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Alsup asks for answers

Some of you might have read about the lawsuit by a number of municipalities (including San Francisco and Oakland) against the major oil companies for damages (related primarily to sea level rise) caused by anthropogenic climate change. The legal details on standing, jurisdiction, etc. are all very interesting (follow @ColumbiaClimate for those details), but somewhat uniquely, the judge (William Alsup) has asked for a tutorial on climate science (2 hours of evidence from the plaintiffs and the defendents). Furthermore, he has posted a list of eight questions that he’d like the teams to answer.

It’s an interesting list. They are quite straightforward (with one or two oddities), but really, pretty much textbook stuff. Andrew Dessler made a quick stab at answering them on Twitter:

But I think we can do better. So what I propose is that we crowd-source the responses. They should be pithy, to the point, with references (not Wikipedia) and, preferentially, accompanied by a good graphic or two. If we can give a credible uncertainty to any numbers in the answer that’s a bonus. I’ve made a start on each, but further voices are needed. Put your response in the comments and I’ll elevate the best ones (giving credit of course) to the main post. If you have any other comments or edits to suggest, feel free to do so. The best of those will also be incorporated. [Update: I realise I can’t possibly incorporate all the good suggestions while still keeping this short. So be sure to read the comments too for additional material. Also, as I should have said to start with, the best responses to these kinds of questions (though not to these specifically) are to be found in the FAQ of the IPCC report, the Royal Society/National Academies report, and the US. National Climate Assessment science report.]

Alsup’s Questions:

  1. What caused the various ice ages (including the “little ice age” and prolonged cool periods) and what caused the ice to melt? When they melted, by how much did sea level rise?
  2. What is the molecular difference by which CO2 absorbs infrared radiation but oxygen and nitrogen do not?
  3. What is the mechanism by which infrared radiation trapped by CO2 in the atmosphere is turned into heat and finds its way back to sea level?
  4. Does CO2 in the atmosphere reflect any sunlight back into space such that the reflected sunlight never penetrates the atmosphere in the first place?
  5. Apart from CO2, what happens to the collective heat from tail pipe exhausts, engine radiators, and all other heat from combustion of fossil fuels? How, if at all, does this collective heat contribute to warming of the atmosphere?
  6. In grade school, many of us were taught that humans exhale CO2 but plants absorb CO2 and return oxygen to the air (keeping the carbon for fiber). Is this still valid? If so, why hasn’t plant life turned the higher levels of CO2 back into oxygen? Given the increase in human population on Earth (four billion), is human respiration a contributing factor to the buildup of CO2?
  7. What are the main sources of CO2 that account for the incremental buildup of CO2 in the atmosphere?
  8. What are the main sources of heat that account for the incremental rise in temperature on Earth?

Alsup’s Answers:

Note this is an updating text. Last edit: March 16, 2018

  1. The “ice ages” are the dominant cycles of change over the last 2.5 million years (Snyder, 2016):

    Ice age cycles from Snyder (2016)

    They vary in extent and duration. They generally were larger in the last 800,000 years, and the duration changed from about 40,000 years in the first half to about 100,000 years in the later period. It was discovered in the 1970s that the cycles were highly correlated to changes in the variability of the Earth’s orbit – the so-called Milankovich cycles (Hays, Imbrie and Shackleton, 1976). More recent work has shown that the growth and collapse of the ice sheets is strongly tied to the incoming solar radiation (insolation) at high latitudes (Roe, 2006):

    The magnitude of the cycles is strongly modified by various feedbacks, including ice-albedo, dust, vegetation and, of course, the carbon cycle which amplify the direct effects of the orbital changes. Estimates of the drivers of global temperature change in the ice ages show that the changes in greenhouse gases (CO2, methane and nitrous oxide) made up about a third of the effect, amplifying the ice sheet changes by about 50% (Köhler et al, 2010).

    The sea level changes over these cycles was large. The difference between the last glacial maximum (20,000 yrs ago) and today is about 120 meters (400 ft), but the high levels during some of the warmest interglacials were 6-9 meters (20 to 30 feet) higher than today. These changes are dominated by the amount of ice volume change.

    The so-called “Little Ice Age” was a cooling of the Northern Hemisphere climate (and possibly less markedly in the Southern Hemisphere) in the period of the fourteenth century to the the 1850’s, approximately. It came after a period of a relatively warm climate called the Medieval Warm Period. The cause of this relatively short lived cooling (it was not a true “ice age”) is likely due to an increase in volcanic eruptions and with some role for a slightly reduced solar activity. Over the Holocene (last 11,000 yrs) there is a small but persistent cooling trend due to the orbital cycles mentioned above.

  2. Greenhouse gases are those that are able to absorb and emit radiation in the infrared, but this is highly dependent on the gases molecular structure. Vibrational modes in molecules with three or more atoms (H2O, CO2, O3, N2O, CH4, CFCs, HFCs…) include bending motions that are easier to excite and so will absorb and emit low energy photons which coincide with the infrared radiation that the Earth emits. Thus it is these molecules that intercept the radiation that the Earth emits, delaying its escape to space. More detailed discussion including the importance of the gases dipole moment can be found here. Diatomic molecules (like N2 or O2) have stretching modes (with the distance between the two molecules expanding and contracting), but these require a lot of energy (so they absorb only at higher energies. Some absorption is possible in the infrared due to collisions but calculations suggest this is a very small part (~0.2%) of the overall greenhouse effect (around 0.3 W/m2, compared to a total effect of 155 W/m2) (Höpfner et al, 2012).

    Figure showing the vibrational modes for CO2. Arrows indicate the directions of motion. Vibrations labeled A and B represent the stretching of the chemical bonds, one in a symmetric (A) fashion, in which both C=O bonds lengthen and contract together (in-phase), and the other in an asymmetric (B) fashion, in which one bond shortens while the other lengthens. The asymmetric stretch (B) is infrared active (allowed by quantum mechanics) because there is a change in the molecular dipole moment during this vibration. Infrared radiation at 2349 (4.26 um) excites this particular vibration. The symmetric stretch is not infrared active, and so this vibration is not observed in the infrared spectrum of CO2. The two equal-energy bending vibrations in CO2 (C and D) are identical except that one bending mode is in the plane of the paper, and one is out of the plane. Infrared radiation at 667 (15.00 um) excites these vibrations. (source)

  3. The Earth’s surface emits infrared radiation. This is absorbed by greenhouse gases, which through collisions with other molecules cause the atmosphere to heat up. Emission from greenhouse gases (in all directions, including downwards) adds to the warming at the surface.

    The figure shows the easiest mathematical description of the greenhouse effect. The downward radiation from greenhouse gases can be easily measured at the surface in nights under clear skies and no other heat sources in the atmosphere (e.g. Philipona and Dürr, 2004).

  4. Yes, but not enough to matter. The latest update to the estimates of radiative forcing of CO2 (Etminan et al., 2016) shows a shortwave effect (i.e. a change in the absorption of downward solar radiation) is about -0.14 W/m2 for CO2 going from 389 to 700 ppm (compared to 3.43W/m2 in longwave forcing) – contributing to about a 4% decrease in the net forcing.
  5. Direct heat generated by the total use of fossil fuels and other forms of energy adds up to about 18TW [IEA,2017]. Spread over the planet that is 0.04W/m2. Compared to anthropogenic forcings since 1750 of about 2.29±1.1W/m2 [IPCC AR5, Figure SPM 5], it’s about 1/100th the size. Locally however (say in cities or urban environments), this can be more concentrated and have a bigger impact.
  6. The grade school calculation is still valid. All animals (including humans) breathe in oxygen and exhale CO2. The carbon in the exhaled CO2 comes from the food that the animals have eaten, which comes (ultimately) from carbon that plants have taken from the atmosphere during photosynthesis. So respiration is basically carbon neutral (it releases CO2 to the atmosphere that came from the atmosphere very recently). Plants do take up CO2 as they are growing. With higher CO2 concentrations (and higher temperature), plants in fact increase their CO2 uptake somewhat but not as much as would be needed to absorb all the human-caused emissions. Of these emissions only about a quarter is absorbed by plants, while another 20% is absorbed by the oceans, but about half of the emissions stay in the atmosphere.

    Note that any net change in biomass (whether trees, or cows or even humans) does affect atmospheric CO2, but the direct impact of human population growth is tiny even though our indirect effects have been huge. For scale, the increase of 3 billion people over the last 40 years, is equivalent to:

    0.185 (fraction of carbon by mass) * 80 kg (average mass of a human) * 3 billion (additional humans) * 10-3 (conversion to GtC) / 40 years = 0.001 GtC/yr

    which, compared to current fossil fuel and deforestation emissions of ~10 GtC/yr is 4 orders of magnitude too small to be relevant.

  7. Main sources of human CO2 emissions are fossil fuel burning and (net) deforestation. This figure is from the Global Carbon Project in 2017.

  8. Prior to ~1750, atmospheric CO2 had been stable (within a few ppm) for millenia sustained by a balance between natural sources and sinks. This figure shows the changes seen in ice cores and the instrumental record.

  9. This is the biggie. What is the attribution for the temperature trends in recent decades? The question doesn’t specify a time-scale, so let’s assume either the last 60 years or so (which corresponds to the period specifically addressed by the IPCC, or the whole difference between now and the ‘pre-industrial’ (say the decades around 1850) (differences as a function of baseline are minimal). For the period since 1950, all credible studies are in accord with the IPCC AR5 statement:

    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.

    The US National Climate Assessment attribution statement is a bit more specific than the one in IPCC:

    The likely range of the human contribution to the global mean temperature increase over the period 1951–2010 is 1.1° to 1.4°F (0.6° to 0.8°C), and the central estimate of the observed warming of 1.2°F (0.65°C) lies within this range (high confidence). This translates to a likely human contribution of 93%–123% of the observed 1951–2010 change. It is extremely likely that more than half of the global mean temperature increase since 1951 was caused by human influence on climate (high confidence). The likely contributions of natural forcing and internal variability to global temperature change over that period are minor (high confidence).

    This summary graphic is useful:

    Basically, all of the warming trend in the last ~60yrs is anthropogenic (a combination of greenhouse gases, aerosols, land use change, ozone etc.). To get a sense of the breakdown of that per contribution for the global mean temperature, and over a longer time-period, the Bloomberg data visualization, using data from GISS simulations is very useful.

    The difference in the bottom line for attribution for the last ~160 years is that while there is more uncertainty (since aerosol and solar forcings are increasingly shaky that far back), the big picture isn’t any different. The best estimate of the anthropogenic contribution is close to the entire warming. The potential for a solar contribution is slightly higher (perhaps up to 10% assuming maximum estimates for the forcing and impacts). In all cases, the forcing from anthropogenic greenhouse gases alone is greater than the observed warming.

    Figure 10.5 from IPCC. Assessed likely ranges (whiskers) and their mid-points (bars) for attributable warming trends over the 1951–2010 period due to well-mixed greenhouse gases (GHG), other anthropogenic forcings (OA) (mainly aerosols), natural forcings (NAT), combined anthropogenic forcings (ANT), and internal variability.

    The role of internal climate variability gets smaller as the time-scale increases, but needs to be accounted for in these assessments. Note too that this can go both ways, internal variability might have wanted to cool overall in one period, and warm in another.


  1. C.W. Snyder, "Evolution of global temperature over the past two million years", Nature, vol. 538, pp. 226-228, 2016.
  2. J.D. Hays, J. Imbrie, and N.J. Shackleton, "Variations in the Earth's Orbit: Pacemaker of the Ice Ages", Science, vol. 194, pp. 1121-1132, 1976.
  3. G. Roe, "In defense of Milankovitch", Geophysical Research Letters, vol. 33, 2006.
  4. P. Köhler, R. Bintanja, H. Fischer, F. Joos, R. Knutti, G. Lohmann, and V. Masson-Delmotte, "What caused Earth's temperature variations during the last 800,000 years? Data-based evidence on radiative forcing and constraints on climate sensitivity", Quaternary Science Reviews, vol. 29, pp. 129-145, 2010.
  5. M. Höpfner, M. Milz, S. Buehler, J. Orphal, and G. Stiller, "The natural greenhouse effect of atmospheric oxygen (O2) and nitrogen (N2)", Geophysical Research Letters, vol. 39, pp. n/a-n/a, 2012.
  6. R. Philipona, and B. Dürr, "Greenhouse forcing outweighs decreasing solar radiation driving rapid temperature rise over land", Geophysical Research Letters, vol. 31, 2004.
  7. M. Etminan, G. Myhre, E.J. Highwood, and K.P. Shine, "Radiative forcing of carbon dioxide, methane, and nitrous oxide: A significant revision of the methane radiative forcing", Geophysical Research Letters, vol. 43, pp. 12,614-12,623, 2016.

246 Responses to “Alsup asks for answers”

  1. 151
    crandles says:

    Re “Estimates of the drivers of global temperature change in the ice ages show that the changes in greenhouse gases (CO2, methane and nitrous oxide) made up about a third of the effect, amplifying the ice sheet changes by about 50% (Köhler et al, 2010).”

    This seems a bit odd giving an answer that ice sheet changes are caused by ice sheet changes as if some circular reasoning hasn’t been resolved. The answer doesn’t seem to explain albedo effect of the ice sheets, which also seems a little odd.

  2. 152
    Larry Gilman says:

    Now that the hearings are actually taking place, I would like to see a RealClimate scientist give a blow-by blow analysis of the actual tutorials and counter-responses. In a new thread, not buried at the bottom of this one.

    [Response: There were a couple of articles about the proceedings, but we need to wait for a transcript to get a sense of what was exactly said scientifically. Note that the Chevron lawyers did not really challenge the science presented by Myles Allen, Gregg and Don Wuebbles. – gavin]

  3. 153
    MA Rodger says:

    The Humour award for Monckton et al mentioned @147 actually involves a paper co-authored by one of our hosts – Lacis, Schmidt, Rind & Ruedy (2010) ‘Atmospheric CO2: Principal Control Knob Governing Earth’s Temperature.’ Apparently, it is all wrong.
    Oh no!!!
    The happy band of denialists (presumably the gang of nine who advise Judge Alsup with their nonsense) have been “quietly but very busily investigating how much global warming we may cause, known as the “equilibrium-sensitivity” question.” Their results are now in the public domain having been sent to Judge Alsup and so Madman Monckton Viscount of Brenchley describes their finding to the denizens of the plnet Wattsupia proclaiming to the world

    “It can be proven that an elementary error of physics is the sole cause of alarm about global warming.”

    The logic of their grand thesis runs something like this:-
    ☻ Lacis et al (2010) calculates that LL GHG forcing in the pre-industrial world provided a direct warming equal to 25% of the 35°C of greenhouse effect they model. (If all LL GHGs disappeared, global temperatures would plunge initially at 4°C/year, thus dropping to maximum-ice-age levels in ~18 months.) But this is, if you are as barmy as Monckton or Willie Soon, apparently all wrong. There is an “elementary error of physics” because their GHG effect (of 32.6°C) comprises the 8°C of forced warming and 24°C of feedbacks but the GHG was only responsible for 3% of the feedbacks. The other 97%, apparently, is due to the 255°C of solar warming of the non-GHG world. So this suggests there is effectively zero climate feedback from any AGW and thus ECS is roughly 1.1°C.
    ☻ Further proof is provided by calculating the linear trend in global temperature using HadCRUT 1850-2011 and thus the temperature increase, and the net forcing from IPCC AR5 for 2011. It is then argued that all feedbacks will have acted so the ΔT & ΔF can be quickly used to calculate ECS confirming the 1.1°C value.
    ☻ This is repeated for ten other (presumably shorter) un-named periods and an average of 1.25°C is obtained. And a further test using HadCRUT 1950-2017 and combined HadCRUT/UAH data 2001-17 demonstrates rates of warming that (in some undescribed way) provides further proof.
    ☻ An electrical model (although it isn’t a model but an empirical test-rig) has been built to show how feedback does not require ‘forcing’ but happens with the un-forced parameters alone. (And this is why there is no tropical hot-spot, apparently.)
    ☻ A laboratory was then employed to do similar work on a more sophisticated test rig and came to the same conclusion, “that, in the presence of a non-zero feedback fraction, even an unamplified input signal would induce a feedback response that would either amplify or attenuate it” although when presented with the Monckton paper, the laboratory reacted badly and thus they will not be named in the paper.

    So there you have it. The final Monckton claim is that there was a grand conspiracy “to perpetrate a single falsehood: that the science was settled,” but it isn’t clear how this squares with their grand thesis. (Surely the science is/was settled and there is/was no conspiracy and only now have Monckton et al provided the grand thesis that will after due process allegedly ‘un-settle’ the presently settled science.)

  4. 154
    crandles says:

    Re Q6: Is the mass of carbon in our bodies of much relevance? Suppose we were like humming birds low mass but using oxidation of carbon at a very high rate to convert carbon to CO2 (and eating lots of carbon but it not staying in body long). So should there also be a calculation of the effect of human biological energy generation on the natural carbon cycle?

    In both effects, I imagine there should be mention that humans cultivate food and fence off such land from other animals. So increase in human population may well be largely?/wholly?/more than? compensated by reduction in other animals.

  5. 155
    MA Rodger says:

    crandles @151,
    There is circularity but of a physical kind rather than a logical kind.
    The paragraph in the OP you quote from as well as the one above it in full are saying that the ice age cycles result from the Earth’s changing orbit round the sun which creates changes in the “incoming solar radiation (insolation) at high latitudes” (Roe (2006) PDF). The resulting increased/decreased ice is amplified by “various feedbacks, including ice-albedo, dust, vegetation and, of course, the carbon cycle which amplify the direct effects of the orbital changes.” The sun is perhaps best considered as the trigger with the climate needing to be ‘loaded’ (either with too much ice or too little ice) for the trigger to work. And the ice does play the major part once the trigger is pulled – more/less-ice >> more/less-albedo >> less/more-solar-warming >> cooler/warmer-climate >> more/less-ice.

  6. 156
    Hank Roberts says:

    Today’s KQED Radio Forum program hosts a reporter who was in the courtroom yesterday.

  7. 157
    Hank Roberts says:

    “It was videotaped and it should be released by the end of today.”

  8. 158
    Hank Roberts says:

    Oil company blames humans for warming but denies guilt
    Debra Kahn, E&E News reporter Climatewire: Thursday, March 22, 2018

    Under active questioning from Alsup, Oxford University physicist Myles Allen explained the details of carbon dioxide’s role in preventing infrared radiation from leaving the atmosphere, how various parts of the Earth absorb the molecules, and how the greenhouse effect works on other planets. He only got through about one-third of his material before he had exhausted his allotted hour.

    Alsup asked the plaintiffs where they differed from Chevron’s positions.

    “They do agree that humans are putting carbon dioxide into the air, that does in fact cause warming, that does in fact cause sea-level rise,” Alsup said. “What critique would you make of what I just heard from the other side? They seem to be largely agreeing.”

    “That’s not what you see at all in the media, and that’s why these points are emphasized,” said Don Wuebbles, a University of Illinois atmospheric scientist who led a special science report for the most recent National Climate Assessment and was assistant director at the Office of Science and Technology Policy under former President Obama. Wuebbles pointed out that over the past century, sea levels off San Francisco have risen 7.7 inches, according to tide gauges.

    “If you look at the time period since 2012, you actually go back to seeing an increase in the region,” he said. “That is a little different than the picture he [Boutrous] was trying to paint in his presentation. Again, the science does not stop in 2012.”

  9. 159
    jgnfld says:


    First one neutron splits one uranium atom which in the process of splitting releases 2 neutrons. But since feedback involves “circular reasoning”, there is no possibility at all of any sort of atomic explosion now is there?

  10. 160


    OT, or at least ‘meta’–but I just tried to do a nice list like that for a comment, and it failed to show up in preview, at least. So, MAR, any pointers on the HTML code you used?

  11. 161
    crandles says:

    Re 159: Perhaps circular reasoning wasn’t quite the right term, I was just trying to suggest that perhaps the answer here could be improved to avoid giving a bad impression rather than suggesting the science was lacking.

  12. 162
    Hank Roberts says:

    Alsup ordered the other defendants in the suit—BP PLC, ConocoPhillips, Exxon Mobil Corp. and Royal Dutch Shell PLC, all of which had representatives at the hearing—to submit briefs within two weeks detailing any points of disagreement with Chevron. “Otherwise, I’m going to assume you’re in agreement,” he said. “You can’t get away with sitting there in silence and then later say, ‘He wasn’t speaking for us.'”

    Plaintiffs criticized Chevron and the other companies’ approach.

    “What we saw today was one oil company begrudgingly accept the scientific consensus while trying to overemphasize the extent of scientific uncertainty,” San Francisco City Attorney Dennis Herrera said in a statement. “The other four major oil companies refused to even participate or recognize the court has jurisdiction over them. Apparently they think they’re above the law.”

  13. 163
    Hank Roberts says:

    The SciAm article was:

    Reprinted from Climatewire with permission from E&E News. E&E provides daily coverage of essential energy and environmental news at

  14. 164
    jgnfld says:


    There is such a thing as actually realizing what statements mean rather than just throwing out big words/concepts.

  15. 165
    Hank Roberts says:

    Thanks to Grist for giving some blow-by-blow details from the hearing (and thanks to Gavin for providing the link earlier, above)

  16. 166
    Hank Roberts says:

    And remember, it’s not the manufacturing, nor the promoting, nor the selling of opiates cheap that causes people to suffer from addiction. It’s ingesting them.

  17. 167

    It seems ever clearer that Judge Alsup is acting ‘architecturally’–getting the scientific foundation laid.

    At the risk of invoking Godwin’s precept, it reminds me of another case involving Holocaust denial, years ago:

    At issue were a number of assertions in ”Denying the Holocaust: The Growing Assault on Truth and Memory,” a book first published in 1993 in the United States by Deborah E. Lipstadt, a professor of modern Jewish and Holocaust studies at Emory University in Atlanta.

    In the book, Ms. Lipstadt wrote that Mr. Irving, now 62, was “one of the most dangerous spokespersons for Holocaust denial” and said that “he is at his most facile at taking accurate information and shaping it to conform to his conclusions.”

    …Mr. Irving, the author of more than 30 books on World War II and the Holocaust, some of which historians have praised, sued Ms. Lipstadt and her publisher, Penguin Books, saying that the book had severely damaged his reputation as a historian.

    He brought the suit [in Britain] because British libel law puts the burden on the defendants — in this case, Ms. Lipstadt and Penguin — to prove the truth of their assertions.

    The judge, Charles Gray of the British high court, handed a resounding victory to Ms. Lipstadt. In a scathing ruling notable for its stern wording, he declared that Mr. Irving was a racist Holocaust denier who deliberately distorted historical evidence in order to cast Hitler in a favorable light. Mr. Irving’s treatment of history, he said, was often “perverse and egregious.”

    Judge Gray, like Judge Alsup, chose to hear the larger issue explicitly in court. At the time some commentators criticized him for doing so, arguing that he should simply have taken judicial notice of the historical reality of the Holocaust. It’s still unclear whether that would have been better or not, but either way Irving’s historical revisionism and denialism received a very stinging rebuke.

  18. 168
    Hank Roberts says:

    It’s a quick handoff in the game of Denialball, as the ball is passed from the oil companies to the auto manufacturers:

    Last month, one of the largest lobbying groups argued in a regulatory filing that the basic science behind climate change is not to be trusted.

    In the same filing, the lobbying group, the Alliance of Automobile Manufacturers, also cast doubt on the negative effects of tailpipe pollution on human health.

  19. 169
    Hank Roberts says:

    Chevron attorney now up – “from Chevron’s perspective there’s no debate about climate science” going to be quoting chapter and verse from IPCC reports. It’s an “amazing resource”

    — Nathanael Johnson (@SavorTooth) March 21, 2018

    It’s convenient that Chevron’s attorney relied on that aging five-year-old report. The next IPCC report isn’t planned for public release until the fall of 2019. Gathering consensus takes time, and the result is that IPCC reports are out of date before they’re published and necessarily conservative.

    The climate models used in these reports grow old in a hurry. Since the 1970s, they’ve routinely underestimated the rate of global warming. Some of the most recent comprehensive assessments of climate science, including last year’s congressionally-mandated, White House-approved, Climate Science Special Report, include scary new sections on “climate surprises” like simultaneous droughts and hurricanes, that have wide-reaching consequences. The scientists representing the two cities knew this, and didn’t limit their talking points to the IPCC.

    “Positive feedbacks (self-reinforcing cycles) within the climate system have the potential to accelerate human-induced climate change,” says a section from that Climate Science Special report, “and even shift the Earth’s climate system, in part or in whole, into new states that are very different from those experienced in the recent past.” None of this was included in the last IPCC report.

    Actually, a helluva lot has changed in our understanding of the Earth’s climate system since the 2013 IPCC report. Here are some of the highlights ….

  20. 170
    Hank Roberts says:

    Grist links to Nathaniel Johnson’s account [@SavorTooth] from the Alsup hearing

  21. 171
    Dan DaSilva says:

    RE 169

    Hello Mr. Hank Roberts,
    This is a virtuous and brilliant move by the oil companies, they can just quote the IPCC whatever they say whenever they say it. The IPCC is an insurance policy for the oil companies. I predict they will start publicly donating money to the IPCC.

    The governments can not say they were being tricked. We the citizens (including all you global warming alarmists) can continue using one of the greatest life-enhancing resources ever discovered. The oil companies can say if you don’t want it don’t buy it. All of us now protected by the IPCC.

    All good except now the hysteria of the delusional left increases: “the IPCC is grossly underestimating the harm of global warming, wait for the next report, you can’t use this one”.

  22. 172
  23. 173
    Dave says:

    ALSUP question number one – Feedback.

  24. 174
    Mr. Know It All says:

    Who predicted the outcome of the lawsuit? :)

    Even a broken clock is right 2 times per day, right?


  25. 175
    SystemicCausation says:

    In the Courtroom, Climate Science Needs Substance — and Style

    So here comes the crux of the thing—a question not of whether climate change is real, but whether you can ascribe blame for it. Leaning heavily on more IPCC quotes, Boutrous showed slides and statistics saying that climate change is a global problem that doesn’t differentially affect the West Coast of North America and isn’t caused by any one emitter. Or even any one source of emissions.

    Anthropogenic emissions are driven by things like population size, economic activities, lifestyle, energy use, land use patterns, and technology and climate policy, according to the IPCC. “The IPCC does not say it’s the extraction and production of oil,” Boutrous said. “It’s economic activity that creates the demand for energy and that leads to emissions.”

    the article concludes with

    Now things might get even more real. If a court attaches culpability for sea level rise in California to petrochemical companies, that might establish causation for a planet’s worth of damage, any disaster someone can plausibly connect to climate change. That’s wildfires, drought, more intense hurricanes. Attribute it to climate, and it could attribute all the way to fossil fuel companies’ bank accounts.

    I think this leads to a logical question.

    When was the last time you filled up your car’s fuel tank?

  26. 176
    Alastair B. McDonald says:

    I find it disappointing that the press are still concentrating on the battle between sceptics and scientists, especially since the oil companies have conceded that point. What I really want to know is what were the answers presented to Judge Alsup, and his reaction to them.

    Will the tutorials be published? That is what I want to see.

  27. 177
    Cody says:

    Just took my first peek at Dressler answers. I may have become ‘Old School,’ but back in the 70’s water vapor was described (canonically) as a “Greenhouse Gas.” Unless conventions have changed, Dressler is not even PHYSICALLY CORRECT [second from last paragraph, sentence two], in his itemization of the causal agents.

  28. 178
    M Passey says:

    Hank Roberts 169:

    I have a couple questions.

    1. The linked Grist article states that since the 1970s the models have routinely underestimated the rate of global warming, linking to an article by Zeke Hausfather. Is that really true? When I look at Gavin’s Climate Model Projections Compared to Observations page I don’t see it.

    2. The latest IPCC report states “low confidence” in detecting a signal from anthropogenic CO2 in floods, droughts, severe storms and cyclones. The Grist article says this is outdated because of advances in modeling extreme weather attribution. Since the IPCC report was published has the actual statistical signal emerged to a greater level of confidence?

  29. 179
    Icarus62 says:

    Can the judge impose any kind of penalties on Happer, Koonin and Lindzen for their efforts to deliberately mislead the court in their submission to him? It must surely be contempt of court, perjury or something.

  30. 180
    Adam Lea says:

    124:, 143:

    If someone makes an assertion, whether the assertion is true or not depends on facts, logic and evidence. The behaviour of the person making the assertion is irrelevant. Unfortunately the human cognition seems to be wired to lazy logical fallacies rather than engaging in the mental effort to check assertions and facts properly.

    I advocate environmental responsibility, and I take measures myself to reduce my carbon footprint. However it is going too far (at least currently) to expect people to live in houses that are at single digit temperatures for four months of the year, to only travel anywhere their legs are capable of taking them, or to only eat food that they can grow/raise themselves by organic processes. For a start, it is not possible for enough people to take extreme measures to make a significant difference. The whole system needs to change. For example, when I sold my car and used a bicycle as a primary mode of transport, the motor traffic levels in my area didn’t noticeably change, but I had to deal with the increased vulnerability, increased exposure to crappy UK weather (which is the same when you grow your own veg), reduction in mobility and increased fatigue.

  31. 181
    Mark says:

    Surprisingly, the Guardian managed to mangle “greenhouse effect” nicely”, viz., . I did try to alert the author and editors but to zero effect. Perhaps they think I’m too fringe; any practicing scientists care to enlighten them before this gets sent to Climate Feedback? I expect better from that newspaper.

  32. 182
    Mark says:

    #175, SystemicCausation asked “When was the last time you filled up your car’s fuel tank?” Er, March 2016. That’s when I ditched the gas car started driving a small EV. Oh — and it’s charged with wind-generated electricity. I prefer to ride my bike tho’, weather permitting.

  33. 183
    Mark says:

    #177 Cody: You do know that water vapor is a condensing greenhouse has at Earth-like temperatures and pressures — right? That’s why it is an amplifying factor, not a causative one.

  34. 184
    MA Rodger says:

    Kevin McKinney @160,
    ♠ In reply to your meta-question, ♥ my own use of symbols to mark-out items in a texty list does not employ HTML ♦ but are simply cut&pasted from the exotic/extended character sets available in word processors (or elsewhere on the thread). ♣ Of old, they would be found in fonts such as WINGDINGS or SYMBOL although these are unsupported by the HTML engine here. ☻ But modern fonts often have significant numbers of UNICODE characters available. ☺ So all the ones I use in this paragraph are from TIMES ROMAN which is supported.◄
    However, if you want to use HTML like this &#x2660, you need to obtain the HTML code for the required character. Thus the following character string & #x2660 will become &#x2660 when the space between the & and the # is deleted. The various codes (decimal or hex) can be found for TIMES ROMAN UNICODE from this page although finding what you want (eg BLACK SPADE SUIT &#x2660) isn’t helped by the length of the character list – over 3,000 of them, mainly non-latin alphabets or accented letters.

  35. 185
    MA Rodger says:

    Further to the above reply to #160, the HTML characters did appear as you would expect when typed into the thread text editor, but they promptly reverted to the code when submitted. A try at using decimal code with end colon – ♠ – may or may not do better – it can’t do worse!

  36. 186

    It’s possible, then, to infer that Alsup was doing more than just getting up to speed on climate change on Wednesday. The physics and chemistry are quite literally textbook, and throughout the presentations he often seemed to know more than he was letting on. He challenged chart after chart incisively, and often cut in on history. When Allen brought up Roger Revelle’s work showing that oceans couldn’t absorb carbon—at least, not fast enough to stave off climate change, Alsup interrupted.

    “Is it true that Revelle initially thought the ocean would absorb all the excess, and that he came to this buffer theory a little later?” Alsup asked.

    “You may know more of this history than I do,” Allen said.

    Yes, I think the Judge has worn a very good poker face.

  37. 187
    Hank Roberts says:

    for M Passey:



    Well, the page you refer to ought to be up to date; if there’s more to add perhaps this will serve as a nudge:

    Climate model projections compared to observations ” RealClimate

    Apr 11, 2017 – Since we have been periodically posting updates (e.g. 2009, 2010, 2011, 2012, 2015, 2016) of model output comparisons to observations across a range of variables, we have now set up this page as a permanent placeholder for the most up-to-date comparisons. …

  38. 188
    nigelj says:

    Dan DaSilva @171

    “This is a virtuous and brilliant move by the oil companies, they can just quote the IPCC whatever they say whenever they say it.”

    Not such a brilliant move, and more of a double edged sword. The oil companies now accepting the science may insulate them from future claims of negligent deception, but doesn’t apply to the current case of course because it comes too late, and it will strengthen the case for a carbon tax because the oil companies cannot now argue the science is wrong.

    In fact we are left with a tiny handful of eccentric climate scientists arguing the science is wrong. The same names occur all the time.

  39. 189
    Hank Roberts says:

    Another link suggestion for M. Passey, about extreme weather attribution:

    which, by the way, includes a pointer to this thread:

  40. 190

    And meanwhile, in a different court, the Administration is told they must consider climate change when making plans for new coal leases on Federal land:

    We’ll undoubtedly be hearing moaning and gnashing of teeth about ‘climate activist judges.’

  41. 191
    SystemicCausation says:

    I refer readers back to this January article on Real Climate

    The six principles are pretty straightforward:

    1) Be a confident communicator
    2) Talk about the real world, not abstract ideas
    3) Connect with what matters to your audience
    4) Tell a human story
    5) Lead with what you know
    6) Use the most effective visual communication
    Each is supported with references to the relevant literature and with climate-related (“real world”) examples that are themselves confidently communicated with effective visuals.

    I am wondering if there is any chance the 8 answers could be re-edited without breaking every one of those 6 Principles along the way?

    If not, then I am afraid the IPCC has wasted several hundred thousand dollars on their new handbook on science communication.

  42. 192
    M Passey says:

    Hank Roberts 187, 189. I have been looking at the histogram of the models spread compared to observational means at the bottom of the Climate Model Projections Compared to Observations page as the definitive way to look at the question of how the models are performing. It sounds like you are saying that I am wrong about that. The Grist article/Zeke Hausfather is right in the contention that the models have routinely underestimated the rate of global warming. Gavin is out of date. Nudge.
    The article you linked to at Then There’s Physics states “We probably have not been able to definitively demonstrate that the rising cost of weather disasters can be formally attributed to the human emission of greenhouse gases. “ So it seems that the answer to my question about whether an actual statistical signal for anthropogenic extreme weather events has emerged to a greater level of confidence since the last IPCC report is no, not definitively.

    The reason I’m interested in this is that this California lawsuit is a tort action. The underlying premise of tort actions is demonstrable damages. As stated in the complaint “…causing harm now and in the future risks catastrophic harm to human life and property.” It will be extremely interesting to see what Judge Alsup takes as proof of this claim. Can they prove in a court of law that Bay Area cities have suffered current damages from anthropogenic climate change? Can they prove that sea level rise at San Francisco has accelerated above the baseline trend? Will the judge take climate models and attribution models as definitive legal proof of compensable future damages? It seems like a big deal to me.

  43. 193

    #192, M. Passey–

    I have been looking at the histogram of the models spread compared to observational means at the bottom of the Climate Model Projections Compared to Observations page as the definitive way to look at the question of how the models are performing.

    But those histograms are not “definitive” as an assessment. They are fine as far as they go, but they are relevant to satellite data, not instrumental data, and are for the mid-troposphere, not the surface.

    On both counts the observational data is much ‘noisier’ than the instrumental data (which of course is basically surface data).

    It would be interesting to see a corresponding histogram for the surface/instrumental data; but I think it’s safe to assume that there’d be considerably more overlap between models and observed trends. The time-series graphs show that observations are pretty much right on the CMIP3 trend, and only a tick lower relative to the forcing-adjusted CMIP5 trend.

  44. 194

    MAR, #184 & 5–

    Thanks! In future, I’ll use the cut-and-paste method, if suitably motivated by the content I’m working with!

    It was interesting to see the codes fail in your comment, somewhat as they did in my attempt. HTML implementation on particular web sites is clearly a much bigger topic than wot I wot of.


  45. 195
    Hank Roberts says:

    > demonstrable damages

    perhaps including increased risk — remember how many decades the tobacco companies go by arguing that no individual smoker could attribute his particular lung cancer to any specific cigarette product? That changed.

    We’ll see how it goes.
    25 Rutgers L.J. 893 (1993-1994)
    An Analysis of New Jersey’s Increased Risk Doctrine
    Science for Judges V Introduction
    MA Berger – JL & Pol’y, 2006

  46. 196
    Radge Havers says:

    SC @ ~ 191

    Oft repeated: First rule of communication is, “Know your audience.”

    Specifically. Adjust the dials accordingly.

    3) Connect with what matters to your audience

    Balanced out and put in context (the requirements of Judge Alsup’s courtroom), there seems to be a functioning connection. We’ll see if it’s enough to inoculate effectively against uncertainty-itis, or if booster shots and patches will be required.

    It looks to me like the oily rhetoric that the carbon companies have been forced into may point to a weak defense of what they knew, when they new it, and what they did about it. The fact that the state of the art has progressed since the period in question shouldn’t be allowed to give them cover. IMO.

  47. 197
  48. 198
    Mr. Know It All says:

    Sea level report update March 28, 2018:

    Sea level indicator visible during daylight hours south of the tip of India (appx 6 PM to 6 AM pacific time).

    Today’s summary: sea levels steady as she goes.

  49. 199
  50. 200
    SystemicCausation says:

    196 Radge Havers, it seems that you and writers here are making huge leaps in assumptions about the ‘audience’. You have the judge’s name and that’s about it.

    Whereas the ‘audience’ is the Judicial system as a whole, and the Media, and the Public aware of this case, including the readers of climate blogs where these ‘answers’ are shared profusely.

    You may be right. You may be wrong. I believe those involved have not properly thought about what they are doing here, and have self-evidently forgotten the advice in the IPCC communication handbook within 2 months about talking about what great advice it is.

    I could be wrong. But if I believed I was wrong I would have remained silent. Feel free to ignore the heads up and remain absolutely certain you’re right as usual.

    Nothing above even went to the Judge. He’s a hypothetical proxy, right?

    To now be claiming the above was meant for him and tailored for him as ‘the audience’ are disingenuous and false. To suggest this now is the equivalent of reinventing history.

    He wasn’t the ‘audience’ Radge, you are! The entire thing is self-referential and ego driven approval seeking.

    It looks to me like the usual rhetoric is a weak defense for the failure of responsibility of climate scientists, the IPCC etc, the elected politicians hold as a collective to of what they knew, when they new it, and what they did about it.

    Then there is the Public. No one holds a gun to the head of people who use Fossil Fuels. But rather than take responsibility for their and your own behavior lets instead put it all on the heads of fossil fuel companies.

    When you filled up your tank the last 30 years or so what do you put in it?

    Mobil, BP, Shell or Lukoil gas? How do climate scientists get to work each day and what power runs their refrigerator at home?

    They never believed the oil companies, nor Monckton’s or Lamar Smith’s ‘spin’ so what’s their excuse for continuing to use fossil fuels for decades.

    Seriously please try to think a little deeper and line up the ducks better before over reacting to the truth of what was said about the incompetent communication of climate science knowledge since Hansen rocked up to a Congress.

    The outcome produced by this little effort to ‘communicate’ the truth of climate science in a way that might be understandable to a journalist, to judge or to the general public gain misses the mark.

    The IPCC Communication Handbook is but one very basic yardstick to compare it against. There are many others that show how badly it fails the test.

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