Tuesday, April 10, 2007
The Great Global Warming Swindle Review: Part I
As noted in a previous post comments, I recently watched "The Great Global Warming Swindle" thanks to a link from Reliapundit. It was a very interesting program, and I'll comment on it at length. I took quite a few notes, including direct quotes from the documentary, but I should warn that they may have slight errors where I missed a word or two.
There are several points and theories advanced in this video, and I intend to address most of them, with the notable exception of any issues related to the Kyoto protocols or the impacts of any such suggested solutions. This will be a topic that will undoubtedly take up several posts over the next few weeks.
In this first one, I will cover some generalized claims from the movie. Many of the specific claims will be dealt with in subsequent posts:
1."The Earth's Climate Is Always Changing"
Yes, it's true that the Earth's climate is always changing and has changed in the past many times with no human intervention. There are several things that can cause changes in the climate: changes in the sun's irradiance, changes in the earth's orbital alignment, changes in the level of particulate matter in the atmosphere, changes in the level of greenhouse gases, and, as this show features prominently, changes in the cloud cover of the planet. But, the number of direct climate drivers is actually relatively small, and at this point, pretty well measured and understood. Climate modeling often takes a hit, because it is essentially impossible to predict how these factors will change, and even what feedback effects will result from maintaining the status quo. However, it is very important to understand the difference between climate modeling to predict the future and climate modeling to explain the past, especially the recent past. When modeling past climate, the factors have all already been determined. The researcher has to measure all of the forcings that were applied to the climate and determine how they should be weighted to best explain the data. When climate scientists make predictions about the future, they are relying on modeling. When they make statements like, "the earth has warmed ~.6 degrees C in the past 30 years and anthropogenic greenhouse gas production is responsible for much of that increase," they are relying on measurements more than modeling.
So, the important fact isn't that the earth's climate changes, it's what's causing the change and with what level of certainty we can make that determination. People often die, but we do autopsies to determine what caused their death when we're not sure of the cause. If it was natural causes, then there is usually no need to delve any further. If it was some type of trauma that caused the death, then there is probably a need for investigation. A scientist saying "the earth's climate is always changing" is like a police officer saying "people die all the time" when pointed to a body lying in the street. It's true, but has little meaning when we can investigate and determine the root cause.
2. There is Nothing Unusual About the Current Temperature Change
That brings us to point 2. Is there something different about the current warming that separates it from past warming events? The directors of "Swindle" certainly conclude that there is not any difference. If we look at the past 2000 years of temperature reconstructions we can see that the current warming is easily the greatest temperature reached during that time. Although much is made of the Medieval Warm Period in the movie, the global temperatures at that time were only warm compared to the other temperatures before 1975. The global temperatures during the Medieval Warm Period did not approach the current global average. So, we're currently experiencing warming that, to the best of our knowledge, has not happened in the past 2000 years. Is that unusual? Going back farther, the reconstructions get more divergent and the granularity of measurement gets less, but, taking the average of reconstructions, we are currently warmer than we have been for 12,000 years (note: dark black line is the average of the reconstructions). Is there anything else that we are currently experiencing that is a climate driver that hasn't been this high in 12,000 years? As a matter of fact, there is. CO2. Can a similar claim be made for any of the other climate drivers we've identified? We'll see, in upcoming segments...
There are several points and theories advanced in this video, and I intend to address most of them, with the notable exception of any issues related to the Kyoto protocols or the impacts of any such suggested solutions. This will be a topic that will undoubtedly take up several posts over the next few weeks.
In this first one, I will cover some generalized claims from the movie. Many of the specific claims will be dealt with in subsequent posts:
1."The Earth's Climate Is Always Changing"
Yes, it's true that the Earth's climate is always changing and has changed in the past many times with no human intervention. There are several things that can cause changes in the climate: changes in the sun's irradiance, changes in the earth's orbital alignment, changes in the level of particulate matter in the atmosphere, changes in the level of greenhouse gases, and, as this show features prominently, changes in the cloud cover of the planet. But, the number of direct climate drivers is actually relatively small, and at this point, pretty well measured and understood. Climate modeling often takes a hit, because it is essentially impossible to predict how these factors will change, and even what feedback effects will result from maintaining the status quo. However, it is very important to understand the difference between climate modeling to predict the future and climate modeling to explain the past, especially the recent past. When modeling past climate, the factors have all already been determined. The researcher has to measure all of the forcings that were applied to the climate and determine how they should be weighted to best explain the data. When climate scientists make predictions about the future, they are relying on modeling. When they make statements like, "the earth has warmed ~.6 degrees C in the past 30 years and anthropogenic greenhouse gas production is responsible for much of that increase," they are relying on measurements more than modeling.
So, the important fact isn't that the earth's climate changes, it's what's causing the change and with what level of certainty we can make that determination. People often die, but we do autopsies to determine what caused their death when we're not sure of the cause. If it was natural causes, then there is usually no need to delve any further. If it was some type of trauma that caused the death, then there is probably a need for investigation. A scientist saying "the earth's climate is always changing" is like a police officer saying "people die all the time" when pointed to a body lying in the street. It's true, but has little meaning when we can investigate and determine the root cause.
2. There is Nothing Unusual About the Current Temperature Change
That brings us to point 2. Is there something different about the current warming that separates it from past warming events? The directors of "Swindle" certainly conclude that there is not any difference. If we look at the past 2000 years of temperature reconstructions we can see that the current warming is easily the greatest temperature reached during that time. Although much is made of the Medieval Warm Period in the movie, the global temperatures at that time were only warm compared to the other temperatures before 1975. The global temperatures during the Medieval Warm Period did not approach the current global average. So, we're currently experiencing warming that, to the best of our knowledge, has not happened in the past 2000 years. Is that unusual? Going back farther, the reconstructions get more divergent and the granularity of measurement gets less, but, taking the average of reconstructions, we are currently warmer than we have been for 12,000 years (note: dark black line is the average of the reconstructions). Is there anything else that we are currently experiencing that is a climate driver that hasn't been this high in 12,000 years? As a matter of fact, there is. CO2. Can a similar claim be made for any of the other climate drivers we've identified? We'll see, in upcoming segments...
Saturday, April 07, 2007
Watching the "Great Global Warming Swindle"
I sat down this morning to watch "The Great Global Warming Swindle," with notepad in hand, ready to see just how good of a presentation anthropogenic global warming deniers would put together. Unreliapundit had helpfully provided a link for me to use to see the video, but, much to my surprise, I clicked on it and got, "This video is no longer available due to a copyright claim by Wag TV." Quick Google and YouTube searches also came up with a few deleted entries, and I didn't see any copies for sale on Amazon or Ebay. For now, I seem to be at an impasse in viewing and reviewing this work. If someone has a working link, please let me know.
Sunday, April 01, 2007
Analyzing Beck's "Gas Analysis of Air by Chemical Methods"
This paper was recently pointed out to me as absolute proof of a huge level of CO2 in the atmosphere around 1940, much greater than the current level. I hadn't seen this paper before, but apparently it has gained much credence with global warming skeptics that don't bother to look at actual scientific papers. So, I wanted to put up a quick review in case anyone else runs across this, giving some quick ways in which it and the underlying data are flawed.
First let me note that this paper does nothing except take previous measurements by other scientists, combine them, smooth them, and present them. There is no discussion or hypothesis on what could lead to such giant rises in CO2 or their subsequent precipitous falls. Naturally, since neither of those topics is discussed, there is no discussion of why, since the CO2 measurements have been continuously recorded since 1958, we don't see either of those phenomenons since that time.
Given that, let's take a look at some of the underlying data and see what we can note from it. First, the sites of these measurements not chosen to be accurate representations of the general atmospheric CO2 as the current sites are. Secondly, looking at the data, we can see that, in many cases, the large fluctuations in measurement weren't year to year or even month to month, but day to day, and even hour to hour. Let's take the Misra data set as an example. Look at the first line of measured CO2 percentage, taken at 06:00:00 on 12/14/1941. They show .052, .063, and .087 at the respective measurement heights. at 10:00:00 4 hours later the measurements were .031, .030, and .037. approximately 1/2 of the CO2 concentration measured just 4 hours earlier. Of course, that's just one data set. Let's look at some more. Duerst, Kreutz, Hock-Schollander, and to a lesser extent, Haldane all show tremendous fluctuations over very, very short periods of time. Ones that don't show these incredible fluctuations, such as Buch and Steinhauser all show measurements much more in line with the ice core record and well below the current CO2 level.
Please also note, the Misra data is especially important, since it is the only titrimetric data measurement between 1939 and 1950 that Beck uses.
One last note. Ever since the modern measurements have been taken, we have seen very regular annual cycles of CO2, peaking in April/May/June and bottoming out in Sept/Oct, causing 10-15 ppm difference. Looking at Kreutz, the volumetric measurement from 1939-1941, we see April/May/June hovering around 340-370 ppm whereas August/Sept shoots up to over 500 ppm.
So, in summary, let me say that wildly varying data (in ways we know that it shouldn’t vary) from 2 scientists in specific locations that are not controlled for any kind of CO2 contamination (Misra's location even seems to be chosen because of the agricultural CO2 contamination) with no even suggested theory as to how these spikes came about or why they dissipated isn't much. I guess that's why this paper was published here, instead of an accepted peer-reviewed journal.
On the other side, we have a method of measuring historic levels of CO2 at a location we know has no contamination issues and that current measurements match almost exactly with the continuous measurements of other locations chosen to avoid contamination. This doesn't seem like much of a contest, but somehow, there seems to be lots of grasping at this particular straw.
Update - 4/3/2007: I wanted to elaborate on two points:
1. The fact that the data is varying so much in the samples above could have one of two explanations. First, it's possible that there is a close source of CO2 or CO2 absorption. In any event, it is clear that what is being measured is not a stable condition of ambient CO2 in the atmosphere. The other explanation is, of course, that the measurements are insufficiently precise.
2. On the subject of precision, the volumetric method used by many of the papers referenced by Beck is discussed in the Erikson paper:
So, the volumetric method, trying to measure something that is approximately 0.030% of the volume of the sample has a error of 0.015%, or half of what it's trying to measure. Great...
First let me note that this paper does nothing except take previous measurements by other scientists, combine them, smooth them, and present them. There is no discussion or hypothesis on what could lead to such giant rises in CO2 or their subsequent precipitous falls. Naturally, since neither of those topics is discussed, there is no discussion of why, since the CO2 measurements have been continuously recorded since 1958, we don't see either of those phenomenons since that time.
Given that, let's take a look at some of the underlying data and see what we can note from it. First, the sites of these measurements not chosen to be accurate representations of the general atmospheric CO2 as the current sites are. Secondly, looking at the data, we can see that, in many cases, the large fluctuations in measurement weren't year to year or even month to month, but day to day, and even hour to hour. Let's take the Misra data set as an example. Look at the first line of measured CO2 percentage, taken at 06:00:00 on 12/14/1941. They show .052, .063, and .087 at the respective measurement heights. at 10:00:00 4 hours later the measurements were .031, .030, and .037. approximately 1/2 of the CO2 concentration measured just 4 hours earlier. Of course, that's just one data set. Let's look at some more. Duerst, Kreutz, Hock-Schollander, and to a lesser extent, Haldane all show tremendous fluctuations over very, very short periods of time. Ones that don't show these incredible fluctuations, such as Buch and Steinhauser all show measurements much more in line with the ice core record and well below the current CO2 level.
Please also note, the Misra data is especially important, since it is the only titrimetric data measurement between 1939 and 1950 that Beck uses.
One last note. Ever since the modern measurements have been taken, we have seen very regular annual cycles of CO2, peaking in April/May/June and bottoming out in Sept/Oct, causing 10-15 ppm difference. Looking at Kreutz, the volumetric measurement from 1939-1941, we see April/May/June hovering around 340-370 ppm whereas August/Sept shoots up to over 500 ppm.
So, in summary, let me say that wildly varying data (in ways we know that it shouldn’t vary) from 2 scientists in specific locations that are not controlled for any kind of CO2 contamination (Misra's location even seems to be chosen because of the agricultural CO2 contamination) with no even suggested theory as to how these spikes came about or why they dissipated isn't much. I guess that's why this paper was published here, instead of an accepted peer-reviewed journal.
On the other side, we have a method of measuring historic levels of CO2 at a location we know has no contamination issues and that current measurements match almost exactly with the continuous measurements of other locations chosen to avoid contamination. This doesn't seem like much of a contest, but somehow, there seems to be lots of grasping at this particular straw.
Update - 4/3/2007: I wanted to elaborate on two points:
1. The fact that the data is varying so much in the samples above could have one of two explanations. First, it's possible that there is a close source of CO2 or CO2 absorption. In any event, it is clear that what is being measured is not a stable condition of ambient CO2 in the atmosphere. The other explanation is, of course, that the measurements are insufficiently precise.
2. On the subject of precision, the volumetric method used by many of the papers referenced by Beck is discussed in the Erikson paper:
The average CO2 found in the Point Barrow samples is near to 0.040 per cent, and hence is seemingly 0.01 per cent higher than the standard value. This discrepancy is, however, within the analytical uncertainty of the method and may be unreal...Within the accuracy of the method (+ or - 0.015 per cent) the carbon dioxide and the oxygen concentrations were found to be constant through the seasons and within the standard values for temperate regions.
So, the volumetric method, trying to measure something that is approximately 0.030% of the volume of the sample has a error of 0.015%, or half of what it's trying to measure. Great...
