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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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Comments 100501 to 100550:

  1. Is it safe to double atmospheric Carbon Dioxide over a 200 year period?
    fydijkstra @ 42... "'Is it safe to double atmospheric CO2 over a 200 year period?' We don't know. Possibly not..." Possibly not? A very, very small possibility. Virtually all the evidence coming out, and that has come out over the past 30 years, suggests that it is not safe. A very small amount of evidence suggests that it might not be a problem. Personally, in a situation like this, my inclination is to err on the side of caution. "With the present state of technology there is no way to avoid doubling CO2 in the next century." We certainly won't avoid it with the attitude that we can't avoid it. Technology is not the problem. The technology is there. It's ready. The only thing lacking is sufficient will.
  2. Lindzen and Choi find low climate sensitivity
    Eric, I mean at least as far as intrinsic forcing is concerned.
  3. Lindzen and Choi find low climate sensitivity
    Eric, BTW, I'm not trying to entrap you with that last question. I'm just attempting to establing that a W/m^2 of power is a W/m^2 of power, independent of where it originates from.
  4. Is it safe to double atmospheric Carbon Dioxide over a 200 year period?
    "Why have the skeptics never developed their own climate models and performed their own model experiments? They have. See Lindzen, Spencer, Soon, Baliunas, Akasofu!" Cool. Where are their models? Can you show us the code to the GCM that, say, Soon and Baliunas wrote? Lindzen? Where's the source code to his GCM? Spencer? Same question. Oh, can't find the source ... OK, how about some model output from the GCMs these various people have written ... I'll settle for that.
  5. Lindzen and Choi find low climate sensitivity
    Eric, At last, I think you now understand what the gain is representing, and you're asking the right question - it is the basis of the argument I've put forth. Before I answer the question, do we also agree that additional forcing from CO2 is the same as solar forcing? In other words, 2 W/m^2 of power from the Sun (existing or hyothetically added) is the same as 2 W/m^2 from increased CO2?
  6. CO2 is not increasing
    #14: "we will get there... " You missed the part about 'and that rate is increasing'? So the bets are in as to when 560 ppm will happen. In the words of that great American philosopher, Dirty Harry: "You gotta ask yourself one question, do I feel lucky?"
  7. Lindzen and Choi find low climate sensitivity
    Ok, so the sun "forces" the climate. After albedo that "forcing" is 238 W/m^2. The "response" is 390 W/m^2. Therefore the "gain" is 1.6 Now add a permanent (hypothetical) 1 W/m^2 to the sun (forcing change by the consensus definition). What is the "response"? 391.6? Thus the temperature response is about 0.3 degrees higher according to your "gain" formula. Now, please show the evidence that a permanent 1W increase in effective solar forcing will only increase earth by only 0.3 degrees.
  8. Lindzen and Choi find low climate sensitivity
    Eric, The graph clearly shows the solar power fluctuting by about 20 W/m^2 from perihelion in January to aphelion in July: http://www.palisad.com/co2/eb/g/flux.png
  9. Lindzen and Choi find low climate sensitivity
    Eric, "Regardless, as I showed in 208 the "gain" term in the paper in #150 does not use the aphelion to perihelion cycle." It's included in the solar input (Psun), which varies according to perihelion/aphelion. 'Psun' is the total power from the Sun and varies - it's not a constant. "The cyclical solar change is not considered in calculating gain." This isn't correct. It's automatically considered because the post albedo power is the incoming solar power minus the albedo and each varies. The gain is based on the aggregate measure of the two, which includes the increased and decreased solar power at perihelion/aphelion, as well as the changes in the albedo. "To put it another way, the gain is not being used to calculate earth's response to the solar change that you and I call forcing." Yes it is. That is in fact precisely what the gain is calculating, albeit albedo adjusted.
  10. CO2 is not increasing
    15 dhogaza Yes I do claim it will be slow and not a problem. The maximum warming with ADO PDO and a monster El Nino and sunspots the largest in recorded history only made the 1978 to 1998 warming rate 1.2 ° C per century. I am underwhelmed. Mother nature did everything she could to help your puny CO2 and that is the best it can do ? No wonder when the ADO and PDO go negative the rate of warming goes flat or negative !
    Moderator Response: You are incorrect that solar activity since 1978 contributed to warming. See "It's the Sun" and especially "Climate Time Lag."
  11. Lindzen and Choi find low climate sensitivity
    In the absence of power from the Sun, the climate would change; therefore, by definition, power from the Sun is forcing the climate. Whether a particular forcing is constant or variable, doesn't make it any less of (or something other than) a forcing.
  12. Lindzen and Choi find low climate sensitivity
    RW1, my and your use of the term "forcing" is different from the others following us. Their definition excludes cyclical forcing like the solar aphelion to perihelion change. Regardless, as I showed in 208 the "gain" term in the paper in #150 does not use the aphelion to perihelion cycle. The gain is simply the solar power that makes it into the earth/atmosphere divided by the surface flux determine from surface temperature. The cyclical solar change is not considered in calculating gain. To put it another way, the gain is not being used to calculate earth's response to the solar change that you and I call forcing. Thus, even using our definition, the gain is not applicable to CO2 forcing or any other forcing other than the average annual solar input.
  13. Is it safe to double atmospheric Carbon Dioxide over a 200 year period?
    'Is it safe to double atmospheric CO2 over a 200 year period?' We don't know. Possibly not. Is it safe to live on this planet with 6.5 billion people, who all want to have their houses heated and their food and electricity supplied? Possibly not. But do we have a choice? Possibly not! Is it safe that many millions of people live in the Ganges delta without proper protection against floods? Not at all! Is it safe that many people live in aereas threatened by earth quakes without properly constructed houses? No! Small uncertainties in the rate of future warming are irrelevant to the risk assessment. What about big uncertainties? How big is the risk of future warming? Is there a real risk of more than 50 centimeters sea level rise? Why should a civilized society not be able to cope with such a sea level rise? Why have the skeptics never developed their own climate models and performed their own model experiments? They have. See Lindzen, Spencer, Soon, Baliunas, Akasofu! Why have the skeptics never compiled their own record of surface temperature? They have! See Loehle and others. It is easy to ask questions to climate skeptics and pretend, that they have no answer wihtout presenting their arguments. It is easy to point to risks whithout showing a way to avoid them. With the present state of technology there is no way to avoid doubling CO2 in the next century. We can better be prepared to cope with the effects of that doubling - if we are able to predict those effects!
  14. CO2 is not increasing
    "The rate may be exponential but if the exponent is very small the increase in warming is itself slow and probably not a problem" The final equilibrium temperature depends on the accumulated amount of CO2 in the atmosphere, not the rate of increase. If the accumulation is fast, then equilibrium will be reached more quickly, of course. We'll be reaching a doubling of CO2 compared to pre-industrial levels this century, and at that point will be committed to about a 3C global rise in temps, with the average temperature over land in the NH being much higher than that (say, double). You claim this is "slow and probably not a problem". Many, many experts say otherwise. I'll listen to the experts rather than someone who tries to wave away exponential increases in the rate of accumulation of CO2 as being "nearly linear".
  15. CO2 is not increasing
    muoncounter(12#) 170 PPM to get to 560 ppm, so we increase around 2 PPM per year. S0 170/2=85 years give or take. We will get there near 2095-2096.
  16. CO2 is not increasing
    Tom Dayton It is no digression. The warming of CO2 is proportional to the log of the amount of CO2. By taking the log of the CO2 we see how fast the warming can take place all other things being equal. The rate may be exponential but if the exponent is very small the increase in warming is itself slow and probably not a problem. This seems to be the case. Taking the log of an exponential function shows us the exponent. The increase in value of this log is an indication of the rate of warming Now go back and read my previous post #10 again.
  17. CO2 is not increasing
    #10: "The slope should tell us how log it would take to have a doubling of effect." Yes, linear trends can be used to extrapolate forever. How's that working for you in the stock market? Bet you won't get a linear fit to these data: . We add more than 2ppm/year and that rate is increasing. Go to the MLO site and look at the annual rate of change. Then go look at an Arctic site like BRW, where the annual rate change is even larger. Look at how the fossil fuel consumption rates are rising worldwide and project forward. Look at how the oceans/biosphere aren't taking as much CO2 out of the atmosphere as they once were. Then tell us when we'll be at 560 ppm. But why do you even care about atmospheric CO2? Is that 'rampy-siney thing' not working for ya?
  18. Lindzen and Choi find low climate sensitivity
    The energy from the Sun is not a forcing agent, while a change in the rate of energy flow is. Do you understand the distinction?
  19. Lindzen and Choi find low climate sensitivity
    #225: "roughly 0.6 C sensitivity is at least as consistent with a 0.8 C rise so far," Incorrect, as shown here. That was 190 comments ago; continuing to deny/ignore the problems inherent in your hypothesis does little other than bloat this thread. As you can see from the patient explanations given above, 'forcing' has with it an inherent rate of change. Your calculated 0.6C per doubling of CO2 will neither match the current temperature change nor the rate of change of temperature change. If a model cannot match behavior that is already observed, it's time for a different model. But of course, the ready comeback will be 'it could be due to something else.' What then is the value of a model that requires an unknown or undocumented 'something else' to explain observed behavior?
  20. CO2 is not increasing
    NETDR, this thread is about the rate of increase in CO2. You had claimed on another thread that CO2 is increasing nearly linearly. I pointed you to a very thorough analysis by a professional time series statistician, showing unequivocally that the increase is exponential. You completely ignored that, instead meandering off into something about doubling the effect of CO2 and something about temperature.
  21. Lindzen and Choi find low climate sensitivity
    RW1, it is you who does not understand the terminology, specifically what is (and what isn't) a forcing. The temperature of the Earth (or the climate, if you will) is merely the sum of all inputs, some positive and some negative. Energy from the sun is one such input. If inputs are stable and there is no change, then the system is in dynamic equilibrium. Changes in inputs, positive or negative, are characterized as "forcings". Therefore forcings represent a change in the dynamic equilibrium of the Earth's energy system/climate. Constant inputs, by definition, have no forcings attached to them. It really is that simple. The Yooper
  22. Lindzen and Choi find low climate sensitivity
    Rw1, Words have meanings. If you can't understand the definition of something as basic as "forcing", then how can you possibly claim any understanding of the complexities of climate science? One more time: the definition of climate forcing is something that is changing the climate. The sun has the potential to act as a forcing, but that is not the same as saying it is a forcing at present.
  23. Lindzen and Choi find low climate sensitivity
    Bibliovermis, The sudden cessation of solar activity definitely qualifies as a change. This, by definition, makes the power from the Sun a forcing of the climate system.
  24. Lindzen and Choi find low climate sensitivity
    My, my - things are much worse that I thought. If we cannot agree that power from the Sun is forcing the climate system, then we are at an impasse. No wonder no one understands anything I've put forth. :(
  25. Lindzen and Choi find low climate sensitivity
    Change is forcing.
  26. Lindzen and Choi find low climate sensitivity
    climate forcing
  27. Is it safe to double atmospheric Carbon Dioxide over a 200 year period?
    Ken Lambert said, Skeptics pointing out weaknesses and inconsistencies in AGW theory does not oblige them to offer a better fit theory to the observations. But skeptics *do* have the obligation to *understand* the theory that they are criticizing. Your posts here clearly indicate that you don't, starting with your failure to understand something as basic as the time-scale difference between gaseous diffusion into surface water vs. that of deep ocean mixing.
  28. Lindzen and Choi find low climate sensitivity
    How does that not make it a forcing? I didn't say a change in forcing - just a forcing. I think you're confusing the two.
  29. Lindzen and Choi find low climate sensitivity
    Rw1, No we are saying you are misunderstanding the definition of forcing. If all you are trying to say is that the sun contributes energy to the climate, then ok yes it does, but that does not make it a "forcing".
  30. Lindzen and Choi find low climate sensitivity
    What part of change do you not understand? The sudden cessation of solar activity definitely qualifies as a change.
  31. Lindzen and Choi find low climate sensitivity
    Daniel, e, and Bibliorvermis, So you are saying the power from the Sun coming in contact with the Earth is having zero effect on the climate system - meaning if the power from the Sun suddenly stopped, the climate would remain exactly as is?
  32. The Physical Chemistry of Carbon Dioxide Absorption
    Dear Hugo. I find that the assertion in your 12 slide (the anthropogenic origin of atmospheric CO2 excess) would benefit of a mention of the Suess effect. The evolution of the isotope ratios rejects other hypotheses with more certainty than the coincidence in the increase of concentrations with anthropogenic emissions. http://en.wikipedia.org/wiki/Suess_effect See also Figure 2.3 in IPCC-AR4 http://www.ipcc.ch/publications_and_data/ar4/wg1/en/ch2s2-3.html#2-3-1 This is just a suggestion for future versions. Thanks for your work. jon
  33. Lindzen and Choi find low climate sensitivity
    Changes in irradiance are the forcing agent; solar activity, orbital parameters, etc. A constant provides no forcing. Yes, that value is always changing. The long-term trend (at least greater than the ~11 year solar cycle) is what is important.
  34. Lindzen and Choi find low climate sensitivity
    RW1, A "forcing" is by definition something that changes the climate, so no, we do not agree that the sun is currently forcing the climate.
  35. Lindzen and Choi find low climate sensitivity
    Re: rw1 (234) If energy from the sun is not changing, then there is no solar forcing, by definition. The Yooper
  36. Lindzen and Choi find low climate sensitivity
    Bibliovermis (RE: 233), I'm not talking about any changes at this point. I'm just trying to first establish that energy emitted from the Sun that travels through space and comes into contacct with the Earth is "forcing" the climate. Is that clearer?
  37. Lindzen and Choi find low climate sensitivity
    ~Changes~ in solar irradiance are a forcing. If you are making the claim that the Sun is currently providing a positive forcing, please continue at argument #1 linked from the top of the left column.
  38. Lindzen and Choi find low climate sensitivity
    Question #1: Do we all agree that power from the Sun is "forcing" the climate?
  39. Lindzen and Choi find low climate sensitivity
    I think the best approach is to take it step by step one question at a time.
  40. Lindzen and Choi find low climate sensitivity
    Eric, Also, the peri/ap is a global effect just like 2xCO2. The only reason I've separated hemispherical/seasonal from global is in regards to ocean heat content and any potential delay or inertia, etc., which the seasonal changes contradict as something taking decades to occur.
  41. Lindzen and Choi find low climate sensitivity
    Eric, I'm going to try to explain the whole thing from a different angle, as people still don't understand what the gain represents. The peri/ap forcing change is completely separate from the seasonal hemispherical responses, which are driven by the earth's tilt and have nothing to do with the distance the earth is from the Sun. The gain I've refered to is the global gain - not the hemispherical gain. 2xCO2 forcing is global - not hemispherical.
  42. Lindzen and Choi find low climate sensitivity
    RW1, the peri/ap forcing change can't be separated from the seasonal response. The seasonal earth tilt difference causes the extra forcing to be absorbed by the extra SH heat capacity (as chris said in 222). The assumption of constant gain across seasons would only be true if the heat capacity were constant across seasons.
  43. Is it safe to double atmospheric Carbon Dioxide over a 200 year period?
    The validity of scientific knowledge is ~always~ decided by consensus. Just like theory, consensus has a different meaning in a scientific context. Consensus is the accumulation of empirical observation and development of validated theory. Dismissal via "fabled 'consensus'" is no different than "just a theory". It is sophistry. Scientific theories are not disproven by pointing at loose threads, but rather by presenting new hypotheses that better explain the empirical observations. Using a "reasonable doubt" standard to determine the validity of scientific theories results in events like the Scopes Trial. There is no one single observation that will cause the scientific theory of anthropogenic global warming to collapse. This philosophy of "loose thread science" explains a great deal about the process of presenting multiple, contradictory & mutually exclusive contentions. Concerning OHC, that has been discussed elsewhere on this site. Further rehashing is not relevant here. Suffice it to say, depending on a currently unknowable quantity is no different than the "god of the gaps" rhetorical tactic common in evolution discussions.
  44. CO2 is not increasing
    #8 Tom Dayton http://www.woodfortrees.org/plot/esrl-co2/from:1958/to:2010/plot/esrl-co2/from:1958/to:2010/trend The increase from 1958 to 2010 is a good indication of modern trends in CO2. It is the biggest "cherry " we have accurate data for. Before that the sites jump around and are hit and miss. How do thy correlate and is one the same as another on the same day ? I doubt it. Besides the argument is what is the trend now not 1,000 years ago ? The argument is that since the effect of CO2 is logarithmic and the increase in CO2 is almost linear the rate of warming should slow down in later years. I wish woodfortrees had a handy app for this but they don't. I pulled the CO2 data for 58 years into excel and did a simple log of the data. If the rate is increasing exponentially with a large enough exponent we should see a straight line output indicating increasing warming. The slope should tell us how log it would take to have a doubling of effect. In other words If y=X^2 and T = log(y) In this test case T is a straight line with a steep slope. [About 3/10 ] If this were the case I would agree this would show that the geometric increase in CO2 would cancel out the logarithmic effect of CO2. If however the effective warming [T] is almost flat the world has little to fear. If I take the data set in to Excel and take the log of the 58 years of data I get a straight line with very little slope [.09 / 58 years or .00155 per year ] at that rate a doubling of effect would take thousands of years. Go to the Mona Loa site and download the data and check me. This indicates to me that we have little to fear from CO2 causing rising temperatures for many hundreds of years.
  45. Lindzen and Choi find low climate sensitivity
    Eric (RE: 226), No, I didn't intend it to be a "new" argument. To me, it is such an obvious given. You mean people actually think the climate over hundred years scales is/was mostly a straight line? At any rate, I want to respond to Chris's #222. For some reason, people aren't understanding the argument I'm making. For one they are mixing up and/or intertwining the perihelion/aphelion with seasonal changes.
  46. Is it safe to double atmospheric Carbon Dioxide over a 200 year period?
    Moderator (Daniel Bailey) #35 "You have merely pointed out three areas where the existing theory seeks more robust data, which no one denies." Daniel, you should join the discussion in your own name - I, and no doubt others are not comfortable with players becoming umpires when the game is still going. Skeptics pointing out weaknesses and inconsistencies in AGW theory does not oblige them to offer a better fit theory to the observations. After all, it is the proponents of AGW who urge immediate drastic action to reduce CO2 release from fossil fuel burning and massive economic cost in converting to 'green' alternatives. The skeptics are not urging any such radical action. So it is for the proponents of such action to prove their case. What you are implying is that the standard of proof is to be decided by the fabled 'consensus' of independent researchers. I would agree that 'beyond reasonable doubt' is probably too tough a standard - because there is already 'reasonable doubt' in key areas such as I exampled in #15 and that it might take much more extensive data and research to achieve that standard if ever. 'Balance of probabilities' is a much lesser hurdle and the AGW theorists would argue that they have already achieved that standard. Scientific theory is not proven by ballot however. The issue is whether or not there is a single (or two) contraverting pieces of robust observation which undermines the current AGW theory and points in a different direction. The answer will probably be found in measurement of OHC.
    Moderator Response: [Daniel Bailey] It is the moderators job to keep threads on-topic. The topic of this thread is whether it is safe to double atmospheric concentrations of CO2. Your 3 items you flagged in your comment 15 above were on ocean acidification, OHC and SLR (all off-topic here). The burden is on you to find the appropriate threads for those and to posit a physics-based alternative to AGW specific to each of your concerns, as you have been repeatedly told in the past. If you wish to be taken seriously here, you will do so.
  47. Dikran Marsupial at 21:11 PM on 25 December 2010
    Do high levels of CO2 in the past contradict the warming effect of CO2?
    Eric (skeptic) @ 14: The CO2 could not have come from the oceans as they were iced over and hence disconnected from the atmosphere. However this means that the oceans were no longer removing CO2 from the atmosphere either*, and mineral weathering on land was also reduced by ice cover (as mentioned earlier in the thread). This means that the relatively small amounts from volcanic eruptions would just accumulate in the atmosphere until the greenh ouse effect was high enough to start melting the ice. Once that happened, there would be feedback from decreasing albedo and from increased water vapour, so it is unlikely that CO2 alone was responsible for the emergence from the snowball Earth. *The exchange of CO2 between the atmosphere is not governed only by temperature, it is also governed by the difference in partial pressures between the atmosphere and the surface waters, so all things being otherwise equal, the oceans would try to remove excess CO2 from the atmosphere (by becoming a net carbon sink), as they are doing now.
  48. Is it safe to double atmospheric Carbon Dioxide over a 200 year period?
    Humans aren't actually that good with risk, and there are a range of reasons for the current situation that I could not do justice to. For example, we typically engage in what the risk managers and economists call 'future discounting' for issues whose consequences are not immediate. We also suffer from confirmation bias. For the case of the red berries, if they made us feel violently ill then sure, we would probably stop eating them. Then again, if the berries made us feel violently ill- but only the day after they made us feel euphoric, and they were addictive, then we may suddenly find our rational judgement of the risk is compromised. Again still, imagine if we could easily see carbon dioxide emissions; from cars, boilers, industrial plants, power stations and even in the color of the sunset. In that instance we may well have taken a different view of the risk. We delude ourselves all the time. That is exactly why we collect data and do science. The point of my article is that I think we need to adopt the correct risk framework whenever we communicate our science, and remind people that science can do this type of thing very well. You wouldn't get on an airplane otherwise.
  49. Dikran Marsupial at 20:49 PM on 25 December 2010
    Is it safe to double atmospheric Carbon Dioxide over a 200 year period?
    cloa513@1 You are completely wrong about food safety. A number of years ago I took part in a government funded project on the potential hazards associated with eating potatoes, a food mankind has been eating in quantity for a very long time. Potatoes produce glycoalkaloids in response to sunlight and/or physical damage, as a defence mechanism, and it is possible to poison yourself by eating potatoes. However the risks are small as most people know not to eat green or damaged tubers or tubers that have been stored for too long, and glycoalkaloids have a bitter taste so it is detectable. You may not be aware of research into the safety of foods, but that doesn't mean it doesn't exist.
  50. CO2 is not increasing
    Here's a good illustration of the changes in atmospheric CO2 concentration over time (h/t to Lou Grinzo for alerting me to this much-updated animation): You can literally watch the Earth "breath"... The Yooper

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