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All IPCC definitions taken from Climate Change 2007: The Physical Science Basis. Working Group I Contribution to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Annex I, Glossary, pp. 941-954. Cambridge University Press.

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  1. 2014 SkS Weekly News Roundup #47B

    At what point do we accept that anthropogenic climate change is actually taking place? If we accept that it is actually occurring now (as many scientists seem to concur) then all weather events must be accepted as being influenced by that change unless it can be proved that any part of our climate system functions independently of the rest.

  2. President Obama's climate leadership faces the Keystone XL challenge

    Rob Honeycutt @25,

    I'm going to take the time to break this down into components, and provide evidence where required.  You're welcome to dispute any point, or the reasoning linking them together.

    1. The Keystone XL pipeline will not reduce the overall supply of crude oil to the USA.
      1. The pipeline's origin will be in Canada and its terminus will be in the United States.
      2. Unless the direction of flow were to be reduced, the pipeline could not possibly reduce the total US supply of crude oil.
      3. Any reduction of crude oil supply in one region of the US (i.e. the Midwest) must necessarily result in an equal increase in crude oil supply further downstream (i.e. the Gulf Coast).
    2. The pipeline will reduce the cost of transporting crude oil.
      1. Transporting crude oil by pipeline is generally cheaper than by rail, at a cost of about $5 a barrel compared with $10 to $15 a barrel.
      2. Canada is currently exporting 163k bpd of crude oil by rail because existing pipelines are already at capacity.
      3. Additional pipeline capacity will reduce the volume of crude being shipped by railcar, reducing average costs.
    3. The pipeline's crude oil payload is not "earmarked for export".
      1. The refineries in the US Gulf Coast are specialized for the processing of heavy crude oil, having invested in complex secondary conversion equipment that breaks down long-chain hydrocarbons to produce greater volumes of higher value light fractions (gasoline, kerosene and diesel) relative to lower value heavy fractions (residual fuel oil, lube oil, asphalt and pet coke).  (Background reading.  Disclosure... I previously worked at McKinsey and advised clients on matters relating to refineries, pipelines, and many other things).
      2. The US currenly imports heavy crude from Mexico (919k bpd) and Venezuela (806k bpd).
      3. The pipeline will have capacity of 830k bpd, which is less than the amount of Latin American heavy oil currently being imported.
      4. The pipeline will displace crude oil imports, but is too small to result in crude oil exports.
    4. The pipeline will not increase exports of refined products.
      1. The US Gulf Coast refineries are operating at full capacity.
      2. Given the option of procuring cheaper fuel via pipeline, refiners will substitute it for more expensive Latin American heavy crude oil, but this will only lower their costs, not increase their output of refined products.
      3. That Latin American crude oil will, in turn, find its way by tanker to refiners in other foreign markets, contributing to foreign supply and lowering foreign prices for both crude oil and refined product.
      4. Since the Keystone pipeline will in no way reduce US demand for refined products, there is no reason that more refined product would be exported, especially since foreign markets would already see increased supply and lower prices.

    Conclusion:

    If the Keystone XL pipeline will result in:

    1. No decline in US crude oil supply,
    2. A reduction in transportation costs,
    3. No increase in exports of crude oil, and 
    4. No increase in exports of refined product,

    then, the pipeline will not cause the average price of US refined products (i.e. gasoline) to rise.

    NB.  The above is not an argument that US gasoline prices will fall.  In all likelihood, the lower costs of inputs and transportation will result in higher profit margins for refiners, with no significant change in the price at the pump.  

    This phenomenon was already observed in the Midwest, as a regional glut of crude oil (caused by insufficient pipeline capacity) brought down the price of crude oil but had no impact on retail gasoline prices.  Where did all the savings go?  To the refiners.

    Read about it for yourself:  The Incidence of an Oil Glut: Who Benefits from Cheap CrudeOil in the Midwest? Borenstein & Kellogg (2014)

    Regarding Keystone XL, the authors conclude:

    "The merits of these capacity expansions—particularly the Keystone XL project—have been a matter of public debate on both environmental grounds and the extent to which it will impact U.S. gasoline prices. While this paper is silent on environmental impacts, it does imply that the impacts on gasoline prices will be extremely limited. Because expanding Midwest crude oil export capacity will have only a minimal impact on Gulf Coast and world oil prices, U.S. consumers outside the Midwest will not experience a decline in gasoline prices. As for Midwest consumers, our results imply that capacity expansions that increase the Midwest crude oil price will not increase the Midwest gasoline price. This price is already being set by gasoline refined using Gulf Coast rather than Midwest oil, despite the depressed Midwest oil price. Resolving the Midwest crude oil transportation bottleneck will not affect this situation, thereby leaving Midwest gasoline prices unaffected as well."

  3. 2014 SkS Weekly News Roundup #47B

    localis: From the SkS Climate Science Glossary:

    Extreme weather event

    An extreme weather event is an event that is rare at a particular place and time of year. Definitions of rare vary, but an extreme weather event would normally be as rare as or rarer than the 10th or 90th percentile of the observed probability density function. By definition, the characteristics of what is called extreme weather may vary from place to place in an absolute sense. Single extreme events cannot be simply and directly attributed to anthropogenic climate change, as there is always a finite chance the event in question might have occurred naturally. When a pattern of extreme weather persists for some time, such as a season, it may be classed as an extreme climate event, especially if it yields an average or total that is itself extreme (e.g., drought or heavy rainfall over a season).

    Definition courtesy of IPCC AR4.

  4. 2014 SkS Weekly News Roundup #47B

    Surely all weather events that are now occurring, extreme or otherwise, are linked to climate change. Weather systems are all connected so it seems nonsense to isolate a particular event and state it is or isn't connected to climate change. We argue for scientific accuracy about what is happening to the climate and classifying individual weather events as "yes or no" seems a matter of opinion rather than accurate science.

  5. Why we need to talk about the scientific consensus on climate change

    Stephen Baines @40

    "econcomically" ... a shining example of "in typo veritas". It has always struck me that those who dismiss climate models are so certain about the predictive power of economic models forcasts of financial devastation when their track record is, to put it charitably, less than robust.

  6. New study shows warm waters are melting Antarctica from below

    dorje @7.

    Further to Rob Honeycutt @8, the temperature profile of Greenland shows only static heat fluxes from below. The changes are all from above and their impact can be used to plot Greenland surface temperatures at the summit of the ice cap back into the last ice age. And this would not be possible if the flux from below were changing with time.

  7. Why we need to talk about the scientific consensus on climate change

    ubrew12.  From I remember, having lived through it as a yong person, frankelfkin is actually correct, for the most part.  The oil embargo by OPEC created a huge increase in gas proces and shortages at gas stations that led to a large recession.  Energy independence was considered a key national security and economic issue by Carter.  His stated energy policy pretty clearly asserts this.  He was also interested in controlling environmental damage, but he was mostly thinking about atmospheric and water pollution by power plants and strip mining — including effects of acid rain.  

    By the time Reagan entered the white house OPEC had adopted a far less econcomically destabilizing pricing scheme - possibly due to competition from other sources.  The issue of energy independence had stopped being a political winner, and he claimed he was interested in market solutions that did not involve government intervention.  Acid rain and ozone would be the major environmental battles of the 80s in the US.

    One thing Carter did do in his policy was have money set aside to study effects of CO2 on the climate.  

    "--The President will request almost $3 million to study the long-term effects of carbon dioxide from coal and other hydrocarbons on the atmosphere (budget)."

    It's down the list a bit though. Doesn't seem like it was the major priority, and I (having lived through it all) don't remember it being mentioned as being important in the political landscape of the time. 

  8. Why we need to talk about the scientific consensus on climate change

    franklefkin@24: you are suggesting that American conservatives don't care about energy independence.  Carter cared: hence-renewables.  Reagan didn't care: hence-no renewables.  Nope.  In American politics, energy independence from the Middle East is a major political talking point among conservatives.  That's been true since the OPEC embargo.  But, if true, why did Reagan nix research that would have led to just such an energy independence?  The result indicates that neither side cares as much about energy independence (the subsequent push for 'Globalization' underscores this point).  What then, spurred Carter's investment?  I say Global Warming.  

  9. New study shows warm waters are melting Antarctica from below

    dorje...  Do you understand that these paper are not claiming that heating from below the ice sheets has changed any time in recent history, that would explain what we attribute to changes in greenhouse gas concentrations? They are merely quantifying the effect, which has likely been unchanged over the past century.

  10. New study shows warm waters are melting Antarctica from below

    Abstract/Summary of "Heat flux variations beneath central Greenland's ice", 2013:
    At the Earth’s surface, heat fluxes from the interior1 are generally insignificant compared with those from the Sun and atmosphere2, except in areas permanently blanketed by ice. Modelling studies show that geothermal heat flux influences the internal thermal structure of ice sheets and the distribution of basal melt water3, and it should be taken into account in planning deep ice drilling campaigns and climate reconstructions4. Here we use a coupled ice–lithosphere model driven by climate and show that the oldest and thickest part of the Greenland Ice Sheet is strongly influenced by heat flow from the deep Earth. We find that the geothermal heat flux in central Greenland increases from west to east due to thinning of the lithosphere, which is only about 25–66% as thick as is typical for terrains of early Proterozoic age5. Complex interactions between geothermal heat flow and glaciation-induced thermal perturbations in the upper crust over glacial cycles lead to strong regional variations in basal ice conditions, with areas of rapid basal melting adjoining areas of extremely cold basal ice. Our findings demonstrate the role that the structure of the solid Earth plays in the dynamics of surface processes.  http://nora.nerc.ac.uk/503004/

  11. New study shows warm waters are melting Antarctica from below

    dorje...  Neither of these papers say anything that would suggest that heat from submarine volcanoes is responsible for the warming of the past 50-100 years.

  12. New study shows warm waters are melting Antarctica from below

    Schroeder paper states:  We also observe high geothermal flux in the upper reaches of the central tributaries that are relatively close to the site of the WAIS Divide ice core (Fig. 3, location B), where unexpectedly high melt and geothermal flux have been estimated.* We estimate a minimum average geothermal flux value of about 114 mW/m2 with a notional uncertainty of about 10 mW/m2 for the Thwaites Glacier catchment with areas exceeding 200 mW/m2 (Fig. 3). These values are likely underestimates due to the low uniform geothermal flux value used in the ice sheet model (9) and the compensating effect of enhanced vertical advection of cold shallow ice in high-melt areas.

    As for Hillier and Watts--the point of course is heat, ocean warming; the source in this case of heat are submarine volcanoes, alot of them.

  13. Why we need to talk about the scientific consensus on climate change

    Russ R wants to make much of the fact that Cook et al did not assess the level of endorsement in the scientific literature (not the level of the concensus per se) about how dangerous AGW is.  He acts as if the level of consensus among climate scientists of how dangerous AGW is has never been assessed, but of course, it has been.  Specifically, In Bray and von Storch (2010), respondents were asked:

    "22. How convinced are you that climate change poses a very serious and dangerous threat tohumanity?"

    Responses were on a seven point scale, with 1 being "not at all convinced", and 7 being "very much convinced", which makes 4 "about 50/50".  In response to that question, a plurality of scientists responded that they were very much convinced that "climate change poses a very serious and dangerous threat to humanity".  In all, 78.9% of respondents are convinced that at least on balance of probabilities, "climate change poses a very serious and dangerous threat to humanity" (response of 5+).  That compares to just 9.3% who think that on balance of probabilities, "climate change [does not pose] a very serious and dangerous threat to humanity" (response of 3-).  10.8% are fifty-fifty on the topic (response of 4).

    Those who are not so sure of the threat may be reacting to the wording, which literally aserts not just a dangerous threat, but a "very serious and dangerous threat", and not just to the economy, or to people in low lying areas, or the poor, but to humanity itself.  On the other hand, I suspect many of those who consider the threat real do not consider it to be an existential threat, but only a generalized threat in which many (even a majority) of the population will not have their lives threatened.  A better defined question may well have had a more overwhelming response, but with a lower modal value.

    I am uncomfortable describing less than  90% assent as a "consensus".  Clearly, however, far more than a super majority of climate scientists consider global warming to be potentially a very serious threat; and among those who disagree, few (1.16%) would consider such an outcome to be unrealistic.  So, while Russ R wants to make it clear that Cook et al (2013) did not address the issue of how dangerous AGW was, the fact remains that there is overwelhming scientific suport for the claim that AGW is dangerous. 

  14. Why we need to talk about the scientific consensus on climate change

    Absolutely agreed.

    Moderator Response:

    [JH] Thank you.

  15. Why we need to talk about the scientific consensus on climate change

    Moderation Comment:

    Rob Honeycutt & Russ R:

    You have now entered into the Neverland of Excessive Repitition. Please cease and desist. Your future posts will be summarily deleted if they repeat what you have already posted on this thread.

  16. Why we need to talk about the scientific consensus on climate change

    I get the sense that you fail to grasp the definition of "implicit."

    im·plic·it
    adjective
    1. implied though not plainly expressed.
    "comments seen as implicit criticism of the policies"
    synonyms: implied, hinted at, suggested, insinuated

  17. Why we need to talk about the scientific consensus on climate change

    And Russ...  There is nothing about "finally admitting" anything. I have said now exactly what I've been saying all along, and the exact same thing that I've been stating since the paper was published.

  18. Why we need to talk about the scientific consensus on climate change

    Russ...  This is getting almost surreal.

    Yes, 97.1% of the papers do endorse the position that humans are causing global warming. Some do so implicitly. Some do so explicitly. Some do so explicitly and also quantify.

    Likewise, 2.9% of the papers reject the position that humans are causing warming. Some do so implicitly. Some do so explicitly. Some do so explicitly and also quantify.

    The example you presented is a paper that implicitly endorses that position, and does not implicitly reject that position.

  19. Why we need to talk about the scientific consensus on climate change

    Rob Honeycutt @30,

    Thank you for finally admitting that a Level 3 rating "does not need to have a specific claim relative to >50% of warming."   That's spelled out very clearly in the paper's methodology.

    But if Level 3 papers don't need to make a specific claim that humans are causing >50% of warming (and most that I've looked at make no such claim), then how can anyone claim that 97.1% of the abstracts find that humans are causing most warming?   The paper itself doesn't even make that claim... it only states:  "Among abstracts expressing a position on AGW, 97.1% endorsed the consensus position that humans are causing global warming."

  20. Why we need to talk about the scientific consensus on climate change

    Russ... Think of the exersize as being like this:

    You have a large bowl of puzzle pieces in front of you. The puzzle pieces come from several different puzzles. Your task is to find out what percentage of them fit one specific puzzle. That puzzle is the IPCC position stating that there is a >95% likelihood that more than half of warming over the past 50 years is due to human causes.

    There are seven other smaller bowls in front of you that you can place the pieces in, ranging from clearly fit to clearly do not fit. And you have one bowl in the middle for pieces that do not fit either way.

    What you are doing is conflating bowls 2&3 with bowls 5,6&7 in order to say that you can only build the puzzle with the pieces from bowl 1. This is clearly wrong. 

    The abstract you're presenting very clearly fits the idea that humans are the primary cause of warming. We have a problem with global warming and they are presenting a study that addresses one small issue related to that problem. 

    There is another puzzle (or likely several different puzzles) that can be constructed with the pieces from the rejection bowls that suggest that humans are not primarily responsible for global warming. The pieces in bowls 2&3 are ones that do not fit those puzzles.

  21. Why we need to talk about the scientific consensus on climate change

    Russ...  Cook13 was not attempting to only locate papers that quantitatively endorse the IPCC position. We were also looking at papers that implicitly endorse, as well as explicitly endorse without quantifying.

    The abstract you posted is a category 3. An implicit endorsement. It's not an implicit rejection since it does not minimize the IPCC position. It does not need to have a specific claim relative to >50% of warming. Any paper that made a specific claim would be an explicit endorsement (cat 2), and any paper quantifying the endorsement would be a category 1, explicit with quantification.

  22. Why we need to talk about the scientific consensus on climate change

    Rob Honeycutt @26 & 27,

    I'm not disputing the rating assigned to the Bronson & Mosier (1991) abstract above.  I just don't see how the abstract as written can possibly be intepreted as a claim that humans cause most (>50%) of warming.


    "We're talking about the endorsement or rejection of the IPCC position on global warming. The paper is offering a mechanism to reduce emissions of methane due to rice cultivation. Why the heck would they be concerned about reducing methane emissions if global warming is primarily a product of natural variation?"


    That's great... it's an implicit endorsement of the IPCC's general position.  But it's not support for a specific claim that most warming is man-made.

  23. Why we need to talk about the scientific consensus on climate change

    "I'd encourage the editors of this site to do likewise whenever they reference the Obama/OFA tweet."

    Then we can also assume that you would expect every "skeptic" blog out there to make similar qualifications every single time they mention the "pause." They must acknowledge when they cherry pick RSS. They must clearly state that there is warming in all the other data sets. They must also acknowledge cherry picking of start dates to present such a claim. And with models they must also clearly acknowledge when they are choosing single year baselines when comparing models to surface temps.

    I could provide you a list a mile long where "skeptics" are vastly more egregious in their presentations of information. But, I don't need to really do that because all you have to do is go to the "Most Used Myths" section of SkS in the left side column of this webpage.

  24. Why we need to talk about the scientific consensus on climate change

    And, btw, your interpretation is clearly incorrect.

  25. Why we need to talk about the scientific consensus on climate change

    Russ @23...  (sigh)

    1) Only categories 1 and 7 quantify.

    2) Ask yourself this question: Does this paper minimise human contribution relative to the IPCC position? 

    We're talking about the endorsement or rejection of the IPCC position on global warming. The paper is offering a mechanism to reduce emissions of methane due to rice cultivation. Why the heck would they be concerned about reducing methane emissions if global warming is primarily a product of natural variation?

  26. Why we need to talk about the scientific consensus on climate change

    Andy Skuce,

    Thank you.  I hadn't previously seen your blog or that post.  I stand corrected.

    Good on you for making that distinction.  

    I'd encourage the editors of this site to do likewise whenever they reference the Obama/OFA tweet.

    Moderator Response:

    [JH] Your recommendation has been duely noted — multiple times in fact. Any future posts by you that repeat your recommendtion will be summarily dismissed. Enough already!

  27. Why we need to talk about the scientific consensus on climate change

    ubrew12 @18,

     

    The reason for the uptake in spending for alternative fuels at that time was due to oil embargos (and general instability of supply) from OPEC nations, not due to any concern over climate change.

  28. Why we need to talk about the scientific consensus on climate change

    Rob Honeycutt @15,

    " No one participating in the rating of abstracts did their ratings as you're stating. Nor did any of the author self-ratings get applied that way."

    Alright then.  Let's be very specific about how abstracts were rated.

    Consider the following abstract to the Level 3 rated paper Effect Of Encapsulated Calcium Carbide On Dinitrogen, Nitrous-oxide, Methane, And Carbon-dioxide Emissions From Flooded Rice, Bronson & Mosier (1991):

    "The efficiency of N use in flooded rice is usually low, chiefly due to gaseous losses. Emission of CH4, a gas implicated in global warming, can also be substantial in flooded rice. In a greenhouse study, the nitrification inhibitor encapsulated calcium carbide (a slow-release source of acetylene) was added with 75, 150, and 225 mg of 75 atom % 15N urea-N to flooded pots containing 18-day-old rice (Oryza sativa L.) plants. Urea treatments without calcium carbide were included as controls. After the application of encapsulated calcium carbide, 3.6 μg N2, 12.4 μg N2O-N, and 3.6 mg CH4 were emitted per pot in 30 days. Without calcium carbide, 3.0 mg N2, 22.8 μg N2O-N, and 39.0 mg CH4 per pot were emitted during the same period. The rate of N added had a positive effect on N2 and N2O emissions, but the effect on CH4 emissions varied with time. Carbon dioxide emissions were lower with encapsulated calcium carbide than without. The use of encapsulated calcium carbide appears effective in eliminating N2 losses, and in minimizing emissions of the “greenhouse gases” N2O and CH4 in flooded rice."

    I've bolded the only the specific references to climate change.  The authors are very clear in pointing out that N2O and CH4, which are released from rice growing, are greenhouse gases.  

    They discuss CO2, another GHG, but without any mention of its warming contribution, and they do so in the same manner as N2, which has no warming potential.

    From the above acknowledgement that CH4 and N2O are GHGs, and that rice growing releases these gases, one can conclude that some warming must be manmade.  But the paper makes no quantification of how much of the total observed warming is manmade, and therefore can't possibly be taken as an endorsement that most warming is human caused.

    So unless I'm mistaken, this abstract fits into the category of endorsing the weak position (humans cause >0%), but not endorsing the strong position (humans cause >50%).  Nor does it minimize human contribution (endorsing <50%).

    Is my interpretation correct?

  29. Why we need to talk about the scientific consensus on climate change

    Russ @19... The challenge here is that the standards you apply are only applied to one side of the issue. You're more than willing to overlook egegious errors on the "skeptic" side but on the side of science the standards are such that no detail is too small to haggle. 

    Again, the OFA was perfectly justified in their phrasing because "dangerous" is clearly an implication of the IPCC position on human causation of climate change. 

  30. Why we need to talk about the scientific consensus on climate change

    Russ: I've yet to see a single clarification from any of them [the authors] pointing out that the description of their findings wasn't entirely accurate.

    Well, I did, in this blog post. I wrote:

    ...The paper received a lot of positive coverage, including Tweets from Barack Obama, Al Gore and Elon Musk. (They didn’t always get the details quite right: our survey was of the literature, not of scientists’ opinions and we had nothing to say about how dangerous climate change would be.)

  31. Why we need to talk about the scientific consensus on climate change

    Russ R. - That Obama tweet may have overstated Cook et al, but is in essence correct. The consensus in climate science is that recent climate change is overwhelmingly identified as anthropogenic in cause, and furthermore (as per AAR5 on Impacts) there is a consensus that climate change will have significant impacts that while a value judgement can quite reasonably be described as "dangerous"

    Unless you think there is support for a consensus that the impacts of climate change won't be expensive, disruptive, and/or harmful. In which case I would expect some references thereof. 

  32. Why we need to talk about the scientific consensus on climate change

    Rob Honeycutt @,

    "My point was that, it's not unjustified for OFA to make such a statement. It was a tweet after all, not an official presidential memorandum."

    And I agree with you on this... as I wrote above:  "It's understandable if a third party (Obama/OFA) mistakenly misrepresents a study's findings."

    I'm not faulting them at all for what's likely an honest mistake in a non-official social media tweet.

    But the authors of the study certainly know better and should't knowingly perpetuate misrepresentations of their findings.  I'm sorry for being repetitive on this point, but the authors repeatedly link to and promote the Obama/OFA tweet (as in this post), and I've yet to see a single clarification from any of them pointing out that the description of their findings wasn't entirely accurate.

    We'll just have to agree to disagree on what standards we expect.

  33. Why we need to talk about the scientific consensus on climate change

    Composer99@10: yes, of course, I see that now.

    Stephen Baines@17: assuming the policy response was driven by scientific consensus (or, at least, authoritative scientific concern) then the fact that Lyndon Johnson felt compelled to address Congress on this issue in 1965 is compelling.  Here is US federal spending on renewable energy, 1975-2005 (in 2005 dollars)US federal spending on renewable energy, 1975-2005 (in 2005 dollars)

    I think a substantial impetus behind those policy decisions, 1975-1980, was concern over Climate Change (with a change in administration the process shifted back to favoring fossil fuels).  And I think that concern reflected the Scientific consensus of its day.

    On policy, the consensus among experts matters, and so does its history for those left picking up the pieces of 'what went wrong'.  To take another example: if you have to delay the invasion of a country to search for WMD, to give the weapons inspectors already in the country time to pack up and leave, something in your information stream has gone horribly awry. 'What did you know, and when did you know it' becomes more than academic, in that case.

  34. Why we need to talk about the scientific consensus on climate change

    ubrew 

    "If Cook etal are casting about for another project, it would be fun to determine through abstracts just how long this overwhelming consensus has existed. I'm guessing, since around 1980."

    If I remember rightly, different elements of the consensus have emerged at different times.   Consensus about the greenhouse mechanisms was probably the 50-60s. Consensus about CO2 increase and the human cause of it was early-mid 60's. Consensus about the effect of how increasing GHGs worked within climate models with various feedbacks and spatial features was late 70s-early 80s. That was the state of the game when I was a grad student.

    Temperature change was not really clear until the late 80s, and some I knew and respected at the time argued it wasn't really certain that change was above natural variation even then (they did not agree with Hansen — we sometimes forget the level of unertainty at the time).  So I would say consensus really developed on that front in the 90s when temp change became clear in a number of ways.  The rest of the time has just been making sure other hypotheses (solar radiation etc) aren't really responsible, and detailing responses to make sure they agree with the GHG predictions. The UAH satellite fiasco probably extended the debate a bit, so it depends on what you mean by consensus. 

    The thing that really absolutely nailed it on for me was the fact  that you simply could not get a climate model to give you the observed temperature change withuot including greenhouse gases.  Interestingly, I always found this convincing for the very reason AGW skeptics find models unconvincing.  If you can't get a climate model, with all the complex processes, approximations and feedbacks involved, to reproduce observed change in global temps, then that almost certainly really rules out natural causes as a possible factor.  In other words, I always focused on the negative result in those papers, which to me is very convincing, especially since natural causes could explain a lot of the climate variations early in the 20th century.

    Anyway, the development of consensus around complicated topics like AGW is always peicemeal and complex.  It would be so cool to really map that out empirically through time, but it would take quite a bit of work!  

  35. Why we need to talk about the scientific consensus on climate change

    Moderation Comment:

    All: Given the SkS Comments Policy's prohibition against dogpiling, I hereby designate Rob Honeycutt as the official responder to Russ R on this thread. 

  36. Why we need to talk about the scientific consensus on climate change

    Russ @12...  No one participating in the rating of abstracts did their ratings as you're stating. Nor did any of the author self-ratings get applied that way.

    Once again, this is a case of deniers attempting to reframe the study in a way that deliberately misinterprets the paper.

  37. Why we need to talk about the scientific consensus on climate change

    Russ...  My point was that, it's not unjustified for OFA to make such a statement. It was a tweet after all, not an official presidential memorandum. 

    On a business-as-usual path, per the IPCC position (which Cook13 was referencing), climate change is very likely to be dangerous. Cook13 did not test for "dangerous" but it's perfectly rational to infer that position based on IPCC reports, the APS statement, NAS statements, etc.

    Spoken/written language is not math. You cannot apply mathematical precision to words. There is no need to issue a correction for the use of the word "dangerous" because, if we do not take action, climate change is very dangerous. The OFA was making broader, and perfectly justifiable, inferences in their use of language.

    The other thing I would note is, the issue of the OFA tweet always comes up as a distraction to the overall point of Cook13. There is a misperception in the general population relative to how certain science is about human causation for climate change. The exact phrasing of a single tweet does absolutely nothing to address or respond to that issue.

    Here's what keeps happening. "Skeptics" (a term I'm getting very tired of using because deniers are clearly not being skeptical at all) jump on the most tiny nuances of accuracy in order to try to reject what is blatantly obvious to the broad scientific community.

  38. Why we need to talk about the scientific consensus on climate change

    JH,

    If anyone can show me where the authors made any effort to publicly correct the error (the word "dangerous") in the Obama/OFA tweet, I'll very happily stand corrected.

    Moderator Response:

    [JH] Please reread my previous comment. It's all about the prohibition of excessive repetition by commenters.  

  39. Why we need to talk about the scientific consensus on climate change

    Tom Curtis,


    "The did, however, test the conensus on whether or not humans have caused at least 50% of recent warming."


    Yes, and they found that 64 out of of 4,014 abstracts which expressed a position (1.6%) offered "explicit endorsement with quantification".

    Abstracts that were rated Level 2 ("explicit endorsement without quantification") or Level 3 ("implicit endorsement") cannot generally be claimed to support the position that humans caused "most" global warming (>50%) if they only endorse the weaker position that humans are a cause of warming (>0%).

    And yes, I understand that abstracts which explicity or implicitly minimized human contribution (<50%) are categorized as Levels 5, 6, and 7.

    Including the Level 2 and Level 3 abstracts which only offer the weaker endorsement of human responsibility as >0%, with those papers that attributed >50% to human activity, and claiming that all of them endorse "most" warming is, in my opinion, a misrepresentation of the study's findings.

    Moderator Response:

    [JH] If my memory serves me correctly, you have previously gone around this track with Tom Curtis and other commenters on the threads to other posts about The Consensus Project. There is no need to regurgitate those discussions on this thread.

  40. Why we need to talk about the scientific consensus on climate change

    Rob Honeycutt,


    "The fact is, climate change is dangerous on a business-as-usual emissions path."


    The fact is, Cook et al did not test the consensus on whether or not AGW was dangerous.

    It's understandable if a third party (Obama/OFA) mistakenly misrepresents a study's findings.  It's unacceptable that the author(s) of that study made no effort to correct the mistake, and instead promoted and perpetuated the misrepresentation.

    Moderator Response:

    [JH] You are entitled to express your own opinions on this website. You are not entitled to repeat them ad naseum. Per the SkS Comments Policy:

    • Comments should avoid excessive repetition. Discussions which circle back on themselves and involve endless repetition of points already discussed do not help clarify relevant points. They are merely tiresome to participants and a barrier to readers. If moderators believe you are being excessively repetitive, they will advise you as such, and any further repetition will be treated as being off topic.
  41. Antarctica is gaining ice

    dvaytw - Long story short, that title is based on a misunderstanding. Frezzotti et al 2013 is discussing the surface mass balance, which is the amount of incoming mass in Antarctica, comparing ice cores to models for that quantity. This is an input quantity only. 

    They are not looking at the total mass balance, the total change of ice mass due to the balance of input (snow) and output (melt, glacier calving), which show Antarctic mass loss. 

    I suspect the emphasis of that 'skeptic' title is due to a misunderstanding of that point. 

  42. Why we need to talk about the scientific consensus on climate change

    ubrew12:

    If Cook etal are casting about for another project, it would be fun to determine through abstracts just how long this overwhelming consensus has existed. I'm guessing, since around 1980.

    Cook et al did look at the extent of consensus over time, at least back to 1990, as per Figure 3 in the paper.

  43. Antarctica is gaining ice

    @dvaytw 367:

    For a detailed discussion of Zwally et al (2005) and similar papers, see Robert Way's article, New and Improved Ice Loss Estimates for Polar Ice Sheets posted on Oct 1. 2014.

  44. Antarctica is gaining ice

    I know someone in the comments section must've already brought it up, but I don't really want to fish through eight pages.  Can anybody tell me what's the deal with the papers from Frezzotti et al and Zwally saying that in fact the Antarctic is actually gaining ice overall over the last 800 years?

    Antarctica gaining Ice Mass (balance*) — and is not extraordinary compared to 800 years of data

    Moderator Response:

    [JH] For future reference, the SkS search engine is a useful tool. 

  45. Why we need to talk about the scientific consensus on climate change

    "scientists should be talking about evidence, rather than consensus."  That's valid... for Scientists.  But the debate in the media and public venues is not a Scientific debate, it's a Policy debate.  This is what the general public should debate, not the Science, for which they are naturally ill-informed.  Indeed, as any denier can tell (as every denier has told you), a single Scientist (a Galileo, if you will?) can with evidence win the Scientific debate.  But policy, as every Galileo will tell you, is made through consensus.  

    Doubly strange, many deniers will pledge fealty to the concept of 'meritocracy', and in the very next sentence, unaware of the irony, will tell you 'those Scientists' don't know their Science.

    If Cook etal are casting about for another project, it would be fun to determine through abstracts just how long this overwhelming consensus has existed.  I'm guessing, since around 1980.  

  46. 2014 SkS Weekly News Roundup #47A

    Al Jazeera now has this coverage, too:

    Cold snap caused by climate change-weakened jet stream, scientists suggest

  47. Why we need to talk about the scientific consensus on climate change

    JoeK @4 & Rob @ 5 & 6.

    While I agree with Rob's comments, the danger is not just BAU emisions for the future but that the inertia in the climate system at 400 ppme CO2 means that with out reduction to 350 ppme CO2 or lower in the next 100 years approximately we have lost the worlds coastal cities! It's not just a metre of sea level rise but 12 -25 metres at equilibrium.

    What is not talked about anywhere near enough is that every developed country person needs to remove 300 tonnes of carbon from the atmosphere for all the coastal cities to be kept and the oceans from loosing fish. People talk about being carbon neutral as if it's the mark to aim for. That is the just "for now" mark to aim for but we really do need to stop coal use dead and then take the 300 tonnes Carbon per westerner out of the air!

    The state of WAIS is that it's now too late to save it from sliding into the sea in the next few hundred years with out a drop to 350 ppm. That is the largest lost of our best arible land since the end of the last ice age.


    The world economy and coastal land is closely tied to the survival interests of a large part of the worlds current population. The inability of a significant portion of the wealthy to end the funding of fossil fuels (at the rate that would pay for the switch to sustainable non carbon energy) is a real and current threat to civilisation for the next 10,000 years as a minimium.

    To end humanities civilisation in one ignorant generation of one eyed wealth is remarkably dangerous by anyones definition of dangerous.


    The danger is that the current CO2 levels take us out of the Holoscene climate state of the last 7 - 10,000 years that has allowed civilisation to develop. The cost to make the needed changes is do-able currently but the door is closing.

  48. New study shows warm waters are melting Antarctica from below

    Same with the Hillier and Watts paper. Neither of these have any relation to climate change or changes in ice mass loss rates in Antarctica.

    LINK

  49. New study shows warm waters are melting Antarctica from below

    Sorry dorje... But the actual Schroeder paper makes none of the assertions you or "tech times" claim.

    http://www.pnas.org/content/111/25/9070.long

  50. New study shows warm waters are melting Antarctica from below

    Dusty Schroeder, lead author of the article announcing the results, helped lead a team that used aerial surveys to create radar maps capable of penetrating the surface of the ice. They found two bodies of water under the glacier which interacted with each other, distributing heat in the process.

    The source of heating is believed to be a tearing apart, or rifting, of the crust under the Antarctic ice sheet. This allows movement of magma and creates volcanic eruptions, melting the ice. Liquid water and geological activity under the sheet allows the massive feature to slip off the continent.

    http://www.techtimes.com/articles/8278/20140610/underwater-volcanoes-climate-change-reason-melting-west-antarctic-ice.htm#ixzz3Jec2ZNjB

    …………………………………………………………………………………………….

    In 2007, oceanographers Hillier and Watts surveyed 201,055 submarine volcanoes. “From this they concluded an astounding total of 3,477,403 submarine volcanoes must reasonably exist worldwide,” said this article by John O’Sullivan.

    Hillier and Watts “based this finding on the earlier and well-respected observations of Earth and Planetary Sciences specialist, Batiza (1982) who found that at least 4 per cent of seamounts are active volcanoes.”

    According to Batiza’s survey, the Pacific mid-plate alone contains an incredible 22,000 to 55,000 underwater volcanoes, with at least 2,000 of them considered active. http://www.themoralliberal.com/2011/05/09/volcano-heats-high-mountain-lake-to-108-degrees/

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