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What You Need to Know about the Forthcoming Climate Change Report

The views expressed are those of the author and are not necessarily those of Scientific American.

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ipcc-logoTalk about management by committee: one group of more than 800 scientist authors to cope with more than 9,000 scientific publications on climate change and more than 20,000 comments from “expert reviewers” (plus another 30,000 or so from various other interested parties.) Now the Intergovernmental Panel on Climate Change is into four days of wrangling in Stockholm between scientists and governments over the wording of a warning on climate change that we’ve all heard before.

They will literally go over it line by line, with countries like Russia asking that plans for gargantuan mitigation projects like geoengineering be included somehow and countries like Saudi Arabia wondering whether climate change is such a big deal after all. Because, you know, the “hiatus,” or “pause,” or whatever you want to call it.

Of course, said plateau in the upward trajectory of average global surface temperatures says nothing about the fundamental physics that involves molecules of carbon dioxide and other greenhouse gases trapping ever more heat within the Earth’s atmosphere and oceans. Nothing has fundamentally changed since the first assessment in 1990 concluded: “emissions resulting from human activities are substantially increasing atmospheric concentrations of greenhouse gases… These increases will enhance the greenhouse effect, resulting on average in an additional warming of the Earth’s surface.”

In other words, thank the vast Pacific Ocean (particularly perhaps its watery deeps) for keeping climate change from accelerating out of control and watch out for the next El Nino, which could well trigger a major uptick in the global thermometer. Or, as IPCC co-chair Qin Dahe of China put it in a press release: “The scientific evidence for anthropogenic climate change has strengthened year by year, leaving fewer uncertainties about the serious consequences of inaction, despite the fact that there remain knowledge gaps and uncertainties in some areas of climate science.” Ahem, clouds (though the most recent science suggests, on balance, clouds are likely to contribute more warming than cooling), aerosols, etc. Yes, uncertainty reigns, but safe is better than sorry. Most of us buy fire insurance after all.

So here’s the preview:

(1) We’re responsible. Period. And CO2 is the main greenhouse gas.

(2) Effects of climate change, like the meltdown of Arctic sea ice or sea level rise, are happening faster than anticipated (in previous IPCC reports, notoriously conservative.)

(3) Ocean acidification continues apace and could end up being the long-term legacy of greenhouse gas emissions from fossil fuel-burning and forest-clearing.

(4) The global warming of surface temperatures has just as good a chance of being not that bad (another 1 degree Celsius by 2100) as terrifyingly bad (plus 4 degrees C this century) with something in the middle most likely.

(5) No matter what we do tomorrow, the greenhouse gases already in the atmosphere will be changing the climate for centuries to come. So get ready to adapt.

The real question is (and always has been): is any of that enough to prompt action? Concentrations of greenhouse gases in the atmosphere touched 400 parts-per-million for the first time in human history this past May, after all. Regardless, watch this website for more throughout the week and in the turbulent decades to come.

David Biello About the Author: David Biello is the associate editor for environment and energy at Scientific American. Follow on Twitter @dbiello.

The views expressed are those of the author and are not necessarily those of Scientific American.

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  1. 1. Sisko 9:04 am 09/24/2013

    David Biello and the IPCC continue to push what they believe is the proper environmental agenda vs. honestly publishing the current science accurately.

    Scientific American refuses to acknowledge the increasing number of highly reputable climate scientists who are stating that the IPCC’s assessment process is deeply flawed and has been circumvented by too many environmentalists promoting a preconceived agenda and not accurate science.

    Based upon early drafts of the AR5, the IPCC seemed prepared to dismiss the pause in warming as irrelevant ‘noise’ associated with natural variability. Under pressure, the IPCC now acknowledges the pause and admits that climate models failed to predict it. The IPCC has failed to convincingly explain the pause in terms of external radiative forcing from greenhouse gases, aerosols, solar or volcanic forcing; this leaves natural internal variability as the predominant candidate to explain the pause. If the IPCC attributes to the pause to natural internal variability, then this begs the question as to what extent the warming between 1975 and 2000 can also be explained by natural internal variability. Not to mention raising questions about the confidence that we should place in the IPCC’s projections of future climate change.

    Nevertheless, David Biello and the IPCC appears to be set to conclude that warming in the near future will resume in accord with climate model predictions.

    Why is many scientist’s reasoning about the implications of the pause, in terms of attribution of the late 20th century warming and implications for future warming, so different from the conclusions drawn by the IPCC? The disagreement arises from different assessments of the value and importance of particular classes of evidence as well as disagreement about the appropriate logical framework for linking and assessing the evidence – reasoning that is weighted heavily in favor of observational evidence and understanding of natural internal variability of the climate system, whereas the IPCC’s reasoning is weighted heavily in favor of unproven climate model simulations and external forcing of climate change.

    Scientists do not need to be consensual to be authoritative. Authority rests in the credibility of the arguments, which must include explicit reflection on uncertainties, ambiguities and areas of ignorance and more openness for dissent.

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  2. 2. David Biello in reply to David Biello 10:37 am 09/24/2013

    I am going to leave your comment up Sisko because it is presented in a reasonable tone. But, just for the record, there is no “increasing number of highly reputable climate scientists” denigrating the IPCC nor disagreeing about the attribution of late 20th century warming etc. As the post notes: “uncertainty reigns but safe is better than sorry. Most of us buy fire insurance after all.” If you really want to learn about the failure to set new records post-1998 (the last El Nino) you can check here:

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  3. 3. Sisko 10:49 am 09/24/2013


    I strongly disagree with your conclusion that there is not an increasing number of respected climate scientists who agree with what I have written.

    As examples look at Judith Curry of Georgia Tech. and Jochem Marotzke, director of the Max Planck Institute for Meteorology, in Hamburg. Both now write that they disagree with the IPCC’s conclusions and the process they have followed and both originally supported the IPCC’s conclusions in 2007.

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  4. 4. David Biello in reply to David Biello 11:13 am 09/24/2013

    It’s true that there has to be room for ambiguity, uncertainty and the like and dissent is an important part of the scientific process. That said, almost no one, not even Curry or Marotzke, disagrees with the fundamental physics of greenhouse gases. Marotzke merely notes that there is a discrepancy between model predictions and actual results, which means that the models are missing something (i.e. simplifications.) Yes, this is true and means with better models we’ll get better results. Care to chip in for the next supercomputer?

    As for Curry, her quibble is with what the fundamental physics portend and, more importantly, what the appropriate response should be. The former is shorthanded as “sensitivity” and remains an outstanding scientific debate:

    though there has been a lot of good work done and we’re running the natural experiment (albeit without any controls). The latter is pure policy, which means we’ll apparently argue about it forever.

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  5. 5. Sisko 11:48 am 09/24/2013

    With all due respect, you seem to be trying to change the discussion. Yes, there is an agreement that all other factors remaining constant that additional atmospheric CO2 will lead to some warming. That has NEVER been a significant argument.

    The disagreements (as you know but seem to be trying to avoid) is about the rate of any warming and what other changes will occur where and when as a result of any warming. If the rate of warming is not significantly amplified by additional forcings then it will be much lower than the IPCC has predicted and will not be of nearly the level of concern to the nations of the world since the changes will occur over greatly extended timescales and can be adapted to reasonably easily.

    BTW- as you also know- there is significant debate about what impact there will be to other conditions as a result of any warming that does occur. In the last IPCC comprehensive report AR4, the authors the IPCC used relied on the outputs of general circulation models (GCM’s) that predicted changes in conditions around the world as a result of AGW. These models made forecasts such as changes in rainfall patterns and changes in the extent of glaziers that were predicted to be disasters for humanity. We now know that these models generally produced inaccurate results in making such predictions don’t we? So how should we use an analysis of a scientist that wrote that life for humans would be worsened due to AGW because it would rain less in a particular area, when the model that was used to make the prediction has been show to be inaccurate?

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  6. 6. David Biello in reply to David Biello 12:03 pm 09/24/2013

    At least we agree on first principles then (not always the case) and, it sounds like, the policy debate, which is where the real disagreement lies. Now “rate of warming” to you is what I called “sensitivity” in my response, so no avoidance there respectfully. Hopefully that clarifies it for you. I’m flummoxed however by your “greatly extended timescales”? Is less than 100 years compared to the geologic rate of climate change not a greatly shortened timescale? It certainly seems so to me.

    One other note: the predicted changes in conditions as a result of AGW are progressing faster than predicted. So, you’re right, the models were wrong… about things like Arctic sea ice, sea level rise, ocean warming, etc. The goal of the modeling is to give a generalized prediction being that any model is, by its nature, a simplification of the real world. Models are always wrong. The more appropriate question is whether they tell you something useful. In the case of climate change, what they are telling us is that outcomes could be bad to really bad so why not take some preventive action, given that it will cost less to do so today than to adapt to big changes in the future.

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  7. 7. Sisko 1:53 pm 09/24/2013

    The climate’s sensitivity to temperature change as a result of changes in CO2 concentration and the potential resulting secondary impacts are the keys to whether a reasonable person concludes that drastic actions are needed to reduce worldwide CO2 emissions. There is also a secondary question as to whether CO2 emissions reductions are economically realistically possible in the amounts necessary to keep overall concentrations from rising for decades to come.

    Let’s look at a few of your key points:
    You wrote- “The predicted changes in conditions as a result of AGW are progressing faster than predicted.”
    My perspective- I disagree. There were many different conditions described by the IPCC which were predicted to change that would negatively impact humanity. Which do you believe happened faster than was predicted?

    You wrote_ “The goal of the modeling is to give a generalized prediction being that any model is, by its nature, a simplification of the real world. Models are always wrong.”

    My perspective- As an engineer who uses models I assure you that models are typically NOT used just to give general predictions. Models are not ALWAYS wrong. (even a broken clock is right occasionally- so writing that models are always wrong sounds cute, but is inaccurate. What a model is supposed to do is perform within a known margin of error. A model is not supposed to be used for other than developmental purposes until that information is known.

    David- it is untruthful for you to write “what they are telling us is that outcomes could be bad to really bad so why not take some preventive action, given that it will cost less to do so today than to adapt to big changes in the future”. There are many, many different models and they do not all provide the same or even similar outputs. You are being inaccurate to write that these models tell us it will cost less to address the issue today vs. later. That is simply untrue. You have no way of knowing how much conditions will or will not change at different levels of CO2.

    David- can you point to ANY other field where the results of many different unvalidated models are averaged and the average result is considered meaningful?

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  8. 8. David Biello in reply to David Biello 2:21 pm 09/24/2013

    I agree completely with your first paragraph, so that’s good.

    Second para: I already listed them (Arctic sea ice, etc.)

    Third para: fair point. There are many different types of models. The ones used in climate change are predictive models, like the ones that tell you whether to bring an umbrella or not. This kind of models is used to refine understanding of a complex system, involving many feedbacks, and is tested against observations.

    Fourth para: I don’t even know what to say. The GCMs (as you noted in your reasoning for distrusting them) all deliver reasonably similar outputs (i.e. more CO2 = more warming, a point on which we all agree.) And the economic models, depending on the inputs (i.e. discount rate, etc.), show us that it will cost less today than tomorrow.

    Final point (with which I conclude this hopefully illuminating back and forth): you seem to think that climate science is all about models. It’s not. It’s in the observations too. We just need the models to give us some dim understanding of what the future holds so we can make reasonable decisions.

    I appreciate the fact that we have not descended into the usual name-calling and whatnot, so thank you for that.

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  9. 9. 3:13 pm 09/24/2013

    Oh, we’re already taking action – just not in the forms some might prefer. Reuters today reported on the new premiums under U.S. federal flood insurance programmes. They focused on a lady in Florida who will see her premiums shoot up from $1,700 a year to $15,000 annually. She’s a realtor and said that the value of her coastal property just fell by half. She thinks she’ll have trouble even selling because adding that flood premium to a mortgage payment would price a lot of buyers out of the market and you can’t get a mortgage without flood insurance in place.

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  10. 10. Sisko 3:36 pm 09/24/2013

    I also appreciate that you have agreed to have a reasonable exchange of information and views and not descended into name calling. I think the exchange will be of value to other readers.

    Regarding what changes in conditions are happening faster than the IPCC forecasted in AR4- You cited “meltdown of Arctic sea ice or sea level rise”. These are actually two separate issues that are somewhat related. I agree that there has been significant summer ice met in the arctic. Why is this a concern to you or anyone else? Regarding sea level rise- there has NOT been a change in the rate since 1992 so it is wrong for you to write that sea level rise has been faster than expected. If anything, sea level has been rising slower that was expected. There is no evidence of an increase in the rate of sea level rise. It may happen in the future- but there is no reliable evidence to make a prediction of how much or when.

    Regarding model performance- David, you are either misinformed or being highly misleading regarding GCMs. There are many different GCMs and they do not all provide similar outputs. I included a link to a simple chart summarizing the performance of just some of the models on just one characteristic they forecast- temperature. General circulation models forecast many different variables for different locations around the globe over time. (sorry for the source, but it was convenient)

    So GCMs are not simple models to tell you whether to bring your umbrella, but some of the most complex computing models ever programmed and they are simply not very accurate. They may be someday, but not today. They certainly are not accurate enough for anyone to use to predict that farming is a particular region will likely be harmed due to lower rainfall that will result from AGW.

    Economic models are something completely different and unrelated to the basic climate debate. I happen to have a masters in economics so this is also very interesting to me.

    David- please consider:
    The IPCC does not have any reliable models to tell them how conditions will be at any particular location around the world as a function of different CO2 levels over time, they have no means of reliably forecasting what changes in conditions will occur and where and when. How are they reliably estimating harms when they can’t even tell what area will get more vs. less annual rainfall? How is the IPCC estimating the benefits of their suggested actions? David- I agree that GCM performance is not the whole story of AGW, but you should agree that they are the basis of the vast majority of the predicted harms. Without GCMs there is no other means to forecast the future conditions reliably, and the current set of GCMs are insufficient for that purpose.

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  11. 11. mihrant 4:03 pm 09/24/2013

    During the past Ice Ages CO2 ranged from 180 to 280 ppm, a 50% rise. During that period temperatures ranged from -4 to -8 degrees C below the 1950 temperature.

    As pointed out in the article, CO2 levels have now risen from 280 ppm to 400 ppm in the past few centuries, corresponding to a 43% range — almost the same percentage range as during the Ice Ages. If CO2 is the major cause of warming, the temperature should have already gone up roughly 4 to 8 degrees C from the 1950 level. It has not, therefore it is clear from comparison with measurement that temperature does not vary linearly with CO2.

    And yet the models display a linear relationship between CO2 and temperature! Not only that, but they show no lag between CO2 rise and temperature rise. The historical data show that there is a lag of roughly 800 years.

    These two disagreements between the model and measured data suggest to me that the today’s climate models are grossly faulty.

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  12. 12. sault 4:18 pm 09/24/2013


    Anthony Watts is NOT a climate scientist and his website is NOT a venue for peer-review. Trusting the falsehoods he puts out is why you are so confused on climate science. Regardless of the misinformation Watts is putting out there, actual sea ice extent (Figure 13) and sea level rise (figure 16) has been EXTREMELY underestimated by the IPCC:

    When Watts and the other deniers out there consistently ignore facts that don’t conform to their beliefs, it’s time to stop listening to them.

    And as far as solutions go, what’s so wrong with ending fossil fuel subsidies and strictly controlling pollution so that negative externalities are minimized? Shouldn’t we want markets to be fair, transparent and incorporate all costs so they can operate more efficiently? Allowing polluters to get away with burdening the rest of us with their waste so they can sell an artificially cheap product is neither good for the economy nor is it the moral choice.

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  13. 13. BruceWMorlan 4:34 pm 09/24/2013

    The back-and-forth between David and Sisko is very refreshing, but r.dresser is very correct to point out an example of second-level coping (the market place has moved even if those who believe in markets have not, ironic, no?). But I believe the bigger question is whether we believe that we can change the short range (say 3 decades) anthrogenic inputs with anything other than raw, brute-force regime changes imposed by military force? I think not. And are we willing to take that step? Again, I think not.

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  14. 14. sault 4:49 pm 09/24/2013


    You are missing huge pieces of the climate science picture! The forcing from increased CO2 is LOGRHYTHMIC, taking the form of:

    “dF = 5.35 ln(C/Co)

    Where ‘dF’ is the radiative forcing in Watts per square meter, ‘C’ is the concentration of atmospheric CO2, and ‘Co’ is the reference CO2 concentration. Normally the value of Co is chosen at the pre-industrial concentration of 280 ppmv.”

    So no, trying to draw conclusions about seemingly equivalent CO2 concentration rises in the past like you do is just silly and shows that you need to do your homework.

    In addition, actual temperature change is expressed by:

    “dT = λ*dF

    Where ‘dT’ is the change in the Earth’s average surface temperature, ‘λ’ is the climate sensitivity, usually with units in Kelvin or degrees Celsius per Watts per square meter (°C/[W/m2]), and ‘dF’ is the radiative forcing.”

    Another glaring hole in your knowledge is that climate sensitivity generally FALLS as the Earth warms (within the temperature ranges of the glacials / interglacials you are referencing). While it will never be as low as the climate deniers (aka misinformers paid off by the fossil fuel companies) would like you to believe, sensitivity MUST fall off or our climate would be a lot more unstable than we’ve seen in the past.

    Several mechanisms are responsible for falling climate sensitivity. For starters, the main difference between climate sensitivity during the depths of the last “Ice Age” and now is that the ice was covering up areas that received a lot more solar energy than what it does currently. For example, melt a glacier over New Jersey and you’ll capture a lot more additional solar energy than melting a New Jersey-sized chunk of Greenland today. In addition, a glacier retreating 5 degrees north from its terminus in New Jersey will uncover a lot more surface area than a glacier retreating 5 degrees north in Greenland, amplifying the effect.

    You also need to account for thermal inertia in the Earth’s climate system since a lot of warming is “already baked into the cake” but hasn’t been expressed by increased global temperatues yet. There is a 30-year or possibly longer lag time in the Earth’s climate just for the fast feedbacks to kick in and maybe closer to a century for all the slow feedbacks to be expressed. Therefore, your comparison is even more deeply flawed.

    There are probably more ways to show how you are incorrect, but you’ve got plenty of homework to do for now…

    Equations and explanations from:

    P.S. – You should look this page over since it explains things very well and uses TONS of peer-reviewed scientific papers to back up its points.

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  15. 15. Sisko 5:11 pm 09/24/2013


    If you take a closer look you will notice the data I posted was put together by Roy Spencer and was only posted at WUWT. If you can find any error in how the results were plotted you would have a valid point. Critizing the website that posted the summary of results is typically silly of you.

    Regarding sea level rise-Why would you post something you know to be old misleading data. Here is the actual data on sea level rise. As you know it has been pretty consistent since late 1992. There is no way to truthfully spin that sea level is rising faster than was predicted by the IPCC in AR4.

    Honesty is important in these types of exchanges.

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  16. 16. sault 5:32 pm 09/24/2013


    You OBVIOUSLY didn’t look at the figures I posted. It’s times like these that I wish SciAm allowed you to post images directly. But regardless, you emulate Watts since you don’t even bother to look at the science.

    I’ve already debunked that nonsense put out by Spencer several times. Limiting your observations to the tropics like he does GUARANTEES that you will miss the vast majority of the warming signal since it is concentrated towards the poles and mid-latitudes. Again, Dr. Spencer is BLATANTLY ignoring evidence that does not fit with his predetermined conclusions. This is par for the course since he has a habit of getting things wrong:

    Why you would still trust this guy is beyond me…

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  17. 17. Sisko 7:50 pm 09/24/2013


    Learn to at least read and understand the links you provide. The link you provided did not provide projections of sea level rise from the IPCC’s AR4. It supposedly shows projections from 1990. AR4 is from 2007.

    Why do you refuse to be honest and review the actual facts? Do you deny the science that the rate of sea level rise has been pretty darn steady for over 20 years with no sign of an increase in the rate. those are honest facts. You do not like dealing with the truth of the situation because they conflict with your beliefs. That is my opinion.

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  18. 18. Postman1 9:05 pm 09/24/2013

    Sisko, thanks, I enjoyed the back and forth with David. Good comments. Don’t engage the saultbot and maybe it will go away.

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  19. 19. rkipling 11:01 pm 09/24/2013

    Mr. Biello,

    I’m flummoxed about all the attention to climate models as if convincing everyone that the models are correct will solve the problem. I would like to know what specific solutions you believe could best deal with the problems the IPCC predict. Without viable solutions all the back and forth about the models is pointless.

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  20. 20. Carlyle 4:06 am 09/25/2013

    Wow. I have been happy to be on the sidelines for this discussion. I did detect a threat of censorship in comment #2 though. The default way to win an argument.

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  21. 21. Sisko 4:59 pm 09/25/2013

    I want to thank David for an informative exchange. It is entirely possible to have productive discussions and not have anyone being described with insulting names.

    Did the exchange teach any of the readers anything?

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  22. 22. rkipling 5:57 pm 09/25/2013

    I’m hopeful but not optimistic that people learned comments need not contain insults.

    I’m not that interested in the argument about climate models. Regardless of what the models predict, and regardless of what people anticipate in the way of AGW drastic action won’t be taken. At least not drastic in terms of mass conversion of energy sources. The economic disruption would not be tolerated by voters in the developed countries. I guess you could argue what increased energy cost most people would consider drastic? But my expectation is economics will limit mediation actions at some level. Mediation actions estimated on par with the entire U.S. federal budget are unlikely for example, and some of the proposals posted on this site are at that level.

    I’m not yet convinced CO2 concentration will affect any significant climate change. Still, measures that could reduce pollution such as nuclear power also reduce CO2 emissions. Where green energy can compete without subsidies, alternative energy is fine too.

    I’m interested to know what Mr. Biello believes are possible real-world solutions?

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  23. 23. Crasher 9:50 pm 09/25/2013

    David, thanks for a nice summary of the IPCC report. I concur with your final statement regarding the depth of the situation and what if anything the world governments are going to do to stave off impending dramatic climate change. We are already starting to experience it and yet those with vested interests (and deep coal mine profits!) are stopping any sensible adaptation. Does the IPCC have any recommendations/thoughts on how to start saving ourselves from ourselves??

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  24. 24. rkipling 10:26 pm 09/25/2013

    Absolutely. I’d like to know the IPCC solutions as well.

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  25. 25. Carlyle 11:58 pm 09/25/2013

    David, on reflection I think your comment #2 was aimed at curbing uncivil conduct by commenters rather than any attempt to curb legitimate debate. I appreciate that has also been your previous approach & that I applaud.

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  26. 26. David Biello in reply to David Biello 2:09 am 09/26/2013

    Correct! There’s no need to devolve to name-calling, even if folks passionately disagree.

    Link to this
  27. 27. rkipling 7:02 am 09/26/2013

    Something everyone can agree with:

    Link to this
  28. 28. Adolphe FABER 5:55 am 09/27/2013

    I totally agree with Sisko’s skeptical opinion. I’d like to add one possible (if exotic) explanation on the close relationship between T (temperature) and CO2 that appears i.a. from the analysis of antarctic ice-cores: There is a chemical relationship between CaCO3 and CaO + CO2. Like all chemical reactions, an equilibrium state exists depending on the T: The higher T, the higher CO2. Both minerals CaCO3 and CaO are common on our planet. Is that perhaps the explanation of the relationship that we observe today and in the very distant past between T and CO2 ? Anyway, in that distant past, there was no industry available as a scapegoat.

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  29. 29. Verity 7:20 pm 09/28/2013

    I don’t see any reports explaining the effects of melting ice as mitigating ocean warming or ocean acidification. Does anyone know how much melting ice has helped hide effects of continuous greenhouse gas output or how much worse climate disruption will be after all our glaciers and ice caps have melted?

    Also, I think climate change is way too delicate a term to describe climate disruption. Agree?

    Link to this

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