For the past year or so I have been following the science and politics of Anthropogenic Global Warming (AGW), which is now supposed to be called "Climate Change," because those who seek political and economic power based on the control of carbon dioxide, in order to "Save the World", do not want to be impeded by the observation that the world has gotten cooler in recent years. In the process of following this science, I have accumulated and digested and enormous library of literature, some of which I hope to eventually post here.A competing theory of why the Earth has, on average, warmed over the past century is based in variations in the Sun's activity. Solar-driven climate change has a great deal of evidence and theory behind it, and many well-qualified scientific proponents. I am convinced that it is the far better theory and have been sharing my conclusions with anyone who will listen.
Scientific arguments for the reality of AGW do exist, as exemplified by the IPCC's Fourth Assessment Report. However, most of what passes for argument against carbon dioxide emission in the public sphere is much more a religious or political stand than an assertion of science, especially when Albert Gore, and others, proclaim that the science is "settled," debate should stop, and bold action needs to be taken. This is to be expected, as Mr. Gore comes from the political world where debate is decided by voting, and the purpose of voting is to silence debate. Scientific debate is never decided by voting. It is decided by demonstrating that your theory succeeds where others fail. Even then the debate is not silenced. It is only a provisional truth, susceptible to revision or replacement by something better. Scientists, or anyone with a duty to the truth, do not defend their theories by condemning those who raise questions as counter-revolutionaries.
For many passionate anti-carbon dioxide activists, anthropogenic global warming is nothing less than the theology of original sin, with a church that regards the breath of human life itself as a taint on a fallen Eden, and a theocracy that would sell indulgences in the form of carbon credits, and tax all production.The debate has taken on a new significance and urgency, because just as the governments of the world seem to be on the verge of capitulating to the global anti-carbon jihad, the world is cooling and the Sun is going through a lull in sunspot activity that is unprecedented in modern times. The current solar cycle's long slide to an ever-lower minimum resembles nothing more than the end of Solar Cycle 4, which led into the Dalton Minimum, a period of cooler temperatures punctuated by the disastrous "Year Without Summer" in 1816, following the eruption of Tambora. Several blogs have taken up the discussion of the controversy. I highly recommend ScienceBits by Israeli physicist, Nir J. Shaviv.
The popular science press has noted the recent drop in sunspot activity, and occasionally connected it to past solar minima and the associated cooling periods. Some have even raised the question of whether the decrease in the sun's activity will "offset" global warming, as if the overall increase in solar activity from 1850 to 2001 were a completely separate phenomenon.
The central controversy, in broad terms, is over how sensitive the climate is to small changes in heat flux. Increased greenhouse gases that trap solar heat contribute a positive heat flux. Increased clouds that reflect light contribute a negative heat flux. Variation in CO2 by itself, at relevant concentrations, traps far too little heat to account for the change that IPCC attributes to it. It requires a "multiplier" and water vapor is offered as the principal multiplier. Working Group 1 of the IPCC's Fourth Assessment Report adopts a model with high sensitivity, based on the fact that the most significant greenhouse gas is not CO2, but rather H2O, and that warmer air contains more moisture, providing a source of positive feedback. Variation in CO2 by itself, at relevant concentrations, traps far too little heat directly to account for the change that IPCC attributes to it.One criticism of the IPCC's model it that it is unstable, being so sensitive to fluctuations in temperature that past CO2 fluctuations would have "run away" in a positive feedback loop many thousands of years ago, which is obviously not seen in the record. Another criticism is one that the IPCC itself calls the largest uncertainty in their model, which is the potential negative feedback effects of low clouds.
Since 1997, Henrik Svensmark has been arguing that most of the historical climate record, both ancient and recent, is explainable in terms of the modulating effects of the solar cycle on cosmic ray flux in the atmosphere. (See Svensmark H. Cosmoclimatology: a new theory emerges. Astronomy & Geophysics 48 (1): 1.18–1.24. A number of scientists, including Willie Soon of the Harvard-Smithsonian center for astrophysics, have produced research that confirms the solar cycle, particularly as it is recorded in proxies for cosmic ray flux, like Beryllium-10 and Carbon-14, is statistically a far better explanation for global temperature changes than is carbon dioxide.
As with carbon dioxide, the variation in the total solar irradiance by itself is far too small to directly explain the observed temperature changes. It too needs a "multiplier", which according to Svensmark comes in the form of the portion of the sun's output that deflects cosmic rays away from Earth. This varies by much more than the 0.1% of total solar irradiance. The part of the atmosphere that would be most sensitive to cloud formation due to increased cosmic ray ionization of the air is exactly the part to which the IPCC uses to amplify the small effects of man-made carbon dioxide, namely the moisture-laden air over warm tropical oceans. But for lack of nucleii for droplet formation, clouds would readily form. Ions produced by cosmic rays are said to form these nuclei.Arnold Wolfendale of Durham University was recently quoted under the headline "Natural causes" not responsible for global warming, as stating that solar variation could not be responsible for more than 14% of the warming seen since 1956. As can bee seen in some of the attached figures, there is mischief in the choice of 1956 as the baseline, which was one year before the modern solar maximum's crescendo. 1956, 1957, 1958, and 1959 were the 12th, 1st, 2nd and 3rd most active solar years in the last 260 years of records. It is a little like saying that New Orleans is not sinking, because the average water level has not risen when compared to the peak of Hurricane Katrina.
The view of the man-made global warming skeptics, which appears sensible, is that the climate is less sensitive, and more stable than the IPCC models, and that this stability is manifest in the historical record, which includes periods that are both much warmer and much colder, and with much more CO2 than today. However, this relative stability can still be powerfully influenced by solar modulation of cosmic-ray seeded cloud formation.
The cruel joke that Nature appears to have played on climate scientists is that the Sun has been in a period of very high activity that rose from the Dalton minimum in the 1800s to a great crescendo in 1957, and has only recently started to subside. That this rising solar activity almost exactly parallels the Industrial Revolution and the increasing burning of fossil fuels has probably led many people astray in ascribing cause and effect. It is looking more and more like the sun is the driver, carbon dioxide is mostly just an effect of warming oceans (as warm soda goes flat), and anthropogenic global warming will join cold fusion and Lysenkoism on the ash heap of scientific history.
Now that we are in a period of very unusual solar quiet, the solar wind is at its lowest recorded level, and cosmic ray flux is at its highest. This not only has significance for climate, but also space exploration, as manned missions outside the Earth's protective magnetic field will be exposed to radiation from galactic cosmic rays at an all-time high, as will electronic components which can not be effectively shielded from these super-high energy particles.
I expect the coming decade will sort out who is right about climate, especially if the Sun persists in its current quiet ways. I hope our politicians don't cripple the global economy further in the name of reducing the output carbon dioxide, which is not a pollutant, and only weakly influential on climate. Although it is less than 0.05% of the atmosphere, carbon dioxide is a most precious resource. Every bit of carbon in our bodies was once CO2 in the atmosphere which nourished a plant, and then eventually us.
