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Post by poitsplace on May 29, 2009 6:37:59 GMT
There's good reason to think the trend is not linear. We know the greenhouse gas forcing in the past 50 years has increased faster than in the first half, so we know we aren't looking at static conditions across the 20th century which can just be extrapolated into the 21st. In addition the response to increased forcing is not instantaneous - think about the time it takes to heat up a pot of water vs an empty pot. Ok, first off the trend on CO2 would AT MOST be linear. The forcing AND feedbacks you're suggesting are logarithmic or basically giving ever-diminishing returns. Second...apparently you're HORRIBLY unobservant and don't see that TECHNICALLY the IPCC guestimates are more or less linear. They're basically assuming a 2.5ish anomaly by 2100, +/- their unknowns. Third...Does it not strike you as odd that in order to reach the temperatures you're talking about the cooling period of the PDO suddenly has to be warming as fast as the warming period that just ended? Doesn't it seem strange to you that the warming rate didn't keep going up and up to get closer to the warming period increases necessary to reach your supposed 3C? It has after all been about 60 years since the rate of CO2 increase reached roughly what it is today. Seriously, look at the scenario you (and the IPCC) are suggesting...it looks COMPLETELY out of place. We don't need experiments to disprove the models...reality does a darned good job of it all by its self.
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Post by steve on May 29, 2009 11:53:23 GMT
There's good reason to think the trend is not linear. We know the greenhouse gas forcing in the past 50 years has increased faster than in the first half, so we know we aren't looking at static conditions across the 20th century which can just be extrapolated into the 21st. In addition the response to increased forcing is not instantaneous - think about the time it takes to heat up a pot of water vs an empty pot. Ok, first off the trend on CO2 would AT MOST be linear. The forcing AND feedbacks you're suggesting are logarithmic or basically giving ever-diminishing returns. If you plot the ln(Ck/280) over time, where Ck is CO2 ppm from the Keeling curve, you get something that is quite close to a straight line. Whether that is any more relevant than your point, I don't know.
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Post by FineWino on May 29, 2009 15:50:54 GMT
If you plot the ln(Ck/280) over time, where Ck is CO2 ppm from the Keeling curve, you get something that is quite close to a straight line. Whether that is any more relevant than your point, I don't know. If you take a sufficiently small segment of any continuous function you can make a so-called "linear approximation." That does not make it linear. Speaking of the Keeling Curve, how do you explain the approximately +/- 3.5 ppm variation on an annual basis of the measured CO2 concentration?
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Post by poitsplace on May 29, 2009 16:01:43 GMT
If you plot the ln(Ck/280) over time, where Ck is CO2 ppm from the Keeling curve, you get something that is quite close to a straight line. Whether that is any more relevant than your point, I don't know. If you take a sufficiently small segment of any continuous function you can make a so-called "linear approximation." That does not make it linear. Speaking of the Keeling Curve, how do you explain the approximately +/- 3.5 ppm variation on an annual basis of the measured CO2 concentration? Seasonable variability can be seen because the northern and southern hemispheres are significantly different (most land is in the northern hemisphere)
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Post by steve on May 29, 2009 17:11:12 GMT
If you plot the ln(Ck/280) over time, where Ck is CO2 ppm from the Keeling curve, you get something that is quite close to a straight line. Whether that is any more relevant than your point, I don't know. If you take a sufficiently small segment of any continuous function you can make a so-called "linear approximation." That does not make it linear. That's why I didn't say it was "linear", and suggested that it was not relevant. My subtext is that the logarithmic thing just sounds to me like a lazy mantra. a) yes climate scientists know that the forcing is roughly a log function of concentration b) the rate of increase of forcing in time is dependent on the rate of increase of CO2 plugged into the formula - it's not logarithmic, linear, hypercubic, or anything else c) whatever that rate of increase is, the impact on the temperature is additionally a function of the *response* of the planet to the forcing. If the planet responds quickly, it will follow the line of the forcing. If it responds slowly, it will follow a different track. Roughly speaking, plants release CO2 in winter and absorb it in summer. You get a much bigger variation in the NH than in the SH, because there are fewer plants in the SH.
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Post by socold on May 30, 2009 1:08:27 GMT
Here's one related to a comment you made in an earlier post: You said: Looks like they spotted some other problems - "The actual ocean mixed layer has a depth on the order of 50 meters. That's why we got such large amplitude and high frequency fluctuations in the previous graph. What value does Roy use for the mixed layer depth? One kilometer." Roy Spencer's response? In Ray’s “Lesson 2″, he claims that I used a much too deep mixed layer depth; I used 1,000 m, and he claimed it should be more like 50 m. Oh, really? Well, if the mixed layer depth of the ocean on multi-decadal time scales is only 50 m, then why are we waiting for the remaining “warming in the pipeline” from our CO2 emissions, as we are constantly told exists because of the huge heat capacity of the ocean? But this is not an answer. Roy Spencer just says "Oh, really?" and then suggests that if it was 50m the ocean wouldn't have a huge heat capacity. It sounds to me that he has no justification for assuming a kilometer, he just plucked the figure out of thin air because it helped him smooth out the other assumption he made.
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Post by socold on May 30, 2009 1:21:04 GMT
There's good reason to think the trend is not linear. We know the greenhouse gas forcing in the past 50 years has increased faster than in the first half, so we know we aren't looking at static conditions across the 20th century which can just be extrapolated into the 21st. In addition the response to increased forcing is not instantaneous - think about the time it takes to heat up a pot of water vs an empty pot. Ok, first off the trend on CO2 would AT MOST be linear. The forcing AND feedbacks you're suggesting are logarithmic or basically giving ever-diminishing returns. Second...apparently you're HORRIBLY unobservant and don't see that TECHNICALLY the IPCC guestimates are more or less linear. They're basically assuming a 2.5ish anomaly by 2100, +/- their unknowns. [/QUOTE] I am talking about the 20th century which you use to form a trend to extrapolate. The ghg forcing trend over the 20th century hasn't been linear: Not if the next warming period of the PDO is warming faster than the warming period that just ended. The PDO cycle would be a slight cycle over a background trend, which has sharpened upward in recent decades. That means not only is the cooling period has less cooling, but the warming period has more warming. From 1900 to 2100 the PDO cycle will have virtually zero contribution to any overall trend, because assuming it is a cycle it will end up where it started at. Any overall change in temperature has to come from something else. How does it look out of place when that could very well happen. If the greenhouse gas forcing continues upwards - and the high end range of the IPCC scenario is based on that, then temperature may indeed rise like that mid century.
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Post by poitsplace on May 30, 2009 4:58:58 GMT
Actually I only used the 1940-present trend so your little chart there (with numbers that seem to have no meaning) isn't really all that important. LOL, it appears that mother nature did the previous warm period increase all by herself. There's not a whole lot of difference between using the 1940-present data and the current trend either.
Sharpened upward in recent decades? Well that explains it, apparently we're not even on the same planet.
And I didn't imply here that the PDO would have an overall affect here other than changing the slope of the increases (and in some cases making it decrease).
Now seriously, shake all that AGW propaganda out of your head for a second and try...just TRY to take an unbiased look at what I'm saying. Your CO2 forcing suggests at most what would APPEAR over such a short period of time to be a linear increase. Now I'm going to entertain your 3C scenario say SURE THING, 3C it is.
Now...looking at the linear increase necessary to do that you should notice a problem...we KNOW the ocean currents were doing their warming thing during the past warming period and yet that's all the warming we've had. In order for us to reach that 3C figure you're talking about the forcing must suddenly increase by an additional .15C/decade. Remember, we've had no hint of this.
CO2 increases have been more or less linear for the past 50 years (now decreasing) and so the forcing over that period or later in that period should follow a logarithmic curve...which for these rates and time scales might as well be flat. In no way was the last warming period pronounced enough for us to reach 3C.
The plain old trend line shows all signs of being a reasonably good projection (+/- a little bit for unknowns). The IPCC models show no signs of being right. They had it wrong. I'm sorry to dash your expectations of "scientists" but this kind of thing has happened all through history. There has simply been a social/political movemnt that decided elevate what would normally be crackpots to the status of respected scientists. They show obvious signs of tampering with the data, making up data, modeling things they do not understand...sorry, they're crackpots.
Any good scientist that looks at the actual data would never say that it points to such high increases. You can believe it if you want to but you're in for letdown (although in this case since you're frightened of the outcome, I guess it will be a relief)
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Post by socold on May 30, 2009 16:33:30 GMT
Actually I only used the 1940-present trend so your little chart there (with numbers that seem to have no meaning) isn't really all that important.[/QUOTE Indeed your argument assumes that the ghg forcing was linear from 1940 onwards. It wasn't, so there's no reason to expect the next PDO cooling cycle to produce a similar temperature trend as the 1940-1970s. Doing so would be assuming that ghg forcing is increasing today at the same rate as the 1940s-1970s which it is not.
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Post by tacoman25 on May 30, 2009 19:28:13 GMT
Ok, first off the trend on CO2 would AT MOST be linear. The forcing AND feedbacks you're suggesting are logarithmic or basically giving ever-diminishing returns. Second...apparently you're HORRIBLY unobservant and don't see that TECHNICALLY the IPCC guestimates are more or less linear. They're basically assuming a 2.5ish anomaly by 2100, +/- their unknowns. I am talking about the 20th century which you use to form a trend to extrapolate. The ghg forcing trend over the 20th century hasn't been linear: Not if the next warming period of the PDO is warming faster than the warming period that just ended. The PDO cycle would be a slight cycle over a background trend, which has sharpened upward in recent decades. That means not only is the cooling period has less cooling, but the warming period has more warming. From 1900 to 2100 the PDO cycle will have virtually zero contribution to any overall trend, because assuming it is a cycle it will end up where it started at. Any overall change in temperature has to come from something else. How does it look out of place when that could very well happen. If the greenhouse gas forcing continues upwards - and the high end range of the IPCC scenario is based on that, then temperature may indeed rise like that mid century. [/quote] But based on observations to date, there is no reason to believe that will happen! Look at how much GHG forcing has risen over the past 100 years....look at how climate scientists 20 years ago were predicting more rapid rises by now...and then look at what has actually happend: NO INCREASE IN WARMING RATE OVER THE PAST 100 YEARS, despite hefty increases in GHG forcing. There is no way around it.
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Post by tacoman25 on May 30, 2009 19:30:46 GMT
There's good reason to think the trend is not linear. We know the greenhouse gas forcing in the past 50 years has increased faster than in the first half, so we know we aren't looking at static conditions across the 20th century which can just be extrapolated into the 21st. In addition the response to increased forcing is not instantaneous - think about the time it takes to heat up a pot of water vs an empty pot. So would you a suggest a 50 year lag from GHG forcing to global temps? That certainly would not agree with the IPCC or any other proponent of AGW science.
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Post by socold on May 31, 2009 1:13:32 GMT
There is a lag. If you increase the forcing say, 2wm-2 instantly for example, it doesn't change the temperature instantly. It's like heating up water in a pot. Simply turning on the stove does not instantly cause it to boil.
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Post by dmapel on May 31, 2009 4:00:23 GMT
socold: "There is a lag. If you increase the forcing say, 2wm-2 instantly for example, it doesn't change the temperature instantly. It's like heating up water in a pot. Simply turning on the stove does not instantly cause it to boil."
Why are you dancing around the question? WHAT IS THE LAG? We know it's like heating up water in a pot. Why do you keep repeating that? How long does it take to heat up? If you don't have a clue, just say so.
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Post by socold on May 31, 2009 14:29:02 GMT
socold: "There is a lag. If you increase the forcing say, 2wm-2 instantly for example, it doesn't change the temperature instantly. It's like heating up water in a pot. Simply turning on the stove does not instantly cause it to boil." Why are you dancing around the question? WHAT IS THE LAG? We know it's like heating up water in a pot. Why do you keep repeating that? How long does it take to heat up? If you don't have a clue, just say so. It's not my problem to give a precise value for the lag, the problem lies with those who want to claim "we've already seen x% of the warming from a doubling of co2". In order to calculate the x one of the things you need to know is how much of the ghg forcing the climate has responded to.
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Post by dmapel on May 31, 2009 17:06:47 GMT
socold: "It's not my problem to give a precise value for the lag, the problem lies with those who want to claim "we've already seen x% of the warming from a doubling of co2".
In order to calculate the x one of the things you need to know is how much of the ghg forcing the climate has responded to."
Thanks for not telling us about the pot of water thing again.
Couldn't you find the answer on realclimate? It would seem that those guys would be very keen on explaining where their missing heat is, since the public is waking up and discarding the catastrophic AGW theory in increasing numbers.
Like you, I can't calculate x either. But my guess is that we have seen about all the heat that we are going to see from the present level of CO2 in the atmosphere. Whatever heat there may be in the "pipeline" is offset by the negative feedback from increased water vapor that is also in the pipeline.
*Disclaimer I got that from one of the many BIG OIL websites that is spreading dis-information on catastrophic AGW, and evolution.
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