Misunderstanding Global Warming: Alexander Cockburn versus Reality.

By Mike Byron, PhD.

Introduction

   I was astonished to read Alexander Cockburn’s essay in the April 28th online edition of Counterpunch entitled “Is Global Warming a Sin?” [i] Cockburn’s thesis is that there is no scientific evidence whatsoever linking anthropogenic (human caused) CO2 emissions with worldwide increases in mean temperature “global warming.”  Comparing the proposed sale of carbon credits to alleviate future global warming to the medieval practice of the Catholic Church selling indulgences to cancel past sins, Cockburn asserts:

   "There is still zero empirical evidence that anthropogenic production of CO2 is making any measurable contribution to the world's present warming trend. The greenhouse fearmongers rely entirely on unverified, crudely oversimplified computer models to finger mankind's sinful contribution. Devoid of any sustaining scientific basis, carbon trafficking is powered by guilt, credulity, cynicism and greed, just like the old indulgences, though at least the latter produced beautiful monuments." [ii] 

   Cockburn bases his conclusions upon the research of Dr. Martin Hertzberg whose conclusions he places above “all the counsels of Al Gore or the jeremiads of the IPCC (Inter-Governmental Panel on Climate Change).” Fair enough, Cockburn wishes to disregard the careful, published, peer-reviewed, findings of essentially the entire global scientific community, in favor of the assertions of his favored climatologist. He can do that; however, we are not compelled follow his astounding leap of judgment. Fairness however, does require me to carefully evaluate and consider Hertzberg’s rival global warming hypothesis and its several assertions.

The Hertzberg-Cockburn Critique of Global Warming

   What are these assertions of Hertzberg’s hypothesis? His argument is that temperature changes are driven by long-term changes in the amount of sunlight striking the Earth. These changes are caused by Milankovitch cycles, named for the Serbian scientist who first described them. Wikipedia defines these as follows:

   "Milankovitch cycles are the collective effect of changes in the Earth's movements upon its climate, named after Serbian civil engineer and mathematician Milutin Milankovitch. The eccentricity, axial tilt, and precession of the Earth's orbit vary in several patterns, resulting in 100,000 year ice age cycles of the Quaternary glaciation over the last few million years. The Earth's axis completes one full cycle of precession approximately every 26,000 years. At the same time, the elliptical orbit rotates, more slowly, leading to a 22,000 year cycle in the equinoxes. In addition, the angle between Earth's rotational axis and the normal to the plane of its orbit changes from 21.5 degrees to 24.5 degrees and back again on a 41,000 year cycle. Presently, this angle is 23.44 degrees. The Milankovitch theory of climate change is not perfectly worked out; in particular, the largest observed response is at the 100,000 year timescale, but the forcing is apparently small at this scale, in regards to the ice ages. Various feedbacks (from carbon dioxide, or from ice sheet dynamics) are invoked to explain this discrepancy." [iii]

   Simply put: the Earth’s orbit around the sun varies somewhat with respect to how circular its orbit is, the degree that is poles are tilted with respect to the plane of its orbit, and the position of its poles with respect to the far stars, which “wobbles” (precesses). These several variations occur regularly in cycles of about 22,000, 26,000, 41,000 and 100,000 years. Their composite effect is to vary the amount of sunlight striking the Earth’s surface. 

   Hertzberg’s assertion is that this process of variation in the strength of sunlight striking the Earth is what drives global climate change. The primary mechanism for this climate change does indeed involve CO2 release in to the atmosphere, according to this thesis. However, the causal order (which variable causes what effect) is reversed from what we would expect:

   "Water covers 71 per cent of the surface of the planet. As compared to the atmosphere, there's at least a hundred times more CO2 in the oceans, dissolved as carbonate. As the postglacial thaw progresses the oceans warm up, and some of the dissolved carbon emits into the atmosphere, just like fizz in soda water taken out of the fridge. "So the greenhouse global warming theory has it ass backwards," Hertzberg concludes. "It is the warming of the earth that is causing the increase of carbon dioxide and not the reverse." He has recently had vivid confirmation of that conclusion. Several new papers show that for the last three quarter million years CO2 changes always lag global temperatures by 800 to 2,600 years." [iv] 

   More sunlight striking the Earth’s surface causes the planet’s oceans, which account for 71 percent of its surface, to heat up. Because the mass of the oceans is much greater than that of the air—about 100 times greater, in fact—there is a considerable lag before oceanic heating becomes sufficient to cause the oceans to release greater amounts of CO2 into the atmosphere. In Hertzberg’s view, the CO2 is an effect and not a cause of global warming. 

   It is this natural process of variation in sunlight striking the planet, and not anthropogenic CO2 emissions, per Hertzberg, which accounts for the increasing amount of CO2 in the Earth’s atmosphere. To “prove” this point, Cockburn asserts that CO2 emissions fell significantly due to the Great Depression, while temperatures continued to increase, thus “proving” that planet-wide temperature increase is independent of atmospheric CO2 levels. 

   Cockburn offers several purported examples from the historical record (the Little Ice Age) and the geological record (the Eocene Period) which supposedly further demonstrate the lack of a link between atmospheric CO2 levels and planetary temperature. He is clearly asserting that there is no causal relationship between atmospheric CO2 levels and planetary temperature whatsoever. In other words planetary temperature is independent of CO2 levels in the atmosphere! Not now, not millions of years ago, never, have atmospheric CO2 increases caused temperature increases! That assertion left me stunned, I must admit.

   What is the atmospheric component which actually accounts for greenhouse effects according to Hertzberg’s theory? Water vapor! Cockburn asserts that climate modeling by the world’s climate scientists (other apparently than Hertzberg) ignores the effects of water vapor:  “And water is exactly that component of the earth's heat balance that the global warming computer models fail to account for.” [v]

   Having discounted anthropogenic effects from having any significant effect whatsoever on the world’s climate, Cockburn then makes a vague reference to the Earth itself as being a cause of planetary warming, asserting: “…the human carbon footprint is of zero consequence amid these huge forces and volumes, and that's not even to mention the role of the giant reactor beneath our feet: the earth's increasingly hot molten core.”  Whether the Earth’s allegedly “increasingly hot molten core” plays a role in Hertzberg’s global warming theory, or is just another a priori belief of Cockburn’s is not specified. I will therefore subsequently ignore this vague assertion until and unless Cockburn chooses to be more specific about it.

Hertzberg-Cockburn Critique of Global Warming Rebutted.

   First of all, until very recently, human civilization has simply not been of sufficient magnitude to cause any significant effects whatsoever upon global climate and temperatures. Therefore, until very recently, natural forces were wholly responsible for changes in the Earth’s climate and its overall temperature. These natural forces were primarily changes in the amount of sunlight striking the planet due to the Milankovitch cycles. The long lag associated with increasing sunlight warming the Earth and the consequent heating of the oceans and frozen bogs (which release methane a greenhouse gas 30 times more potent that CO2) constitutes a kind of “thermal inertia.” However, as these positive (that is, amplifying) feedback loops kick in, including oceanic warming, ice melting (affecting the planet’s reflectivity) permafrost melting etc., the process of warming begins to accelerate. 

   So it is indeed true that across the geological history of our planet, that at first, planetary surface temperatures increase incrementally due to natural cycles--primarily due to Milankovitch cycles. This natural, external to our planet, warming then triggers greenhouse gas emissions. So far there is agreement between objective reality and Hertzberg’s thesis. However, these emissions themselves trigger additional planetary warming, which Hertzberg’s model disregards. 

   Eventually, falling levels of sunlight due to these natural cycles reverse the warming process. And that was how it was across countless millions of years, until fossil-fueled human civilization began to become a significant factor affecting the planetary climate in the past 100 or so years.

   The primary fallacy in Hertzberg’s thesis is the argument that because natural cycles accounted for all global warming (and cooling) in past ages, it follows that this is still true, and therefore, human activity can be discounted. This fallacy rests upon the supposed lack of any causal relationship between atmospheric CO2 levels and temperature. If this is correct, then our carbon emissions are simply irrelevant to the global climate. Instead, it is asserted by Hertzberg-Cockburn that both planetary temperature and CO2 levels are caused by increasing solar radiation, which by heating the oceans, evaporates more water vapor into the atmosphere. This water vapor is purported to be the actual greenhouse gas, instead of CO2.

   Yet CO2 unambiguously does cause heat to be trapped on planetary surfaces. Our nearest planetary neighbor, Venus, is about the same size and mass as the Earth. It is only about 25 million miles nearer to the sun than our planet. Originally, it is believed by planetary scientists to have been temperate with liquid water on its surface about 4 billion years ago. Yet, solar radiation on Venus eventually triggered a runaway greenhouse effect which has cloaked the planet in a dense blanket of CO2 which is about 100 times the thickness of our own atmosphere. The effect of all of this atmospheric CO2 is to make Venus’s present-day surface temperatures hot enough to melt lead! [vi] Such is the global warming power of CO2!

   On Earth, the relationship of CO2 and temperature since the industrial revolution began is quite clear, as shown in the figure below:


   Source: Whole-systems.org [vii]

   What we need to understand is that with the onset of the Industrial Revolution something new and unprecedented occurred: anthropogenic CO2 releases compounding over a brief time interval triggered escalating temperature increases, along with overall climate change on a global scale. There is no thousand-year lag in this relationship, simply because the triggering agent is not gradually increasing levels of sunlight; rather, it is humans burning fossil fuels, thereby rapidly releasing carbon into the atmosphere. A thousand year lag is evidence of natural climate change. Rapid onset temperature increases are evidence of something unnatural at work: human civilization.

   We know where all of this CO2 which suddenly appeared in or atmosphere comes from: it comes from the fossil fuels we’ve just burned for energy. Period. It is not caused by increasing levels of sunlight. As we shall see presently, these levels have actually been decreasing in recent decades!

   We know the physics of CO2 with respect to its trapping heat in the atmosphere. It is the same on Earth as it is on Venus, because the laws of physics are universal. Contrary to Hertzberg’s assertion, climate models do indeed account for water vapor in the atmosphere. They may do this imperfectly, however this is a far cry from asserting that these models “fail to account for” this greenhouse gas. 

   As to the assertion that declines in the rate of CO2 emissions during the Great Depression did not cause corresponding temperature decreases, Cockburn fails to understand that CO2 concentrations are cumulative. Once released, the gas remains in the atmosphere for centuries—unlike water vapor, which quickly precipitates out of the atmosphere as rain or snow. Temperatures did not fall because, although there was a slowdown in atmospheric buildup of CO2, overall levels of CO2 in the atmosphere were still increasing. 

   Interestingly, the graph above seems to show a pause in temperature increases, just after the Depression induced slowdown of CO2 emissions. This relationship is what would be expected to be seen if CO2 levels did indeed directly affect temperatures. It certainly does not disprove a causal relationship, as Cockburn misguidedly asserts. 

   Finally, I would note that throughout recent decades, the amount of sunlight striking the Earth’s surface has actually been diminishing, not increasing, as Cockburn asserts. This process is called global dimming. [viii] It is also anthropogenic, as it is caused by atmospheric pollutants blocking sunlight from striking the Earth’s surface. If the Hertzberg-Cockburn theory were correct, it would follow logically that planetary temperatures would decrease due to global dimming, and not increase as they have done. 

   Empirical observation thus falsifies the Hertzberg-Cockburn theory. In fact, observation shows that nature behaves exactly as anticipated if the causal relationship of CO2 and temperature were both true and a major climate factor.

Conclusion

   In summary, the Hertzberg-Cockburn thesis is falsified by empirical data. The Hertzberg-Cockburn thesis conflates natural and human-caused climate change, while ignoring the fact that this latter process has massively overridden all natural climatic factors. It has also ignored or conflated with natural cycles, anthropogenic factors which act to cool the planet such as pollution-caused global dimming.

   Why has Alexander Cockburn made and publicized this unfounded assertion? I believe him to be a decent and honest man. I certainly do not believe that he is, for example, a paid disinformation agent, or something along those unsavory lines. 

   Rather, my take is that Cockburn is in denial. The magnitude of the problems facing humanity, and the consequent possible future of our civilization is so bleak, that it is far easier to deny this reality. Yet that is the worst possible course of action to take if humanity is to have a positive future. I encourage Mr. Cockburn, along with everyone else who feels similarly, to open your eyes.

   I am the author of a recently released book which was written for just this purpose. It is entitled Infinity’s Rainbow: The Politics of Energy, Climate and Globalization. Several months ago I e-mailed Mr. Cockburn to inquire if he would like a copy. He responded that he would, so I sent him one. So in closing, I’d like to address a personal note to Mr. Cockburn: Please go back and read (or re-read) this book.

i From Papal Indulgences to Carbon Credits Is Global Warming a Sin? Counterpunch, April 28, 2007, http://www.counterpunch.org/cockburn04282007.html
ii IBID
iii Wikipedia, The Free Online Encyclopedia, Milankovitch Cycles, http://en.wikipedia.org/wiki/Milankovitch_cycles
iv IBID #1 From Papal Indulgences to Carbon Credits Is Global Warming a Sin?
v IBID #1 From Papal Indulgences to Carbon Credits Is Global Warming a Sin?
vi Wikipedia, The Free Online Encyclopedia, Atmosphere of Venus, http://en.wikipedia.org/wiki/Atmosphere_of_Venus
vii CO2 and Global Temperature Change, http://www.whole-systems.org/co2.html
viii Wikipedia, The Free Online Encyclopedia, Global Dimming, http://en.wikipedia.org/wiki/Global_dimming See also: http://www.bbc.co.uk/sn/tvradio/programmes/horizon/dimming_prog_summary.shtml
---------------