For the more recent period (1950 onwards) the claims are even stronger—that effectively all the warming is caused by human activity with only a ~10% uncertainty due to internal variability. One can always find something to disagree with in such a statement,
    Such as V Venema and G Schmidt.
    “—the CMIP5 simulations did not have sufficient volcanoes, and did not predict the decrease in solar activity over the last decade or so (Schmidt et al, 2014*).”
    Did he really say that?

  36. Gavin Schmidt, Director, NASA Goddard Institute for Space Studies:
    “that effectively all the warming is caused by human activity with only a ~10% uncertainty due to internal variability.”
    Timothy Osborn, Professor, University of East Anglia,
    “the IPCC’s assessment range extends beyond 99 percent, because natural influences may have offset some of the warming from human activity. making a broader, more conservative range to account for those that can’t be quantified.”
    By extending the range to 110% this effectively makes natural variation worth 20%. Think about it.

  37. By extending the range to 110% this effectively makes natural variation worth 20%. Think about it.

    Not necessarily. It could be 10% either way (i.e., contributed 10% of the warming, or produced a cooling effect that offset 10% of the anthropogenic warming). Of course, the actual “extremely likely” range for anthropogenic warming is something like from 50% to 160%, so the natural contribution could be quite large (maybe even 50%) but this is seen as rather unlikely.

  38. ATTP
    “Of course, the actual “extremely likely” range for anthropogenic warming is something like from 50% to 160%, so the natural contribution could be quite large (maybe even 50%) but this is seen as rather unlikely.”‘
    Thank you for expressing an opinion on the range.
    If we wish to acknowledge 110% as human contribution then the AW range should be 60% to 160%.
    AW of up to 50% unlikely is also rather large though within the ranges
    This figure seems very imprecise to me and not something I thought most warmists would agree with.
    It must come from
    “Timothy Osborn, Professor, University of East Anglia, and Director of Research, Climatic Research Unit:
    Judith Curry’s interpretation of the IPCC’s assessment as meaning a range from 51 to 99 percent is incorrect. First, the range extends beyond 99 percent, because natural influences may have offset some of the warming from human activity. Second, because it suggests a uniform likelihood within that interval whereas the likelihood that the real contribution is near the edges of the range (i.e., as low as 51 percent of the observed warming or as much as one and a half times the observed warming).”
    You and Judith have more in common than I thought.

    • angech,

      If we wish to acknowledge 110% as human contribution then the AW range should be 60% to 160%.

      No, the observed warming is 100%. If the human contribution is 110%, then something else (nature) has produced a 10% cooling effect.

      You and Judith have more in common than I thought.

      Given that you appear to have completely misunderstood what I’ve said, maybe you should refrain from telling me who I have something in common with?

      • ? The 110% estimate is the center of a probability distribution that has a confidence range from ~60% to ~160% which excludes the probability of it being less than 51 percent.

      • Apologies , I have completely misunderstood. I should have realized that any appearance of common ground would mean I had misunderstood and I did not.

      • captdallas2 0.8 +/- 0.3 | April 16, 2017 at 6:45 am |
        “? The 110% estimate is the center of a probability distribution that has a confidence range from ~60% to ~160% which excludes the probability of it being less than 51 percent.”
        “Timothy Osborn, gives a graph centering AGW on 110% in ” Attribution of Surface temperature trends since 1950.”
        ATTP gives an eyeball range of 50% to 160% which I agree with. As it is a bell-shaped curve centered on 110% with presumable equal causes on either side I merely questioned that the distribution ranges should be 60% to 160%.
        This may be wrong, the IPCC may have formulated a non bell shaped curve.
        Not sure where your quote “which excludes the probability of it being less than 51 percent.” comes from. Does the 51% refer to the IPCC contention that AGW is more than likely the dominant cause which if one considers only two causes means it must be greater than 50%. The actual graph actually allows surface temps to be due 100% to natural variability, just that the chance of this being true is vanishingly small.

      • angech,

        As it is a bell-shaped curve centered on 110% with presumable equal causes on either side I merely questioned that the distribution ranges should be 60% to 160%.
        This may be wrong, the IPCC may have formulated a non bell shaped curve.

        I think it is a normal distribution, so my 50% to 160% with a best estimate of 110% was eye-balled, but (pedantically) is wrong; it might be 55% to 165%, with a best estimate of 110%. Don’t think this makes much difference to the overall point that it is extremely unlikely to be less than 50%.

        Not sure where your quote “which excludes the probability of it being less than 51 percent.” comes from.

        The distribution is the anthropogenic contribution and although less than 50% is possible, it is extremely unlikely (only a very small chance).

        The actual graph actually allows surface temps to be due 100% to natural variability, just that the chance of this being true is vanishingly small.

        Yes, it is possible, but the probability of this being the case is vanishingly small.

      • Eyeballing the distribution, 60% and 160% are approximately equal probability in 0.01% range. 50% and 170% would be ridiculously small probabilities. So your 60% to 160% would be a reasonable estimate range. ATTP’s ~50% to 160% would imply the range is skewed to the lower side which isn’t correct. He probably needs his eye re-calibrated.

      • Eyeballing the distribution, 60% and 160% are approximately equal probability in 0.01% range. 50% and 170% would be ridiculously small probabilities. So your 60% to 160% would be a reasonable estimate range. ATTP’s ~50% to 160% would imply the range is skewed to the lower side which isn’t correct.

        Indeed, as I’ve alread acknowledged. I keep forgetting that I’m dealing with nit-picking pedants.

      • “Indeed, as I’ve alread acknowledged. I keep forgetting that I’m dealing with nit-picking pedants.”

        Isn’t that the sport of scientific kings?

      • The bell curve derives from this IPCC Figure. It helps to show where 110% comes in being the size of the anthopogenic total of GHGs and aerosols labeled OA for other anthropogenic forcings because it may also include landcover changes.

      • and Then There’s Physics: I keep forgetting that I’m dealing with nit-picking pedants.

        You need to write more carefully.

      • > You need to write more carefully.

        Writing in a contrarian-proof manner is hard. I rather like this way of writing things off:

        The final total, as I see it: One error of fact (the IPCC’s best estimate for anthropogenic contribution is ~100%, not <95%), one error of logic (double-counting evidence that the IPCC has already included), and one case of the answer being different because the question is different (1951-2010 vs. 1975-2013).

        http://climatechangenationalforum.org/your-logic-escapes-me-by-john-nielsen-gammon/

  39. Judith: FWIW, one can estimate man’s contribution to global warming without using climate models. Pick your favorite estimate or reasonable lower bound for TCR and for anthropogenic forcing during the period of interest. If you use this approach, you will probably find it hard to believe that the anthropogenic contribution could be less than 50%.

    That doesn’t mean that unforced variability couldn’t have accounted for more than 50% of warming. Unforced or naturally-forced changes near 1 K have occurred. However, based on the lowest likely value for TCR and forcing, we estimate that the anthropogenic fraction must(?) have been more than 50% in this case.

    • This has always been a futile argument because “anthropogenic” forcing starts at some undetermined point in time. A recent Pages2K paper implies “anthropogenic” forcing started warming the tropical oceans circa 1820 and goes on to surmise that the warming effect on the southern hemisphere oceans will lag by 60 to 100 years or so.

      Since there has always been some volcanic activity, “normal” volcanic activity and related atmospheric aerosols along with “normal” wild fire activity by natural and/or pre-industrial man would need to be determined before you could determine post industrial man’s influence.

      What your are supposed to do is deny that it matters since there is more than enough evidence to inspire your favorite policy direction :)

    • This is a good point, but the TCR values from both models and historical observations don’t account for multi-decadal variability (Nic Lewis made a token attempt to account for this by selecting two periods with same AMO index).

      • David Wojick

        Indeed, TCR is an abstraction, not a prediction. It need not occur at all. Climate could cool when CO2 doubles. Abstract TCR does not rule this out.

      • Steven Mosher

        TCR is not supposed to account for that. It’s a model metric based on a 70 year time frame.

        Decade variability is canceled out in that time frame.
        In observations there is no decadal variability worth discussing. 1/10ths here and there. In fact there is only decadAl variability to discuss IF you first accept the records.

        If you reject the records or undermine them there is no natural variability to even discuss.

      • Actually, the issue is multi-decadal and longer time scale internal variability

      • Judith: Thank you for your reply. I glad you recognize that we can get at the anthropogenic component of warming through TCR. We know man must be causing SOME warming, but – given the record of unforced and naturally-forced variability in climate – man doesn’t have to be responsible for the majority of warming since 1950. Your personal expectations for minimum TCR could provide a floor for your personal estimate of the anthropogenic contribution to warming – a floor that doesn’t depend on climate models.

        So what is the lowest value of TCR you personally belief is likely given the evidence?

        a) Did you co-author with Nick Lewis assuming that more than half of observed warming could be due to unforced variability and discuss that caveat? L&C2014 covers periods of 65 and 130 years. Otto2013 covers one 40-year period and four 10-year periods (when aerosol forcing didn’t change). All of these period provide a central estimate for TCR of about 1.4 K. In other words, unforced variability – which certainly could distort the results – doesn’t seem to have a big impact on TCR. If you believe that the anthropogenic contribution to warming is less than 50%, doesn’t that imply that the unforced contribution to warming must have been fairly constant and large over the past 130 years AND that TCR is below 1 K? (Without considering these studies in combination, I agree with your argument that the unforced component of warming since 1950 is unknown.)

        b) TCR is linked to ECS through ocean heat uptake. (TCR/ECS = 1 – dQ/dF or about 0.7) So your minimum estimate for TCR could be derived from your minimum estimate for ECS and its reciprocal, the climate feedback parameter. Every year, we observe a climate feedback parameter associated with the 3.5 K seasonal cycle – which is an easily measured 8 W/m2 increase in outgoing LWR that has been observed from space many times. LWR feedback is very linear, -2.2 W/m2/K, from both clear and cloudy skies. LWR feedback is equivalent to an ECS of 1.7 K. (Feedback in the SWR channel does not vary linearly with temperature.) To that, we need to add surface albedo feedback (which must be positive, but is only about 0.3 W/m2/K in most models) and SWR cloud feedback – the big unknown. Do you think SWR feedback can be NEGATIVE enough to produce a TCR below 1 K?

        Manabe (2013) http://www.pnas.org/content/110/19/7568.short

        To be fair, the seasonal 8 W/m2 change in outgoing LWR could be partially due to hemispheric differences. The average location in the NH warms about 9 K and the average location in the SH cools about 3 K, to produce a seasonal increase in GMST of 3.5 K. Seasonal warming is not an ideal model for global warming (particularly in the SWR channel). Climate models do a good job of reproducing seasonal changes in LWR from clear skies (WV+LR feedback), so they made be getting water vapor right.

        When I work through this line of reasoning, I find it difficult to believe ECS and TCR can be much less than the central estimates produced by energy balance models. A belief that the anthropogenic contribution to warming is less than 50% of observed warming doesn’t make much sense to me. The average AOGCM produces estimates of ECS and TCR that are much higher than energy balance models. What AOGCMs call “50% of warming” is not the same as what energy balance models would call “50% of warming”. I see no problem with arguing that climate models (that are running hot) assign too much warming to man. I see a big problem with arguing that less than 50% of the warming used in energy balance models is anthropogenically-forced.

        This is why I think it doesn’t make sense to argue that less than 50% of warming could be due to humans. If ABOUT 50% of warming (according to climate models that are running hot) is due to man, the IPCC’s projections are far too pessimistic. The key issue is TCR and ECS, not attribution.

      • IF all the warming is forced, then I agree that human contribution is more than half. If most of the warming is from internal variability, then human impact is less than half. We are starting to get a handle on the contribution from multi-decadal variability (and it is substantial). We do not yet account in any way for longer term internal variability. We are also not including solar indirect effects in the attribution analyses.

      • franktoo, Thanks for the details. If half the recent warming is due to natural causes, then Lewis and Curry probably overestimates TCR. I think most however would say it is unlikely to be less than 1.0 in any case so there is not much wiggle room to go much lower.

        It is clear as you say that attribution is a secondary issue and better understanding of TCR is more important.

      • franktoo,

        Thank you for your reply to Judith. I look forward to Judith’s reply to you last comment. This is an interesting and informative discussion (for me).

      • Judith,

        Thank you for your reply to franktoo at 10:18 am. This discussion is interesting.

        As an aside from the discussion of the multi-decadal variability, there are also other time scales of climate variability up to tens and hundreds of millions of years. It seems the longest (tens and hundreds of Ma) are actually the most significant climate control knob. The locations of the tectonic plates, ocean gateways and ocean currents seem to be the most significant influences on the climate over the long term, not CO2. I haven’t yet seen a persuasive argument that GMST can increase much while the continents are in the present locations. It seems we are locked in a coldhouse phase for many tens of millions of years. Therefore, CO2 and warming are not a threat – but abrupt cooling is!

        Scotese (2016) Some Thoughts on Global Climate Change: The Transition from Icehouse to Hothouse Conditions https://www.researchgate.net/publication/275277369_Some_Thoughts_on_Global_Climate_Change_The_Transition_for_Icehouse_to_Hothouse_Conditions

        E J Barron Plate Tectonics and Climate — Episodes of Extensive Glaciation and Extreme Global Warmth https://www.ucar.edu/communications/gcip/m10histclimvar/m10pdfc1.pdf

      • The role of external forcing and internal variability in regulating global mean surface temperatures on decadal timescales

        Abstract

        Global mean surface temperature (GMST) shows considerable decadal variations superimposed on a pronounced warming trend, with rapid warming during 1920–1945 and 1977–2000 and warming hiatuses during 1946–1976 and 2001–2013. The prevailing view is that internally generated variations associated with the Interdecadal Pacific Oscillation (IPO) dominate decadal variations in GMST, while external forcing from greenhouse gases and anthropogenic aerosols dominate the long-term trend in GMST over the last hundred years. Here we show evidence from observations and climate models that external forcing largely governs decadal GMST variations in the historical record with internally generated variations playing a secondary role, except during those periods of IPO extremes. In particular, the warming hiatus during 1946–1976 started from a negative IPO but was later dominated by the eruption of Mount Agung in 1963, while the subsequent accelerated warming during 1977–2000 was due primarily to increased greenhouse gas forcing. The most recent warming hiatus apparent in observations occurred largely through cooling from a negative IPO extreme that overwhelmed the warming from external forcing. An important implication of this work is that when the phase of the IPO turns positive, as it did in 2014, the combination of external forcing and internal variability should lead to accelerated global warming. This accelerated warming appears to be underway, with record high GMST in 2014, 2015, and 2016.

      • Judith wrote: “We are starting to get a handle on the contribution from multi-decadal variability (and it is substantial).”

        As best I can tell, the consistency of estimates for TCR over various periods suggests that unforced variability hasn’t been a major player in the last century.

        Almost by definition, unforced variability is the difference between observation and forced variability, both anthropogenically- and naturally-forced variability. As best I can tell, one needs some theory or model to convert forcing into temperature change. So any argument based on unforced variability may be inherently circular.

        Which bring me back to the same question: What is your personal estimate for the lowest possible value for TCR/ECS and how do you rationalize it? (Above I summarized some observations of large seasonal changes in OLR associated with seasonal warming that might put a lower limit on climate sensitivity.

      • franktoo | April 16, 2017 This is where you went wrong.
        “We know man must be causing SOME warming”
        You either just believe this is so,
        or you can prove it.
        Proof requires a little bit more than C02 increase is linked to temperature rise and man has increased CO2.
        Proof must be theoretical and observational and take in every factor.
        For instance aerosol production produces a temperature drop.
        If, [If] the aerosol production associated with CO2 is high enough it could counteract the CO2 and even produce a temperature drop.
        So you are wrong in your initial premise.
        We surmise, we do not know.
        Not to mention cloud albedo effect, more moisture in the air , less radiation getting through to have a greenhouse effect with.
        The true level of ECS is not known. Hence the lower it might be through albedo the more chance the aerosols have of causing a cooling effect.
        Now I agree it is unlikely but you have no proof of the actual holistic *atmospheric effect of extra CO2, and no idea of the actual effect of aerosols.
        Reading Dirk Gently at the moment*.

      • Angech wrote: “This is where you went wrong. “We know man must be causing SOME warming”. You either just believe this is so, or you can prove it. Proof requires a little bit more than C02 increase is linked to temperature rise and man has increased CO2. Proof must be theoretical and observational and take in every factor.”

        When there is a radiative imbalance at the TOA from a forcing, the law of conservation of energy demands that there must be warming somewhere below the TOA. (That law doesn’t say where the heat will accumulate, but our atmosphere is fairly efficiently mixed vertically, longitudinally and latitudinally. So the logical assumption is the some of that warming will be experienced at the surface.)

        Proof that higher GHGs will reduce radiative cooling to space and therefore create a radiative imbalance begins with measurement of the absorption cross-sections of GHGs in the laboratory under conditions relevant to our atmosphere. Then we model the atmosphere as a series of layers thin enough to have an effectively uniform temperature, pressure, and composition. That data comes for observations of our atmosphere. Then we use the laboratory data to calculate how the intensity of upward radiation will be changed by an increase in GHGs due to increased absorption by and emission from GHGs. (More sophisticated calculations include clouds.) We have also tested the ability of those calculations to predict the radiative fluxes that have been measured in our atmosphere.

        Unlike forcing (measured in W/m2), feedbacks are changes in radiative imbalance that are mediated via a change in temperature (and measured in W/m2/K). So a forcing must produce some temperature change before it can be modified by a feedback. So we never have the situation where forcing produces 1 K of warming and feedback produces 1 K of cooling and completely negates all of the forcing.

      • franktoo | April 17, 2017 at 5:40 am |
        ” So a forcing must produce some temperature change before it can be modified by a feedback. So we never have the situation where forcing produces 1 K of warming and feedback produces 1 K of cooling and completely negates all of the forcing.”
        True. In Physics but not Sociology. Shudder. Pure Lucia.
        “When there is a radiative imbalance at the TOA from a forcing, the law of conservation of energy demands that there must be warming somewhere below the TOA.”
        Halftrue. Pedantic* see ATTP above.
        Correct is when there is positive* radiation imbalance as in the case [here] of an increasing greenhouse gas holding more energy in transit then there must be warming. Radiative imbalances can be positive or negative depending on circumstances causing cooling or warming.

        “We know man must be causing SOME warming”
        False.
        Proof must be theoretical and take in every factor.
        For instance aerosol production produces a temperature drop.
        If the human aerosol production associated with CO2 production is high enough it could produce a temperature drop greater than that of the CO2 rise.
        Would you care to deny that aerosol levels can cause temperature drops?
        And were blamed for doing so during the pause?
        To such an extent that they even overcame the claimed CO2 effect?
        A little, false, knowledge is a dangerous thing.

      • Steve Mosher wrote: “TCR is not supposed to account for that. It’s a model metric based on a 70 year time frame.”

        Although TCR was first defined for 1% increase per year model runs, TCR is relevant to both models and observations. Mathematically, ECS is the reciprocal of the climate feedback parameter that relates a change in Ts to a change in radiative imbalance at the TOA (an increase in OLR or in reflected SWR). TCR/ECS is 1 – dQ/dF, where dQ is the heat flux into the ocean when the forcing change is dF. So the concept of a transient response can be meaningful even when CO2 is not increasing 1% per year.

        Suppose the climate feedback parameter is 1 W/m2/K (ECS 3.7 K). When CO2 has doubled in 70 years (dF = 3.7 W/m2) and dT is 2 K, then there should be 1.7 W/m2 of heat flowing into the ocean at the end of 70 years. If CO2 doubles in 10 years and the thermal inertia of the ocean has limited warming (dT) to 1 K (the “10-year transient response”), then we should observe 2.7 W/m2 of heat flowing into the ocean. If doubling takes 500 years, the system will be near equilibrium and warming (dT) might be 3.5 K (the “500-year transient response”) and there would be only 0.2 W/m2 flowing into the ocean. And if the deep ocean has reached equilibrium with the surface and no heat is flowing into the deep ocean, then the transient and equilibrium responses are the same. Observed warming is less than 1% per year, but the effective TCR measured from observed warming isn’t going to be very different from the 70-year TCR.

      • “So a forcing must produce some temperature change before it can be modified by a feedback.”

        Feedback is a response to any temperature rise but “sensitivity” is a function of only CO2 by definition. A “feedback” to non-CO2 related warming/cooling would have to result in offsetting response or the system wouldn’t exist. To think that there has to be a warming response to any external forcing appears to be opposed to nature.

        It also means that non-CO2 related “feedbacks”, anthropogenic or not, need to be carefully accounted for since there is supposedly an amplification. For example a 0.9 Wm-2 “forcing” by black carbon would have some Wm-2/K feedback which could completely overwhelm a 1.5 Wm-2 CO2 “forcing.” And if there happens to be a 0.5K “natural” warming component that in reality is just an unaccounted for variable, there could be a 1.5+ wm-2 forcing/feedback assigned to the wrong account.

      • Angech wrote: “For instance aerosol production produces a temperature drop. If the human aerosol production associated with CO2 production is high enough it could produce a temperature drop greater than that of the CO2 rise. Would you care to deny that aerosol levels can cause temperature drops? And were blamed for doing so during the pause?”

        Frank replies: An unstated assumption that is being made is that radiative forcings from different phenomena are additive. A doubling of CO2 reduces radiative cooling to space (TOA or tropopause OLR) by 3.7 W/m2. Anthropogenic tropospheric aerosols reflect 0.8 W/m2 of incoming SWR. The surface reflects 0.3 W/m2 of SWR because we cut down forests. By definition, things that warm the earth have a positive sign. +3.7 + (-0.8) + (-0.3) = +2.6 W/m2 of net anthropogenic forcing. If* these phenomena don’t interact directly with each other (via feedbacks that are not mediated by warming measured at the surface), then additivity makes sense. The forcing from aGHGs alone is always positive. Total anthropogenic forcing could be positive or negative. Locally the net effect of burning high-sulfur coal could be a net negative forcing. This should produce less warming in the NH than the SH. I believe that the absence of a large hemispheric difference in warming is the main reason that estimates for aerosol forcing have become less negative.

        * One direct interaction that is not mediated by warming is the aerosol indirect effect on clouds. More aerosols should temporarily produce smaller droplets, making clouds more reflective. CFC’s destroy ozone. These interactions are converted to separate forcings that can be added. Dave Evans at Joan Nova argues (un-persuasively IMO) for more direct interactions between forcings.

        * In 4XCO2 experiments, AOGCMs detect large effects on clouds that develop before there has been significant surface warming. This happens because the heat capacity of the upper atmosphere is low and it warms up faster than the surface of land and especially before the mixed layer of the ocean. However, these 4XCO2 experiments are extremely unrealistic and put the world into a transient state (very low lapse rate in the atmosphere and very high lapse rate in the ocean) that it will never experience during AGW. The assumption is that heat from forcing is eventually distributed into all compartments whether that heat is delivered slowly from gradual forcing or quickly from instantaneous forcing. I find this assumption dubious for the ocean.

        New technology for measuring volcanic aerosols came online around 2000 and measured the “forcing” from volcanic aerosols from a series of medium-sized volcanos that had been undetectable in the past. The Pause was PARTIALLY blamed on these aerosols. However, 1) we had previously been unable to detect such low levels of aerosols and 2) a forcing is a CHANGE (from pre-industrial). Therefore no forcing had been clearly demonstrated. Since many other explanations for the Pause were sought, I suspect many weren’t persuaded by this forcing – which was at the edge of detectability, but became important because it persisted for a long time.

      • Capt Dallas wrote: “Feedback is a response to any temperature rise but “sensitivity” is a function of only CO2 by definition. A “feedback” to non-CO2 related warming/cooling would have to result in offsetting response or the system wouldn’t exist. To think that there has to be a warming response to any external forcing appears to be opposed to nature.”

        IMO the Captain doesn’t clearly understand the difference between forcing and feedback. Feedback is a response to warming, not to any forcing agent. The best way to understand this is to consider UNFORCED warming. El Nino is partially caused by a slowing of upwelling of cold deep water near South American and downwelling of warm water in the Western Pacific Warm Pool. This alone is an example of unforced variability. It is not caused by a radiative imbalance at the TOA, but by a redistribution of heat within the ocean and atmosphere, caused by a chaotic fluctuation in ocean currents and the surface winds that drive them. Let’s imagine that such unforced variability persisted until GMST rose 1 K (or more).

        (In the Atlantic, a slowing down of the MOC might have produced an LIA of about -1 K.)

        Changes are initially localized near the change in ocean currents, but eventually spread unevenly around the world. What happens to the planet’s radiative imbalance at the TOA in response such UNFORCED changes in GMST? a) Changes in temperature produce a roughly -3.5 W/m2 increase in emission of thermal infrared radiation to space – Planck response (negative because it is a heat loss). Water vapor and lapse rate and clouds and surface albedo (mostly seasonal snow cover) also respond. The overall change in radiation at the TOA – the climate feedback parameter – is an X? W/m2 increase in TOA OLR plus reflected SWR per degree of surface warming or X W/m2/K. To a first approximation, it makes NO DIFFERENCE whether the change in surface temperature is unforced or forced by some anthropogenic change. However, it is much easier to understand feedback when you remove forcing from the scenario and simply imagine feedbacks in response to unforced warming or cooling.

        Feedbacks can only modify forcing after forcing has cause at least some temperature change. Feedbacks can never completely negate a forcing because there will be no temperature change to drive the “negating” feedbacks. Notice that feedbacks in response to unforced warming do not negate anything.

      • franktoo, “Feedbacks can never completely negate a forcing because there will be no temperature change to drive the “negating” feedbacks.”

        When you have coupled systems with different time constants, feedback can produce oscillations which can more than offset the forcing. The climate change use of forcing and feedback is pretty simplistic by necessity.

        The multi-decadal pseudocyclic oscillations in most long term temperature reconstructions resemble weakly damped oscillations with a period of 60 to 90 years and a settling time of roughly 500 years. When feedbacks cannot overshoot forcing, you would not have oscillations, the system would be ideally damped.

      • CaptDallas wrote: “When you have coupled systems with different time constants, feedback can produce oscillations which can more than offset the forcing. The climate change use of forcing and feedback is pretty simplistic by necessity.”

        You are partly correct – in theory. What feedbacks have different time constants? Radiative cooling (Planck feedback) responds instantly to temperature change. The average water vapor molecule remains in the atmosphere for 9 days between evaporation and precipitation. Clouds are constantly being created, evaporating and precipitating. The lapse rate is constantly changing. Trade winds moving tropical air 1000 kilometers per day and the jet stream moves an order of magnitude faster. The majority of feedbacks are fast – in equilibrium with the current temperature or possibly lagged by a month – and we average temperature data monthly. So I suspect we don’t observe any oscillations in monthly temperature data or feedbacks because most systems reach a steady state with local temperature too quickly.

        Feedbacks involving surface albedo – ice caps but not seasonal snow cover – can occur on a slower timescale. They might be subject to oscillations as you suggest. (The Stadium Wave in the Arctic? D-O Events in Greenland during the last ice age?)

        The high heat capacity of the ocean means that the ocean responds on much slower time scales than the atmosphere. However, classical feedbacks occur in the atmosphere, not the ocean.

      • “The forcing from aGHGs alone is always positive.”
        True for all additions of GHG, anthropogenic or not, considered in isolation.
        Total anthropogenic forcing could be positive or negative.
        Thanks.
        The atmosphere is not in a glass jar and the other effects of CO2 and temperature increase mean that the ECS could be a lot less than expected if negative feedbacks outweigh positive feedbacks. Something very likely given the billions of years without runaway temps despite very high past levels of CO2.
        The fact that aerosols will settle in time makes it less likely that such an effect could match a CO2 forcing that incremented over time hence your original premise has a lot of promise on its side, just that none of us have seen it happen yet.

        .

      • “Feedbacks involving surface albedo – ice caps but not seasonal snow cover – can occur on a slower timescale. They might be subject to oscillations as you suggest. (The Stadium Wave in the Arctic? D-O Events in Greenland during the last ice age?)

        The high heat capacity of the ocean means that the ocean responds on much slower time scales than the atmosphere. However, classical feedbacks occur in the atmosphere, not the ocean.”

        Yep, the oceans would be part of the system and the part responsible for multi-decadal and longer oscillations or long term response. Paleo evidence just indicates that all longer term response results in weakly damped (quasi-conserved if you like) oscillations. So if you have a long term oscillation of +/- 1K in the oceans plus the latent component, you have significant “unforced” or lagged response to forcing, potentially greater than the combined atmospheric forcing related to CO2 and other anthropogenic factors.

        Now compare the actual energy associated with a 5 K change in Arctic winter with a 0.5K change in temperature of the tropical oceans with associate latent at 28C. Energy wise, the minor change in the tropical oceans completely overwhelms a 5K change from -60C to -55C, so you have thermodynamic apples and oranges with an idealized control theory that applies of a fraction of the total energy.

        Unfortunately, theory is supposed to apply to the complete system, not just the simplified parts.

    • I find it difficult to attach any meaning to the terms TCR or ECS – outside the assumption of a stable equilibrium or – at a stretch – a purely periodic climate system.

      Could it be that sensitivity is dynamic in the real world – as it is in this EBM?

      Ghil’s model shows that climate sensitivity (γ) is variable. It is the change in temperature (ΔT) divided by the change in the control variable (Δμ) – the tangent to the curve as shown above. Sensitivity increases moving down the upper curve to the left towards the bifurcation and becomes arbitrarily large at the instability.

      The problem in a chaotic climate then becomes not one of quantifying climate sensitivity in a smoothly evolving climate but of predicting the onset of abrupt climate shifts and their implications for climate and society. The problem of abrupt climate change on multi-decadal scales is of the most immediate significance. They do –
      however – add up to changes in climate means and variance over millennia.

      • Robert asked: “Could it be that sensitivity is dynamic in the real world – as it is in this EBM?”

        Sure, but your figure shows massive changes in temperature. For predicted AGW (say 4 K), climate sensitivity is approximately linear. The existence of ice ages suggests that climate may be more sensitive to perturbations that cool rather than perturbations that warm

      • After a relatively short simulation period the many thousands of plausible climate model solutions each solution is dominated by model dynamics rather than by simulations of fundamental processes. Predictions are a theoretical impossibility.

        “Sensitive dependence and structural instability are humbling twin properties for chaotic dynamical systems, indicating limits about which kinds of questions are theoretically answerable. They echo other famous limitations on scientist’s expectations, namely the undecidability of some propositions within axiomatic mathematical systems (Gödel’s theorem) and the uncomputability of some algorithms due to excessive size of the calculation.” http://www.pnas.org/content/104/21/8709.full

        Neither models or the real world are linear at any scale – from moments to millennia.

        https://watertechbyrie.com/2014/06/23/the-unstable-math-of-michael-ghils-climate-sensitivity/

        The EBM of Micheal Ghil is an illustrative example – here’s another even simpler one just for you.

      • Robert wrote: “Sensitive dependence and structural instability are humbling twin properties for chaotic dynamical systems, indicating limits about which kinds of questions are theoretically answerable.”

        The last ice age saw abrupt and large changes in climate in Greenland. Ice ages themselves represent massive and rapid changes in temperature with little precedent in the preceding 100 million years. It seems that our planet may be vulnerable to large changes in the cold direction from today. If you look at the last ten millennia of ice core data, global temperature and sea level appears reasonably stable. When considering what might happen in the next century, I place more weight on the modest unforced and natural variability of the past 10 millennia, than on the more unstable conditions of the last million years. You are free to make other choices.

        And I recognize that we have experienced catastrophic climate change in the last 10 millennia despite apparent stability in temperature – desertification of the Sahara. Was that a predictable event driven by orbital mechanics or a bifurcation?

        IMO, it makes sense to project the future assuming that climate behaves in a smooth manner (as in the past 10 millennia) and then qualify those projections with the uncertainties that concern you. If you worry about that first, you’ll never get anywhere. “The weather is unpredictable”! Weather was unpredictable, now we have useful info for about a week in the future, especially for big storms and hurricanes. And we have some vague information about the coming three months of weather, directed partly by ocean temperature anomalies. “Climate is unpredictable! Look at the Hiatus!” Today the hiatus is looking more like a decade-long blip on a half century record of anthropogenic warming albeit warming at the lowest end of the IPCC’s projections.

      • It makes no sense at all to assume a smooth evolution of climate on even decadal scales.

        The Sahel drying by the way – is associated with a shift from La Nina dominance to El Nino dominance that accompanied the mid-Holocene solar transition. There is a Holocene ENSO proxy in the link above.

    • franktoo, thanks for your succinct explanation linking increased GHGs to a radiative imbalance and then to an increased forcing at the Earth’s surface. I disagree with your calling it a proof, though. The weak links for me are the application of a model to predict with confidence the response of the atmosphere to increasing GHGs and your assumption that any additional warming will necessarily be experienced at the surface.

      In simple terms, GHG forcing is a result of absorption and emission of IR radiation in an atmosphere with a lapse rate. If absorption and emission in the atmosphere didn’t occur, there would be no forcing regardless of lapse rate. If the lapse rate were zero, there would be no forcing regardless of the extent of atmospheric absorption and emission.

      Adding GHGs to the atmosphere will change its thermodynamic characteristics. With additional CO2, intuitively I would guess that the lapse rate should reduce but I don’t think the lapse rate is understood well enough to confidently predict how it will respond to this change. How much it reduces will determine whether the surface experiences any warming.

      I may be old school, but if you wish to use the word ‘proof’ then I think you need an actual, measured observation.

      • With additional CO2, intuitively I would guess that the lapse rate should reduce but I don’t think the lapse rate is understood well enough to confidently predict how it will respond to this change.

        The GCMs indicate the “hot spot” of course, which is a dramatic decrease in lapse rate for sub-polar regions ( from ~60S to ~60N, with the greatest decrease in the tropics ). This hasn’t happened, at least for the satellite era to date, but it’s worth reiterating that this is not a radiative prediction, but a dynamic one. It seems to have failed so far because the models create too much precipitation along the ITCZ. But the ITCZ is a function of the “C” – the convergence from polar air masses from each hemisphere’s poles. The radiative features of the GCMs appear more or less correct, it’s the dynamic features that are suspect – but that’s what the GCMs were supposed to do, predict the dynamics! We knew all along that the dynamics were chaotic and unpredictable – so this is kinda like gambling behavior: Intelligent people know they can’t know the future, but still predict it through their wagers. Climate models can be no better.

      • A Global Mean Lapse Rate as a function of altitude is needed to determine whether the increasing CO2 levels are affecting the lapse rate. The data would need to be collected over a number of years (to compare with increasing CO2 levels) and the “GMLR” measurement would probably need to have an accuracy of 1% or less (to determine whether the surface temperature actually changes with radiative forcing).

      • Willb01 wrote: “The weak links for me are the application of a model to predict with confidence the response of the atmosphere to increasing GHGs and your assumption that any additional warming will necessarily be experienced at the surface”.

        These are sensible concerns. The clearest evidence that our calculations for radiative transfer give correct answers can be seen from studies of DLR. All of the radiation begins with emission by the atmosphere and then transmission through the atmosphere. If we can accurately reproduce the spectrum of DLR under different conditions, then we can have confidence in our calculations for OLR. (We have studied the spectrum of OLR from space also.) The general idea is that a radiosonde is sent overhead to measure temperature, humidity (and pressure?) at all altitudes immediately overhead and we calculate the expected flux of DLR from that information and compare it to observations. Such experiments are discussed at the link below using figures from an excellent textbook by Grant Petty “A First Course in Atmospheric Radiation”. The host of scienceofdoom.com rarely expresses any hints about his opinion about CAGW, his obsession is the correct physics of AGW. I recommend the website for physics or the textbook (only $40).

        https://scienceofdoom.com/2010/07/24/the-amazing-case-of-back-radiation-part-two/

        Does heat deposited somewhere under the TOA actually reach the surface? Almost certainly. Vertical motion in the atmosphere can be assessed by the turnover of water vapor in the atmosphere: The average water vapor molecule remains in the atmosphere for 9 days (calculated from total precipitation and total column water vapor). So air is traveling from the surface to the upper troposphere and back about once a week! Average trade winds at the surface are fast enough to circle the earth in about a month and the jet stream at the tropopause in a few days. Undulations in the jet stream mix latitudinally and so do the Hadley cells and the Ferrel cells. In the latter cases, both vertical and latitudinal transport are coupled. Roy Spenser claims it takes about a month for the heat from El Nino’s high STTs to reach the upper atmosphere. The atmosphere is fairly well mixed on a monthly time scale.

        The ocean is stably stratified and mixes much more slowly, but radiative forcing only heats the top layer of the ocean that is well mixed by winds. Ocean temperature follows SST down to about 50 m – the mixed layer.

      • franktoo, I agree with you that radiative transfer calculations are highly accurate. I have much more confidence in the validity of the radiative transfer models than I have in the models for atmospheric heat distribution.

        You say: “Does heat deposited somewhere under the TOA actually reach the surface? Almost certainly.” I have no doubt that’s true. I also have no doubt that the heat deposited under the TOA originated from the Earth’s surface and some of it will be lost to space. The question is, does more heat circulate back to the surface as CO2 increases, or does more heat radiate to space?

      • Willb01 wrote: “The question is, does more heat circulate back to the surface as CO2 increases, or does more heat radiate to space?”

        Surface temperature is generally controlled by the lapse rate, not by radiation. The average location on the surface receives about 160 W/m2 of SWR. Convection removes about 100 W/m2, and net radiation (OLR-DLR) about 60 W/m2. OLR-DLR rises less than 1 W/m2 per K rise in surface temperature, so it is hard to increase the upward heat flux using by a rise in surface temperature and thermal radiation. Relative humidity rises 7% per K or 5.6 W/m2/K. So convection can remove heat from the surface far faster through via radiation than via radiation. As the atmosphere thins and dries with altitude, radiation carries more heat upward and less convection is needed. Convection is no longer needed at the tropopause. If an unstable lapse rate exists, convection can carry as much heat upward as needed. However, if too much heat builds up in the upper troposphere, the lapse rate will no longer be unstable and buoyancy-driven convection will stop. So the rate of radiative cooling to space by the upper troposphere is critical and the lapse rate from there to the surface controls surface temperature. Radiative cooling to space depends to some extent on how effectively rising air has been dried by precipitation (and how much CO2 it contains). In climate models, the entrainment parameter controls the mixing between moist rising and dry descending air, and has a big impact on climate sensitivity.

        The climate feedback parameter controls the rate at which radiative cooling to space (plus reflection of SWR) rises with surface temperature. If a 1 K rise in surface temperature increase the flux to space by 3.7 W/m2 (or 3.7 W/m2/K), then ECS is 1 K. If 1.8 W/m2/K, ECS is 2 K. If 1.2 W/m2/K, then ECS is 3 K. If 0.9 W/m2/K, then ECS is 4 K. “Does more heat escape to space?” is exactly the right question. The answer is: We don’t know.

        A blackbody near 255 K emits 3.8 W/m2/K more radiation as it warms, so we say that the no-feedbacks climate sensitivity (except for Planck feedback) is about 1.0 K. If you prefer, a graybody near 288 K with an emissivity of 0.61 emits 3.3 W/m2/K more radiation as it warms, for a no-feedbacks climate sensitivity of 1.15 K. However, the Earth has feedbacks and they slow down the rate at which radiative cooling to space rises with surface temperature. How much?

    • franktoo: “Surface temperature is generally controlled by the lapse rate, not by radiation.”

      This is my understanding as well. If the lapse rate in the troposphere decreases, the surface becomes cooler. If the lapse rate increases, the surface warms. And if the lapse rate goes to zero, the GHE goes away. So two questions then:
      1. Does increasing the atmospheric CO2 concentration affect the lapse rate?
      2. If it does, will the lapse rate increase or decrease with CO2 increasing from its current level?

      It’s possible that increasing the atmospheric CO2 concentration may actually decrease the lapse rate slightly. The added CO2 will transport more heat to higher altitudes via radiation. If the upper troposphere warms slightly relative to the lower troposphere, the (average) lapse rate will decrease.

      You also wrote “… convection can remove heat from the surface far faster … than via radiation.”

      I agree with this (assuming I quoted you correctly). At the Earth’s surface, heat exchange between the air and the ground/sea is very much dominated by conduction, convection and evaporation. This makes me skeptical of the ability of DLR from GHGs to actually contribute in any meaningful way to surface warming. DLR energy transferred to the surface from any given layer of air will result in an equivalent loss of energy from that layer. To maintain thermal equilibrium, heat energy from the surface will immediately flow back into that air layer. Not only that, but OLR energy equivalent to the DLR energy will at the same time also be lost from that layer. Heat energy from the surface will have to compensate for that loss as well.

      • Willb01: Above I wrote: “So convection can remove heat from the surface far faster through via radiation than via radiation.

        I meant to say: “So convection can remove more heat than radiation in response to surface warming.”

        You asked: “1. Does increasing the atmospheric CO2 concentration affect the lapse rate? 2. If it does, will the lapse rate increase or decrease with CO2 increasing from its current level?”

        The dry adiabatic lapse rate is Cp/g and the change in CO2 is not going to change heat capacity appreciably. The amount of water vapor has a significant impact on the moist adiabatic lapse rate, so “water vapor feedback” will reduce the lapse rate in response to warming. However, by convention we call this “lapse rate feedback” and we reserve the term “water vapor feedback” for its effect on radiative heat transfer. The two feedbacks are linked, but can vary with altitude. IIRC, no one understands why the global average lapse rate is 6.5 K/km, so there appears to be no reason why it can’t change for other reasons besides humidity.

        You said: “This makes me skeptical of the ability of DLR from GHGs to actually contribute in any meaningful way to surface warming.”

        At some point I thought climate sensitivity depended on whether the extra heat from increasing CO2 was removed by an increase in convection or by an increase in thermal radiation. The latter requires surface temperature to rise, but the former might not. I’ve since decided that the rate of convection depends more on how fast the upper troposphere can radiatively cool to space. More DLR won’t result in more convection without more radiative cooling to space in the upper troposphere or warming at the surface. The surface energy balance perspective is interesting, but firmly linked to the TOA balance via the lapse rate.

    • franktoo, you write “IIRC, no one understands why the global average lapse rate is 6.5 K/km, so there appears to be no reason why it can’t change for other reasons besides humidity.”

      That’s an interesting statement for two reasons:

      – First, if surface temperature is dependent on the lapse rate and no one knows why the lapse rate is what it is, then I find it difficult to accept with confidence anyone’s estimate of TCR or ECS.

      – Second, because the global average lapse rate is already well below the dry adiabatic lapse rate, this leads me to believe that increasing CO2 levels might possibly be a contributing factor to this reduced lapse rate. If so, there may be no “extra heat from increasing CO2”.

  40. From Mauna Loa CO2 data, the smooth stair stepped increase appears only affected by up and down ENSO conditions. It ignores the up and down nature of fossil fuel use. The ice cores demonstrate a CO2 lag to other proxies of temperature. How the ice cores encorporate yearly CO2 into its layers over time is unclear thus cannot be spliced with direct atmospheric measures as if they are of the same precision. The greening of the Earth, which has happened many times before now, due to favorable water cycle processes provides more CO2 each year through its own seasonal decay and the natural increase in the animal kingdom as a direct result of increased available food. The past 800,000 years demonstrates repeated rapid, tipping point-like, almost run-away warming that peaks and then jaggedly falls again. I may be missing something here but I don’t see human influence in this collection of evidence.

  41. The National Science Teachers Association says there is no climate science debate:
    “First, scientists don’t disagree about climate change or its causes,” David Evans, the executive director of NSTA, wrote in a letter to members earlier this week. “Second, labeling propaganda as science does not make it so. Third, science teachers are the critical bastion in the war against reason. And the special interests know it.”
    https://insideclimatenews.org/news/07042017/heartland-institute-climate-change-denial-science-education?utm_source=Inside+Climate+News&utm_campaign=9dd147715e-Weekly+Newsletter&utm_medium=email&utm_term=0_29c928ffb5-9dd147715e-327531733

    Skepticism is a “war against reason.”
    Pity the children.

  42. As an outside observer – albeit one who is more inclined towards the “Red Team” view (the original one, not other Mosher snark one), I have to say that this comment thread is yet another rehash of the same discussions repeated ad nauseam. No doubt due to the fact that the same gallery of “consensus” types is involved: Jim D, ATTP and Mosher.
    Sadly, the reality of real world behavior not matching anything remotely approaching GCM models continues.
    Personally, I don’t even bother attempting to change “hearts and minds” anymore – time and reality will do that instead.
    What’s really amusing is that the people above continue to fixate on the same issue. Maybe there’s a conspiracy theory dynamic at work? Reprise of the aether/continental migration/Clovis/you name it scientific consensus fails?

    • The thing is, it is not just GCMs but observations that support AGW. With already 1 degree for a half doubling, this is on track. Asserting that AGW can’t be right at all when the observational evidence supports it seems to be an irrational position to take.

      • Jimd

        The best part of 300 years of warming, although not in a linear fashion.

        Backed up by observations of glacier melt, sea level rise and arctic sea ice reduction through this period. It is not a modern phenomenon

        Tonyb

      • It is difficult to tell where the minimum is. Nick Stokes posted a plot on this thread where it was more like 200 years ago, but the sharp rise starts after that.

      • The thing is, it is not just GCMs but observations that support AGW. With already 1 degree for a half doubling, this is on track. Asserting that AGW can’t be right at all when the observational evidence supports it seems to be an irrational position to take.

        As with politics, there’s a matter of talking past one another.
        Most seem to support AGW.
        To what extent, and to what effect, and what benefit?

      • Then they need to be asking the question of whether we want the BAU 700 ppm and rising by 2100 or something nearer where we are now. Consequences of 700+ ppm or stabilizing at 600, 500, 450, whatever target is chosen, need to be weighed up. Some still want to disconnect the CO2 level from its consequences, despite what you say. If there is to be a debate on science, that is the topic, not the side-tracked nonsense in the House hearing that seems geared towards not caring where the CO2 level ends up.

      • Jim D | April 16, 2017
        “It is difficult to tell where the minimum is?”
        Jim D seems to find it though at different times apparently depending on what the argument is at that time.
        “Asserting that AGW can’t be right at all when the observational evidence supports it seems to be an irrational position to take.”
        Decode.
        So you take the position that one only uses the observational data when it supports your AGW argument and ignore it when it does not? That seems quite rational to you? Better people than I, Eli for example, could point out a slight flaw in that argument.

      • This is the most basic and consensus observational data you can get. More than a century of surface thermometer data that shows it had warmed a degree, and CO2 data that shows it has increased 40% in the same period, both with about 75% of the change since 1950. These datasets everyone agrees on also show what AGW would predict. No one is surprised by the amount of warming except for a few “skeptics” who are still somewhat mystified, but in a determined way, that CO2 can have such an effect.

  43. In comments above, matthewrmarler and Jim D say this:

    matthewrmarler: “How many scientists agree with the statement that at least 90% of the warming since 1885 was caused by anthropogenic CO2?”

    Jim D: “How many? I would say nearly all that study it, know what forcings are, and calculate sensitivities. The reason being that the positive imbalance means that the forcing accounts for all the warming so far with more in the pipeline, and people who study this are aware of that, while many skeptics don’t fully understand this critical part of the information.”

    Let’s assume for purposes of argument that the information contained in this graph is sufficiently persuasive, and that it is sufficiently valid and defensible as scientific evidence, to convict anthropogenic CO2 in the court of public opinion as being the cause of recent global warming.

    Climate justice has costs as well as benefits, costs which the voting public must pay. Is the information presented in this graph of sufficient weight and importance to justify whatever measures are necessary to impose a sentence of life imprisonment on anthropogenic CO2?

    • Emissions can be phased out, and incentives to provide alternative energy and fuel and ways to store it can be given. Attaching the right cost to carbon drives the market in that direction. Investments in fossil fuels will not be seen as long-term, and already are not. This process has started already. Trump’s attempts to bring back coal are falling on deaf ears globally, as he found out at the G7.

      • Jimd

        I am not a proponent of fossil fuels in general or coal in particular. However they provide an amount of energy that can be readily calculated, come in a convenient portable form and the means of supply and consumption are reliable.

        Your optimism over coals demise seems optimistic

        https://www.eia.gov/todayinenergy/detail.php?id=26212

        Coal and liquid fuels remain very mportant sources of energy with the former plateauing around current levels and liquid fuels increasing substantially as demand for energy grows nearly 50% over the next few decades.

        China is the key as it consumes almost as much as the rest of the world put together. However, as it reduces its reliance it appears that India will take up the slack

        Tonyb

      • There is now a global peer pressure on emissions tracking, and anyone not doing all they can may be named and shamed. While China has started investing in alternatives, India is currently well below the global average emissions per capita, and these countries are understandably given leeway in the near term.

      • Jimd

        That may be so, but continued reliance on fossil fuels at much the saml’elefanteel as today’s means the amount of co2 in the atmosphere is likely to increase in the next fifty Years at much the same rate as for the last fifty years.

        So we look set for another 100ppm. Mind you, I have never been convinced we will see a doubling from pre industrial, I.e to around 600 ppm so do not think the temperature estimates given are realistic. Bearing in mind that it costs tens of billions to reduce temperatures even by a action of a tenth of a degree, it’s probably likely that we will continue much as we are currently dong.

        Tonyb

      • Even the number you state amounts to a mitigation effort because 2ppm/yr is 80% of the current rate and you want to sustain that even with development and population growth in much of the world. It is not as easy as you think, and I suspect you will think twice when you realize you have actually proposed mitigation. Limiting it to 100 ppm in 50 years is also not the same thing as limiting it to 500 ppm as a stable level because that requires a ramp-down.

      • Does it matter which peer-reviewed/equivalent paleo reconstruction is used?

    • Beta, I would say the information in the graph you present is uncertain particularly the projections to 2100. Relying on MBH99 is not convincing to me either.

      • Beta Blocker

        dpy6629: “Beta, I would say the information in the graph you present is uncertain particularly the projections to 2100. Relying on MBH99 is not convincing to me either.”

        Let’s draw a distinction between mainstream climate science as embraced by the Democrats and by the progressive left versus insurgent climate science as embraced by the Republicans and by the social-economic conservatives.

        The hockey stick remains an essential element of today’s mainstream climate science. It is the most convincing body of evidence independent of the models that CO2 is the primary control knob of the earth’s climate system — not the only control knob, certainly, but the one with the most influence by far on the earth’s climate dynamics as they operate in this era of the earth’s geologic history.

        The hockey stick is important scientifically in that if the Medieval Warm Period was worldwide and saw temperatures as as high or higher than today’s temperatures, confidence in the how well the models reproduce the earth’s actual climate dynamics would be much reduced. It is for this reason that mainstream climate scientists who doubt the hockey stick are few and far between, if any such people exist at all inside the mainstream community.

        Let’s also draw a distinction between the science of climate issues and the politics of climate issues.

        The value of the hockey stick politically as a tool for influencing general public opinion concerning the science of climate issues cannot be understated. The science nominally behind the stick is easily understood, at least in its general premise as the public currently understands that premise. The science message is simple, stark, and easily comprehended; i.e., that anthropogenic CO2 is the main cause of most of the earth’s warming since at least the 1880’s.

        Looking at the graph’s Year 2100 temperature projection scenarios, all three scenarios have a precedent in the historical climate record, depending upon which time frame one chooses. Each of the precedent time frames contains one or more episodes where the rate of temperature increase slows considerably for a period of at least two decades. However, the shorter and more recent the precedent time frame that is chosen, 1975-2016 for example, the higher is the rate of increase once the periodic slowdown ends.

        Any number of reasons can be assigned as to why these periodic slowdowns occur, some of which might include the influence of natural variability. But these periodic episodes are followed by periods where a sharp acceleration in the general rate of temperature increase occurs. If CO2 is indeed the climate system’s primary control knob, why should we not expect this same pattern to repeat itself again, either at the end of this decade or at some point in the early 2020’s?

        At any rate, insurgent climate science now has the upper hand in Washington, DC, at least for purposes of public policy decision making. But sooner or later, the Democrats will regain control of the federal government, at which point mainstream climate science will replace insurgent climate science as our nation’s policy making foundation. Once they are back in power, will the Democrats enact strong anti-carbon measures, or will they do what they’ve done in the past and throw a few bones to the climate change activists while spending most of their political capital on other priorities?

      • The hockey stick remains an essential element of today’s mainstream climate science.

        No.

      • JCH, let me fix that for you

        The hockey stick remains an essential element of today’s mainstream climate science…. scam of the public.

        There, that’s better.

      • Beta Blocker

        Beta Blocker: “The hockey stick remains an essential element of today’s mainstream climate science.”

        JCH: “No.”

        In my last remarks, I offered a justification for my claim that the hockey stick remains an essential element of mainstream climate science; i.e., that if the Medieval Warm Period was worldwide and saw temperatures as high or higher than today’s temperatures, confidence in how well the climate models reproduce the earth’s actual climate dynamics would be much reduced.

        JCH, in light of the debate which is occurring in numerous other comments on this thread concerning how the earth’s climate system actually operates; and in light of the fact that the hockey stick confirms the climate modeler’s view of the role of CO2 more powerfully than any other independent body of evidence, I ask you to offer an explanation for why the hockey stick is not an essential element of today’s mainstream climate science.

  44. Much focus on sensitivity of global mean temperature wrt GHG increases.

    May obscure larger questions of whether GMT is particularly significant.

    More and more it appears that climate models don’t indicate a very significant change in the distribution of net radiance. And so, it’s appearing more and more that there is not a significant amount of climate change to occur from greenhouse forcing.

    This does not preclude radiative forcing, nor warming in the global mean.

    But climate change appears to be a falsifying premise.

  45. > Let’s look at the statements they were asked to respond to […]

    I’m not sure they were asked to respond to specific statements.

    Looks more like a fish-and-barrel thing.

  46. Many proxies show temperatures were warmer in the past. As such temperature change is a result of the choice on endpoints. It is a mathematical construct. It is not a fact.

  47. Michel:

    Re your post of April 16, 3:06 E.D.T:

    You had written that “anthropogenic warming is no theory but just a belief” and I had written that, no, man made warming did exist, but that it had nothing to do with CO2 .

    The SO2 discussion was unavoidable, since its concentration in the atmosphere is, as I have shown, the actual control knob for Earth’s climatic behavior.

    You said, “I only note that you establish a mere correlation linking SO2 emissions peaking in the 70’s and warming following it”

    As stated in my article, the warming following it was completely predictable, based solely upon the amount of net reduction in global SO2 aerosol emissions, with a prediction accuracy of .02 deg. C, or less. This is far from a “mere” correlation. It is an exact correlation.

    The “stagnation” over the past “19 years” was simply due to Western Clean Air SO2 reductions being offset by increases in Eastern SO2 emissions, so that the NET amount of change in global SO2 emissions was greatly reduced (Figure 1 in my article).

    Your link to the article written in French was Greek to me!

    As also is your comment “Only it tells that attribution and q

  48. Carbon dioxide emissions from fossil fuels and cement production – from 1750 to 2011 – was about 365 billion metric tonnes as carbon (GtC), with another 180 GtC from deforestation and agriculture. Of this 545 GtC, about 240 GtC (44%) had accumulated in the atmosphere, 155 GtC (28%) had been taken up in the oceans with slight consequent acidification, and 150 GtC (28%) had accumulated in terrestrial ecosystems.

    Net warming over a relevant period is some 0.09 degrees C/decade – with nothing to suggest that there should be an acceleration in the rate of warming anytime soon. Except for models in which solutions over time are far more the result of internal, chaotic dynamics than simulation of fundamental climate processes – a mathematical fact that makes prediction of future climate states theoretically impossible. All in all – the chances of getting even 1.5 degrees C warming within decades seems ludicrously remote.

    Climate and ecologies are chaotic – and this implies that these systems are both unpredictable and vulnerable to small changes. Small changes initiate large and rapid changes in internal dynamics. It is the key reason why caution is warranted when changing such a fundamental system as the atmosphere. An example – carbon dioxide increase allows plants to reduce the size and number of stomata. Plants can access the same amount of carbon dioxide for growth and lose less water resulting in a change in terrestrial hydrology. It is impossible to foresee the ramifications of this.

    But it is possible to return much of the atmospheric carbon increase to vegetation and soils in ways that improve agricultural productivity, enhance food security, conserve biodiversity and create more flood and drought tolerant food production systems. While buying time for the development of 21st century energy systems to supply cheap and abundant energy for the essential needs of humanity. Already land use and forestry in the US is an 11% sink of US emissions and agriculture is well on the way to reversing carbon loss from soils – accounting for another 10% offset at least.


    http://www.c-agg.org/cm_vault/files/docs/Chambers_Paustian_Lal_Soil_Carbon_and_4_per_1000-1.pdf

    The solutions otherwise are ultimately technological – and this hasn’t changed over the decades of the global warming scare. The world needs cost competitive 21st century energy sources. The pertinent example is fracking – a low cost source of energy that rapidly transformed US energy infrastructure and is the basis for meeting the US Paris commitment. No one in the US is going back to coal – but that does release supplies for export to China and India.

    Natural gas supplies are – however – very limited and another US energy transition will be required within decades. The next big thing in my view – and in existing US energy policy – is advanced, modular, fast neutron, nuclear reactors.

  49. Michel:

    Somehow my previous comment was sent before I had finished typing.

    To continue, ” Only it tells that attribution and quantification of it cannot be assigned to only one pet parameter. In this sense, such claims are refuted (falsified)”

    Arrant nonsense!

  50. “Interdecadal 20th century temperature deviations, such as the accelerated observed 1910–1940 warming that has been attributed to an unverifiable increase in solar irradiance (4, 7, 19, 20), appear to instead be due to natural variability. The same is true for the observed mid-40s to mid-70s cooling, previously attributed to enhanced sulfate aerosol activity (4, 6, 7, 12). Finally, a fraction of the post-1970s warming also appears to be attributable to natural variability.” http://www.pnas.org/content/106/38/16120.full

    Something far more reasonable than Jimmy D’s grab bag of dubious assumptions – repeated endlessly – or Mosher’s science free faux logical constructs.

    Odd thing is – satellite data shows that most late century warming was quite natural as well.

    All for a combined warming rate of 0.09 degrees C per decade – something not likely to persist this century.

  51. It’s not a science at all.

    The next step after going into the sociology of science is analysis of science gestures, not to see what convinces the public but to see what convinces the participants.

    Bits of it can be science but nothing like the whole field.

    “Uncertainity” conceals that underlying problem, a gesture towards some future science.

  52. New Paper: N. Hemisphere Temps Rose 4–5°C Within ‘A Few Decades’ 14,700 Years Ago – 40 Times Faster Than Today’s Rates

    This post plus the previous two show that AGW is false and before this decade ends will be obsolete.

    The climate what will determine it from this point in time going forward is a very low solar/increased albedo /decrease overall sea surface temperature combination.
    These in response to very low solar conditions which will promote less UV light cooling overall sea surface temperatures while an increase in major volcanic activity ,global cloud coverage/snow coverage will result in an increase in albedo. Even .5% increase in albedo would wipe out the natural warming that occurred from1840-2005 which was due to very active solar conditions throughout that time frame.

    Already cooling is present and the sun has just started to approach my low average value solar criteria in order to accomplish this, despite some of the solar parameters remaining above my criteria that being the ap index/solar wind speed but those will be coming in line as sunspot activity diminishes which in turn will dry up coronal hole activity.

  53. “The responders argue that climate models shouldn’t be expected to predict short term (e.g. 20 years) temperature variations correctly. ”

    I have long held this to be an absurdity.

    The whole point of using a mathematical model for an initial value problem (the climate problem) is:

    Start with a known configuration at T0.
    Apply differential equations to get the resulting configuration at a nearby time, T1.
    Repeat to get the configuration at a more distant time, TN.

    Hence, if at any intermediate point Tj the configuration is wrong, all steps after that are wrong (or, if correct, merely by chance).

    As the total configuration degrades, or diverges from the true solution, so does any functional of that total configuration, i.e. something like average temperate. Average temperature is a computation resulting from the total configuration, not some mystical number that comes about from the configuration as a result of spells and divinations. The more correct the total solution, the more correct the average temperate. Average temperate may maintain, for a time, a level of accuracy slightly better that that of the total solution, through cancellation of errors, but, ultimately, as the whole configuration degrades, so does any functional of it. This cancellation of errors not understood, and is, for some, a quest for the holy grail on the forefront of numerical computational mathematics.

    Numerical solutions to differential equations degrade in accuracy over time. Initial value problems are basically just a form of extrapolation.

    To think that magically a solution can go from known (initial condition) to wrong and then magically circle back to correct is, as Putin says, a “Куча дерьма”, aka pile of crap.

  54. Judith Curry says: ”How much warming is caused by humans is THE key issue of debate.”
    The answer of my own I have written in my comment https://judithcurry.com/2017/03/20/discussion-thread-improving-the-interface-between-climate-science-and-police/#comment-842716 :
    ”As we well know CO2 content in atmosphere is controlled by striving for dynamic balance between all CO2 emissions from sources to atmosphere and all CO2 absorptions from atmosphere to other parts of environments. If the emissions are more than absorptions, the CO2 content in atmosphere is increasing, but if they are less, the CO2 content in atmosphere is decreasing.
    Recently the CO2 content in atmosphere has increased about 2.2 ppm a year. As the total amount of CO2 emissions to atmosphere has then contained only about 4 % CO2 from fossile fuels, in this yearly increase of 2.2 ppm in the atmospheric CO2 content there has been only about o.o88 % CO2 from fossile fuels, at the most.
    You see that already influence of the CO2 emissions from fossile fuels on the recent increase of CO2 content in atmosphere is minimal. Even though the total increase of CO2 content in atmosphere would dominate the present climate warming, the share of CO2 content from fossile fuels would there be too minimal in order to cause any threat of climate warming. In addition, according to geological and recent observations, trends of CO2 content in atmosphere follow trends of climate temperature and not vice versa. There are no observations in reality, according to which cutting of anthropogenic CO2 emissions could have prevented or lessened climate warming. As, for instance, CO2 cuttings according to the Kyoto protocol have caused only losses, the same kind of failures can be expected concerning cuttings based on the Paris agreement.”

  55. Past climatic history shows no relationship between co2 and global warming further co2 always follows the temperature never leads it.

  56. … In addition, the oceans lost a lot of heat to the atmosphere. So 2015-2016 were warm because of internal variation – more solar absorbed and more heat from the oceans. Such things occur on longer time scales as well. – TE

    OHC as of 12/31/2016 was slightly higher that it was when the 15-16 El Niño started, which was at the end of the last 1/4 of 2014.

    • Between the last quarter of 2014 and the third quarter of 2016, the oceans lost 5 x 1022 Joules, presumably to the atmosphere.

      Now, there’s uncertainty and variance. There was an increase of roughly 2 x 1022 Joules in the last quarter.

      Still, through the third quarter, that’s 20% of all the heat the oceans accumulated since 1979, so, yeah, that was a big deal.

    • 0 – 2000 meters:

      It’s possible some of the change in these numbers results from water being forced down below 2000 meters during La Niña and negative neutral conditions and coming back across the 2000 meter cutoff during positive neutral and El Niño conditions.

      2016-12, La Nina, is larger than 2014-12, onset of El Niño.

  57. Judith Curry says: ”How much warming is caused by humans is THE key issue of debate.”

    Another key issue is how much positive feedback from warming there will be.

  58. “New research findings make it all but certain that CO2 is not a pollutant but rather a beneficial gas that should not be regulated.” ~Joseph D’Aleo, Petition to EPA to begin a formal Reconsideration of its January 15, 2009 CO2 Endangerment Finding

  59.  
    …there is no mathematically proper validated proof that CO2 has had, or ever will have, a statistically significant impact on global average surface temperatures.

    ~Joseph D’Aleo

  60. Regarding ” Every scientist who is not senile and has considered this problem says human contribution is > 0.”

    I hope that I am not senile, but as I read the satellite record there is zero evidence of GHG warming. The only warming in the entire record is coincident with the giant ENSO. Flat before and flat after, but a little warmer. The so-called surface warming looks to be a statistical artifact. GHGs cannot warm the surface without warming the atmosphere and that has not happened.

    • During the satellite record, ENSO has both La Niña and El Niño events. one will dominate over the other. Since 1979, take a guess on which one it is.

      • JCH:

        For your information, I have discovered that all El Ninos are man made events.

        See my preprint “The Cause and Timings of El Nino Events” at OSF.io

      • Well, they is a recent peer-reviewed paper that suggests something similar.

      • Burl Henry

        Here is a book that includes a list of El Nino’s back 10000 years. Can you clarify why you believe them to be man made events?

        https://www.amazon.com/El-Ni%C3%B1o-History-Storming-Through/dp/0813020999

        I note used copies are available for as little as $3.55.

        tonyb

      • Tonyb:

        Thanks for the book reference (I just ordered a copy!)

        My finding is that all El Ninos since 1855 have coincided with man made reductions in SO2 aerosol emissions, which have temporarily increased ENSO temperatures enough to become an El Nino event.

        For earlier periods, it is doubtful that man would have had much of an effect, because of lower anthropogenic SO2 levels and smaller impacts from reduced business activity.

        It is more probable that increased sea surface warming from cloudless, stagnant weather patterns triggered many of the earlier El Ninos, with perhaps a touch of volcanic SO2 reduction thrown in.

  61. JCH:

    4-18-27 9:39 am

    Could you provide me a link to the paper?

  62. No, not to that remark

  63. Burl Henry

    Here is a book that includes a list of El Nino’s back 10000 years. Can you clarify why you believe them to be man made events?

    https://www.amazon.com/El-Ni%C3%B1o-History-Storming-Through/dp/0813020999

    I note used copies are available for as little as $3.55.

    tonyb

  64. Gavin Schmidt has a new post responding to Curry on the attribution question. I commented but it seems to have disappeared. The thrust of my comment was that the first figure is a very weak defense of AOGCM’s use for attribution since AOGCM’s get plenty of other things rather wrong including patterns of climate change, which are critical for attribution studies.

  65. Pingback: Judy Curry’s attribution non-argument – Climate, Forests & Woodlands

  66. Congress thinks that for $26 million we can overcome natural weather chaos and make reliable forecasts up to 2 years out. How silly.

    “Through an authorization of $26.5 million out of funds appropriated to NWS through fiscal year 2018, the legislation lays the groundwork for significant improvements in usable and reliable forecasts for time periods of 2 weeks to 2 years. This improvement in forecasting would, for example, allow farmers to make more informed decisions about when and what to plant.”

    https://science.house.gov/news/press-releases/congressional-statements-enactment-weather-research-and-forecasting-innovation

  67. Pingback: O's digest con vaccino HPV e farmacovigilanza - Ocasapiens - Blog - Repubblica.it

  68. Judith Curry, in previous Congressional testimony you claimed Arctic sea ice was in recovery. Why did you not use this opportunity to correct your past errors to Congress?

  69. Koonin endorses Red Team effort. Behind WSJ paywall but here are the first few paragraphs. I agree.

    Tomorrow’s March for Science will draw many thousands in support of evidence-based policy making and against the politicization of science. A concrete step toward those worthy goals would be to convene a “Red Team/Blue Team” process for climate science, one of the most important and contentious issues of our age.

    The national-security community pioneered the “Red Team” methodology to test assumptions and analyses, identify risks, and reduce—or at least understand— uncertainties. The process is now considered a best practice in high-consequence situations such as intelligence assessments, spacecraft design and major industrial operations. It is very different and more rigorous than traditional peer review, which is usually confidential and always adjudicated, rather than public and moderated.

    The public is largely unaware of the intense debates within climate science. At a recent national laboratory meeting, I observed more than 100 active government and university researchers challenge one another as they strove to separate human impacts from the climate’s natural variability. At issue were not nuances but fundamental aspects of our understanding, such as the apparent—and unexpected—slowing of global sea level rise over the past two decades.

    https://www.wsj.com/articles/a-red-team-exercise-would-strengthen-climate-science-1492728579

    • I certainly endorse the Red Team approach. However, a monster Issue Tree diagram would be even better. The big shortcoming of the Red Team method is that each line of argument is scattered among numerous documents. The starter document makes a given claim or argument. Then the first Red Team document probably makes several responses to that argument. The next Blue Team document offers responses to the Red Team responses, and so it goes, document after document.

      Note that this is a tree structure (the issue tree) because often one response elicits multiple responses, level after level. One can only see these response-response-response, etc. paths by going from document to document to document, etc. The Issue Tree diagram displays all of this in one easy to see place. One document. Mind you the diagram will be very large, because that is the nature of the climate debate.

      See my crude little textbook on this at http://www.stemed.info/reports/Wojick_Issue_Analysis_txt.pdf

      I have been trying to get someone to fund a climate debate issue tree project for many years. But it seems no one wants to show the other side’s arguments. Maybe now that will change.

  70. “How can they argue that there is NOT disagreement over this issue, when two reputable, widely published scientists that have received external recognition (e.g. myself and Christy) clearly disagree?”

    Yeah, in the end it is a numbers game. Despite the sceptics carping “science-is-not-consensus”, often with deference to Galileo, and protesting “abdication-of-the-scientific-method” — as defined by the blogger, the consensus is ultimately what gives us our best view of reality. Assuming of course it’s of experts judging the evidence. And how many experts? Ten thousand, twenty thousand, thirty thousand?

    Lamar Smith’s characterisation of the journal Science as biased rather gives the little game away.

    • Dennis:

      Lamar Smith is correct.

      I have had two “contrarian” Climate papers rejected by the editors, without peer review.

      1. ” Even If proven to be technically correct, we would not publish it”.

      2. “We have read your submission. but will not be publishing it”.

  71. Science is a high-impact journal that needs make no apology to Lamar Smith or anyone else in the world. Here: http://dialoguesonglobalwarming.blogspot.co.nz/2015/07/so2-decrease-not-responsible-for-global.html
    Christopher Keating writes: “I wish I had something to make you rejoin reality.”
    Maybe the editors of Science are kinder.

    • Dennis:

      Use the DuckDuckgo search engine.

      Search for “Climate Change Deciphered” (second entry down, when I search)

      I think that you will agree that SO2 IS responsible for global warming, in spite of Dr. Keating’s comments.

  72. Pingback: In an attempt to discredit Judith Curry, Gavin at RealClimate shows how bad climate models really are | Watts Up With That?

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