Friday, March 14, 2008
Also! I've been traking the blog hits, and we had 25 hits the day before I stopped posting. So, I'm going to make a post on the Cool Blue Blog, mention this blog again, and hopefully I'll see more and more visitors.
The new address is http://climatechangeskeptic.wordpress.com/ Remember to bookmark it and tell anyone who might be interested.
Thursday, March 6, 2008
For global warming skeptics, this conference marked the beginning of the end of the anthropogenic (human in origin) global warming scare. The conference was capped at 550 attendees, with 56 Ph.D.s, 9 scientists or economists with other advanced degrees, many other scientific experts, plenty of policy experts, and many enthusiasts, like myself. Such big names as John Coleman (founder of the Weather Channel), Dr. Craig Idso (www.co2science.org), Dr. Craig Loehle (author of a new paleoclimate reconstruction), Dr. Ross McKitrick (works with Steve McIntyre of www.ClimateAudit.org to deconstruct the Hockey Stick graph), Dr. Patrick Michaels (UVA professor), Steven Milloy (www.junkscience.com), Dr. Fred Singer (professor of George Mason University), Dr. Willie Soon (Astrophysicist and Geoscientist at the Solar, Stellar, and Planetary Sciences Division of the Harvard-Smithsonian Center for Astrophysics), Dr. Roy Spencer (very famous research scientist from the University of Alabama at Huntsville), John Stossel (ABC News correspondent who focuses on reporting junk science), and of course, the President of the Czech Republic, Dr. Vaclav Klaus. The schedule made time for several important scientific presentations to the entire audience during breakfast, lunch and dinner, but for the rest of the time, it was divided into six tracks with a total of eight 1.5 hr blocks of time for each track in which two to four experts would speak. The tracks included paleoclimatology, climatology, impacts, economics, politics, and movies. I mostly stayed with the paleoclimatology and climatology tracks, so I have a lot of new information about scientific developments that I’ll talk about in later posts.
Here are a few general observations that I made while I was there.
For many of these scientists, they had only interacted with each other through email, and at this conference, we began to see real organization begin. The Heartland Institute, which ran the conference, is working with the scientists on two projects: to create a scientific journal and peer-review process (I assume/hope) to publish skeptical scientists’ work, which is often received poorly by some hostile scientific journals, and to create a long, 300-400 page, Non-Governmental International Panel on Climate Change (NIPCC) report that would use only information in the IPCC Fourth Assessment Report to refute the claims made in that report.
The cosmic ray theory attracted mixed reactions, though, from what I could tell, most scientists agreed that this theory is the mechanism by which the sun can significantly impact the Earth’s temperature. One scientist, in particular, spoke against the cosmic ray theory on the basis that the data is flawed and manipulated, and the mechanism is impossible. Dr. Willie Soon mentioned this only in passing during his presentation, so I approached him Monday morning during breakfast to ask him to explain. According to Dr. Soon, he used to be at the forefront of cosmic ray research, yet now he completely disagrees with the theory. He said that the Swedish scientists (referring to Svensmark and others) are just looking for some “sexy, new theory,” and that charged particles cannot create clouds in the lower atmosphere because of the abundance of cloud condensation nuclei. I asked him to explain how large ships leave contrail-type clouds behind them, and if that would be an example of creation of clouds in the lower atmosphere through aerosol ionization. He didn’t have a great response to that (yes!), though there very well may be a way to explain it. I plan to read some of Soon’s criticisms of the theory soon.
An interesting theory was proposed by Dr. Ferenc Miskolczi, a relatively unknown European scientist. His theory, through the combination of various atmospheric mathematical laws, essentially states that the optical depth of the greenhouse gases in the atmosphere must remain constant. In other words, the greenhouse effect is cannot be enhanced; as humans add more CO2 into the atmosphere, water vapor (the most important greenhouse gas) leaves in the form of precipitation. He went on to use various observations from both the Earth and Mars to confirm his theory. Although much of the mathematics flew right over the head of many of us in the room, his theory seems to be very strong, and it would have huge implications. Essentially, it means that it would be physically impossible for human emission of greenhouse gases to at all change the temperature of the Earth. He was having a lot of trouble getting this published (no wonder), so this theory hasn’t really been exposed to much scrutiny. I emailed him and asked for his paper, which I then forwarded to Dr. Ben Herman, an expert on this sort of scientific research. He responded, saying that he will read it as soon as he can. When he responds, I’ll post his response and the implications of it. If this theory works, it may finally lay to rest the anthropogenic climate change theory.
This conference was of huge importance to the skeptic community. The amount of organization and networking that was created will be of great use trying to coordinate efforts. The conference was extremely well-run, and hopefully, it will attract many more scientists at next year’s conference in London. The Heartland Institute, which hosted the event, will be posting the PowerPoint presentations made by the various experts, and when that happens, I’ll put up a link.
One quick note about media coverage of the event. The NYT just couldn’t help itself. A relatively unbiased article ended with this: “The meeting was largely framed around science, but after the luncheon, when an organizer made an announcement asking all of the scientists in the large hall to move to the front for a group picture, 19 men did so.” Most of the scientists had already left the room; it would’ve taken very little time for the NYT to go online and find the real numbers that I mentioned.
Thursday, February 28, 2008
Cosmic Rays=Galactic Cosmic Radiation (GCR)
Solar Wind=Geomagnetic Activity=Interplanetary Magnetic Field (IMF)
Radiant Energy Emitted from the Sun=Total Solar Irradiance (TSI)
w/m^2=watts per square meter
Cloud Condensation Nuclei=CCN
When confronted with about a 0.9 degree C increase in temperature over the past century, we look to the obvious. Aside from the core, which shows no variation in heat output, the Sun is the Earth’s heat source, and it’s the obvious place to turn to explain perceived changes in surface temperature. Yet, we as we investigate this idea, a major problem comes forth. Although observational analysis might imply a correlation between changes in Total Solar Irradiance (a description of the total radiant energy emitted by the sun over all wavelengths), physically, it seems that TSI couldn’t possibly account for the warming experienced since 1900. Radiative output varied only 0.1% over the last solar cycle; this amounts to a mere 0.3 w/m^2 of heat input at the top of the atmosphere. The UN IPCC estimates that the sun can only account for under 0.5 w/m^2 relative to 1750. For comparison, the IPCC suggests that changes in greenhouse gases have had a warming effect of slightly under 2.5 w/m^2 over that same interval.
could be large enough to explain the warming.
1. Galactic cosmic radiation (GCR), produced by galactic activity, constantly bombards the Earth.
3. Cosmic rays ionize the lower atmosphere at altitudes of 35km and below.
4. The ionization of the lower atmosphere creates aerosols from which cloud condensation nuclei (CCN) can form.
5. Low clouds increase albedo and cool the Earth.
So where do GCR originate? Unfortunately for us, GCRs vary in energy, and those with the highest energy are the least understood. At the same time, they are incredibly energetic and very rare. Only about 100 GCRs with extremely high energy have ever been observed. While these GCRs are not relevant to the climate change debate (for now…), I’m going to indulge my curiosity a bit and explain the seemingly predominant theory.
There is no controversy surrounding this phenomenon. As I explained, the solar wind is flow of energetic charged particles that block incoming cosmic radiation; the region in which this occurs is called the shock front. Low-energy cosmic rays are sapped of their energy before they make it into the atmosphere, but the more powerful ones are able to make it past the shock front and into the upper atmosphere. When the cosmic radiation hits the atmosphere, showers of secondary particles (protons, neutrons, and muons) are produced by nuclear collisions. These secondary particles continue to travel through the atmosphere, undergoing more collisions and creating even more particles. Around 16km from sea level, the secondary particles have lost too much energy to continue colliding. Below this, electrons and muons (produced by the highest energy cosmic rays) are responsible for the ionization.
2. Interplanetary Magnetic Field/Solar Wind/Geomagnetic Activity
Here are a few graphs demonstrating the connection between TSI and IMF, along with IMF and related data trends. Note how TSI lags behind IMF by approximately ten years.
In the very beginnings of this theory, it was believed that cosmic ray bombardment would effect cloud formation at all altitudes. Theoretically, there seemed to be no reason that it wouldn’t, and the observational data of high and low clouds seemed to support the idea (mid-altitude clouds showed no correlation with GCR bombardment). Yet, once the data was updated to include more modern data, it was clear that post-1989 data on middle and high clouds showed absolutely no correlation with the decreasing GCR bombardment.
Over the past few decades, GCR is clearly very closely correlated to low cloud cover. Because IMF is a solar phenomenon, it contains TSI’s signal with a ten-year cycle, and because low cloud cover closely follows GCR bombardment (which is inversely related to IMF and TSI (though TSI lags behind)), low cloud cover has a ten-year cycle. During that cycle, low cloud cover varies by ~2%; this is calculated to exert a 1.2w/m^2 forcing on the Earth.
So we’ve established both the physical and theoretical defense for the theory (though, I admit I skimmed over the actual ionization process because I do not understand it fully), but all good theories must stand the scrutiny of experiment.
The 111-page long CLOUD proposal reads,
“The primary scientific goals of the CLOUD experiment are as follows:
1. To study the link between cosmic rays and the formation of large ions, aerosol particles, cloud droplets, and ice crystals.
2. To understand the microphysical mechanisms connecting cosmic rays to changes in
aerosol and cloud particle properties.
3. To simulate the effects of cosmic rays on aerosol and cloud properties under atmospheric conditions.”
So we’ve established the physical mechanisms that drive this theory, but we haven’t yet explored the ramifications of it. By comparing trends in the Earth’s temperature and GCR, it seems to suggest that the solar modulation of cosmic rays could be the primary driver of climate on the decadal scale, the millenial scale, and even the multi-million year scale.
A Cosmic Signal in the Icehouse Cycle
Higher levels of cosmic ray flux seem to correspond with the Icehouse cycle, which is characterized by a 100 million year cycle composed of warm periods (hothouses or greenhouses), when no ice or snow exists on Earth, and icehouses, when the Earth bounces back and forth between today’s climate and ice ages.
To determine if temperature and cosmic ray flux correspond over the past millennium, we need to determine what temperature reconstruction to use. I have written one post (with more to come) criticizing Michael Mann’s “hockey stick” reconstruction for being methodologically unsound, intellectually dishonest, and absolutely corrupted by tricky statistical methods, and in its place, I will use Loehle’s 2007 reconstruction, which uses no tree rings, and every set of data has been peer-reviewed and adjusted for local temperature (a feat that has never been accomplished before in paleoclimatology). Loehle’s reconstruction shows a strong warm signal during the Medieval Warm Period (MWP) (900-1300 AD) and a strong cold signal during the Little Ice Age (LIC) (1400-1850). Cosmic ray bombardment data shows a very strong correlation with these trends; as shown by the graph, during the MWP, GCR bombardment was especially low, and during the LIC, GCR bombardment was especially high. This correlation that implies GCR flux is the dominant force in cloud cover over long time periods came as somewhat of a surprise. It is important to note that temperatures during the coldest part of the LIC follow the same trend as the solar-modulated GCR flux, rather than TSI itself. Although it seemed possible that changes in GCR flux could significantly alter decadal changes in cloud cover, the suggestion that it could dominate multi-decadal, millennial, and even geological cloud cover despite the massive climate forces and cycles at work is unbelievable, yet, at the same time, the evidence is there to confirm it.
In short, it flies in the face of the enhanced greenhouse effect hypothesized by numerous federal agencies, many climate scientists, the UN, and the liberal media. While some warming remains to be explained, the discovery of this cosmic connection lends credibility to the idea that solar variability is a first-order climate forcing. Although I should refrain from making broad, overarching statements, I’m going to go ahead and say that at least 70% of all changes in temperature up until 1980 can be attributed to changes in the solar magnetic field and thus GCR flux. This theory, coupled with increased pollution, even explains the somewhat mysterious global cooling experienced during the post-WW2 era. It is after 1980 that things become slightly more complex. GCR flux, following Solar magnetic field intensity, has continued in its ten-year cycle, but the amplitude of the cycle has remained unchanged, and no upward shift in the cycle has occurred. Over at Real Climate, they claim this as evidence to discredit the entire idea, though they do admit it is an issue that deserves attention. Increasing levels of CO2, global brightening (the reversal of global dimming through the disintegration of post-WW2 aerosol pollutants), and the recent large collective magnitude of the oceanic cycles could all explain recent warming, though increased CO2 levels are most likely playing a greater role in temperature variations.
What does this mean for the future?
Tuesday, February 26, 2008
Now I said I wouldn’t bother delving into the “consensus” debate, but there has been a paper released by
Fergus W.M. Brown, CPE, UCLAN, Preston, UK
Roger A. Pielke Sr. CIRES, University of Colorado, Boulder, CO
James D. Annan, FRCGC/JAMSTEC, Yokohama, Japan.
The paper is Is there agreement amongst climate scientists on the IPCC AR4 WG1?
"ABSTRACT. An online poll of scientists' opinions shows that, while there is strong agreement on the important role of anthropogenically-caused radiative forcing ofCO2 in climate change and with the largest group supporting the IPCC report, there is not a universal agreement among climate scientists about climate science as represented in the IPCC's WG1. The claim that the human input of CO2 is not an important climate forcing is found to be false in our survey. However, there remains substantial disagreement about the magnitude of its impacts. The IPCC WG1 perspective is the mean response, though there are interesting differences between mean responses in the USA and in the EU. There are, also, a significant number of climate scientists who disagree with the IPCC WG1 perspective."
The text reads,
"In our poll, there were 140 responses out of the 1807 who were contacted by the first author. The authors participated along with poll specialist David Jepson (Bsc Hons) in writing the polling questions (see Table 1 for the questions), but had no knowledge of who participated in the polling. It is interesting to note, however, that among the respondents were a substantial number of senior scientists and leading figures in science, whose support and interest in the poll were much appreciated. It is important to recognize that we are not presenting the results as representing anything other than the views of those who responded as we have no way to assess the relationship of the responders with the total relevant population.The results are quite informative. No scientists were willing to admit to the statement that global warming is a fabrication and that human activity is not having any significant effect on climate [0%]. In total, 18% responded that the IPCC AR4 WG1 Report probably
overstates the role of CO2, or exaggerates the risks implied by focusing on
CO2 dominated Anthropogenic Global Warming (AGW), to a greater or lesser degree. A further 17% expressed the opinion that the Report probably underestimates or
seriously underestimates the consequences of anthropogenic CO2 -induced AGW and that the associated risks are more severe than is implied in the report. The remaining 65% expressed some degree of concurrence with the report’s science basis, of which the largest group [47% of all respondents] selected option 5. The exact response rates are given in Figure 1." [Emphasis added.]
Keep in mind that these statistics are based on the 140 responses received out of the 1807 polls sent out. Only a small portion of the climate science community is represented here, and while the numbers may indicate the general position of climate science community, it could be somewhat skewed.
(These were the options given in the poll. Options 1-3 were grouped together as scientists who feel the UN IPCC has overstated the threat.)
"Which one statement most nearly matches your personal opinion about the physical science basis of global warming, as exemplified by the IPCC WG1 report?
* [If your personal opinion falls between two adjacent statements, please mark both]
1. There is no warming; it is a fabrication based on inaccurate/inappropriate measurement. Human activity is not having any significant effect on Climate. The data on which such assumptions are made is so compromised as to be worthless. The physical science basis of AGW theory is founded on a false hypothesis.
2. Any recent warming is most likely natural. Human input of CO2 has very little to do with it. Solar, naturally varying water vapour and similar variables can explain most or all of the climate changes. Projections based on Global Climate Models are unreliable because these are based on too many assumptions and unreliable datasets. 3. There are changes in the atmosphere, including added CO2 from human activities, but significant climate effects are likely to be all within natural limits. The ’scares’ are exaggerations with a political motive. The undue emphasis on CO2 diverts attention away from other, important research on climate variability and change.
4. There is warming and the human addition of CO2 causes some of it, but the science is too uncertain to be confident about current attributions of the precise role of CO2 with respect to other climate forcings. The IPCC WG1 overestimates the role of CO2 relative to other forcings, including a diverse variety of human climate forcings.
5. The scientific basis for human impacts on climate is well represented by the IPCC WG1 report. The lead scientists know what they are doing. We are warming the planet, with CO2 as the main culprit. At least some of the forecast consequences of this change are based on robust evidence.
6. The IPCC WG1 is compromised by political intervention; I agree with those scientists who say that the IPCC WG1 is underestimating the problem. Action to reduce human emissions of CO2 in order to mitigate against serious consequences is more urgent than the report suggests. This should be done irrespective of other climate and environmental considerations.
7. The IPCC WG1 seriously understates the human influence on climate. I agree with those scientists who say that major mitigation responses are needed immediately to prevent catastrophic serious warming and other impacts projected to result from human emissions of CO2. We are seriously damaging the Earth’s climate, and will continue to face devastating consequences for many years."
This recent paper’s results are about what I would have expected; a clear majority of climate scientists agree with the UN or believe it is too conservative in its predictions, yet by no means do the results of the poll justify the description of a “consensus” in the climate science community. This, of course, means that statements made by many in government, especially on the left (although Republicans don’t have a clean record either) have made and continue to make false statements on the state of the debate on climate change. There is no consensus. The debate is not over. The science is not settled. I can think of a lot of issues where much less than 20% of those involved turned out to be wrong. In fact, it would be very interesting to see what percent of climate scientists bought into the “global cooling” scare of the ’70s (This could be large or small; I truly have no idea.).
It may be tempting to say that the science favors the AGW (Anthropogenic Global Warming) proponents because the results of the poll favored them. I would contend that when science becomes politicized, it becomes a business. Activist groups, universities, and government organizations can buy the conclusions that they need. As skeptics are being compared to “holocaust deniers” and as climate change is becoming a human rights issue, universities that are supposed to be supporting open discourse are suppressing it. When the judgment is foregone, the necessity for debate perishes, and academia has allowed this to happen. We must also beware of federal and intergovernmental organizations, for the issue of climate change is a great way to expand bureaucratic power and influence.
The state of open discourse concerning climate change in the global community is horrific. Today, those who stand up against the “consensus” are shot down as “deniers” and few will publicize their opinions. There has even been problems with publishing this specific paper. I quote this next passage from Roger Pielke Sr.’s weblog, Climate Science:
"After the survey was completed last summer and the article written, it was submitted to the AGU publication EOS as a “Forum piece. The EOS description of a Forum is that it ”contains thought-provoking contributions expected to stimulate further discussion, within the newspaper or as part of Eos Online Discussions. Appropriate Forum topics include current or proposed science policy, discussion related to current research in our fields especially scientific controversies, the relationship of our science to society, or practices that affect our fields, science in general, or AGU as an organization. Commentary solely on the science reported in research journals is not appropriate.”I would like to conclude by saying that academia must stop treating the climate change issue as a foregone conclusion. There is nothing wrong with encouraging debate, and providing a forum for open discourse is the best way to create leaders for tomorrow. By turning opinion into fact, and by treating contentious issues as simple moral issues, we are creating followers, not leaders for the next century.
Our article certainly fits this description. However, after 4 months without a decision, our contribution was summarily rejected by Fred Spilhous without review. He said our article did not fit EOS policy. We disagreed, of course, based on the explicit EOS policy given above, but our follow request for an appeal was ignored. We then submitted to Nature Precedings where their policy states “Nature Precedings is a
place for researchers to share pre-publication research, unpublished manuscripts,
presentations, posters, white papers, technical papers, supplementary findings, and other scientific documents. Submissions are screened by our professional curation team for relevance and quality, but are not subjected to peer review. We welcome high-quality contributions from biology, medicine (except clinical trials), chemistry and the earth sciences.”
Our article was quickly rejected without explanation.
From this experience, it is clear that the AGU EOS and Nature Precedings Editors are using their positions to suppress evidence that there is more diversity of views on climate, and the human role in altering climate, than is represented in the narrowly focused 2007 IPCC report."
This coming Sunday, Monday, and Tuesday, I will be attending the 2008 International Conference on Climate Change, sponsored by the Heartland Institute. Somewhere around 60 skeptic experts will be speaking, including Craig Loehle and Ross McKitrick (who I will definitely attempt to talk to). Craig Loehle recently published a paper titled A 2000-Year Global Temperature Reconstruction Based on Non-Treering Proxies. This is important because, as Steve McIntyre of ClimateAudit put it,
“… Loehle’s network is the first network to be constructed using series in which every proxy as input to the network has already been calibrated to temperature in a peer reviewed article. This is pretty amazing when you think about it. It’s actually breathtaking. Every prior network has included some, if not a majority, of uncalibrated proxies.”Loehle’s findings were in contradiction to Michael Mann’s hockey stick graph, and in my opinion, Loehle’s reconstruction is much more reliable than Mann’s. Ross McKitrick is part of the McIntyre-McKitrick team that has systematically torn apart Michael Mann’s treering reconstruction. The conference should be very exciting, and many of the big names will be there. When I return, I’ll write up a summary of the presentations.
Sunday, February 24, 2008
Here are a few statements made in the show that epitomize the fear-mongering media at its worst.
“Some scientists predict a ten degree drop in some areas.”
“Raging ice storms with high wind velocity [would] batter New York.”
“Berlin [would be] a snowbound relic of the past.”
“Some scientists predict that this sudden change in climate could occur in our lifetime.”
“Massive blizzards and severe storms could become the new norm in weather in the U.S. and Europe.”
“England, France, Germany might begin to resemble Alaska, Canada.”
Yet, the narrator quickly concedes that “Many climate scientists now discount this potential big freeze.” He never brings up this fact again, and unless the listener was paying very close attention, the rest of the show would make it seem like this idea of massive temperature reversal in the coming decades is accepted in the scientific community.
Later in the show, the narrator states that some scientists disagree. I was expecting that the History Channel would go on to explain the rarity of such an argument in order to maintain some sort of professional integrity; I was mistaken. According to the narrator, those scientists who disagree might contend that the effects will be much harsher in the world outside of Europe and North America.
Now, I’m not arguing that the History Channel has an environmental bias (this show actually attributed the Little Ice Age to weak solar activity!); I would merely like to point out the alarmism that it unintentionally spreads to get more viewers. The hour before this show featured the projection of a global depression and disintegration of civilization (as evidenced by a montage of chaotic videos in the History Channel video library) if we do not change our fossil-fuel dependence within the next few decades. The next hour featured the inevitable tsunami that will destroy the West coast of the United States.
The History Channel is seen as a reliable authority on both historical and modern issues. In my opinion, it loses all credibility when it runs programs like “Mega Disasters” that pay no attention to the science and too much attention to ratings. The theory being presented in this specific episode is not accepted in the scientific community. The Intergovernmental Panel on Climate Change Fourth Assessment Report (the Environmentalist’s holy text) predicts a 2.0 to 11.5 degrees Fahrenheit increase in temperature in the next century . . . not very compatible with a coming ice age. So if the environmentalist community doesn’t buy in to such a proposition, and no skeptic would ever suggest a coming ice age without a large change in solar output, who exactly supports this theory? The media - because its knows how many viewers it can lock in place with a scare show like that.
Thursday, February 14, 2008
McIntyre and McKitrick have been fully endorsed by the Wegman Panel Report (headed by Edward Wegman of George Mason University and the Chairman of the National Academy of Science Committee on Theoretical and Applied Statistics), have testified before Congress, have significantly influenced the National Research Council Report on the issue, have presented to the National Academy of Sciences, has have been published in the Geophysical Research Letters, Energy and Environment, and Nature. McIntyre runs a weblog (www.ClimateAudit.org) in which he uses the statistical skills that he used in the private, mine prospecting sector to analyze claims made in climate science from both sides of the debate. I read it every day, and I find his work to be as unbiased and professional as it is illuminating. In 2007, the site tied for the “Best Science Blog” in the weblog awards in 2007.
In my last post, I wrote three reasons why temperature reconstructions over the past millennium are relevant to the modern global warming debate. For ease of reference, here they are again:
1. It would shed light on the idea that today’s temperatures are out of the natural variability.2. It would possibly correlate temperature with societal development.3. By establishing the behavior of the curve, we would gain greater insight into the strength of solar intensity as a climate modifier. Specifically, if temperatures followed the same trend as solar intensity, then we could suggest that perhaps solar intensity has a dominant role in climate change. Yet, we have to be careful; this is merely speculation. To actually make a scientific case for a strong solar sensitivity, we would have to establish the mechanics by which such a process would work as well as the historical correlation.
Now, the most well-known and publicized reconstruction is often described as the “hockey stick” chart, and those who support it (specifically, authors of Real Climate) are dubbed the “hockey team.” Specifically, the reconstruction is MBH98 (and more recent variations) and the lead scientist is Dr. Michael Mann of Penn State. Here’s what his weblog, Real Climate, says about him:
Dr. Michael E. Mann is a member of the Penn State University faculty, holding joint positions in the Departments of Meteorology and Geosciences, and the Earth and Environmental Systems Institute (ESSI). He is also director of the Penn State Earth System Science Center (ESSC).
While I was relatively balanced in my description of paleoclimate issues in the last post, things will begin to change, especially concern Mann and the hockey stick, for it is an issue that I am especially passionate about. Michael Mann’s team has successfully infiltrated television, magazines, textbooks, movies, and popular society with his reconstruction that is filled with deceitful statistical tricks and unreliable tree ring proxies.
The result is a chart with a slightly negative temperature trend until mid-19th century, at which point there is a sharp uptick in global temperatures.
So let’s go back to the three reasons millennial paleoclimate is important.
1. It suggests that modern temperatures are far from natural variability.
2. Any perceived societal development during the Medieval Warm Period would have been unrelated to climate, which shows no upward trend in temperature during that time.
3. Temperature trends seem to closely follow co2 trends, while solar trends seem completely irrelevant. This implies that atmospheric greenhouse gas concentration is the most important climate forcing, which would suggest that modern waming is indeed due to changes in co2, not total solar irradiance (TSI).
For reference, here are three graphs: the Hockey Stick temperature reconstruction, TSI (measured by changes in atmospheric C14 levels), and CO2 concentration.
Now that I have given a brief introduction to the issue, it’s time to start exposing the manipulation that Mann did to achieve the desired reconstruction. This post will look specifically at what Mann described as a “new statistical approach.” What was “new” about it was the way he used Principle Component Analysis (PCA) to mine for the hockey stick shape. In order to effectively draw out trends and use data, the large collection of data from specific proxy reconstructions is condensed into a single series (y). This series takes the form
y = a1x1 + a2x2 + . . . + akxk,
where xn is a single data set, and an is the weight assigned to that data set.
To determine the average of the data, the weight for each data set would be 1/k, so that the entire set would add up to equal 1, but because Mann used PCA, the weights were given different values, dependent upon the variation of the datasets from a given value. This means that the graph of the series will be significantly altered by datasets with large variance, while datasets with low variance will not be very relevant to the end product. This series, y, is referred to as the first Principal Component, PC1. After PC1, there is still some unexplained variance from datasets with less variance. So, PCA also yields PC2, which describes the second Principal Component. This pattern continues until the PC is close to zero. Thus, PCA is an important way to identify variance in a set of data. For PCA to work properly, the data has to be standardized (given a mean of 0 and a variance of 1).
So how did Mann take advantage of this perfectly legitimate method for statistical analysis? To determine the variance, one must determine the mean, and instead of determining the mean for the period under investigation (1400-1980), he applied to mean of the period 1901-1980 to determine the variance. This shouldn’t have caused a lot of issues, for in most of the North American tree ring group, there is not significant variation in temperatures from 1980 back to 1400. Well, actually that’s not completely true, so I need to explain exactly what I mean before I continue. A proxy is defined as an indirect reading of something, in this case - temperature.
When the dendrochronologist reads the width of tree rings, it does not tell him or her the exact temperature of that year. Instead, it gives a width that then can be compared to other years, specifically ones that we know the temperature of through modern instrumental data collection. Through that process, the magnitude of changes in temperaure is established. Therefore, although the temperature magnitude of the changes is large, the departures from the mean over extended periods of time are much smaller, and that is what I mean by my statement that there is no significant variation in temperatures back to 1400 in most of the tree ring proxies.
And although most proxies show no variation (in comparison to previous centuries) beginning in the 1800s, a select few do - specifically, Bristlecone Pine tree rings. Because the mean year to determine variance was set in the 1900s, pre-industrial revolution temperatures are given higher weights, and thus, those Bristlecone Pines are given a tremendous sway in the reconstruction graph. There are significant problems that I will comment on in a later post concerning the use Bristlecones as a proxy, but in this current argument, I’m only trying to show that an undue amount of emphasis was added to these select few proxies from the Southwest USA.
To give an example, the Graybill-Idso Bristlecone proxy was given 390 times more weight than a normal, non-Bristlecone proxy from Mayberry Slough, AR through Mann’s “new” statistical approach. While normal PCA would allow the Graybill-Idso Bristlecone proxies only 8% of the variance, Mann’s technique allows the proxies account for almost 40% of the variance. It is in this manner that Mann et al. essentially “mine” for a hockey stick.
There will be more criticisms to come.
For the papers from which I take my information, visit McIntyre and McKitrick’s project page at http://www.uoguelph.ca/~rmckitri/research/trc.html.