Global warming-6: The public and the paradigm

In the previous post, I discussed how after a paradigm is adopted, scientists tend to communicate only with each other. They are now freed from the need to explain and justify the basic premises of the field to a lay public, and no longer have to make a political case to justify what they are doing. This results in them developing a more technical, insider language and jargon that is opaque to nonscientists, and the technical paper addressed to similarly trained scientists and published in specialized journals becomes the chief means of communication.

But while this rapidly speeds up the pace of scientific progress, the general public gets left behind and unable to comprehend the language of the scientists. This can result in a disconnect arising between what the public knows and understands about the topics that scientists are investigating. Communicating with the general public and explaining the science to them in laymen’s terms now becomes delegated to a new class of people, the popularizers of science, who are either journalists or scientists (like Carl Sagan) who have chosen to play that role. In scientific quarters, such people are in danger of not being considered ‘real’ scientists, the sole yardstick by which to identify the latter being the publication of technical papers in technical journals.

But these popularizers play a valuable role as translators, by taking the papers that are written in esoteric and mathematical language and published in technical journals, and making at least the results intelligible to lay people, even if the complex science and mathematics that lead to those results remain incomprehensible.

Eventually, the general public becomes used to the ideas underlying scientific paradigms and goes along with them. For example, no nonscientist today really questions the scientific paradigm that the Earth revolves around the Sun, even though their senses argue the opposite. People have just accepted that piece of scientific knowledge as a fact. Similarly, no one contests the paradigm that there exist positive and negative electric charges and that electric current consists of the flow of these charges, even though they cannot see it and really have no reason to believe it. People also do not question the fact that continents move, even though that idea is really, on the surface, quite preposterous and it is quite amazing that people nowadays accept it without question.

This just shows that eventually people will believe anything if they are told it over and over again by authority figures. In this case, they have been told something by scientists, who have based their assertions on data and evidence. But data and evidence are not necessary to achieve these ends. Religions get the same result simply by repeatedly telling people myths that have no basis.

But it does take some time for the general public to come to terms with the scientific consensus and during that transition there can be tensions, especially if the scientific paradigm goes counter to strong beliefs based on non-scientific sources. For example, the initial reaction to Darwinian ideas was negative as the mutability of species is not something readily seen in everyday life, and the idea that humans and chimpanzees share a common ancestor is anathema to those who see human beings as special creations of god. In the rest of the world, the scientific paradigm in biology that is called the neo-Darwinian synthesis was eventually largely accepted, but this is not the case in the US where a particular variant of Christianity-based thinking challenges the very premise of that paradigm.

The global warming paradigm is in its infancy, barely a decade old, and one should not be surprised that it encounters considerable resistance. Just a couple of decades ago, global warming was only slightly better than a conjecture. The coalescing of scientists around the consensus view has only occurred very recently so one should not be surprised that the general public is still lagging behind. This lag-time had little consequence when it came to ideas such a planetary motion or evolution or continental drift, since nothing could be done about those phenomena and there were no adverse consequences associated with whether the public accepted them or not. But getting the public on board quickly on the global warming issue is important because it is only action by them that can solve the problem. Scientists can study the problem and suggest how it can be fixed but it is only mass action that can produce changes.

The global warming paradigm is being resisted by some not because of strong pre-existing beliefs (who really knew or cared about the average temperature of the planet before this became a topic of conversation?) but because it goes counter to the economic interests of some powerful groups, notably the energy, automobile, and other greenhouse gas producing industries. They are well aware of the power of public opinion on this issue and they have attempted to try and argue that there is a scientific controversy in order to forestall any government action that might have a negative impact of their financial interests.

We have seen before these kinds of attempts to create in the public’s mind the idea that scientists have strong disagreements on an issue and that therefore no action should be taken until further studies are done to ‘resolve’ the outstanding questions. This strategy is similar to what the tobacco industry tried to do with the health hazards of smoking. There too the paradigm that smoking is responsible for a whole variety of health problems took some time to be accepted and it took repeated litigation and legal losses by the tobacco industry to show the fraudulence of their claims that there was a scientific controversy about whether smoking caused cancer and other diseases. Their attempts to deny that scientific consensus eventually failed and hardly anyone anymore questions that smoking causes cancer, emphysema, and a host of other diseases.

We have also seen such an attempt at creating a fictitious scientific controversy in the case of evolution. This attempt has been more successful, partly because the fundamentalist religious mindset in much of America makes people predisposed to wanting to believe that evolution is not a fact.

In both smoking and evolution, the courts have played a major role in the discussions, The attempts by the industries to challenge the scientific consensus on global warming may not end up in courts because the impact is not on individuals or in the short term but on the long-term health of the planet as a whole. So it is not clear who has the legal standing to sue governments and industries to do something about the problem.

Hence the debate is going to have to be fought in the public and political arena and that is why is so important that the general public understand the science behind it.

Next: The current status of scientific knowledge on global warming.

POST SCRIPT: Ohio Board of Education, district seven

Many members of the Ohio’s state Board of Education are elected. District Seven (comprising Summit, Portage, Ashtabula and Trumbull Counties) is currently represented by Deborah Owens Fink, one of the most ardent advocates of inserting intelligent design creationism into Ohio’s science standards and curriculum. She is being challenged by Dave Kovacs who opposes her on this issue.

I have been asked to help publicize Kovacs’ challenge. I don’t know anything about him other than what is on his campaign website so this is not an endorsement. All I know, from my past experience with Ohio’s science standards advisory board, is that Owens Fink has been a very negative influence on the Board.

Those who live in that region and care about this issue might want to look more closely into this contest.

Global warming-5: The emergence of a paradigm

The need to take global warming seriously is not slam-dunk obvious to most people. In my own case, over time I have slowly became convinced that there was an emerging consensus among scientists studying the issue that planetary warming was a serious matter. Like most people, I do not have the time or the expertise to have studied the question in detail, but I have enough respect for the scientific process and the way that scientists make collective judgments as a community that when I see a scientific consensus emerging on anything, I tend to take it seriously. In fact the global warming issue is a great example of seeing, before our very eyes, a transition in science from a pre-paradigmatic state to a paradigmatic state.

In his book The Structure of Scientific Revolutions, Thomas Kuhn argued that during the early, pre-paradigmatic days of any scientific field, one has different schools of thought and different theories underlying them. These schools exist and function almost independently of one another. They investigate different problems, operate under different rules, and have different criteria for evaluating their successes and failures. Each develops along its own path and has its own adherents and practitioners. But at some stage, for a variety of reasons, the community of scientists coalesce around one school of thought and this becomes the dominant paradigm in that field, and all scientists start working within the framework of that paradigm.

This transition occurs at different times for different sciences. For optics, Newton’s corpuscular theory was the first paradigm. For electricity, it was Franklin’s theory. For geology, it was Lyell’s work. In biology, the Darwinian theory was the first paradigm in evolution. It should be noted that the adoption of a paradigm does not mean that the paradigms are true or that the problems in that field were solved once and for all. Newton’s optics paradigm and Franklin’s electricity paradigm were completely overthrown later, and the advent of molecular genetics resulted in the early Darwinian theory being modified to what is now called the neo-Darwinian synthesis. But the adoption of a paradigm significantly alters the way that the scientific community does its work.

Once a scientific community adopts a paradigm, the way its members work changes. Before the adoption of a paradigm, each school of thought challenges the basic premises of the others, examines different problems, uses different tools and methods, and uses different criteria for evaluation of problems. Once a paradigm is adopted however, there are no more controversies over such basics. The scientific community now tends to agree on what problems are worth focusing on, they tend to use the same terminology and tools, and they share a common understanding of what constitutes an acceptable solution to a problem. Scientists who do not adapt to the dominant paradigm in their field become marginalized and eventually disappear.

The conversion of the scientific community to a new paradigm is usually a long drawn out process with many scientists resisting the change and some never breaking free of the grip of the old paradigm. Historian of Science Naomi Oreskes gives an example:

In the 1920s, the distinguished Cambridge geophysicist Harold Jeffreys rejected the idea of continental drift on the grounds of physical impossibility. In the 1950s, geologists and geophysicists began to accumulate overwhelming evidence of the reality of continental motion, even though the physics of it was poorly understood. By the late 1960s, the theory of plate tectonics was on the road to near-universal acceptance.

Yet Jeffreys, by then Sir Harold, stubbornly refused to accept the new evidence, repeating his old arguments about the impossibility of the thing. He was a great man, but he had become a scientific mule. For a while, journals continued to publish Jeffreys’ arguments, but after a while he had nothing new to say. He died denying plate tectonics. The scientific debate was over.

So it is with climate change today. As American geologist Harry Hess said in the 1960s about plate tectonics, one can quibble about the details, but the overall picture is clear.

It should emphasized that adoption of a paradigm does not mean that scientists think that everything has been solved and that there are no more open questions. What it does mean, among other things, is that the methods used to investigate those questions are usually settled. For example, in evolution and geology, establishing the age of rocks and fossils and other things are important questions. Dating those items uses, among other methods, radioactivity. This field assumes that radioactive elements decay according to certain laws, that the decay parameters have not changed with time, and that the laws of physics and chemistry that we now work with have been the same for all time and all over the universe. This common agreement with the basic framework enables geologists and evolutionists to speak a common language and arrive at results that they can agree on and build upon.

Some creationists, in order to preserve their notion of the universe being 10,000 years old or less, have either rejected radioactive dating entirely or jettisoned parts of it, such as that the radioactive decay constants have stayed the same over time. In doing so, they have stepped outside the framework of the paradigm and this is partly why they are not considered scientists. Kuhn’s book discusses many other cases of this sort.

Kuhn argues that once a science has created its first paradigm, it never goes back to a pre-paradigm state where there is no single paradigm to guide research. Once a paradigm has been established, future changes are from thenceforth only from an old paradigm to a new one.

A key marker that a science has left a pre-paradigmatic state and entered a paradigmatic state can be seen in the way that scientists communicate with each other and with the general public. In the pre-paradigmatic stage, the book is the primary form of publication, and these books are aimed at the general public as well as other scientists, with an eye to gaining more support among both groups. As a result, the books are not too technical and there is an ongoing dialogue between scientists and the public.

But after a paradigm is adopted, scientists are freed from the need to explain and justify the basic premises of the field to a lay public, and no longer have to make a political case to justify what they are doing. They now tend to communicate only with each other. This results in them developing a more technical, insider, language and jargon that is opaque to nonscientists, and the chief means of communication becomes the technical paper addressed to similarly trained scientists and published in specialized journals. They start addressing their arguments to only those who work within their own narrow field of specialization. As a result of this increased efficiency in communication, science then tends to start making very rapid progress and the rules by which scientific theories get modified and changed become different. It now becomes much harder to overthrow an established paradigm, although it can and does still happen

But one consequence of this change in communication patterns is that, as in the global warming case, a disconnect can emerge between the consensus beliefs of scientists and the general public, and how to combat this is an interesting question.

Next: What happens to the public after a science becomes paradigmatic.

POST SCRIPT: Request for information

During the week of August 14, I will be driving with my daughter to San Francisco. Driving across the US is something I have always wanted to do to get a chance to personally experience the vastness of this country and some of its natural beauty.

We will be stopping near Denver to visit some friends on the way. I was wondering if people had any recommendations about the sights we should see between Denver and San Francisco. Here are some constraints:

1. I would like to see natural beauty as opposed to human creations. So suggestions about which national parks are worth a visit and what specific things should be seen in those parks would be most welcome.

2. We don’t have much time and I cannot hike, so the sights should be such that they are accessible using an ordinary car (not an SUV or other type of off-road vehicle).

Global warming-4: Is there a scientific consensus on global warming?

Is there a scientific consensus on global warming? Naomi Oreskes from the Department of History and Science Studies Program, University of California at San Diego, thinks so. She published a study in the journal Science (December 3, 2004, volume 306, p. 1686) which argued that the scientific community had arrived at a consensus position on “anthropogenic climate change.” i.e. that global warming was occurring, and that “Human activities . . . are modifying the concentration of atmospheric constituents . . . that absorb or scatter radiant energy. . . . [M]ost of the observed warming over the last 50 years is likely to have been due to the increase in greenhouse gas concentrations”

Her study looked at the scientific databases of the Institute for Scholarly Information (ISI) and searched on the keywords “climate change.” She then examined the abstracts of the 928 papers that were returned and classified them under six categories: explicit endorsement of the consensus position, evaluation of impacts, mitigation proposals, methods, paleoclimate analysis, and rejection of the consensus position.

Her results were that “75% fell into the first three categories, either explicitly or implicitly accepting the consensus view; 25% dealt with methods or paleoclimate, taking no position on current anthropogenic climate change. Remarkably, none of the papers disagreed with the consensus position.” (my italics)

She is careful to point out that some of the authors of the minority 25% may not have agreed with the consensus view but none of those papers explicitly took such a stand. She also pointed out that scientific bodies such as the Intergovernmental Panel on Climate Change (IPCC, created in 1988 by the World Meteorological Organization and the United Nations Environmental Programme), the National Academy of Sciences (2001), The American Meteorological Society (2003) , the American Geophysical Union (2003), and the American Association for the Advancement of Science (AAAS) had all issued statements endorsing the consensus viewpoint.

This does not necessarily mean that there is complete unanimity among scientists about all aspects of this issue. Richard Lindzen, who is an MIT professor of meteorology and a member of the NAS panel on climate change that issued the report cited by Oreskes, argued in a Wall Street Journal op-ed on June 11, 2001, that as far as he was concerned, all he was agreeing with was that “(1) that global mean temperature is about 0.5 degrees Celsius higher than it was a century ago; (2) that atmospheric levels of carbon dioxide have risen over the past two centuries; and (3) that carbon dioxide is a greenhouse gas whose increase is likely to warm the earth (one of many, the most important being water vapor and clouds).” But he went on “we are not in a position to confidently attribute past climate change to carbon dioxide or to forecast what the climate will be in the future” and he argued that the case for reducing the level of carbon dioxide emissions, as called for by the Kyoto treaty in 1997, was not compelling. He argues that the process of warming we currently observe may be part of the normal cyclical variations of the Earth, and that other greenhouse gases (such as water vapor and methane) may be more important players in producing warming than carbon dioxide.

Lindzen repeated much of the same arguments in a critical review of the documentary An Inconvenient Truth, that appeared in the op-ed pages of the Wall Street Journal on June 27, 2006, where he also explicitly challenged Oreskes’ 2004 study.

In a previous post on belief preservation I wrote about the fact that there are many strategies that can be adopted to preserve one’s existing beliefs. The latest issue of Physics and Society, published by the American Physical Society (vol. 35, no.3, July 2006) illustrates this. It has a letter (p. 25) by a global warming skeptic who also argues for the “natural cycles” theory and also adds that the Earth is so big that human activity is unlikely to have an impact on it. Looking on the bright side, the author argues that some parts of the Earth are too cold now anyway, and that even if global warming should occur, we might be better off figuring out better crops that can be grown in warmer conditions, and taking steps to protect ourselves from the flooding that would ensue from the rise of ocean levels.

This raising of alternative speculative ideas against a scientific consensus is not uncommon and can confuse non-scientists into asking “Well, is there a scientific consensus or not?” This sense of confusion is encouraged by those industries (such as automobile and energy) that are the chief producers of carbon dioxide, and who oppose actions that would require them to reduce emissions. Such people know that if there is a sense of controversy over an issue, and especially if that issue has economic costs associated with it, the natural impulse of the general public is to wait until the dust settles and a clear policy emerges. So kicking up dust is a good strategy if you want nothing to be done. This is not unlike what was done by the tobacco industry concerning the adverse health effects of smoking (an effort which ultimately failed) and by intelligent design creationists concerning evolution (which is ongoing). These people take advantage of the media’s propensity to do “one the one hand, on the other hand” type stories, balancing the quotes of scientists warning of the dangers of warming with those of skeptics. This results in there being a much wider divergence in media coverage of the global warming issue than there is in the scientific community.

All these interests have used such strategies to dispute the conclusion that there is a scientific consensus that anthropogenic global warming is occurring. Oreskes addresses these arguments head-on in a recent Los Angeles Times op-ed on July 24, 2006:

[S]ome climate-change deniers insist that the observed changes might be natural, perhaps caused by variations in solar irradiance or other forces we don’t yet understand. Perhaps there are other explanations for the receding glaciers. But “perhaps” is not evidence.

The greatest scientist of all time, Isaac Newton, warned against this tendency more than three centuries ago. Writing in “Principia Mathematica” in 1687, he noted that once scientists had successfully drawn conclusions by “general induction from phenomena,” then those conclusions had to be held as “accurately or very nearly true notwithstanding any contrary hypothesis that may be imagined. . . “

Climate-change deniers can imagine all the hypotheses they like, but it will not change the facts nor “the general induction from the phenomena.”

None of this is to say that there are no uncertainties left – there are always uncertainties in any live science. Agreeing about the reality and causes of current global warming is not the same as agreeing about what will happen in the future. There is continuing debate in the scientific community over the likely rate of future change: not “whether” but “how much” and “how soon.” And this is precisely why we need to act today: because the longer we wait, the worse the problem will become, and the harder it will be to solve.

The fact that you never run out of alternative hypotheses and explanations for anything is an important point to realize. Philosopher of science Pierre Duhem addressed this way back in 1906 in his book The Aim and Structure of Physical Theory when he pointed out that you can never arrive at a correct theory by a process of eliminating all the possible alternatives because “the physicist is never sure that he has exhausted all the imaginable assumptions.”

It is easy to come up with alternative explanations for any phenomenon. That is why evidence plays such an important role in evaluating theories and scientists use published research in peer-reviewed journals as indicators of whether an idea has any merit or not. And Oreskes’ 2004 (peer reviewed) study in Science, showing that in the technical (peer-reviewed) journals a scientific consensus exists on anthropogenic climate change, has to be taken seriously. As she says in that paper:

The scientific consensus might, of course, be wrong. If the history of science teaches anything, it is humility, and no one can be faulted for failing to act on what is not known. But our grandchildren will surely blame us if they find that we understood the reality of anthropogenic climate change and failed to do anything about it.

Sensible words. But if you prefer, you can always listen to George Bush’s ideas about global warming, courtesy of Will Ferrell.

Global warming-3: The science behind global warming

To understand the science behind global warming, it may be helpful to look at a simplified version of the science behind it.

Consider two objects, one that is luminous (i.e., an object that we can see without the aid of a light source) and another that is not luminous. Examples of luminous objects are the Sun (which generates energy due to nuclear reactions within it and sends a lot of that energy out as light) or a light bulb (that converts electrical energy into light energy). Examples of non-luminous objects are the Earth or a person in a room. The energy radiated by the luminous source spreads out in all directions and some of it will fall on the non-luminous object.

What is important to understand is that even what looks like a non-luminous object also radiates energy into space. In fact every object radiates energy. So in a sense, every object is ‘luminous’ in the sense that it sends out energy, but we usually reserve that term for objects that emit visible light. Not all radiated energy is visible. A human being radiates energy at a rate of about 500 watts, or the equivalent of five 100 watt bulbs, but the reason we do not “see” the radiation energy emitted by people is due to it being outside the visible range

The rate of energy emission of an object radiates depends to a large extent on its temperature (it actually goes as the fourth power of the temperature) and the nature of its surface (such as color, texture, material). So just as the Sun radiates energy into space, so does the Earth, except that the Sun’s radiation is much greater since it is at a much higher temperature.

The important thing about global warming is understanding what happens when the energy radiated by a luminous source (say the Sun) falls upon a non-luminous object (say the Earth). Part of it is immediately reflected back into space, and does not affect the temperature of the Earth. But the rest is absorbed by the Earth and, in the absence of anything else happening, will tend to cause the Earth’s temperature to rise. The relative amounts of the Sun’s energy that are absorbed and reflected by the Earth depends on the nature of the Earth’s surface. (As an example, a person in a room absorbs energy from the surroundings at a rate of about 400 watts, thus adding a person to a room is the net heat equivalent of turning on a 100 watt bulb.)

But as the temperature of the object rises due to it absorbing energy, the amount it radiates out again also increases, and at some point the object reaches equilibrium, which occurs when the energy absorbed by it from outside equals the energy it radiates away. Once an object reaches this state of thermal equilibrium, its temperature stays steady.

If for some reason we alter the ratio of energy absorbed by the Earth to the energy reflected, then the state of equilibrium is disturbed and the Earth’s temperature will shift to a new equilibrium temperature. If relatively more energy gets absorbed, then the equilibrium temperature will rise until the energy radiated again becomes equal to the energy absorbed. Conversely, if relatively more energy now gets reflected, then the equilibrium temperature will drop, i.e., the Earth will cool. The people warning of global warming argue that human activity is causing the former situation and they say that the reason for this is that we are changing the nature of the Earth’s surface, especially its atmosphere.

To understand what is happening at the Earth’s surface and atmosphere, we need to understand something about the energy radiated by the Sun. This comes largely in the form of “electromagnetic energy.” This is an umbrella term that encompasses X-rays, ultraviolet, light waves, infrared, microwaves, radio waves, etc. All these types of radiation are identical except for one single factor, which is called the wavelength of the radiation. The items in the list differ only in their wavelengths, with X-rays having the smallest wavelength and radio waves having the longest. (Similarly, all colors of visible light are also identical except for the wavelength, which increases as you go from blue to green to yellow to red.)

When this broad range of electromagnetic radiation from the Sun hits the Earth’s atmosphere, almost all of it, except the visible light portion, gets absorbed by the atoms and molecules in the atmosphere and does not reach us on the ground. Of the portion that does reach the ground, some of it gets directly reflected unchanged and escapes back into space. The remainder gets absorbed by the ground. It is the energy that is absorbed by the ground that is the source of concern.

Recall that the Earth, like any object, also radiates energy away. But since the temperature of the Earth is different from the temperature of the Sun, the distribution of the wavelengths in the energy radiated by the Earth is different from the distribution that we receive from the Sun (although the total energy involved is the same in both cases for an object in equilibrium). This affects how much is absorbed by the atmosphere as it passes through it. Some of the Earth’s radiation will get absorbed by the gases in the atmosphere (i.e., is trapped), while the rest passes through and goes off into space.

This is a crucial point. If the gases in the atmosphere change significantly, then you can change the relative amounts of the Earth’s radiated energy that escapes into space and the amount that is trapped by the atmosphere . The so-called ‘greenhouse gases’ (carbon dioxide, water vapor, methane, nitrous oxide, and others) are those that are very good at absorbing the energy at the wavelengths radiated by the Earth, preventing them from escaping into space.

Global warming scientists argue that human activity is increasing the concentration of greenhouse gases (especially carbon dioxide) in the atmosphere. Hence more of the energy radiated by the Earth is being absorbed and less of the energy is escaping into space. Note that the incoming visible light from the Sun is not affected much by the concentrations of greenhouse gases since they are at a different wavelength, and the greenhouse gases do not absorb them as much. As a result of this increase in the absorption levels of the outbound radiation, the equilibrium temperature of the Earth will rise.

At this point, there are various scenarios that can unfold. One is that we arrive at a new and higher but stable equilibrium temperature. If the change in equilibrium temperature is small, the consequences might not be too disastrous, although there will be some adverse effects such as some temperature-sensitive organisms (such as coral reefs) becoming destroyed or some species going extinct if they cannot evolve mechanisms to cope. If the change is large, then there could be massive floods and droughts and other catastrophes.

The worst case scenario is a kind of runaway effect, where a rise in temperature results in effects that cause an even more rapid rise in temperature and so on, in a series of cascading effects.

Some argue that we are already seeing some signs of runaway effects, and point to the melting of the polar ice caps and the general decrease in glaciers and snow coverage worldwide. Snow is white and thus reflects back unchanged into space almost all the sunlight that hits it at the Earth’s surface. When this snow melts and becomes water, not only is the amount of reflected energy decreased but water absorbs light energy. Hence the major loss of snow cover (apart from adverse environmental and ecological consequences) has a major effect on the reflection/absorption balance of the Earth, shifting it towards greater absorption. So more energy is absorbed by the Earth, resulting in even greater warming, resulting in further snow loss, and so on.

Another possible runaway factor is the amount of green cover. On balance, plants, because of photosynthesis, tend on average to be net absorbers of carbon dioxide and emitters of oxygen. Thus they reduce one of the greenhouse gases. If global warming results in less green cover of the Earth (say caused by prolonged droughts), then that would result in more greenhouse gases remaining in the atmosphere and causing yet more warming and more droughts. Human activity such as deforestation can accelerate this process.

Those are the basic elements of the science underlying global warming and the factors that go into building the models that try to predict long term climate change.

Next: The emerging scientific consensus over global warming.

POST SCRIPT: Colbert takes media apart again

As you may recall, the mainstream media did not take kindly to Stephen Colbert’s demolishing them at the White House Correspondents Association Dinner. Now he takes them apart again.

Global warming-2: Understanding the problem

Understanding global climate concerns is not easy because it is a complex issue which involves many factors and theories, is based on data that span millennia and is not easy to extract, involves sophisticated theories and computer modeling, and requires long chains of inferential reasoning to arrive at conclusions. Compared to it, evolution, that other anathema of Bush and his anti-science Christian base, is a model of clarity.

At least with evolution, the progression shows a clear pattern, with life evolving from simple single cell organisms to the wide array of complex multi-cell systems we see today. If we started discovering anomalous organisms that seem to violate that temporal ordering, that would require a major restructuring of evolutionary theory.

With global warming, on the other hand, there isn’t such a steady progression. It is not as if global warming implies that the temperature at each and every location on the Earth rises steadily with time. If it did, then people might be more easily convinced. But that is not how it works. Instead, the relevant data always deal with averages that are calculated (1) over very long time scales (involving tens and hundreds and thousands and even millions of years) and (2) over the whole planet or at least large areas of it.

It is quite possible to have wide fluctuations over shorter time periods and in localized areas that go counter to the long-term trend. Unfortunately, this means that there are plenty of opportunities for those who either do not understand that only averages are relevant, or who are deliberately trying to mislead others, to seize upon these fluctuations to argue that global warming is either not occurring or is not a serious problem. I can surely predict that if, for example, the next winter is colder than average in Cleveland, there will be many snickering comments to the effect that this ‘proves’ that global warming is a myth. Similarly, the current heat wave in France and California cannot, by themselves, be used, to argue in favor of global warming either. Scientists’ conclusions will be unaffected since they know that data from a single year or location has only a tiny effect on averages.

These are the questions that need to be considered when we evaluate whether global warming is serious or not.

1. Is warming occurring? In other words, are average temperatures rising with time?

2. If so, is it part of normal cyclical warming/cooling trends that have occurred over geologic time or is the current warming going outside those traditional limits?

3. Are the consequences of global warming such that we can perhaps live with them (slightly milder winters and warmer summers) or are they going to be catastrophic (causing massive flooding of coastal areas due to rising ocean levels, severe droughts, blistering heat waves, total melting of the polar regions, widespread environmental and ecological damage)?

4. How reliable are the theories and computer models that are being used study this question?

5. What are the causes of global warming? Is human activity responsible and can the process be reversed?

My own ideas on this issue have changed over time. I started out by being somewhat neutral on this issue, not sure whether warming was occurring or not. Like most people, I didn’t really understand questions about climate and tended to make the mistake of equating climate with weather. My understanding of weather was strongly influenced by the one feature about weather that we all grow up with, and that is its variability and unpredictability. This tends to create a strongly ingrained belief that we cannot really predict weather and I am sure this spills over into thinking that climate is also highly variable and so should not worry too much about warming since it might just as easily reverse itself.

But the key difference between weather and climate is that while weather systems are chaotic, climate change is not, at least as far as I am aware. In everyday language, chaos means just mess and disorder and confusion. But chaos, in science, is a technical term with a precise meaning. A chaotic system is one that progresses according to particular kinds of mathematical equations, usually coupled non-linear ones, such that the end state of the system is highly sensitive to initial conditions.

With non-chaotic systems, like a thrown ball, a small change in the initial conditions results in small changes in the final state. If I throw the ball slightly faster or at a slightly different angle, the end point of its trajectory will be only slightly different as well. This is what enables us to have expert athletes in any sport involving thrown or struck balls, because based on previous attempts, the professionals know how to make slight adjustments to hit a desired target. The reason that they can do so is because the ball’s trajectory obeys non-chaotic dynamical equations.

But with a chaotic system, that is no longer true. A change in the initial conditions, however small, can result in the end state being wildly different, with the divergence increasing with time. But in order to predict the future of any system, we need to specify the current conditions. Since we can never know the initial conditions with perfect accuracy, this means that reliable long-term predictions are impossible. An analogy of a chaotic system might be river rapids. If you place a leaf at one point in the rapids, it might end up at some point further down the river. But making even a tiny change in your initial position will result in you ending up in a completely different place, even if the river flow itself is unchanged.

For example, suppose the mathematical quantity pi enters into a calculation. We know that the value of pi=3.1415927. . . , a sequence that goes on forever. But in performing actual calculations we cannot punch in an infinite sequence of digits into our computers and need to truncate the sequence. Usually for most problems (which are non-chaotic) we can treat pi as being equal to 3.14 or 22/7 or even just 3 and get fairly good results. We can adjust the precision of this input depending on the required precision of the output. But if pi was a particular part of a chaotic system of equations, then using 3.1415927 or rounding up to 3.141593 would give wildly different results. This is why this kind of chaos is better described as “extreme sensitivity to initial conditions.”

Weather is thought to obey a chaotic system of equations. This is why, despite “Doppler radar” and other innovations that can give quite accurate measures of the state of weather-related parameters at any given time, weather forecasts become notoriously unreliable after three or four days, or even fewer. There is a reason that your local TV newscasts do not go beyond five-day weather forecasts. They are at the limits of predictability and already pushing their luck.

But the equations that drive climate calculations are not believed to be chaotic. Hence, given a model, one can hope to make reasonable predictions about global temperatures in the next century with some confidence in their reliability, even though one does not know if it is going to rain next week.

(In the terminology of chaos theory, sometimes climate is referred to as a “strange attractor” of the weather system, or a “boundary value problem,” whereas weather is an “initial value problem.” Basically, weather and climate are thought to evolve according to different kinds of mathematics.)

It is important to realize that the predictability of the results is possible only once a particular model of climate change has been chosen. One could get different results by choosing a different model altogether, although the range of possible models is strongly limited because they have to conform to the fundamental laws of science and be compatible with what we know about the behavior of related systems. The difference with weather is that with weather one can very different results while using the same model, simply because of our inability to specify exactly the initial values of the problem.

Next: The emerging scientific consensus over global warming.

Global warming

It is undoubtedly true that, while the increasing level of warfare in the Middle East in the immediate issue of concern, the question of global warning is the preeminent long term issue facing the planet today. It represents one of the rare situations when the health of the entire planet is at stake. The only other thing that has similar global consequences is an all-out nuclear war between major nuclear powers since that could also unleash an atmospheric catastrophe that could destroy the planet.

But while we can avoid a nuclear winter by simply doing nothing, i.e. not using the weapons, global warming is an issue where doing nothing is the problem. A strong case has been made that if we continue on the present course, the planet is going to suffer irrevocable harm, changing its climate and weather patterns in ways that will dramatically affect our lives, if not actually destroy them.

One would think that global warming is one scientific question where politics would play a minor role, and where the debate would be based on purely scientific evidence and judgments. Unlike issues like stem cell research and cloning where the scientific questions have to contend with religion-based arguments, as near as I can tell the Bible, Koran, and other religious texts are pretty much agnostic (so to speak) on the issue of whether global warming is something that god has strong views on. While god has a lot to say about things like the proper ways to sacrifice animals or how sinners should be put to death, he seems to not be concerned about the weather, expect for using it as a tactical weapon, like unleashing the occasional deluge to drown everyone but Noah and his family or creating a storm to chastise his prophet Jonah.

Hence it is surprising that some people (including the Bush administration) perceive the case being made that global warming is a serious problem as some kind of ‘liberal’ plot, tarring the proponents of the idea that global warming is real and serious as political enemies, seeking to somehow destroy truth, justice, and the American way. Glenn Greenwald argues that this is the standard mode of operation of the Bush administration, saying “What excites, enlivens, and drives Bush followers is the identification of the Enemy followed by swarming, rabid attacks on it.”

Once that bugle call of politics sounded, Bush devotees dutifully fell into line. They know the script and exactly what they must do and have rallied to the cause, trying to discredit the scientific case and the scientists behind it, arguing that the whole global warming thing is a fabricated crisis, with nothing more to be worried about than if we were encountering just a warm summer’s day. Senator James Inhofe (R-OK) says “With all of the hysteria, all of the fear, all of the phony science, could it be that man-made global warming is the greatest hoax ever perpetrated on the American people? It sure sounds like it.” And this man is the Chair of the Senate’s Committee on 
Environment and Public Works.

The administration and its supporters have gone to surprisingly extreme methods to suppress alarms about climate change, such as changing the wording of reports by government scientists in order to play down the threat of global warming and muzzling government climate experts, in order to prevent information from getting to the public.

Take another example in which the administration has sought to divert government’s scientist’s focus from global warming:

From 2002 until this year, NASA’s mission statement, prominently featured in its budget and planning documents, read: “To understand and protect our home planet; to explore the universe and search for life; to inspire the next generation of explorers. . .as only NASA can.”

In early February, the statement was quietly altered, with the phrase “to understand and protect our home planet” deleted. In this year’s budget and planning documents, the agency’s mission is “to pioneer the future in space exploration, scientific discovery and aeronautics research.”

David E. Steitz, a spokesman for the National Aeronautics and Space Administration, said the aim was to square the statement with President Bush’s goal of pursuing human spaceflight to the Moon and Mars.

But the change comes as an unwelcome surprise to many NASA scientists, who say the “understand and protect” phrase was not merely window dressing but actively influenced the shaping and execution of research priorities. Without it, these scientists say, there will be far less incentive to pursue projects to improve understanding of terrestrial problems like climate change caused by greenhouse gas emissions.

“We refer to the mission statement in all our research proposals that go out for peer review, whenever we have strategy meetings,” said Philip B. Russell, a 25-year NASA veteran who is an atmospheric chemist at the Ames Research Center in Moffett Field, Calif. “As civil servants, we’re paid to carry out NASA’s mission. When there was that very easy-to-understand statement that our job is to protect the planet, that made it much easier to justify this kind of work.”

Several NASA researchers said they were upset that the change was made at NASA headquarters without consulting the agency’s 19,000 employees or informing them ahead of time.
. . .
The “understand and protect” phrase was cited repeatedly by James E. Hansen, a climate scientist at NASA who said publicly last winter that he was being threatened by political appointees for speaking out about the dangers posed by greenhouse gas emissions.

The attempts to downplay the extent of the problem, divert attention away from actions to study and remedy it, and distort the science behind the global warming issue has been helped by the fact that although the consensus conclusions of the scientific community are pretty straightforward (that global warming is occurring, it is largely caused by human activity, and that we need to take steps to reverse it or face disastrous consequences), the actual science behind it is complicated. This enables those who wish to blur the issue to find ways to cast doubt on that scientific consensus.

Next: Understanding the problem