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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?
    archiesteel (#48), According to the FACE experiment (Nicolas School of the Environment), CO2 does make plants grow more. When CO2 concentrations are increased, plants grow faster until scarcity of some other nutrient intervenes. You don't need university researchers to tell you this kind of thing. Enhancing the CO2 in greenhouses has been a common practice for decades. If you are right, global temperatures will rise as a result of doubling the CO2 concentration in the atmosphere. However, you are in error to link desertification to increased temperatures. It is falling temperatures that increase desertification, while rising temperatures cause increased precipitation.
  2. Ice isn't melting
    Over on Neven's Arctic Sea Ice blog, a reader has done an analysis of the Arctic sea ice loss, with a log-fit (R2=0.933253) showing 2011 as the last full-ice year: So much for the "recovery". The Yooper
  3. Is it safe to double atmospheric Carbon Dioxide over a 200 year period?
    #46: "The plants are going to love it but nobody listens the them ... " Nice of gc to entertain with his Lorax imitation. Unfortunately, messing with Mother Nature can produce surprising results: The direct, physiological response of plants to elevated CO2 generally acts to weaken the earth’s hydrologic cycle by lowering transpiration rates across the globe. Lowering transpiration alone would tend to enhance soil moisture. However, reduced recirculation of water in the atmosphere, which lowers precipitation, leads to more arid conditions overall (simulated global soil moisture decreases by 1%), particularly in the Tropics and midlatitudes. And if altering the hydrologic cycle isn't a big enough gamble, here's evidence for another unintended consequence: Elevated levels of atmospheric carbon dioxide (CO2), a consequence of anthropogenic global change, can profoundly affect the interactions between crop plants and insect pests and may promote yet another form of global change: the rapid establishment of invasive species. So that could add famine, locusts and probable cattle diseases to our list. Just how many Biblical-style plagues do the deniers consider 'safe'?
  4. Is it safe to double atmospheric Carbon Dioxide over a 200 year period?
    it sounds very much like the cheapest and most reliable nightmare.
  5. Is it safe to double atmospheric Carbon Dioxide over a 200 year period?
    To be fair to the skeptics, reducing our dependence on fossil fuels will be difficult. It won't be the end of civilisation as we know it, which is what skeptics think. But we do need to make the judgement, "Are the risks of global warming sufficient to justify the cost of abandoning fossil fuels?" I think it is worth it, but others may differ. It does bug me when they argue that global warming isn't happening, and our CO2 emissions aren't causing it.
  6. Lindzen and Choi find low climate sensitivity
    @RW1: "The graph clearly shows the solar power fluctuting by about 20 W/m^2 from perihelion in January to aphelion in July" Who cares? It's a fluctuation, as you point out yourself. The additional 4 W/m³ for a doubling of CO2 is an actual increase (and raises temperatures in both seasons). Seriously, go read a book or something.
  7. Is it safe to double atmospheric Carbon Dioxide over a 200 year period?
    "Small uncertainties in the conventional science are used to reinforce the notion that doubling atmospheric carbon dioxide is entirely safe." Not only that, but skeptics want us to think doing something about climate change will be unsafe.
  8. Lindzen and Choi find low climate sensitivity
    @RW1: "If this is true, then power from the Sun and power from CO2 cannot both be expressed in W/m^2 as they are." Sure they can. The fact they have different signatures doesn't mean they can't all be reduced to relative W/m² values. RW1, it's clear you have some serious issues understanding simple scientific fact. Rather than waste everyone's time here, I suggest you start taking science classes (and pay attention, this time).
  9. Greenland ice mass loss after the 2010 summer
    @Camburn: "This is interesting as the ice loss of present does not seem to be much different than the ice loss from the 30's and 40's." You should actually read the articles you link to. From the article: "Their evidence reinforces the belief that glaciers and other bodies of ice are exquisitely hyper-sensitive to climate change and bolsters the concern that rising temperatures will speed the demise of that island's ice fields, hastening sea level rise." "The fact that recent changes to Greenland's ice sheet mirror its behavior nearly 70 years ago is increasing researchers' confidence and alarm as to what the future holds. Recent warming around the frozen island actually lags behind the global average warming pattern by about 1-2 degrees C but if it fell into synch with global temperatures in a few years, the massive ice sheet might pass its “threshold of viability” – a tipping point where the loss of ice couldn't be stopped."
  10. Is it safe to double atmospheric Carbon Dioxide over a 200 year period?
    @gallopingcamel: simply increasing CO2 won't make plants grow more. I don't think plants are too keen on increased temperatures and desertification. That's not what I heard from the grapevine. Yes, the actual grapevine.
  11. It's cooling
    @Chris: "What do you make of that?" Uh...that it's utter nonsense? Number of facts the person got wrong: 1) We are *not* in a cooling trend 2) There have been more record hot temperatures than record cold temperatures 3) There is a difference between science and how the media reports it: compounding the two is an illogical thing to do 4) Global Warming doesn't mean it's going to get warmer everywhere all the time 5) It is neither proven nor obvious that the world isn't warming 6) Other long-term factors are not currently affecting climate to a greater degree than CO2 This person you were talking to bases its entire argument on faulty assumptions and outright falsehoods.
  12. It's cooling
    In a recent debate I had with someone they offered this: "I would like to comment on Global Warming. Makes me smile when I hear Global warmer’s these days dismissing the third year of record cold temperatures as, “Just weather” and the big picture is what really counts! They are of course exactly correct in saying this, it’s what reasonable people have been saying all along, but rest assured that global warmers have been forced into the position they find themselves in. Before the record cold set in every story concerning a shortage of rainfall, lack of snow on the Iditarod trail, a heat wave anywhere, etc, etc, was all linked to the rapped and unstoppable effects of man made global warming. Before the cooling trend every story that could possibly be linked to the immediate affects of AGW, was. The fact is that the world is not warming, everyone knows this, it’s obvious AND it’s proven but let us be extremely generous in this Christmas season and say, for the sake of argument, that yes man kind’s production of CO2 gas can heat the earth. Then we would have to say at this point that there are other factors also affecting the earth’s temperature and that very likely CO2 gas is a minor factor easily made insignificant by the natural forces of nature." What do you make of that?
  13. Is it safe to double atmospheric Carbon Dioxide over a 200 year period?
    Ooops! Single malt scotch can affect one's grammar. What I meant was: "The plants are going to love it but nobody listens to them for fear of being dressed in a straitjacket."
  14. Is it safe to double atmospheric Carbon Dioxide over a 200 year period?
    Someone needs to speak out in favor of doubling the CO2 concentration. The plants are going to love it but nobody listens the them for fear of being dressed in a straitjacket. If I believed that doubling the CO2 concentration would cause a significant increase in global temperatures I would sell my electric car and buy a really large SUV. Here's wishing you all peace and prosperity in 2011 so that you can increase your carbon footprints.
    Moderator Response: [muoncounter] Gratuitous cheap shots will get you nowhere.
  15. Lindzen and Choi find low climate sensitivity
    Eric, "Each added 1 W/m^2 of power from the sun is equivalent to each added 1 W/m^2 of power from CO2. Feedback doesn't matter in the previous statement." Do we also agree that power from the Sun and power from CO2 are both "forcing" the climate system?
  16. Lindzen and Choi find low climate sensitivity
    scaddenp, "However, all forcings induce feedbacks. Feedbacks are not equal however, depending on the nature of the forcing. Thus the signature for a CO2 forcing is different from the signature of a solar forcing. This is the point of several other postings. If this is true, then power from the Sun and power from CO2 cannot both be expressed in W/m^2 as they are.
  17. A new resource - high rez climate graphics
    John, a really useful hi-res graphic would be to expand the Wiki graph of the 400,00 year ice-cores which plot: temperature, (Milankovich) solar insolation at 65 degree latitude, CO2 and CH4 levels, and sea-levels - by (1) adding vertical and horizontal grid-lines, and (2) expanding the horizontal axis out four-fold (either by scrolling out sideways, or printing four separate A4 graphs as one per ice-age cycle, preferably in portrait format). The correspondence between temperature and greenhouse gases levels is striking, and provides vivid evidence of the greenhouse effect. However, this is somewhat lost in the current Wiki plot. Is anybody prepared to have a go at it? See Image: Vostok 420ky 4 curves insolation.jpg
  18. Is it safe to double atmospheric Carbon Dioxide over a 200 year period?
    @fydijkstra: " They have. See Lindzen, Spencer, Soon, Baliunas, Akasofu!" I guess the OP meant models that withstood scrutiny. These guys have all been shown wrong, many times. @KL: "The skeptics are not urging any such radical action." Actually, such radical action on fossil fuels is needed *whether or not* AGW theory is correct (it is, but some politically-minded commentators still want to debate it, I guess). Unless you've been living under a rock, fossil fuels are a strategic and ecological nightmare any way you cut it. The only people still pushing for oil are, well, oil people. I see that contrarians are still hard at work on Christmas. Gotta admire that dedication, even if it is completely misguided. Peace y'all, and merry Christmas if that's your thing.
  19. Lindzen and Choi find low climate sensitivity
    Eric, "New power flux is added which causes an increase to T+delta, "gain" is much higher. That's because "gain" is not a constant as KR explained in 210." Can you explain what you mean here? Again, I'm not sure.
  20. Greenland ice mass loss after the 2010 summer
    This is interesting as the ice loss of present does not seem to be much different than the ice loss from the 30's and 40's. http://researchnews.osu.edu/archive/grnlndice.htm
  21. Lindzen and Choi find low climate sensitivity
    And 1W/m2 of forcing from whatever source will induce around 0.3C of surface temperature change without considering feedbacks. However, all forcings induce feedbacks. Feedbacks are not equal however, depending on the nature of the forcing. Thus the signature for a CO2 forcing is different from the signature of a solar forcing. This is the point of several other postings.
  22. Do high levels of CO2 in the past contradict the warming effect of CO2?
    FYI, current astrophysical models put the solar constant increase at around 7% per billion years, which works out to ~40 W/m² since the Ordovician. Meanwhile 4000 ppmv of CO2 would imply about 14 to 18 W/m² without feedbacks. This is again a pretty good indication that CO2 feedbacks are strongly positive, otherwise the entire Ordovician would have been glaciated.
  23. Lindzen and Choi find low climate sensitivity
    RW1, yes T is temperature. Each added 1 W/m^2 of power from the sun is equivalent to each added 1 W/m^2 of power from CO2. Feedback doesn't matter in the previous statement.
  24. Lindzen and Choi find low climate sensitivity
    Eric, Again, I'm talking about intrinsic forcing - meaning before any potential gain or feedback (positive or negative). I just want to make sure we agree that each 1 W/m^2 of power from the Sun is equivalent to each 1 W/m^ of power from CO2.
  25. Lindzen and Choi find low climate sensitivity
    Eric, "Not the same, although you didn't define "same". Existing power flux is in equilibrium at T, "gain" = 1.6. New power flux is added which causes an increase to T+delta, "gain" is much higher. That's because "gain" is not a constant as KR explained in 210." I'm not sure what you mean here. I know the gain is not a constant. Is the "T" you're refering to temperature or something else?
  26. Lindzen and Choi find low climate sensitivity
    RW1 asked "2 W/m^2 of power from the Sun (existing or hyothetically added) is the same as 2 W/m^2 from increased CO2?" Not the same, although you didn't define "same". Existing power flux is in equilibrium at T, "gain" = 1.6. New power flux is added which causes an increase to T+delta, "gain" is much higher. That's because "gain" is not a constant as KR explained in 210. If instead you asked "2 W/m^2 of power from the Sun (hypothetically added) is the same as 2 W/m^2 from increased CO2?", the answer is yes.
  27. 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.
  28. Lindzen and Choi find low climate sensitivity
    Eric, I mean at least as far as intrinsic forcing is concerned.
  29. 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.
  30. 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.
  31. 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?
  32. 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?"
  33. 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.
  34. 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
  35. 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.
  36. 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."
  37. 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.
  38. 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.
  39. 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!
  40. 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".
  41. 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.
  42. 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.
  43. 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?
  44. 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?
  45. 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?
  46. 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.
  47. 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
  48. 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.
  49. 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.
  50. 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. :(

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