Guest Post by Willis Eschenbach
Following up on the excellent initiative of Dr. Judith Curry (see Judith’s post and my response ), I would like to see what I can do to rebuild the justifiably lost trust in climate science. I want to bring some clarity to terms which are used all the time but which don’t seem to have an agreed upon meaning. In the process, I want to detail my own beliefs about the climate and how it works.
Figure 1. Dr Judith Curry tries to warn the greenhouse warming scientists … from Cartoons By Josh.
I don’t know about you, but I’m weary of the vague statements that characterise many of the discussions about climate change. These range from the subtle to the ridiculous. An example would be “I believe in climate change”. Given that the climate has been changing since there has been climate, what does that mean?
We also hear that there is a “consensus” … but when you ask for the actual content of the consensus, what exactly are the shared beliefs, a great silence ensues.
Often we see people being called unpleasant terms like “deniers”, with the ugly overtones of “Holocaust deniers”. I’ve been called that myself many times … but what is it that I am being accused of denying?
In an attempt to cut through the mashed potatoes and get to the meat, let me explain in question and answer format what I believe, and provide some citations for my claims. (These are only indicative citations from among many I could provide on each topic.) I will also indicate how much scientific agreement I think there is on the questions. First, some introductory questions.
Preface Question 1. Do you consider yourself an environmentalist?
I bring this up to get rid of the canard that people who don’t believe the “consensus science” on global warming are evil people who don’t care about the planet. I am a passionate environmentalist, and I have been so since 1962 when I first read Silent Spring upon its publication. I believe that we have an obligation to respect the natural ecosystems that we live among. My reasons are simple. First, we have a responsibility to be good guests and good stewards here on this amazing planet. Second, I worked extensively in my life as a commercial fisherman, and I would like for my grandchildren to have the same opportunity. The only way to do this is to monitor and be careful with our effects on the earth and the biosphere.
Preface Question 2. What single word would you choose to describe your position on climate science?
Heretic. I am neither an anthopogenic global warming (AGW) supporter nor a skeptic, I believe the entire current climate paradigm is incorrect.
Question 1. Does the earth have a preferred temperature which is actively maintained by the climate system?
To me this is the question that we should answer first. I believe that the answer is yes. Despite millennia-long volcanic eruptions, despite being struck by monstrous asteroids, despite changes in the position of the continents, as near as we can tell the average temperature of the earth has only varied by about plus or minus three percent in the last half-billion years. Over the last ten thousand years, the temperature has only varied by plus or minus one percent. Over the last 150 years, the average temperature has only varied by plus or minus 0.3%. For a system as complex and ever-changing as the climate, this is nothing short of astounding.
Before asking any other questions about the climate, we must ask why the climate has been so stable. Until we answer that question, trying to calculate the climate sensitivity is an exercise in futility.
I have explained in “The Thermostat Hypothesis” what I think is the mechanism responsible for this unexplained stability. My explanation may be wrong, but there must be some mechanism which has kept the global temperature within plus or minus 1% for ten thousand years.
I am, however, definitely in the minority with this opinion.
Question 2. Regarding human effects on climate, what is the null hypothesis?
If we are trying to see if humans have affected the climate, the null hypothesis has to be that any changes in the climate (e.g. changes in temperature, rainfall, snow extent, sea ice coverage, drought occurrence and severity) are due to natural variations.
Question 3. What observations tend to support or reject the null hypothesis?
As I show in “Congenital Climate Abnormalities”, not only are there no “fingerprints” of human effects in the records, but I find nothing that is in any way unusual or anomalous. Yes, the earth’s temperature is changing slightly … but that has been true since the earth has had a temperature.
There is no indication that the recent warming is any different from past warmings. There is more and more evidence that the Medieval Warm period was widespread, and that it was warmer than the present. The Greenland ice cores show that we are at the cold end of the Holocene (the current inter-glacial period). There have been no significant changes in rainfall, floods, sea level rise, Arctic temperatures, or other indicators.
In short, I find no climate metrics that show anything which is anomalous or outside of historical natural variations. In the absence of such evidence, we cannot reject the null hypothesis.
Question 4. Is the globe warming?
This is a trick question. It is a perfect example of a frequently asked question which is totally meaningless. It shows up all the time on public opinion polls, but it is devoid of meaning. To make it meaningful, it needs to have a time period attached to it. Here are some examples of my views on the question:
1 During the last century, the earth warmed slightly (less than 1°C).
3 The earth has generally warmed since the depths of the Little Ice Age around 1650, at a rate somewhere around a half a degree Celsius per century. See Akasufo, the Central England Temperature (CET), and the Armagh records.
4 The largest warming in any instrumental record occurred around 1680 – 1730. See the CET and Armagh records.
5 The earth was either stable or cooled slightly from about 1945 to 1975.
6 The earth warmed slightly from about 1975 to 1998.
I would say that there is widespread scientific agreement on the existence of these general trends. The amount of the warming, however, is far less certain. There is current controversy about both the accuracy of the adjustments to the temperature measurements and the strength of local effects (UHI, poor station siting, warmth from irrigation, etc.). See e.g. McKitrick, Spencer, Christy and Norris, Ladochy et al.., Watts, SurfaceStations, and Jones on these questions.
Question 5. Are humans responsible for global warming?
This is another trick question that often shows up on polls. The question suffers from two problems. First is the lack of a time period discussed above. The second is the question of the amount of responsibility. Generally, the period under discussion is the post-1900 warming. So let me rephrase the question as “Are humans responsible for some part of the late 20th century warming?”
To this question I would say “Yes”. Again, there is widespread scientific agreement on that simplistic question, but as usual, the devil is in the details discussed in Question 4.
Question 6. If the answer to Question 5 is “Yes”, how are humans affecting the climate?
I think that humans affect the climate in two main ways. The first is changes in land use/land cover, or what is called “LU/LC”. I believe that when you cut down a forest, you cut down the clouds. This mechanism has been implicated in e.g. the decline in the Kilimanjaro Glacier. When you introduce widespread irrigation, the additional water vapor both warms and moderates the climate. When you pave a parking lot, local temperatures rise. See e.g. Christie and Norris, Fall et al., Kilimanjaro.
The second main way humans affect climate is through soot, which I will broadly define as black and brown carbon. Black carbon comes mostly from burning of fossil fuels, while brown carbon comes mostly from the burning of biofuels. This affects the climate in two ways. In the air, the soot absorbs incoming solar radiation, and prevents it from striking the ground. This reduces the local temperature. In addition, when soot settles out on ice and snow, it accelerates the melting of the ice and snow. This increases the local temperature by reducing the surface albedo. See e.g. Jacobson.
There is little scientific agreement on this question. A number of scientists implicate greenhouse gases as the largest contributor. Other scientists say that LU/LC is the major mover. The IPCC places values on these and other so-called “forcings”, but it admits that our scientific understanding of many of forcings is “low”.
Question 7. How much of the post 1980 temperature change is due to human activities?
Here we get into very murky waters. Is the overall balance of the warming and cooling effects of soot a warming or a cooling? I don’t know, and there is little scientific agreement on the effect of soot. In addition, as shown above there is no indication that the post 1980 temperature rise is in any way unusual. It is not statistically different from earlier periods of warming. As a result, I believe that humans have had little effect on the climate, other than locally. There is little scientific agreement on this question.
Next, some more general and theoretical questions.
Question 8. Does the evidence from the climate models show that humans are responsible for changes in the climate?
This is another trick question. Climate models do not produce evidence. Evidence is observable and measurable data about the real world. Climate model results are nothing more than the beliefs and prejudices of the programmers made tangible. While the results of climate models can be interesting and informative, they are not evidence.
Question 9. Are the models capable of projecting climate changes for 100 years?
My answer to this is a resounding “no”. The claim is often made that it is easier to project long-term climate changes than short-term weather changes. I see no reason to believe that is true. The IPCC says:
“Projecting changes in climate due to changes in greenhouse gases 50 years from now is a very different and much more easily solved problem than forecasting weather patterns just weeks from now. To put it another way, long-term variations brought about by changes in the composition of the atmosphere are much more predictable than individual weather events.” [from page 105, 2007 IPCC WG1, FAQ 1.2]
To me, that seems very doubtful. The problem with that theory is that climate models have to deal with many more variables than weather models. They have to model all of the variables that weather models contain, plus:
• Land biology
• Sea biology
• Ocean currents
• Ground freezing and thawing
• Changes in sea ice extent and area
• Aerosol changes
• Changes in solar intensity
• Average volcanic effects
• Snow accumulation, area, melt, and sublimation
• Effect of melt water pooling on ice
• Freezing and thawing of lakes
• Changes in oceanic salinity
• Changes in ice cap and glacier thickness and extent
• Changes in atmospheric trace gases
• Variations in soil moisture
• Alterations in land use/land cover
• Interactions between all of the above
How can a more complex situation be modeled more easily and accurately than a simpler situation? That makes no sense at all.
Next, the problem with weather models has been clearly identified as the fact that weather is chaotic. This means that no matter how well the model starts out, within a short time it will go off the rails. But the same is true for climate, it is also chaotic. Thus, there is no reason to assume that we can predict it any better than we can predict the weather. See Mandelbrot on the chaotic nature of climate.
Finally, climate models have done very poorly in the short-term. There has been no statistically significant warming in the last fifteen years. This was not predicted by a single climate model. People keep saying that the models do well in the long-term … but no one has ever identified when the changeover occurs. Are they unreliable up to twenty-five years and reliable thereafter? Fifty years?
Question 10. Are current climate theories capable of explaining the observations?
Again I say no. For example, the prevailing theory is that forcing is linearly related to climate, such that a change of X in forcing results in a change of Y in temperature. The size of this temperature change resulting from a given forcing is called the “climate sensitivity”. In 1980, based on early simple computer climate models, the temperature resulting from a change in forcing of 3.7 watts per square meter (W/m2) was estimated to result in a temperature change of between 1.5 and 4.5 degrees Celsius. See e.g. Green and Armstrong 2007.
Since 1980, there has been a huge increase in computing power. Since 1980, there has also been a huge increase in the size and complexity of computer models. Since 1980, thousands of man hours and billions of dollars have been thrown at this question. Despite these advances, the modern estimate of the climate sensitivity is almost unchanged from its 1980 value.
To me, this lack of any advance in accuracy indicates that we have an incorrect understanding of the forces governing the climate. Otherwise, our bigger, faster and better models would have narrowed the uncertainty of the climate sensitivity. But they have not.
Question 11. Is the science settled?
To this one I would answer no, no, a thousand times no. We are just a the beginning of the study of climate. New information and new theories and new forcings are put forward on a regular basis. See e.g. Lu. The data is poor, short, and full of holes. The signal is tiny and buried in a huge amount of noise. We don’t know if the earth has a thermostat. In short, the study of climate is an infant science which is still poorly understood.
Question 12. Is climate science a physical science?
Well, sort of. It is a very strange science, in that to my knowledge it is the only physical science whose object of study is not a thing, not a physical object or phenomenon, but an average. This is because climate is defined as the average of weather over a suitably long period of time (usually taken to be 30 years.) The implications of this are not widely appreciated. Inter alia, it means that statistics is one of the most important parts of climate science.
Unfortunately, a number of what I might call the “leading blights” of climate science, like Michael Mann with his HockeySchtick, have only the most rudimentary understanding of statistics. This initially got him into trouble in his foray into the area of paleoclimate statistics, trouble which he has only compounded by his later statistical errors.
Question 13. Is the current peer-review system inadequate, and if so, how can it be improved?
There are several easy changes we could make in peer review that would help things immensely:
1. Publish the names of the reviewers and their reviews along with the paper. The reviews are just as important as the paper, as they reveal the views of other scientists on the issues covered. This will stop the “stab in the back in the dark” kind of reviewing highlighted in the CRU emails.
2. Do not reveal the names of the authors to the reviewers. While some may be able to guess the names from various clues in the paper, the reviews should be “double-blind” (neither side knows the names of the others) until publication.
3. Do the reviewing online, in a password protected area. This will allow each reviewer to read, learn from, and discuss the reviews of others in real time. The process often takes way too long, and consists of monologues rather than a round-table discussion of the problems with the paper.
4. Include more reviewers. The CRU emails show that peer review is often just an “old-boys club”, with the reviewing done by two or three friends of the author. Each journal should allow a wide variety of scientists to comment on pending papers. This should include scientists from other disciplines. For example, climate science has suffered greatly from a lack of statisticians reviewing papers. As noted above, much of climate science is statistical analysis, yet on many papers either none or only the most cursory statistical review has been done. Also, engineers should be invited to review papers as well. Many theories would benefit from practical experience. Finally, “citizen scientists” such as myself should not be excluded from the process. The journals should solicit as wide a range of views on the subject as they can. This can only help the peer review process.
5. The journals must insist on the publication of data and computer codes. A verbal description of what mathematics has been done is totally inadequate. As we saw in the “HockeyStick”, what someone thinks or says they have done may not be what they actually did. Only an examination of the code can reveal that. Like my high science teacher used to say, “Show your work.”
Question 14. Regarding climate, what action (if any) should we take at this point?
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”. At that page I also list the type of actions that we should be taking, which are “no regrets” actions. These are actions which will have beneficial results whether or not the earth is warming.
So that is where I stand on the climate questions. I think that the earth actively maintains a preferred temperature. I think that man is having an effect on local climate in various places, but that globally man’s effect is swamped by the regulating action of clouds and thunderstorms. I think that the local effect is mainly through LU/LC changes and soot. I think that the climate regulating mechanism is much stronger than either of these forcings and is stronger than CO2 forcing. I think that at this point the actions we should take are “no regrets” actions.
Does that make me a “denier”? And if so, what am I denying?
Finally, I would like to invite Dr. Judith Curry in particular, and any other interested scientists, to publicly answer these same questions here on Watts Up With That. There has been far too much misunderstanding of everyone’s position on these important issues. A clear statement of what each of us thinks about the climate and the science will go a long way towards making the discussion both more focused and more pleasant, and perhaps it will tend to heal the well-earned distrust that many have of climate science.