[QUOTE=Kimstu]
I don’t get this complaint. Why is it necessarily a good thing for media coverage to be “balanced”, even if it is discussing an issue where one side of the debate is far more scientifically credible than the other?
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But unless and until the skeptics come up with a non-anthropogenic hypothesis that explains the evidence equally successfully, they don’t really have a scientific debate; they just have a list of (comparatively minor) suggestions for improvement.
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Sorry, that’s not how science works. It’s not necessary to propose an alternative hypothesis in order to disbelieve in some hypothesis. In the 1600’s, although the composition of the moon was not known, it was still not widely believed to be made out of green cheese.
In fact, in a subject as poorly understood as the climate, it may not even be possible to present an alternative hypothesis … it may be caused by something like a change in a combination of DMS, albedo, and the solar wind, but the truth is, we don’t know.
Since there is very little evidence for the CO2 hypothesis (bear in mind that a computer can be programmed to give any desired result, so model results are not evidence), the onus is not on the people who don’t believe the CO2 hypothesis to disprove it, but on those who believe in the hypothesis to substantiate it.
This will be somewhat difficult, given that for a good part of the time (about 1945 to 1975, and 2001 to 2006) CO2 levels were rising steadily, while the temperature was dropping or staying level. This is explained away by those who believe in AGW as being due to aerosols, but that doesn’t even pass the laugh test. That’s because the aerosols are concentrated in the northern hemisphere, but both hemispheres cooled. If the “CO2 is the main driver of climate, except for the aerosols” theory were correct, the Southern Hemisphere should have shown a different response than the Northern … but it didn’t. And why has there been so little warming in the Southern Hemisphere?
Also, CO2 theory proposes that the poles will warm faster than the equator, but while the North Pole has warmed, the South Pole has not. And why have the oceans cooled in the last couple of years, and not warmed much in the years before that? (References available upon request, it’s all in the scientific literature).
Here’s another question. Much is made of the fact that temperature and solar irradiance were quite correlated until about 1980, but have “decoupled” since then. This is taken as “proof” that CO2 is to blame, because we don’t have an alternative explanation for the recent warming, of the type you are requesting. Here’s the problems with that kind of reasoning.
One is that there is very little in the field of climate science that is agreed upon as solid fact. One of the things which is least resistant to criticism is the metric we are discussing, the continued increase in global temperature since 1975. Phil Jones (of the HadCRUT temperature record) has refused to open his data to public view, which means that it is worthless scientifically. There are a variety of problems with the individual ground stations, which are known to exist but whose total effect is unknown. There is an unknown amount of urban (more properly local) warming. There is no central documentation of the history, location, and layout of the world’s ground stations. In short, we don’t have a good grasp of even the dimensions of the divergence you are asking people to explain.
Another problem is that air temperature is a horrible metric, because it does not measure the energy in the air. To do that, you need to include the amount of water vapor in the air, and we have very poor figures on that.
Even ignoring the water vapor issue, we don’t even have any agreement on how to measure the “average global temperature”. Should we use area-averaging, or EOF averaging? Should we average the whole world, or average each of the hemispheres individually and then average them (the more common method)? How do we deal with gridcells where there is only fragmentary data? For coastal areas, should we use the ocean temperature or the land temperatures? For the ocean, should we use the air temperature records, or the sea temperature records? How do we deal with gridcells that contain a great variety of microclimates, perhaps at different elevations? How do we adjust for the fact that as we go further back in time, the number of stations changes? How do we deal with missing data? How do we adjust for the fact that for a good chunk of the world, we have absolutely no temperature data at all? How many daily records must be present in a month, or in a year, to say we have enough to use? Each of these questions has no inherently “correct” answer, and each one has its scientific proponents and detractors. Thus, even the question about how much the temperature has risen since 1975 can’t be answered.
Beyond the difficulties of measurement and measurement error, our understanding of the climate is very primitive, simply because the climate is so complex. Climate is an immense, multi-stable, driven, chaotic, optimally turbulent, constructally organized tera-watt scale heat engine, with dozens of forcings and feedbacks, both internal and external, and both known and unknown. It is composed of five major subsystems (ocean, atmosphere, lithosphere, cryosphere, and biosphere), none of which are well understood. Each of these subsystems has its own forcings and feedbacks, again both known and unknown, which affect both itself and the system as a whole.
In addition, because of the sheer size of the system, our measurements of the various phenomena have large error margins. Even with satellites, we don’t have good figures for such basic things as total upwelling radiation at different frequencies, the albedo, global average downwelling radiation, or the temperature of the lower atmosphere. Our scientific understanding of complex, chaotic, driven, turbulent systems is so poor, and our measurements are so uncertain, that we can not predict the next month’s weather or the next decade’s climate in anything more than the most general terms.
Despite (or perhaps because of) this lack of knowledge, the ugly truth is that many climate scientists seem extremely reluctant to say “we don’t know”. As a result, the mystique has grown up that we understand the climate, and people like yourself and others expect or request that we explain short-term (25 year) fluctuations in the climate. Unfortunately, given our current state of knowledge, this is not necessarily possible.
Take for example the effects of the solar magnetic field on climate. This effect is known, but is very poorly understood. Is it responsible for the recent warming? There is much current scientific investigation of this question, but still, we don’t know.
This is separate from the effect of solar coronal mass ejections and the solar wind on climate, which is even less understood. And all of that is made even murkier because it is the interaction between the earth’s magnetic field and the solar magnetic field which shapes the final field, and that interaction is poorly understood.
Or how about the effect of land use changes? NOAA has said publicly that they may have a greater effect than CO2 changes. Are they responsible for some, part, or all of the recent warming? We don’t know.
It is well known that there are a variety of short-term (multi-decadal) oscillations or shifts in the climate system, such as the Pacific Decadal Oscillation, the Arctic Oscillation, the Atlantic Multidecadal Oscillation, and others. These have significant effects on the global temperature. Could one of these, or a combination of these, or other unknown natural oscillations have caused the recent warming? We don’t know.
Methane is not a well-mixed gas. Levels vary all over the world. It has recently been discovered that plants emit methane, perhaps a third of the global totals. This methane is concentrated in the lowest levels of the atmosphere. Worldwide, the planet is greening. What effect has this had on the instrumental temperatures, which are measured in the lowest layers of the atmosphere? We don’t know.
It has recently been discovered that plankton emit a gas (DMS) that cause the formation of clouds above them. What effect does this have on the climate? We don’t know.
How much has the sun’s irradiance changed since 1975? Despite satellite records, there is scientific dispute about that question as well, because of the lack of overlap between satellites that have given very different answers.
What about the electrical effects? The tops of thunderstorms are electrically charged to about 6 kilovolts compared to the bottom … what effect do changes in that electrical potential, which is modified by things like the solar wind, have on the total energy released? And how is that accounted for in the models? … oops, forgot, the models don’t have thunderstorms …
How about albedo changes? Could they have caused the temperature changes? Unfortunately, again, we don’t have good measurements of the albedo either, so we don’t know.
Finally, how do these (and a host of other forcings and feedbacks) affect each other? What happens if a swing in the PDO occurs at the same time as a swing in the cosmic ray intensity, or any of hundreds of other possible interactions? This we really, really don’t know.
In fact, of the 12 forcings listed by the IPCC in the Third Annual Report, the “Level of Scientific Understanding” (LOSU) of nine of them is rated as “Low”, or “Very Low” … that’s a very poor understanding of the majority of the forcings (and doesn’t even include some known forcings, or any of the forcings we haven’t discovered), yet despite that, people like yourself say “explain the historical record”. Sorry, but … we don’t know.
Now, faced with this lack of knowledge, the standard response from the AGW crowd is “it must be CO2? … but why must it be CO2? Not knowing is certainly not proof of anything. In addition, the change doesn’t fit the theoretical model of CO2 effects. Why would CO2 cause very little effect until 1975 (as evidenced by the close correlation between solar activity and temperature up to that point) and then suddenly cause a large effect? Why would the sun suddenly stop affecting the temperature in 1975? We don’t know, but saying “we can’t explain it, so it must be CO2? is nonsense.
So, despite the existence of a wide variety of possible explanations, I regret that I cannot offer you any solid hypothesis about what caused the divergence. We don’t even have any evidence that is resistant to criticism regarding whether the divergence is of the claimed size. It is one of the many, many unsolved mysteries of the climate.
However, the fact that I don’t have an alternative hypothesis does not prove that your hypothesis is correct. All any of this proves is that there are still many, many things about the climate we don’t know.
Finally, given the amount of scientific uncertainty, given that actual studies of climate scientists reveals wide disagreement on these questions, given that a number of those who disagree with the AGW hypothesis are PhD scientists with dozens of peer reviewed publications, given that even scientists involved in the UN IPCC process disagree with the what the UN says, given the UN IPCC’s ugly habit of freezing out world-renowned scientists who don’t believe the revealed AGW wisdom, given that the IPCC has publicly stated that they will change what the scientists say so that it matches what the politicians say, given that the debate continues both here and around the world, I find the AGW supporters calls for media censorship under the false flag of “balanced reporting is unfair” to be pathetic, but all too typical.
w.
PS - there is an unfortunate tendency by AGW supporters to echo Bush’s widely (and properly) reviled line that “if you’re not for us, you’re against us”, as though this were a binary debate, CO2 on one side, “Not CO2” on the other. This is not the situation at all.
Have humans had an effect on the climate? I, and most scientists, would say yes. But that’s not the question. There are actually two unresolved questions, “how?”, and “how much?” There is a lot of evidence saying that one of the main culprits is black carbon (soot), not CO2. There is a lot of evidence saying that land-use changes have been the major factor. Aerosols are likely a factor, but our understanding of aerosols is very poor. There is also a lot of evidence that natural forcings play a major role.
These are more than theoretical questions. If we spend billions, perhaps trillions, to reduce CO2 only to find out that the real culprits were black carbon and land-use change, we will have committed an enormous crime against our children and the poor of the world.
Even among scientists who believe that there is a discernible human influence on climate, there is wide disagreement about “how” and “how much”. In this situation of great scientific uncertainty, calling for an end to balanced reporting is a sick Orwellian joke.
However, I only think it is fair to present Gavin’s