A bunch of stuff here, but the 2001 paper describes the buffering model. There may be more recent stuff of interest.
A bunch of stuff here, but the 2001 paper describes the buffering model. There may be more recent stuff of interest.
Tree ring / carbon isotope argument overview with references here: http://www.realclimate.org/index.php?p=87
Whoa whoa whoa....what is all this science and facts stuff? This is LR! No facts or data. Just the simple idea, "we don't know". That is enough to allow your average american to carry on doing whatever they feel like.Get with the program!
rose colored glasses? wrote:
Nevermind, I've found an answer to my question:
rose colored glasses? wrote:- my bigger issues are with the interpretation of atmospheric chemistry. The basic assumption is that the chemical signatures of the air bubbles trapped in the ice retain an unaltered record of atmospheric conditions at the time the bubbles were trapped. I have significant doubts that this is a valid assumption. There must be some chemical interaction between the trapped gas and the surrounding ice crystals, and I think there must necessarily be some transport of both gas and supercooled fluids within the ice over that kind of time period. I would expect to see some "averaging" of chemical properties through diffusion and other processes that would soften (filter out) high frequency peaks and valleys, such as the apparent peak we are reportedly entering presently
looking at the NATURE paper (Petit et al, 1999), I reference the caption to Figure 3, which presents the guts of their findings, and is the basis for the alarming blue graph mentioned earlier, the one with the sharp hockeystick trajectory of CO2 concentration starting in 1950-ish.
"The mean resolution of the CO2 (CH4) profile is about 1500 (950) years. It goes up to about 6000 years for the CO2 in the fractured zones and in the bottom part of the record, whereas the CH4 time resolution ranges between a few tens of years to 4500 years"
Readers with a scientific background should understand right away that this means each datapoint in the ice core plot represents an average value over some time on the order of ~ 1000 years. Hence high frequency fluctuations would certainly be filtered out. Their basic claim that "present day atmospheric burdns of these two important greenhouse gases seem to have been unprecedented during the past 420,000 years" seems, to me, entirely unfounded. One cannot compare a single annual value, or even decade-average or century average, to astring of data based on a 1000-year moving average.
Fat Drunk & Stupid wrote:
Whoa whoa whoa....what is all this science and facts stuff? This is LR! No facts or data. Just the simple idea, "we don't know". That is enough to allow your average american to carry on doing whatever they feel like.
Get with the program!
rose colored glasses? wrote:Nevermind, I've found an answer to my question:
rose colored glasses? wrote:- my bigger issues are with the interpretation of atmospheric chemistry. The basic assumption is that the chemical signatures of the air bubbles trapped in the ice retain an unaltered record of atmospheric conditions at the time the bubbles were trapped. I have significant doubts that this is a valid assumption. There must be some chemical interaction between the trapped gas and the surrounding ice crystals, and I think there must necessarily be some transport of both gas and supercooled fluids within the ice over that kind of time period. I would expect to see some "averaging" of chemical properties through diffusion and other processes that would soften (filter out) high frequency peaks and valleys, such as the apparent peak we are reportedly entering presently
looking at the NATURE paper (Petit et al, 1999), I reference the caption to Figure 3, which presents the guts of their findings, and is the basis for the alarming blue graph mentioned earlier, the one with the sharp hockeystick trajectory of CO2 concentration starting in 1950-ish.
"The mean resolution of the CO2 (CH4) profile is about 1500 (950) years. It goes up to about 6000 years for the CO2 in the fractured zones and in the bottom part of the record, whereas the CH4 time resolution ranges between a few tens of years to 4500 years"
Readers with a scientific background should understand right away that this means each datapoint in the ice core plot represents an average value over some time on the order of ~ 1000 years. Hence high frequency fluctuations would certainly be filtered out. Their basic claim that "present day atmospheric burdns of these two important greenhouse gases seem to have been unprecedented during the past 420,000 years" seems, to me, entirely unfounded. One cannot compare a single annual value, or even decade-average or century average, to astring of data based on a 1000-year moving average.
Are they really comparing 1000-year moving averages to single year averages? If so, I don't know how you can make any sort of judgement based on that data.
asdeee wrote:Are they really comparing 1000-year moving averages to single year averages? If so, I don't know how you can make any sort of judgement based on that data.Well, the mean resolution for the CO2 data is claimed to be 1500 years, so more like a 1500 year moving average I guess.
Citizen Runner wrote:Tree ring / carbon isotope argument overview with references here:
http://www.realclimate.org/index.php?p=87
Thanks for the links. I'll admit to being very wary about anything written at realclimate.org.
For fun, I went looking for more climate data. Here is a west coast town with 106 years of data:
I've inserted some "best fits" for the full data set, pre-1950 and post-1950. While there's no doubt they all show an increasing trend, please pay attention to the scatter. I think you would find a least squares analysis of constant T = 7.1C would give as good a fit to these data as the little sloped lines.
rose colored glasses? wrote:
Citizen Runner wrote:Tree ring / carbon isotope argument overview with references here:http://www.realclimate.org/index.php?p=87Thanks for the links. I'll admit to being very wary about anything written at realclimate.org.
For fun, I went looking for more climate data. Here is a west coast town with 106 years of data:
Image:
http://i44.tinypic.com/x2ngid.jpgI've inserted some "best fits" for the full data set, pre-1950 and post-1950. While there's no doubt they all show an increasing trend, please pay attention to the scatter. I think you would find a least squares analysis of constant T = 7.1C would give as good a fit to these data as the little sloped lines.
What happens if you remove what looks like 1957 and 1955 (the two lowest points after 1950)? Those two data points seem to drive most of the perceived increase.
asdeee wrote:What happens if you remove what looks like 1957 and 1955 (the two lowest points after 1950)? Those two data points seem to drive most of the perceived increase.
I prefer not to play that game, snipping out points you don't like. I think the data stand on their own. The main point I take from looking at data like that is that the variability is significant, and has a controlling influence on the interpretation of trends, imagined or real.
In case anyone doesn't understand why I am inclined to dismiss the CO2 plot inferred from the ice core, here is the same 100+ years of average temperature data for the west coast town with also 5 year, 10 year and 20 year moving averages. You can see most of the fluctuation is removed from the data, even at the first pass of filtering (5 year average).
Now imagine 15 of these graphs, end to end, and average all of that data into a single point. That's what has effectively been plotted in the big scary blue graph.
When we try to compare a single point containing 1500 years of records averaged into a single point against one year, or a series of 10 or 100 years, we are not comparing apples with apples.
Note, this doesn't mean I'm fixed in my position (of ambivalence), but I continue to find that when I probe with any kind of force, the arguments are a little soft. Perhaps I'm generalizing too broadly, so nobody take any offence. I'm still climate-illiterate so my (unformed) opinions meand nothing and should offend noone.
rose colored glasses? wrote:
asdeee wrote:What happens if you remove what looks like 1957 and 1955 (the two lowest points after 1950)? Those two data points seem to drive most of the perceived increase.I prefer not to play that game, snipping out points you don't like. I think the data stand on their own. The main point I take from looking at data like that is that the variability is significant, and has a controlling influence on the interpretation of trends, imagined or real.
In case anyone doesn't understand why I am inclined to dismiss the CO2 plot inferred from the ice core, here is the same 100+ years of average temperature data for the west coast town with also 5 year, 10 year and 20 year moving averages. You can see most of the fluctuation is removed from the data, even at the first pass of filtering (5 year average).
Image:
http://i44.tinypic.com/2qa2qh5.jpgNow imagine 15 of these graphs, end to end, and average all of that data into a single point. That's what has effectively been plotted in the big scary blue graph.
When we try to compare a single point containing 1500 years of records averaged into a single point against one year, or a series of 10 or 100 years, we are not comparing apples with apples.
Note, this doesn't mean I'm fixed in my position (of ambivalence), but I continue to find that when I probe with any kind of force, the arguments are a little soft. Perhaps I'm generalizing too broadly, so nobody take any offence. I'm still climate-illiterate so my (unformed) opinions meand nothing and should offend noone.
It's not a game, it's just doing a sensitivity analysis of sorts.
Best troll thread in recent memory
Just so nobody thinks I'm only looking to "disprove" something, here's another "random" dataset (I say random, it's just the second one I grabbed that had ~ 100 years of temperature data - the last one was on the west coast, this is in the prairies, northern Saskatchewan):
There's still tremendous scatter, but one could hardly ignore that the trend is upward again. Can't see any sharp "hockeystick" mind you.
rose colored glasses? wrote:
Thanks for the links. I'll admit to being very wary about anything written at realclimate.org.
Why so? To be sure it's an article written for the layman, not a peer reviewed technical piece. Even if you believe they have a biased perspective the article, as is typical for that site, has references to peer reviewed literature which would allow you to drill down and convince yourself whether their response is valid or not. You seem to have avoided the IPCC report as well. It strikes me as bizarre that you claim to be weighing the validity of a theory of which you clearly have little understanding and your first steps are something other than understanding the theory.
For fun, I went looking for more climate data. Here is a west coast town with 106 years of data . . .
While this may be fun, data from one town by itself doesn't say much of anything about global climate.
Citizen Runner wrote:(1) It strikes me as bizarre that you claim to be weighing the validity of a theory of which you clearly have little understanding and your first steps are something other than understanding the theory.
(2) While this may be fun, data from one town by itself doesn't say much of anything about global climate.
(1) My process is to work with data first before looking at someone else's interpretation, hence general avoidance of summary work as a general preference.
(2) True true, I didn't suggest otherwise. Just trying to build a picture for myself.
One more post to show why I think the "big blue graph" with CO2 levels is essentially meaningless.
Here again are the data for the west coast town, this time only showing the 20 year trailing average. The red line shows the maximum average annual value recorded during that ~ 100 year period. The higher green line shows the approximate highest DAILY average temperature recorded during the same period:
So when you look at a ~ 1500 moving average curve, the only thing you can conclude is that the 1500 year moving average probably never exceeded some peak value in your data. You can't say anything at all about the highest single year value, or the highest ~ 60 year value, except that it was CERTAINLY higher than the highest recorded 1500 year moving average value.
Hence the claim that past CO2 levels have never exceeded some specific value is simply (very) bad science, unless the claim comes with the clarifier, "the 1500 year moving average value never exceeded...," and the comparison to current levels is made with a current 1500 year moving average.
I'm really not trying to argue against anyone on this thread, or against the idea of human induced climate change, I'm simply scrutinizing the "science" that's being used to popularize the notion.
I haven't got to the tree ring or ocean buffer stuff yet, but will do so sometime this week.
rose colored glasses? wrote:
One more post to show why I think the "big blue graph" with CO2 levels is essentially meaningless.
"Meaningless" is a strong word. The original paper was clear on the time resolution of the data. As I noted previously, for your theory of rapid variations in atmospheric CO2 to be plausible, you would have to propose a mechanism for rapid change in that parameter. The fact that temperature changes rapidly is meaningless as an analogy beyond showing the mathematics of a moving average.
You can't say anything at all about the highest single year value, or the highest ~ 60 year value, except that it was CERTAINLY higher than the highest recorded 1500 year moving average value.
Hence the claim that past CO2 levels have never exceeded some specific value is simply (very) bad science, unless the claim comes with the clarifier, "the 1500 year moving average value never exceeded...," and the comparison to current levels is made with a current 1500 year moving average.
The "Gases in Ice Cores" paper cited earlier discusses other sample sets with much better time resolution (30 years in one case) going back to the 1300s with CO2 variation of +/- 5 ppm. Apparently they get much better resolution from cores where the ice accumulates quicker, but they can't go back as far in time.
http://cdiac.ornl.gov/trends/co2/graphics/lawdome.gifCitizen Runner wrote:(1) for your theory of rapid variations in atmospheric CO2 to be plausible, you would have to propose a mechanism for rapid change in that parameter. The fact that temperature changes rapidly is meaningless as an analogy beyond showing the mathematics of a moving average.
(2) The "Gases in Ice Cores" paper cited earlier discusses other sample sets with much better time resolution (30 years in one case) going back to the 1300s with CO2 variation of +/- 5 ppm. Apparently they get much better resolution from cores where the ice accumulates quicker, but they can't go back as far in time.
http://cdiac.ornl.gov/trends/co2/graphics/lawdome.gif
(1) No actually I don't need to propose anything. The only meaningful comparison, regardless of mechanism, is to a current 1500 year moving average, which seems to be around 280 ppm. You are free to believe differently.
(2) Thanks, can you cite the source for that graph?
A bit more on this one (I really would like to see the source paper):
Citizen Runner wrote:The "Gases in Ice Cores" paper cited earlier discusses other sample sets with much better time resolution (30 years in one case) going back to the 1300s with CO2 variation of +/- 5 ppm. Apparently they get much better resolution from cores where the ice accumulates quicker, but they can't go back as far in time.
http://cdiac.ornl.gov/trends/co2/graphics/lawdome.gif
First, the CO2 data from the Mauna Loa observatory show annual fluctuations of CO2 away from the general trend on the order of 5-10 ppm, so fluctuations of that size would seem to be normal.
Second, the graph you've linked seems to show CO2 levels skyrocketing around 1850-ish. Should we not therefore be seeing temperatures having begun to skyrocket since back then? The older papers with the Antarctica ice core data show a 10-12 degree range in temperature correlating with CO2 values swinging between ~ 180 to 280 ppm. So another 100 ppm jump, as suggested, should coincide with a 10-12 degree jump in average temperatures over the period of increase, no?
rose colored glasses? wrote:
First, the CO2 data from the Mauna Loa observatory show annual fluctuations of CO2 away from the general trend on the order of 5-10 ppm, so fluctuations of that size would seem to be normal.
I believe they were referencing +/-5 ppm variation on the ~30 year moving average. The Mauna Loa observatory (and other direct CO2) see a seasonal variation which is what I presume you are refering to. The ice core samples would not resolve seasonal variation.
Here's a link to one of the Law Dome ice core papers:
http://www.agu.org/journals/jd/v101/iD02/95JD03410/95JD03410.pdfSecond, the graph you've linked seems to show CO2 levels skyrocketing around 1850-ish. Should we not therefore be seeing temperatures having begun to skyrocket since back then? The older papers with the Antarctica ice core data show a 10-12 degree range in temperature correlating with CO2 values swinging between ~ 180 to 280 ppm. So another 100 ppm jump, as suggested, should coincide with a 10-12 degree jump in average temperatures over the period of increase, no?
There are two flaws in your reasoning per current theory. First is that any greenhouse gas induced warming will necessarily lag the increase in the forcing function. As a stupidly simple example, when you turn on the burner under a pot of water, it takes awhile for the water to warm up. One consequence of the GW theory which I don't believe the public generally grasps is that elevated CO2 levels are persistant and even if we were to significantly reduce emissions immediately, it will take a long time for the "burner" to go out completely.
Second, concerning the 100 ppm jump, I assume you're refering to the difference in CO2 and temperature between the glacial and interglacial periods. Theory has it that these rises in CO2 level are an effect of the warming in the interglacial and not the cause of that warming.
Citizen Runner wrote:(1) ...The Mauna Loa observatory (and other direct CO2) see a seasonal variation which is what I presume you are refering to. The ice core samples would not resolve seasonal variation.
(2) Theory has it that these rises in CO2 level are an effect of the warming in the interglacial and not the cause of that warming.
(1) Yes, exactly. There is variability (some seasonal, as under discussion here), and some on other time scales associated with other phenomena (other than changing of the seasons), all of which are filtered out by a 1500 year moving average.
(2) Which is it... does CO2 cause warming, or does warming cause CO2??? You can't have it both ways. Unless you're saying the (presumed) cause and effect relationships are complex and beyond our understanding, or instead you're simply claiming a temporal correlation. Both of which I find, on the basis of what I've read so far, to be more plausible than the claim of a direct cause and effect.
Citizen Runner wrote:(1) ...The Mauna Loa observatory (and other direct CO2) see a seasonal variation which is what I presume you are refering to. The ice core samples would not resolve seasonal variation.
(2) Theory has it that these rises in CO2 level are an effect of the warming in the interglacial and not the cause of that warming.
rose colored glasses? wrote:
(1) Yes, exactly. There is variability (some seasonal, as under discussion here), and some on other time scales associated with other phenomena (other than changing of the seasons), all of which are filtered out by a 1500 year moving average.
The Law Dome ice core doesn't have a 1500 year moving average, it has ~30 year moving average. You seem to be fixating on the Vostok data set.
rose colored glasses? wrote:
(2) Which is it... does CO2 cause warming, or does warming cause CO2??? You can't have it both ways. Unless you're saying the (presumed) cause and effect relationships are complex and beyond our understanding, or instead you're simply claiming a temporal correlation. Both of which I find, on the basis of what I've read so far, to be more plausible than the claim of a direct cause and effect.
Atmospheric CO2 causes warming by the greenhouse effect. Warming causes a rise in atmospheric CO2 by reducing the dissolved gas carrying capacity of the oceans. That's a simplistic view of a system that involves more variables, but it's essentially the "have it both ways" cause and effect relationship. Clearly the interactions involved in global climate are complex but, at some reasonable level, not beyond understanding.
