How robust is the science that concludes that the planet is warming and that humans are the cause? How likely are catastrophic results from a warmer climate? The following post will attempt to shed a little light on these subjects and analyze claims by scientists and others that may not be as clear as we would like.


Using back of the envelope calculations, I estimated the average temperature of the earth without an atmosphere. Assuming the moon would be a good comparison, I came up with an average of -15ºC. About what it is outside my window right now. (We are having a cold March so far.) An internet search showed that I was in pretty close agreement to estimates by scientists.


Earths average temperature is very difficult to determine, but most estimates would put it at around 15ºC. I guess that would mean that our atmospheric blanket keeps us about 30º warmer than we would otherwise be. We are of course ignoring any heat retaining properties of the earth's land surfaces or oceans. That may be a rather large discrepancy. The moon has no water, as well as little atmosphere, so an extra factor is thrown in that could lead to a large error.


What we could say, that is likely true, is that the earth is warmer than the moon because it has water and an atmosphere.


The mass of the Earths hydrosphere is many times that of the atmosphere, and water vapor makes up a significant portion of the atmosphere. Could it be true that water and water vapor are far more significant in regulating the Earths temperature than atmospheric gases?


It seems that water and water vapor is almost totally ignored by the global warming and alarmist camps. So much so that when I googled “what is the GWP (global warming potential) of water vapor”, this site was at the top of the page. You guessed it, that would be a “denier” site in the opinion of most warmists.


Things are even more complicated than simple volume, mass or effectiveness calculations. Carbon dioxide only exists as a gas at the temperature and pressures of the earth's surface so no phase change energy need be calculated. Water exists in three phases (solid, liquid and gaseous) at temperatures and pressures found at the earth's surface and throughout the troposphere. Energies involved in the change from one state to another are significant. Easily experienced in the cooling effect of water evaporating from your skin or the effect of ice in your drink. 


It has long been admitted that CO2 by itself is insufficient to create significant atmospheric warming. It is dependent on feedback loops, of which the most important would be water vapor increases caused by warming from CO2. The problem is, it has never been possible to quantify water vapor changes in the atmosphere or determine the share of various causes of the changes. It is also entirely possible that humidity increases could lead to more cloud formation. That could lead to albedo changes, and possibly even a net cooling effect. This only adds to the uncertainty of the effect of carbon dioxide increases in the atmosphere.


I am still having great difficulty getting my head around the process by which CO2 increases the warmth of the atmosphere. Of course, it doesn’t add any heat but rather delays the loss of heat to space. The following links are interesting. The mathematics of carbon dioxide. part 1, part 2, part 3, part 4.


Carbon dioxide is transparent to visible light so will neither absorb or reflect that part of the spectrum. Apparently, it does absorb parts of the infrared spectrum which it then radiates (possibly) out again, I presume until it reaches temperature equilibrium with the surrounding air. Is this the same process that occurs when a forge or sun heated piece of iron radiates its heat until it reaches equilibrium with its surroundings? This happens rather slowly in air and rather rapidly in water. Of course, this process utilizes all three methods of heat transfer (conduction, convection, and radiation.) Could the carbon dioxide be considered saturated as soon as it reaches equilibrium with the surrounding air. That would occur through both the cooling of the CO2 molecule and the warming of the surrounding atmosphere, as our example of a piece of iron.


What would happen in a jar full of CO2 left in the sun? Apparently, not much. 


So does that mean that CO2 is analogous to window glass? Window glass which absorbs or reflects most of the infrared spectrum but is transparent to most of visible light. That would mean that the greenhouse effect is a good analogy although gases reflect almost no light.


At Muana Loa CO2 levels are measured by measuring the IR radiation that passes through a chamber of air. Easily calibrated, it is very accurate assuming the sample is representative. Although you cannot know how representative it is for the entire globe, they go to great lengths to be certain it is representative of the site. I believe the data to be precise and valuable.


The sensitivity of this method for measurement diminishes as concentrations increase. This is readily admitted by NOAA. This would seem to be an indication that climate sensitivity also decreases as concentrations increase. In fact, some scientists believe that we are near the point where increased concentrations of CO2 will not have a discernible effect.


Of course, there is an opposing view from other scientists that can appear just as reasonable.


I cannot vouch for the credibility of either scientist as to the views expressed in the above links. Either may be right, partly right or spectacularly wrong. I lean more to the limited effect but that may just be my innate optimism showing through. The very fact that you can measure CO2 levels by the NOAA method would seem to indicate that CO2 in the atmosphere is not absorbing IR at the levels theoretically possible. Does CO2 block some IR by reflection/refraction? The refractive index of CO2 is very close to 1, at standard conditions, but is it possible there is a difference under varying atmospheric conditions. I will leave a big question mark there, as I am not sure that line of reasoning is valid.


This scientist, Robert H. Essenhighstarts with the question "Does CO2 really drive global warming? then promptly answers "I don't believe it does." So much for consensus.   His opinion can be found here.


You may want to read this post.   A rebuff to a climate alarmist.


I am not going to get into the physics of greenhouse gases, mostly because I am not capable of fully understanding that aspect. I suspect that many physicists may have the same problem. The experimental and mathematical proofs are very hard to relate to the actual atmosphere. I think observational evidence may be the best route to understanding, but it will likely be many years or possibly centuries before the evidence can be considered conclusive.


One thing to bear in mind is that the atmospheric concentration of CO2 got down to 180 ppm during the glacial periods of the ice age the Earth is currently in (the Holocene is an interglacial in the ice age that started three million years ago). Plant growth shuts down at 150 ppm, so the Earth was within 30 ppm of disaster. Terrestrial life came close to being wiped out by a lack of CO2 in the atmosphere.”


The above is a quote from a post by David Archibald in a guest post to Anthony Watts blog. 


CO2 has varied throughout geologic time, and during some periods may have been so low as to greatly limit plant growth and reproduction.” “From the studies that have been conducted, it is clear that modern C3 plant genotypes grown at low CO2 (180–200 ppm) exhibit severe reductions in photosynthesis, survival, growth, and reproduction,” By Laci M. Gerhart and Joy K. Ward in New phytologist.


Most agricultural plants are of the so-called C3 type.


The above may seem irrelevant, but if we are considering the dangers of increased CO2 we should at least have a brief look at the dangers of decreased levels. It seems that decreased CO2 can be a severe limiting factor to plant growth.


The following quote is from CO2 Science.

Stated very simply, carbon dioxide, or CO2, is nearly transparent to the solar radiation emitted from the sun, but partially opaque to the thermal radiation emitted by the earth. As such, it allows incoming solar radiation from the sun to pass through it and warm the earth's surface. The earth's surface, in turn, emits a portion of this energy upwards toward space as longer wavelength or thermal radiation. Some of this thermal radiation is absorbed and re-radiated by the atmosphere's CO2 molecules back toward earth's surface, providing an additional source of heat energy. Without water vapor, CO2, and other radiatively-active trace gases in the air, the planet's average temperature would be about 34°C cooler than it is at present.”

This explanation is so full of assumption and so incomplete as to be totally misleading. The first sentence states that CO2 is nearly transparent to solar radiation. Closer to the truth would be that CO2 is transparent to most incoming solar radiation (the visible light portion). There is probably enough IR of the right frequencies to use up the absorption capacity of the carbon dioxide that it strikes. Of course, there is a much higher percentage of those frequencies in the radiation re-emitted by the earth. That does not address the actual quantity of that radiation from either source. They gloss over the fact that the radiation is re-emitted (if in fact, it is radiated) in all directions and that most of those directions are away from the earth. The statement that it provides an additional source of heat energy is totally false. There is no additional energy. It is the same energy being bounced around. The sole source of energy is the sun (other than an insignificant amount as a result of nuclear decay). The last statement is closer to the truth but ignores all other sources of heat loss delay or heat storage. I do not think that their simplistic explanation has much chance of being proven as fact.


One of the difficulties in understanding the greenhouse gas effect is the lack of a clear analogy. There have been several attempts to provide one. Here and here.


I think the basic's for understanding the effect is in understanding that the main components of our atmosphere (excluding water), nitrogen and oxygen, are mostly transparent to most solar radiation, and cannot be heated discernibly except by conduction from contact with other heated objects. A forced air furnace works by passing air over a heated surface, the heat exchanger. Radiant heat works by heating objects that in turn heat the air. The earth is warmed by radiant heat from the sun. In the case of the atmosphere, those objects that transfer heat to the air, are the earth's land masses, water bodies and other components of air such as CO2, water vapor and aerosols that can be heated by radiative energy. Greenhouse gas theory holds that IR is absorbed and re-radiated as IR rather quickly, meaning that a portion is directed back to the earth. Of course, that requires an assumption that most of the radiation absorbed originates from the earth or the result is an equal warming and cooling effect. If conduction is at play, then much of the energy may be transferred directly to the atmosphere. It seems to me that conduction would make GHGs that much more effective since all the heat is retained in the atmosphere until convection carries it to the outer limits of the atmosphere to radiate to space. By this scenario, the atmosphere itself is the main warmth conserving factor and CO2, as a relatively small proportion, loses much of its importance, and its contribution would be in direct relationship to its abundance and effectiveness. A water vapor feedback is irrelevant.


No one seems willing to apply a GWP (global warming potential) to water vapor, but some have estimated that there is 45 times as much in the air as there is CO2.. This does not include all the other forms of water (clouds, fog, rain, hail, snow) that is in the atmosphere at any given time. We do know that it can absorb a wider range of IR frequencies than can CO2. Warmer air does hold more water vapor and this is what the hypothesis of CO2 as an effective control knob for global temperature depends on.The problem is that this is not even established theory but could only be considered a hypothesis.


So, does CO2 cause warming? Well maybe, but there seems to be rising evidence that it has only a minor or insignificant effect. “Hence, there are no historical analogues for CO2-induced climate change; but there are many examples of climate change-induced CO2 variations.” a quote from CO2 Science.


There is only one way that the earth can maintain a constant average temperature. The heat gained, from all sources, must exactly match the heat lost to space. This is an impossible situation, in spite of the fact that physical laws ensure that equilibrium is the preferred state. If the earth is warming it will continue in that direction until it is losing more heat than it is gaining at which point it will begin to cool. The considerable differences in the average temperature over long time periods would indicate that there are many factors, relating to climate, that we have little or no understanding of. It is possible that it is such a chaotic system that we can never possibly gain a complete understanding.


This flow chart diagrams the steps of the scientific method. Photo Credit: Anne Helmenstine


This post is quite critical of climate change science. If you are someone who is convinced of dangerous global warming, then start at the last two paragraphs to find some support.


There are many diagrams that show the general direction of the scientific method, but most are basically the same as the above.


Although the general public often sees science as infallible, and this conclusion is often reinforced by the popular media, it is possible for the scientific process to break down at any one of the above steps. Bias, self-interest or even fanaticism can enter the picture and as a result, the science can be corrupted and even useless. In climate science (if such a science even exists in itself) there is such a preponderance of data and so many relative specialties that almost any conclusion can be shown to have support. History, however, is littered with once generally accepted scientific theory, that has been proven wrong. Even our best and brightest such a Albert Einstein, have been wrong in some instances, sometimes spectacularly so. 


Back to the chart. The top square is titled observation. Already we can see where things can go wrong. What if the observation itself does not result in a rigorous conclusion. The data used may be faulty, the margin for error large, the variations statistically insignificant, a normal may not be satisfactorily established, or interpretations of the data may be biased.


Of course, some observations are inarguable. The story of an apple falling on Newton's head is an example of a pure observation, easily repeatable. It led to Newton's hypothesis that there was an attraction between the earth and the apple and eventually his theory of gravitational attraction. Good science even if the theory was woefully incomplete. The story of the apple may not be true but makes a good narrative.


The science of climate change (or global warming, which still confuses me) should be straightforward. A changing climate is easily observable and evident over long, intermediate or recent short time spans. So far very simple, although the evidence comes from myriad scientific endeavors. There can be virtually no doubt that the climate changes. What it does is raise a multitude of questions which spawn many more hypotheses to attempt an explanation of some part of climate change.


Someplace along the line, a few scientists (Jim Hanson, Michael Mann) thought they could observe an unusual, rapid warming of our planet (I use the term planet although the original concept only included the atmospheric temperatures). They quickly formed the hypothesis that temperature increases were the result of increased atmospheric levels of CO2 and that the increased CO2 was the result of human activity. Someone coined the term Anthropogenic climate change.


The problem is that the scientific method breaks down almost immediately. The observation of global warming was a conclusion supported by data from mostly land-based instrumentation. Data that, for many reasons, is suspect, particularly at such small differentials. It was, however, about the only data, other than some proxy evidence (tree ring data used by Michael Mann), available at the time (seventies decade). One of the most inexcusable lapses was ignoring satellite data starting from about 1980, which is likely far more accurate, more global, and shows a much less significant warming trend. Another glaring bias shows in the use of charts to show the extent of global warming. Almost every chart shows data which starts at a cold period in recent history and uses a large scale to make a tiny increase in temperature appear significant. If you used a straight line from any high point in the last 3000 years the result would show a slight cooling


So we are starting from an inconclusive and controversial observation. The next step is hypothesis built on shaky ground. Somehow this hypothesis went almost directly to a mostly accepted theory without addressing the steps between. Obviously, direct experimentation is not possible since we only have one planet with these circumstances to work with, so scientists relied on something commonly called studies. Yes, studies, of data of their choice from sources sometimes undisclosed, and results of related experiments that may have been faulty or with results that may not have been duplicated. In some cases, other unsupported hypotheses are used as evidence.


The following two quotes are related to medical science. Similar to climate science in that direct experimentation is difficult, and many of the conclusions are derived from inconclusive results of studies. These quotes are from an article in The Atlantic.


A decade ago, Stanford’s John P. A. Ioannidis published a paper warning the scientific community that “Most Published Research Findings Are False.” (In 2012, he coauthored a paper showing that pretty much everything in your fridge has been found to both cause and prevent cancer—except bacon, which apparently only causes cancer.)


For Ioannidis, the key reason for this exaggeration and misrepresentation in research can be summed up in one word: bias. “This can be conscious, subconscious, or unconscious,” he said of these deviations from the truth – beyond chance or error – that pervert science. His favorite offender is ‘publication bias,’ which gives a falsely exaggerated impression of the science on a subject because not all studies that get conducted get published and the ones that do tend to have extreme results. It’s like doing a bunch of tests to find out whether your new vacuum works, and even though most tests fail, only reporting the one time the vacuum turned on.


I Have even found an example where a record number of records is used as evidence of global warming. How far from reality can we actually get? -- “All in all, the United States has already set more than 2,800 new record high temperatures this month. It has only set 27 record lows.” – From The Atlantic writing about Feb. 2017 temperatures.


I have also seen reference to studies of studies to support a position. What?


And this one, which actually purports to show that a model which predicts warming is still correct in spite of observations showing cooling. That is quite a stretch, in my book. From



"These are hypothetical data that illustrate the fact that whether or not a model worked should be evaluated based on whether or not the observed data fell within the 95% confidence interval of the model."


What have we got so far? Most would agree that we have seen an apparent warming in recent years, but many argue that it is insignificant or well within the range of natural variability. Some would even argue that it is statistically insignificant or within accepted margins of error. I am pretty certain that it has warmed in my lifetime, but there is evidence to indicate that it may have been at least as warm, about 1940, just before I was born.


The thesis built on this rather controversial observation was that human-caused increases in atmospheric CO2 were the reason for warming. Partly because no other culprit was obvious. This was expanded to predict rapidly rising temperatures would lead to catastrophic consequences.


Has CO2 increased? The science and observations supporting this seem very sound. Measurements are reasonably consistent and close to homogeneous around the globe. Very few would argue with the fact of rising levels.


Is the rise caused by human emissions? The evidence for this is also substantial, if not totally conclusive. The correlation to industrialism is strong and carbon signatures indicate anthropogenic sources. It seems an inescapable conclusion that human emissions are responsible for at least a substantial portion of the recent CO2 increases.


So does increased CO2 lead to a warmer climate? Experiments have shown that CO2 absorbs radiation in certain infrared frequency bands. In fact, this trait is taken advantage of to measure levels of CO2 in the atmosphere. From this, it is assumed that the gas can retain heat in the atmosphere. There is little doubt that it could contribute to the ambient temperature. Because it could, however, does not mean that it actually does in any significant way.


Correlation of carbon dioxide levels to past warming periods is often cited as evidence of CO2 causing warming. The problem here is that all the data I have seen indicates that CO2 levels rose following warming events rather than preceding them. In other words, warming may have caused the increases. The other possibility is mere coincidence, which doesn’t seem likely. Correlation does not even seem to hold for recent warming where we have seen a steady rise of CO2 but a spiked record of temperatures.


The statement was often made that there was no other plausible cause for warming. That may have been partly true in the seventies, but in years since a number of hypotheses have been put forward that could, either singly or collectively, create a change in climate. Many seem at least as plausible as CO2 levels. The difference is that most are neither caused or controllable by mankind.


What have we so far? We seem to have ended up with a theory of dangerous global warming (not climate change) derived from an unproven hypothesis supported by unproven hypotheses and doubtful data. Okay, how did it happen to get dangerous? We have been bombarded by dire threats of submerged coastal cities and boiling hot highlands punished by unsurvivable storms. Pretty scary, until you realize that even if such results were possible they will not occur for many centuries if not for several millennia. Most of the threats seem to be a fantasy dreamed up by the most pessimistic of media personalities, which sometimes included scientists.


What has happened so far? Well, the warnings started over thirty years ago, and have only gotten more catastrophic with time, while nothing much seems to have happened. Sea levels may have gone up about an inch or two, about the same rate of increase that has been happening for a few thousand years. Temperatures have risen a little bit, but not consistently. Most of the data seems to indicate a decrease in most types of extreme weather, although you will find considerable disagreement there, almost all evidence of increases seems to be anecdotal or circumstantial. The ice caps are still there, although arguably a little reduced. Greenland may be a little warmer, much to the delight of its residents. The world has become substantially greener (not in the sense of less pollution), probably as a result of increased CO2 levels. The world’s farmers are producing more and more food in defiance of the predictions of worsening conditions for agriculture. If we are getting more warm spells, then we are also getting fewer cold spells, a welcome change for many of us. Consequences of storms have gotten worse in terms of dollar losses but things have improved considerably in terms of lives lost. And all the while carbon dioxide levels have continued to rise and the world use of fossil fuel is continuing to expand.


Is the science then wrong? Well, not necessarily so. The dangerous part is sloppy- prediction, with not much bona fide science behind it, but scientists can often be intuitively right, even if their science is sloppy or inconclusive. We may be facing a warmer future. It may not result in catastrophe, but there is not much doubt that we will face some degree of change, perhaps substantial. It would only be wise to prepare.


There is little doubt that we are facing a future where some types of fossil fuel will become rapidly more expensive. Oil will likely be the first. If we do not have viable alternatives that can be deployed in time, we will face global-recession and economic collapse as oil products become unaffordable to the average wage earner.