Guest Post by Willis Eschenbach
First, I would like to thank Dr. Meier of the National Snow and Ice Data Center (NSIDC) for answering the questions I had posed (and had given my own personal answers) in “Trust and Mistrust”. I found his replies to be both temperate and well-reasoned. Also, I appreciate the positive and considerate tone of most of those who commented on his reply. It is only through such a peaceful and temperate discussion that we can come to understand what the other side of the debate thinks.
Onwards to the questions, Dr. Meier’s answers, and my comments:
Question 1. Does the earth have a preferred temperature, which is actively maintained by the climate system?
Willis says that he “believes the answer is yes”. In science “belief” doesn’t have much standing beyond initial hypotheses. Scientists need to look for evidence to support or refute any such initial beliefs. So, does the earth have a preferred temperature? Well, there are certainly some self-regulating mechanisms that can keep temperatures reasonably stable at least over a certain range of climate forcings. However, this question doesn’t seem particularly relevant to the issue of climate change and anthropogenic global warming. The relevant question is: can the earth’s temperature change over a range that could significantly impact modern human society?
My comment: Since unfortunately so little attention has been given to this important question, my idea of how it works is indeed a hypothesis. Therefore, “belief” is appropriate. However, I have provided several kinds of evidence in support of the hypothesis at the post I cited in my original answer to this question, “The Thermostat Hypothesis”.
Next, Dr. Meier says that there are “some self-regulating mechanisms that can keep temperature reasonably stable at least over a certain range of climate forcings.” Unfortunately, he does not say what the mechanisms might be, at what timescale they operate, or what range of forcings they can handle.
However, he says that they can safely be ignored in favor of seeing what the small changes are, which doesn’t make sense to me. Before we start looking at what causes the small fluctuations in temperature that we are discussing (0.6°C/century), we should investigate the existence and mechanism of large-scale processes that regulate the temperature. If we are trying to understand a change in the temperature of a house, surely one of the first questions we would want answered is “does the house have a thermostat?” The same is true of the climate.
Question 2: Regarding human effects on climate, what is the null hypothesis?
I will agree with Willis here – at one level, the null hypothesis is that any climate changes are natural and without human influence. This isn’t controversial in the climate science community; I think every scientist would agree with this. However, this null hypothesis is fairly narrow in scope. I think there is actually a more fundamental null hypothesis, which I’ll call null hypothesis 2 (NH2): are the factors that controlled earth’s climate in the past the same factors that control it today and will continue to do so into the future? In other words are the processes that have affected climate (i.e., the forcings – the sun, volcanic eruptions, greenhouse gases, etc.) in the past affecting climate today and will they continue to do so in the future? A basic premise of any science with an historical aspect (e.g., geology, evolution, etc.) is that the past is the key to the future.
My Comment: I assume that Dr. Meier has temporarily overlooked the fact that a null hypothesis is a statement rather than a question. Thus, his Null Hypothesis 2 (NH2) should be:
NH2: The factors that controlled earth’s climate in the past are the same factors that control it today and will continue to do so into the future
However, this formulation has some serious problems. First, a null hypothesis must be capable of being falsified. My null hypothesis (NH1) could be falsified easily, by a showing that measurements of the modern climate are outside the historical values.
Dr. Meier’s NH2, on the other hand, extends into the future … how can we possibly falsify that?
Second, to determine if the factors that controlled the climate in the past are the same factors that control it now, we must know the factors that controlled climate in the past, and we must know the factors that control climate now. But that is exactly the subject being debated – what controls the climate? We don’t know the answer to that for the present, and we know even less about it for the past. So again, his NH2 is not falsifiable.
Finally, there is a more fundamental problem with NH2. The null hypothesis has to be the logical opposite of the alternate hypothesis, so that if one is true, the other must be false. My null hypothesis NH1 is that the currently observed climate variations are the result of natural variation. The opposite of my null hypothesis is the alternate hypothesis, that currently observed climate variations are the result of human-caused GHG increases.
However, what is the opposite of NH2, which states that the factors that controlled climate in the past are those that control climate today? The opposite of that is the alternate hypothesis that the factors that controlled climate in the past are not those that control climate today.
But I have never once, in this entire decades-long debate, heard anyone make the claim that some factors that affected climate in the past have stopped affecting the climate. As a result, NH2 is a straw man. It is the null hypothesis for an alternate hypothesis that no one is propounding.
Since it is not falsifiable, and since it is a straw man null hypothesis, Dr. Meier has not proposed a valid null hypothesis. As a result, his arguments that follow from that null hypothesis are not relevant.
Question 3: What observations tend to support or reject the null hypothesis?
Let me first address NH2. We have evidence that in the past the sun affected climate. And as expected we see the current climate respond to changes in solar energy. In the past we have evidence that volcanoes affected climate. And as expected we see the climate respond to volcanic eruptions (e.g., Mt. Pinatubo). And in the past we’ve seen climate change with greenhouse gases (GHGs). And as expected we are seeing indications that the climate is being affected by changing concentrations of GHGs, primarily CO2. In fact of the major climate drivers, the one changing most substantially over recent years is the greenhouse gas concentration. So what are the indications that climate is changing in response to forcing today as it has in the past? Here are a few:
1. Increasing concentrations of CO2 and other GHGs in the atmosphere
2. Rising temperatures at and near the surface
3. Cooling temperatures in the stratosphere (An expected effect of CO2-warming, but not other forcings)
4. Rising sea levels
5. Loss of Arctic sea ice, particularly multiyear ice
6. Loss of mass from the Greenland and Antarctic ice sheets
7. Recession of most mountain glaciers around the globe
8. Poleward expansion of plant and animal species
9. Ocean acidification (a result of some of the added CO2 being absorbed by the ocean)
It is possible that latter 8 points are completely unrelated to point 1, but I think one would be hard-pressed to say that the above argues against NH2.
My Comment: Saying “it is possible that the latter 8 points are completely unrelated to point 1” begs the question. It is possible that they are related, but that is the question at hand that we are trying to answer. If Dr. Meier thinks that they are related, he needs to establish causation, not just say it is “possible that [they] are completely unrelated”.
Whether his points argue for or against NH2 is not relevant, since NH2 is not falsifiable, and is a null hypothesis for a position no one is taking. In addition, they are presented as “indications that climate is changing in response to forcing today as it has in the past” … but it is a mix of statements about forcings, and responses to increasing warmth. So I don’t see how that applies to NH2 in any case.
Despite those problems, let me address them, one by one, starting with one without a number:
In the past we’ve seen climate change with greenhouse gases (GHGs): This cries out for a citation, but there is none. When did we see that, who showed it, what evidence is there to support it?
1. Increasing concentrations of CO2 and other GHGs in the atmosphere: Yes, GHGs are increasing. However, this says nothing either way about NH2.
2. Rising temperatures at and near the surface: Yes, temperatures generally have been rising, and they have been ever since the Little Ice Age in the mid 1600’s. But again, what does this have to do with NH2?
3. Cooling temperatures in the stratosphere (An expected effect of CO2-warming, but not other forcings): I would greatly appreciate a citation to the claim that this is an expected result of GHG forcing but not other forcings. Given our general lack of understanding of the climate, it would be a very difficult claim to establish.
For one of the reasons why it would be hard to establish, here is the actual change in the stratospheric temperatures:
Now, how on earth (or off earth and in the stratosphere) is that an “expected effect” of increasing GHGs? Since recovering from the Pinatubo eruption stratospheric temperatures have been stable … which climate model projected that outcome? What theoretical calculations showed that flat-line response?
4. Rising sea levels: Sea levels have been rising since 1900. If GHGs were driving the rise, we would expect to see an acceleration in the rate of rise corresponding to the acceleration in the rise of GHGs. However, we have seen no such acceleration in the long-term, and we see deceleration in the short-term. Here are two long-term records. Fig.2 is from Church and White and Jevrejeva:
Figure 2. Church & White and Jevrejeva sea level records from tidal stations. Photo is of Dauphin Island Tidal Station. PHOTO SOURCE
There is good agreement between the Church & White and the Jevrejeva records. As they were calculated in different ways, this increases the confidence in the result. Note that, despite increasing CO2, there is no increase in the rate of sea level rise.
Next, we have a short-term but presumably more accurate sea level record from the TOPEX satellite. Fig. 3 shows that record:
Figure 3. Sea level record from the TOPEX satellite. Black line is the trend from 1993 to 2004, and is projected to 2007 in gray. Red line is the trend since 2004.
As you can see, rather than increasing, the rate of sea level rise has dropped in recent years. And while it may well start to rise again, it is certainly not accelerating as the AGW hypothesis requires.
5. Loss of Arctic sea ice, particularly multiyear ice: As Dr. Meier would agree, the satellite record of Arctic ice is quite short, much shorter than the long-term changes in Arctic temperatures. The Arctic was as warm or warmer in the 1930s, and many records from that time attest to greatly reduced ice conditions. Both the Polyakov and the NORDKLIM records [see Update 10] show the time around 1979 as being about the bottom of the Arctic temperature swing, so reducing Arctic sea ice is to be expected since 1979. In addition, I was surprised that Dr. Meier did not mention the last three years, which have seen both increasing Arctic sea ice and increasing multiyear sea ice.
6. Loss of mass from the Greenland and Antarctic ice sheets: NASA reports that the GRACE satellite data shows the Antarctic and Greenland ice sheets to be losing a total of ~ 1,700 cubic km of ice per year. While this sounds large, this is about 0.005% of the total ice in the two sheets … I hardly see this as indicating anything but a confirmation that the earth has been warming for centuries, and is generally continuing to do so with the usual fits and starts. Since at the current rate of loss it will take about two hundred years to lose 1% of the ice, I don’t see this as a critical issue.
7. Recession of most mountain glaciers around the globe: According to the NSIDC, the excellent organization that Dr. Meier works for, there are about 100,000 glaciers on the planet. Again according to the NSIDC, we have measured the mass balance on 300 of them, and we have continuous records since 1960 for only 60 of them … so we have at least one record on 0.3% of the glaciers, and decent (although short) records on 0.1% of the glaciers. Given those percentages, “recession of most mountain glaciers” seems to be a bit of an overstatement of what scientific research actually has shown …
It is true that many of the glaciers we have measured have receded since the colder period of the 1960s when the records started. It is also true that some are advancing. Many of the known glaciers have been generally receding since sometime after the Little Ice Age in the 1600’s. Before that, they were advancing, so much so that in 1678 the village of Aletsch in Switzerland made a formal church vow to live virtuously if only the nearby advancing glacier would not over-run their village … a vow which they are now trying to recant as the glacier recedes. That dratted climate never stops changing.
All this shows is that when the earth cools, glaciers generally advance, and when it warms, they generally retreat. Surprising, huh? It says nothing about whether or not GHGs control the temperature.
8. Poleward expansion of plant and animal species: Animals and plants advance and retreat with the seasons and with the climate. In a time of general warming, like the last 300 years, we would expect them to move slightly polewards. However, care is required, because climate change is blamed for everything. For example, in this South African study (subscription required), they say (emphasis mine):
Evidence from the Northern Hemisphere and simple theoretical models both predict that climate change could force southern African birds to undergo poleward range shifts. We document the chronology and habitat use of 18 regionally indigenous bird species that colonised the extreme south-western corner of Africa after the late 1940s. This incorporates a period of almost four decades of observed regional warming in the Western Cape, South Africa. Observations of these colonisation events concur with a ‘climate change’ explanation, assuming extrapolation of Northern Hemisphere results and simplistic application of theory. However, on individual inspection, all bar one may be more parsimoniously explained by direct anthropogenic changes to the landscape than by the indirect effects of climate change. Indeed, no a priori predictions relating to climate change, such as colonisers being small and/or originating in nearby arid shrublands, were upheld.
9. Ocean acidification (a result of some of the added CO2 being absorbed by the ocean): Again, this appears to be happening, although we have very little in the way of data. If verified, this would indicate that atmospheric CO2 levels are rising … but we knew that already.
Overall, Dr. Meier’s points show that when the world warms we are likely to see various phenomena related to that warming. But that says nothing about his null hypothesis NH2, nor about my null hypothesis. None of them either support NH2 nor falsify NH2, as NH2 is a straw null hypothesis that cannot be falsified. They also say nothing about whether GHGs are currently causing unusual warming.
Next, Dr. Meier addresses NH1, my null hypothesis:
Of course none of the above says anything about human influence, so let’s now move on to Willis’ null hypothesis, call it null hypothesis 1 (NH1). Willis notes that modern temperatures are within historical bounds before any possible human influence and therefore claims there is no “fingerprint” of human effects on climate. This seems to be a reasonable conclusion at first glance. However, because of NH2, one can’t just naively look at temperature ranges. We need to think about the changes in temperatures in light of changes in forcings because NH2 tells us we should expect the climate to respond in a similar way to forcings as it has in the past. So we need to look at what forcings are causing the temperature changes and then determine whether if humans are responsible for any of those forcings. We’re seeing increasing concentrations of CO2 and other GHGs in the atmosphere. We know that humans are causing an increase in atmospheric GHGs through the burning of fossil fuels and other practices (e.g., deforestation) – see Question 6 below for more detail. NH2 tells us that we should expect warming and indeed we do, though there is a lot of short-term variation in climate that can make it difficult to see the long-term trends.
So we’re left with two possibilities:
1. NH2 is no longer valid. The processes that have governed the earth’s climate throughout its history have suddenly starting working in a very different way than in the past.
2. NH1 is no longer valid. Humans are indeed having an effect on climate.
Both of these things may seem difficult to believe. The question I would ask is: which is more unbelievable?
This is a false dichotomy, created by using my real null hypothesis NH1, and Dr. Meier’s straw man null hypothesis NH2. Yes, both CO2 and temperatures rose over the 20th century … but correlation is not causation, and CO2 does not correlate any better with temperature than a straight line correlates with temperature. Next, Dr. Meier seems to think that NH1 and NH2 are somehow related, so that one or the other must be false. But both could easily be true. It could be true that the climate variations are natural (NH1), and also true that the historical forcings still apply (NH2). So his “one true / one false” duality is not valid.
At the end of the day, as Dr. Meier says himself, none of what he has said falsifies the null hypothesis NH1 that the observed climate changes are natural variations rather than human-caused. Since it is not falsified, we have nothing for the AGW hypothesis to explain. This is an important conclusion.
Skipping over some questions where we generally agree, we come to:
Question 6: How are humans affecting the climate?
Willis mentions two things: land use and black carbon. These are indeed two ways humans are affecting climate. He mentions that our understanding of these two forcings is low. This is true. In fact the uncertainties are of the same order of as the possible effects, which make it quite difficult to tell what the ultimate impact on global climate these will have. However, Willis fails to directly mention the one forcing that we actually have good knowledge about and for which the uncertainties are much smaller (relative to the magnitude of the forcing): greenhouse gases (GHGs). This is because GHGs are, along with the sun and volcanoes, a primary component that regulates the earth’s climate on a global scale.
My Comment: First, despite the IPCC claims, our knowledge of the effects of the GHGs is not as good as our knowledge of the effects of black carbon or deforestation. This is because we can actually measure the effects on the temperature of chopping down a forest. We can actually measure an amount of black carbon on snow, and see what difference it makes to the melting rate of the snow, and the temperature above the snow.
But we cannot make any such measurements for CO2. All of our numbers for the GHG forcings are based on climate models rather than measurements. The IPCC, and many scientists, give them great credence. I, and a number of scientists, do not.
Dr. Meier again:
It might be worth reviewing a few things:
1. Greenhouse gases warm the planet. This comes out of pretty basic radiative properties of the gases and has been known for well over 100 years.
My Comment: This is one of the most widely held misconceptions in the field. Here’s an example of the identical incorrect logical jump, from another field:
It is clear from the basic radiative properties that solar radiation warms what it hits. Therefore, if I walk out into the sunshine, my core body temperature will rise.
Clearly, the mere fact that a source is radiating does not mean that it will necessarily cause whatever the radiation strikes to warm up …
This is a crucial point, and one which is either overlooked or ignored by AGW proponents. Here’s another example. If your house has an air conditioner on a thermostat, despite the sun getting warmer and warmer as the day goes on, the house does not warm up. Again, we have a radiation source which does not cause what it strikes to warm up.
So yes, we know that CO2 is a greenhouse gas. And we know it will increase the forcing, although the amount is not well established.
But we absolutely do not know if that will cause the earth to warm over time. This is why my Question 1 above, about whether the Earth has a thermostat, is so important. If the earth has a thermostat, there are many basic assumptions that need to be reconsidered. I discuss this issue in detail at “The Unbearable Complexity of Climate”.
The short version of that post is that “basic radiative properties” are far from enough to determine what will happen from increased forcing in a complex system such as the climate or the human body, or even in a simple system like an air-conditioned house.
2. Carbon dioxide is a greenhouse gas. This is has been also been known for well over 100 years. There are other greenhouse gases, e.g., methane, nitrous oxide, ozone, but carbon dioxide is the most widespread and longest-lived in the atmosphere so it is more relevant for long-term climate change.
My Comment: Agreed.
3. The concentration of CO2 is closely linked with temperature – CO2 and temperature rise or fall largely in concert with each other. This has been observed in ice cores from around the world with some records dating back over 800,000 years. Sometimes the CO2 rise lags the temperature rise, as seems to be the case in some of ice ages, but this simply means that CO2 didn’t initiate the rise (it is clear that solar forcing did) and was a feedback. But regardless, without CO2 you don’t get swings between ice ages and interglacial periods. To paraphrase Richard Alley, a colleague at Penn State: “the climate history of the earth makes no sense unless you consider CO2”.
My Comment: As temperatures warm and cool, the CO2 levels go up and down. We can see that in the ice core records. SInce CO2 lags temperature in the Vostok ice core records of these changes, this means that the CO2 is not the cause of temperature change. Instead, it is a result of the warming ocean giving off more CO2. So far, Dr. Meier and I totally agree.
He then says “sometimes the CO2 rise lags the temperature rise.” This is not borne out by the data, where the correlation with lagged CO2 is greater than with un-lagged CO2 for the entire dataset. This indicates that the lag is a phenomenon common to the entire time period of the data.
Then Dr. Meier makes the claim that the CO2 “was a feedback”. If this were true, once the CO2 started to rise or fall, we should see a change in the rate of temperature rise or fall. To my knowledge no one has ever mathematically demonstrated such a feedback-driven change in temperature rise or fall in the actual ice core data. In addition to searching the literature for such a demonstration, I have used a variety of mathematical methods to try to find such a lagged feedback effect in the data, without any success. So why does Dr. Meier say that CO2 is operating as a feedback?
Dr. Meier may not even realize it, but he has totally conflated reality and models. What Dr. Meier is trying to say is that “without CO2 the models don’t get swings between ice ages and interglacial periods.” And what Richard Alley has shown is that “the modelled version of the climate history of the earth makes no sense unless you consider CO2”. Neither of them are talking about reality, they are discussing model-ice on Model-world, not ice on the Earth.
This blurring of the line between reality and models is a recurring and very frustrating feature of the climate discussion. I’m talking about reality, and meanwhile, without saying so, Dr. Meier is discussing model results. This habit of climate scientists, of talking about models as if they were discussing reality, is very frustrating and impedes communication.
4. The amount of carbon dioxide (and other GHGs) has been increasing. This has been directly observed for over 50 years now. There is essentially no doubt as to the accuracy of these measurements.
My Comment: Agreed
5. The increase in CO2 is due to human emissions. There are two ways we know this. First, we know this simply through accounting – we can estimate how much CO2 is being emitted by our cars, coal plants, etc. and see if matches the observed increase in the atmosphere; indeed it does (after accounting for uptake from the oceans and biomass). Second, the carbon emitted by humans has a distinct chemical signature from natural carbon and we see that it is carbon with that human signature that is increasing and not the natural carbon.
My Comment: Agreed.
6. Given the above points and NH2, one expects the observed temperature rise is largely due to CO2 and that increasing CO2 concentrations will cause temperatures to continue to rise over the long-term. This was first discussed well over 50 years ago.
My Comment: We have no evidence (not model results but evidence) that at the current general temperature equilibrium, changes in GHG forcing affect the temperature. We have no evidence that they affected temperature in the transitions between glacial and interglacial periods. We have no evidence that there is a linear relationship between temperature and forcing, it may well be temperature dependent and asymptotically approach zero at equilibrium. Yes, as Dr. Meier points out, forcings affect temperature in those situations (and all others) in the models. But I’ve been programming computers for almost fifty years now, and I’ve written too many computer models and I know too much about computers to trust untested, unverified models that are tuned to reproduce the past. Too many parameters, too many degrees of freedom, too much error propagation, too little understanding of important processes, they have, as Kipling said, been “twisted by knaves to make a trap for fools”.
Question 7: How much of the post-1980 temperature change is due to humans?
Here Willis says we get into murky waters and that there is little scientific agreement. And indeed this is true when discussing the factors he’s chosen to focus on: land use and soot. This is because, as mentioned above, the magnitudes of these forcings are small and the uncertainties relatively large. But there is broad scientific agreement that human-emitted CO2 has significantly contributed to the temperature change.
My Comment: Post 1980, the temperatures rose, peaked in 1998, and have been basically level since then. While there is broad agreement on something like “CO2 contributes significantly”, how significantly did it contribute to the post 1998 period of basically no temperature change? The answer, presumably, is unknown. Some scientists see CO2 as a second order forcing, after land use/land cover change (LULCC) and black/brown carbon forcing, particularly for the Arctic. My point is that there is still ongoing scientific discussion on the question of how much each forcing might affect the climate, particularly given that the temperature hasn’t risen in the last decade.
Question 8: Does the evidence from the climate models show that humans are responsible for changes in the climate?
Willis answers by claiming that climate models don’t provide evidence and that evidence is observable and measurable data about the real world. To me evidence is any type of information that helps one draw conclusions about a given question. In legal trials, it is not only hard physical evidence that is admitted, but information such as the state of mind of the defendant, motive, memories of eyewitnesses, etc. Such “evidence” may not have the same veracity as hard physical evidence, such as DNA, but nonetheless it can be useful.
My Comment: I fear this answer makes no sense. Dr. Meier says evidence is “any type of information that helps one draw conclusions”. Many people are helped to draw conclusions by astrology. Does that make astrology evidence? The conclusions of some scientists are shaped by their religious beliefs. Does that make religious beliefs evidence? Hunches and intuition help scientists draw all kinds of conclusions … are they evidence?
I don’t think Dr. Meier really believes what he is saying here. For example, said that above that I think that the earth has a thermostat. The first thing that Dr. Meier said in response to that was “Scientists need to look for evidence to support or refute any such initial beliefs.”
I don’t think he was referring to astrology, or my state of mind, or the memories of eyewitnesses. I think he was talking about data, observations, facts to support my hypothesis. And that is what I have provided at the citation listed above, for the same reason that he asked – because science is based on evidence, data, facts, measurements, and not on states of mind. The modeller’s mantra says “All models are wrong … but some models are useful.” Yes, they are often useful, but they don’t produce evidence.
Regardless, let me first say that I’m a data person, so I’ve always been a bit skeptical of models myself. We certainly can’t trust them to provide information with complete confidence. It may surprise some people, but most modelers recognize this. However, note that in my response to question 6 above, I never mention models in discussing the “evidence” for the influence of human-emitted CO2 on climate. So avoiding semantic issues, let me say that climate models are useful (though far from perfect) tools to help us understand the evidence for human and other influence on climate. And as imperfect as they may, they are the best tool we have to predict the future.
My Comment: As anyone who has looked at a weather forecast for next weekend knows, some models may be the best tool we have and still be no better than flipping a coin.
As to whether the models are useful, we have some simple ways to determine whether a model is useful. One is to see if they can make falsifiable predictions of the future states of a given system. To date, the models have failed miserably at this test. The current hiatus in warming was not predicted by a single model that I know of. Even if the GHG forcing were overwhelmed by natural variations, according to the models the stratosphere should have continued to cool. It did not do so. They have not been able to forecast the trend in the numbers of hurricanes, despite making a host of claims after the recent single-year peak in hurricane numbers. The claim is often made that the models are not accurate in the short-term, but they are accurate in the long-term. I’m still waiting … how long a term does it take until their accuracy starts to show up? Twenty-six years? Fifty-three years? Where is the theory that tells us when they will start to be right?
Another way to judge a model’s usefulness is if it can identify missing factors in a system. The classic example is the discovery of Neptune based on what was missing in models of the solar system. But the climate models are assumed to already contain all the important forcings, so they cannot discover any possible missing forcings. What verified new facts have the models told us about the operation of the climate that we did not already know?
Another way to judge the models is to see if the results of various models agree or not. Figure 4 shows the amount of clouds by latitude from a number of climate models:
Figure 4. Cloud cover of the Earth by latitude, as shown by 31 climate models, from the AMIP study (1999). Black line is the observed cloudiness by latitude.
Dr. Meier, if you think that any of those model results are evidence for the actual cloud cover by latitude, I fear that we have vastly different definitions of “evidence”. They are model results, and are not evidence of latitudinal cloud cover in even the most expansive conceivable definition of evidence. Models can be useful, but their results are not evidence of anything.
Question 9: Are the models capable of projecting climate changes for 100 years?
Based on Willis’ answer to Question 1, I’m surprised at his answer here. If the earth has a preferred temperature, which is actively maintained by the climate system, then it should be quite easy to project climate 100 years into the future. In Question 1, Willis proposed the type of well-behaved system that is well-suited for modeling.
My Comment: I see no theoretical reason that a complex chaotic system with a preferred temperature would be any simpler to model than a complex chaotic system without a preferred temperature. I have provided links in my Thermostat Hypothesis to two simple models of such a system, one by Bejan and one by Ou. However, I do not think that either of them produce evidence, or that either can project the climate a hundred years from now.
However, Willis claims that such a projection is not possible because climate must be more complex than weather. How can a more complex situation be modeled more easily and accurately than a simpler situation? Let me answer that with a couple more questions:
1. You are given the opportunity to bet on a coin flip. Heads you win a million dollars. Tails you die. You are assured that it is a completely fair and unbiased coin. Would you take the bet? I certainly wouldn’t, as much as it’d be nice to have a million dollars.
2. You are given the opportunity to bet on 10000 coin flips. If heads comes up between 4000 and 6000 times, you win a million dollars. If heads comes up less than 4000 or more than 6000 times, you die. Again, you are assured that the coin is completely fair and unbiased. Would you take this bet? I think I would.
But wait a minute? How is this possible? A single coin flip is far simpler than 10000 coin flips. …
I fear I don’t know where to start explaining the host of reasons why this doesn’t work as a metaphor for the difference between a weather model and a climate model, or as an explanation of how climate models could possibly project a hundred years out. But I’ll give it a shot.
Both weather and climate models are what are called “iterative models”. The model looks at the current state of the weather, and predicts what the weather will look like after the next time step (typically under an hour in modern models).
This type of model is very, very hard to get right, because the errors “propagate”. This means that if your calculation of the weather at one time step of the model is off a little, the next time step will likely be off a little more, and on ad infinitum. Error propagation of this type is an unavoidable feature of iterative models. It is one of the main reasons that weather models diverge from the actual weather over a very short period of time. This makes long-term forecasts very difficult.
Predicting the number of heads in 100 flips or a million flips, on the other hand, does not suffer from this problem. It is a simple and well understood statistical problem which can be solved with a single equation. In fact, the more flips, the less error you will find in the result. Ahhh, would that climate could so easily be reduced to a single equation …
Next, coin flips do not contain any variables. They are not affected by things such as humidity or temperature. It’s just the coin, period. That’s why we use them as a decision tool, because they are random, they are not dependent on variables. Weather models, by contrast, have a host of variables: temperature, humidity, barometric pressure, wind speed, wind direction, and many others. They are anything but random.
And while one coin flip has the same number of variables as a thousand coin flips (none), climate models must include a host of variables that can be neglected in weather models. These include variables like terrestrial biology, sea biology, ocean currents, variations in soil moisture, slow changes in ice cover, and lots of others. This makes climate models much more complex than weather models … and in iterative models, this means more sources of error.
Finally, both climate and weather are chaotic. This introduces a host of other problems into any attempt to model the climate or the weather.
As a result, the idea that climate models can project the climate a hundred years out because “a single coin flip is simpler than 10000 coin flips” is untrue, simplistic, and in no way a metaphor which would help us understand the problem with long-term climate model projections of the future.
Moving along, I find:
Question 13: Is the current peer-review system inadequate, and if so how can it be improved?
There is always room for improvement and Willis makes some good suggestions in this regard. Speaking only from my experience, the process works reasonably well (though not perfectly), quality papers eventually get published and bad papers that slip through the peer-review process and get published can be addressed by future papers.
My Comment: I love the idea that “quality papers eventually get published”. It just sounds so good. However, please read Ross McKitrick’s saga with his paper on Surface Temperatures, and Bishop Hill’s post on Caspar and the Jesus Paper, before you become too enamoured of the idea that the system is self-correcting and works in the end. A review of the CRU emails in this regard is in order as well.
From my own experience, I wrote a paper explaining the problems with a study by Michael Mann that had been published in Geophysical Research Letters (GRL). His study claimed that the best way to extend a smooth (Gaussian or otherwise) to the end of a series was to pad the end of the series by reflecting it around both the x and y axes. (This results in forcing the smooth through the last point of the series, which is absolutely the last thing you want to do).
The paper was rejected by GRL because one reviewer said I was too hard on poor Mike. So I set off to re-write it.
Within a few months, Mann published a new paper in GRL on the subject, incorporating my ideas as his own. Coincidence? You be the judge … I threw up my hands, my paper never got published. I think the present peer-review system sucks. The CRU emails contain hosts of references to this kind of scientific malfeasance, stacking peer-review panels with people who will give papers an easy pass, circulating papers like mine to other scientists, blackballing journals, and pressuring editors. We know it is happening, we have their emailed confessions.
Yes, I understand that Dr. Meier’s personal experience is different, and I respect that. But only looking at his own experience is a very restricted view of the situation. The repeated refusal of many climate scientists to go outside their own experience and honestly look at the scientific malfeasance going on in their own field is a constant source of amazement to me.
Question 14: Regarding climate, what action (if any) should we take at this point?
This is of course an economic and political question, not a scientific question, though the best scientific evidence we have can and should inform the answer. So far there isn’t any scientific evidence that refutes NH2 and we conclude that the processes that influenced climate in the past are doing so today and will continue to do so in the future. From this we conclude that humans are having an impact on climate and that this impact will become more significant in the future as we continue to increase GHGs in the atmosphere. Willis answers no and claims that the risks are too low to apply the precautionary principle. The basis for his answer, in practical terms, is his conclusion that NH2 is no longer valid because while GHGs have been a primary climate forcing throughout earth’s history, they are no longer having an impact. This could of course be true, but to me there doesn’t seem to be much evidence to support this idea. But then again, I’m a skeptic.
My Comment: First, NH2 is not falsifiable and is a straw null hypothesis. Second, I make no claim that the factors operating now did not operate in the past. I did not conclude that “NH2 is no longer valid because while GHGs have been a primary climate forcing throughout earth’s history, they are no longer having an impact” as Dr. Meier claims, and I am mystified that my words could be misunderstood in that way.
Also, I did not say that “the risks are too low to apply the precautionary principle”. I said “I disagree with those who say that the “precautionary principle” means that we should act now. I detail my reasons for this assertion at “Climate, Caution, and Precaution”. And nothing at that link says that the issue is that the “risks are too low”, I have no clue where Dr. Meier got that claim.
Regrettably, after explaining why he thinks that I’m wrong about what action to take, Dr. Meier does not say what action (if any) he thinks we should take.
Final Conclusions, in no particular order
1. Reading Dr. Meier’s answers to the questions has been very interesting and very productive for me. It has helped to identify where the discussion goes off the rails.
2. Understanding how the guy on the other side of the table sees the situation is valuable for everyone concerned.
3. Dr. Meier’s answers were well thought out and well expressed. He obviously has considered these matters in detail, answered honestly and fully, and taken the time to lay them out clearly.
4. As I didn’t discuss most of the questions where Dr. Meier and I were in basic agreement, it likely appears that I disagreed on almost all points. This is absolutely not the case.
5. I wish that Dr. Meier had included citations for his assertions. Not having them makes it harder to discuss his ideas.
6. I sincerely hope that I have not offended Dr. Meier. I am a reformed cowboy, but despite going to the cowboy reform meetings and following the twelve steps, sometimes the raw ranch kid shines through. I am passionate about these matters, and sometimes I overstep the bounds. I apologize for any sins of omission or sins of commission I may have committed, and I hope that Dr. Meier considers my words in the spirit of vigorous scientific debate.
7. Since the null hypothesis that the climate variations are natural has not been falsified, the AGW hypothesis is still a solution in search of a problem.
8. As I have found out more than once to my own cost, putting one’s ideas out on the web for people to find fault with is a daunting prospect, and one which may not always end well. I offer Dr. Meier my profound thanks and my respect for his courage and willingness to put his ideas on the firing line, as it is not an easy thing to do.