Thursday, December 10, 2009

Vegan Flier

Here's a vegan flier that I made:
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Since this is a bit wordy I usually put it up in places where I can expect a captive audience, for example public restroom stalls, slipped into free newspapers, and other places where people are likely to be waiting. They also make great materials to hand out while tabling.

For other things like public bulletin boards I usually use materials from Vegan Outreach, which can be found here.

Occassionally I'll mix some of these materials up with materials from Peaceful Prairie Animal Sanctuary as well:

Let me know if you try any of these materials out and what works well for you.

Richard Dawkins: A Worldview Informed by Evolution

By the late 20th century the scientific consensus behind evolution was well established; nonetheless, political challenges and religious opposition to evolution continued from the public. As an ethologist, Richard Dawkins was forced by the historical context in which he lived to challenge both the religious opposition to evolution and the closely related Cartesian views of non-human animals.

René Descartes was a prominent philosopher, mathematician, and physicist of the early 17th century. Descartes wrote during the scientific revolution and promoted a mechanistic worldview, arguing that the universe could best be understood as a purely mechanical system. In 1641, Descartes published his philosophical work titled Meditations. This work argued that the mind existed apart from the physical universe, deeply tied to the religious concept of the soul, and, since animals did not possess a soul, they were nothing more than complex automata (autonomous machines), unable to experience consciousness, suffer, or feel pain.[6] This view of non-human animals as unconscious automata, unworthy of moral consideration, continued as common belief even into the 21st century.

Richard Dawkins was born on March 26, 1941 in Nairobi, Kenya, which at the time was a British colony. Dawkins describes his childhood as “a normal Anglican upbringing”[1] and states that he did believe the religion he had been brought up with. At the age of eight Dawkins’ family returned to England, where Dawkins attended Oundle School, one of the most prominent boarding schools in the country. There Dawkins learned about the theory of evolution, which Dawkins describes as a turning point in his religious belief. “By then, of all the classical arguments for the existence of God, only the argument from design seemed to me to carry any weight, and I finally toppled that in my mind when I learned about evolution.”[1] The argument for design is an argument for the existence of a god based upon perceived evidence of purpose, order, or design in the universe. Dawkins would later describe in his book The Blind Watchmaker that “Although atheism might have been logically tenable before Darwin, Darwin made it possible to be an intellectually fulfilled atheist.”[2, p. 6] While Pierre-Simon Laplace had previously provided a natural explanation for the stability and origin of the solar system and David Hume had argued that design was unnecessary to explain the origin of life[3], Darwinian evolution had filled in the final necessary step in making atheism a full explanation for Dawkins.

After graduating from Oundle, Dawkins attended Baliol College, one of the constituent colleges of the University of Oxford. There he studied zoology under the supervision of Nobel Prize winning ethologist Nikolaas Tinbergen. After receiving his PhD in 1966, Dawkins became an assistant professor of zoology at the University of California in Berkeley. In 1970 Dawkins returned from Berkeley to become a lecturer in zoology at New College, Oxford.

Dawkins time at Oxford coincided with a sudden intellectual push for animal rights within Oxford University. In the mid 1960s a group now known as the Oxford Group began publishing essays advocating for the rights of non-human animals within Oxford University. These intellectuals challenged the Cartesian assumption that humans were the only species with interests worthy of consideration and argued that membership of a particular species was not a valid basis upon which to deny a being of consideration.[25]

Dawkins’ return to Oxford also coincided perfectly with the rise of the animal rights movement within England as a whole. From the early 1960s onward, a group called the Hunt Saboteurs Association had been disrupting hunting events throughout England. In 1971, Ronnie Lee and Cliff Goodman created a group called the Band of Mercy, an offshoot of the Hunt Saboteurs Association, which took protecting animal rights to the next level by engaging in non-violent property damage to those who exploited animals (human or non-human) for profit. The Band of Mercy would later change its name to the Animal Liberation Front (ALF) in 1976. The previous year, Peter Singer had published his world renowned book Animal Liberation. The book was an instantaneous hit within the animal rights movement, and served to popularize the term “speciesism”, which similar to its counterparts, racism and sexism, means inequitable treatment based solely on the classification of species, rather than the ability of the being to possess interests, and this term has since been used by Dawkins on countless occasions.

It was within this social climate that Dawkins published his first book, The Selfish Gene, in 1976. According to Mark Ridley, Dawkins first book caused “a silent and almost immediate revolution in biology.”[4] Dawkins shows less of his poetic social commentary in this book than in his other works, but he uses his gene theory to show that all organisms, whether human, animal, plant, or otherwise are merely successfully hit upon “survival machines” for replicating our DNA. It is a gene that creates a “survival machine” that is more suitable for getting the gene replicated, which is more likely to proliferate, rather than organisms or species being the units in control of evolutionary change. Dawkins enlightened the world that all organisms are driven into existence by nothing more than bits of nucleic acid which through generations of natural selection have been selected to act “as if” they want to survive.[5] This understanding of evolution made quite clear that an appeal to the supernatural was not necessary to explain something as seemingly unmechanistic as consciousness.

The early 1980s was full of small single issue victories that brought attention to the animal rights movement. While Voltaire had written in opposition of the Cartesian treatment of non-human animals as early as 1764[7], it was not until the 1980s that public finally began to speak up to the abuses that were being brought to its attention. This culminated in 1980 with the cosmetics company Revlon ending its use of the Draize Test, a test which administered substances directly to the eyes of captive rabbits, which was quickly followed by several other cosmetics companies following suit. 1984 also saw a raid by the ALF on a University of Pennsylvania head injury clinic, exposing monkeys with their heads cemented into helmets being knocked about at forces of 1000g. This film further helped bring the attention of the public to the gross excesses of those who exploit non-human animals for menial human benefit.

In 1982 Dawkins published his second book, The Extended Phenotype, which built upon his gene-centered view of evolution to further explain that the effects of genes did not just extend to the proteins they coded for, or the bodies they created, but to everything that happened as a result of that particular gene existing in a body. An example of this Dawkins gives is the gene (or set of genes) that cause beavers to build dams do not help beavers replicate because building dams is particularly beneficial, but as a result of that dam building phenotype, they have created a lake, which serves as an ideal habitat to catch food and evade predators, which thereby causes the genes for dam building to survive. In this book Dawkins coined the term “meme” to describe cultural replicators, or replicators that use the machinery of human minds and technology to spread themselves. Dawkins has repeatedly used religions as examples of memes that have evolved to promote their spread, particularly in his 1991 essay Viruses of the Mind and later in his 2006 television documentary for the BBC titled The Root of All Evil.

It was not until Dawkins’ third novel, The Blind Watchmaker that Dawkins’ commentary on social issues began to emerge through his work. The title of the work stems from William Paley’s work titled Natural Theology published in 1800. In it Paley argues that just as if we found a watch on the ground we should assume that there existed some watchmaker, we should similarly assume when we see the complexity of a living organism there must be some creator behind that organism.[8] Paley’s argument was one still regularly recited by creationists in Dawkins’ time. Dawkins uses The Blind Watchmaker to demonstrate that evolution provides an explanation for this perceived design in living organisms, and thus no appeal to the supernatural is necessary to explain the universe. In explaining how evolution works, Dawkins brings up Fleeming Jenkin’s 1867 criticism of On the Origin of Species, in which Jenkin argues that in the case of a white stranded on an island of “negroes”, “our white’s qualities would certainly tend very much to preserve him to good old age, and yet he would not suffice in any number of generations to turn his subjects’ descendents white.”[9] Dawkins replies to this in his book by stating, “Don’t be distracted by the racist assumptions of white superiority. These were as unquestioned in the time of Jenkin and Darwin as our speciesist assumptions of human rights, human dignity, and the sacredness of human life are unquestioned today.”[2, p. 114] Dawkins used this very important point in his book to compare racism, one of the most detestable forms of inequality of his time with the feelings the majority of his readers still held towards non-human animals. Dawkins later continues,

“Our legal and moral systems are deeply species-bound. The director of a zoo is legally entitled to ‘put down’ a chimpanzee that is surplus to requirements, while any suggestion that he might ‘put down’ a redundant keeper or ticket-seller would be greeted with howls of incredulous outrage. The chimpanzee is the property of the zoo. Humans are nowadays not supposed to be anybody’s property, yet the rationale for discriminating against chimpanzees in this way is seldom spelled out, and I doubt if there is a defensible rationale at all. Such is the breathtaking speciesism of our Christian-inspired attitudes, the abortion of a single human zygote (most of them are destined to be spontaneously aborted anyway) can arouse more moral solicitude and righteous indignation than the vivisection of any number of intelligent adult chimpanzees!”[2, p. 262-3]

Dawkins specifically mentions Christianity as the source of our Cartisian attitudes towards animals, and claims that he doubts any rational explanation for this discrimination could be given. The Blind Watchmaker served not only as a place to counter creationist opposition to evolution, but to also challenge religiously inspired Cartesian views towards the place of humanity within nature.
Because of Dawkins prominence as an ethologist, and his comments in his previous works, he was asked to contribute an essay to the 1993 book The Great Ape Project. The purpose of the project was to support a United Nations Declaration of the Rights of Great Apes, which would confer basic legal rights on chimpanzees, bonobos, gorillas, and orangutans. Several other ethologists contributed to the work including Jane Goodall, who spent 45 years studying the behavior of chimpanzees in Tanzania, along with prominent utilitarian philosopher Peter Singer.[10]

Dawkins contributed an essay titled Gaps in the Mind to the project, in which he repeats that a continuum can be drawn not just between humans and great apes, but between humans and all living organisms. Only an organism’s capacity to possess interests and suffer should be given consideration, not its irrelevant categorization of species. To further this point Dawkins cites the previous work of Jeremy Bentham, a prominent 18th century utilitarian, who had written, “a full-grown horse or dog is beyond comparison a more rational, as well as a more conversable animal, than an infant of a day, or a week, or even a month, old. But suppose the case were otherwise, what would it avail? The question is not, 'Can they reason?' nor, 'Can they talk?' but, 'Can they suffer?'”[12] Dawkins writes regarding human animals versus non-human animals that,
“There is an unquestioned yawning gulf between them such that the life of a single human child is worth more than the lives of all the gorillas in the world. The 'worth' of an animal's life is just its replacement cost to its owner — or, in the case of a rare species, to humanity. But tie the label Homo sapiens even to a tiny piece of insensible, embryonic tissue, and its life suddenly leaps to infinite, uncomputable value.”[11]

Dawkins challenges the Cartesian assumption that some drastic qualitative difference exists between human and non-human animals as being in direct opposition to Darwinian evolution. Dawkins further critiques this insistence upon categorizing and separating, labeling it “the discontinuous mind”. Dawkins describes lawyers and our current legal system as being examples of this discontinuous way of thinking, citing how, for years, South Africa’s apartheid government had, “done a brisk trade adjudicating whether particular individuals of mixed parentage count as white, black or coloured.”[11] Once again Dawkins chooses to make a comparison between abandoned forms of racial discrimination and the contemporary species discrimination of his time. Dawkins describes that while the intermediates between ourselves and modern chimpanzees are dead (although they are not in the case of ring species like the herring gull and the lesser black-backed gull), we can be connected to this evolutionary cousin of ours by a surprisingly short chain of intermediates. Dawkins then makes the point that, “as far as morality is concerned, it should be incidental that the intermediates are dead. What if they were not?”[11] In Dawkins belief, “We need only discover a single survivor, say a relict Australopithecus in the Budongo Forest, and our precious system of norms and ethics would come crashing about our ears. The boundaries with which we segregate our world would be all shot to pieces. Racism would blur with speciesism in obdurate and vicious confusion.”[11] Dawkins points out that race and species are nothing more than variations of degree on the same concept, and thus to define an arbitrary point, as Descartes does, where the soul suddenly enters is in stark opposition to the Darwinian worldview. Dawkins concludes his essay by stating that,

“if somebody succeeded in breeding a chimpanzee/ human hybrid the news would be earth-shattering. Bishops would bleat, lawyers would gloat in anticipation, conservative politicians would thunder, socialists wouldn't know where to put their barricades. The scientist that achieved the feat would be drummed out of politically correct common-rooms; denounced in pulpit and gutter press; condemned, perhaps, by an Ayatollah's fatwah. Politics would never be the same again, nor would theology, sociology, psychology or most branches of philosophy. The world that would be so shaken, by such an incidental event as a hybridization, is a speciesist world indeed, dominated by the discontinuous mind.”

Dawkins once again points out how the Cartesian view of non-human animals falls apart under a Darwinian worldview. Through Dawkins contribution to The Great Ape Project, he made clear that a finely gradated scale existed between all species, contrary to the sharp disconnect Descartes had put between human and non-human animals.

Dawkins unique style of writing, often referred to as “poetic prose”, came to the attention of Microsoft billionaire Charles Simonyi, who, in 1995, endowed the Simonyi Professor for the Public Understanding of Science position at the University of Oxford with the intention of Dawkins being its first holder. From this position Dawkins published a slew of new books including, River Out of Eden, Climbing Mount Improbable, Unweaving the Rainbow, A Devil’s Chaplain, and The Ancestor’s Tale. Each of these shared scientific and evolutionary knowledge with the public in a new and exciting way, many of them building upon ideas he had originally shared while giving the Royal Institution Christmas Lecture, which he titled “Growing Up in the Universe”, in 1991. The dominant work of this period, however, was The God Delusion, a book whose purpose was to illuminate the logical fallacies behind religious belief and its consequences in our modern world. While many of Dawkins’ previous works had strong commentaries on religion, particularly The Ancestor’s Tale, in which Dawkins discusses the dangers of the American president George W. Bush’s religious beliefs and his not accepting evolution, The God Delusion was dedicated entirely to discussing religion. The book came out right around the same time as Sam Harris, Christopher Hitches, and Daniel Dennett were also publishing popular books promoting atheism. This period was partially incited as a backlash to the Sept. 11th attacks of 2001, along with growing exasperation from the worldwide community regarding religion promoting challenges to evolution in public classrooms[13], conducting strong proselytizing in the military[14][15], creating strong opposition to atheists in public office[16], threatening violence at atheist events[17], putting up walls to birth control and abortion[18][19], promoting inequality against women[20], denying medical care to children[21], along with generally teaching people not to question and explore their worlds[22]. Because of this environment into which Dawkins released this book, it instantly became a worldwide hit, selling over 8.5 million copies in the three years after its release, and catapulting Dawkins from being at the forefront of the ethological community, to one of the most widely recognized names in the world. While The God Delusion was solely intended as a place for Dawkins to address what he saw as the flaws and logical inconsistencies of religious belief, this didn’t prevent him from commenting about how animal rights may be a part of the secular ethics of the future, stating,

“The Philosopher Peter singer, in Animal Liberation, is the most eloquent advocate of the view that we should move to a post-speciesist condition in which humane treatment is meted out to all species that have brainpower to appreciate it. Perhaps this hints at the direction in which the moral Zeitgeist might move in future centuries. It would be a natural extrapolation of earlier reforms like the abolition of slavery and the emancipation of women.”[23, p. 271]

Dawkins argues that in a secular world, the extension of consideration of interests to all beings capable of possessing interests is the logical conclusion of similar reforms that had occurred in the past. Once the world broke free of the grasp of religion, Dawkins saw the Cartesian view of non-human animals falling by the wayside over time as well.

Dawkins would appear on the Point of Inquiry podcast on December 7, 2007 to discuss The God Delusion, where he fielded a question from Peter Singer himself enquiring as to how the, “Darwinian view undermines the basis for some of the distinctions we draw between ourselves and animals, undermines the idea that we are special because we are made in the image of ‘God’, or that ‘God’ gave us dominion over the animals.”[24] Singer directly asks if Dawkins finds the Darwinian worldview in opposition to the Cartesian view of non-human animals to which Dawkins replies by stating,

“It is a logical implication of the Darwinian view that there is continuity between all species, at least theoretical continuity. I’m very fond of pointing out that it’s an accident of history that the evolutionary intermediates between ourselves and, for example, chimpanzees, or actually between ourselves and any other species… it’s an accident that they happen to be extinct.”[24]

Dawkins states frankly that the Cartesian view is in stark opposition to the continuity inherent in Darwinian evolution, and that no clear line can be drawn in which the common Cartesian soul can be inserted. He later continued,
“If only all the intermediates had survived […] then the only way we could maintain our present speciesist morality, which draws an absolute wall around Homo Sapiens, and distinguishes us from every other species on the planet, the only way we could maintain that under the conditions of the thought experiment that I’ve advanced would be to have courts exactly like the apartheid courts in South Africa, which decided whether so-and-so would pass for white, and when you put it like that, we all shrink back in horror from such a prospect, and yet most of us accept without question the presumption that we are a completely unique species, and in many ways we are a completely unique species, but many other species are that.”[24]

Dawkins admits that had the intermediates between ourselves and chimpanzees survived, as they very well could have, then the only way we could continue our current method of discrimination would be to have courts determine who should pass as human and who should not. No clear objective way exists to determine which intermediates possess a soul, and which, as Descartes would put it, were merely automata. If no grounds exist to show evidence of such a soul existing, then on what grounds does Descartes argue for the soul’s existence? Dawkins repeats this again in his response testifying that,

“Nobody can possibly deny, unless they deny evolution of course, but as long as we are evolutionists, as long as we are Darwinians, nobody could possibly deny that, which means that all of us who are meat eaters including me, are in a very difficult moral position. We are, at least speaking for myself, what I’m doing is going along with the fact that I live in a society where meat eating is accepted as the norm, and it requires a level of sort of social courage that I haven’t yet produced to break out of that. It’s a little bit like the position which anybody, not everybody, but many people would’ve been a couple hundred of years ago over slavery, where lots of people felt morally uneasy about slavery, but went along with it because, I don’t know, the whole economy of the South depended upon slavery.”[24]

Dawkins concisely states that anyone who accepts the Darwinian evolutionary worldview cannot deny that the current way we use non-human animals for our most menial human interests is unacceptable. The speciesism of Dawkins’ contemporaries was in downright opposition to the evolutionary consensus of the time, and to challenge it was essential to promoting the public understanding of science. Only by challenging the deeply ingrained disconnect many humans held between themselves and other animals could Dawkins further the cause of teaching evolution to a public audience.

As an ethologist in the late 20th century, Dawkins was forced to do more than merely research, but also challenge the deeply held public beliefs in opposition to properly understanding his field. Dawkins used his understanding of evolution to show that the Cartesian views towards non-human animals were in opposition to the established scientific understanding of the time. Only by challenging such deeply engrained religious dogma was Dawkins able to promote a consistent worldview and ultimately advance the public understanding of science.

[1] "Culturewatch - A Devil's Chaplain: selected essays by Richard Dawkins; Unweaving the Rainbow; The Root of all Evil?" Damaris Home Page. Web. 09 Dec. 2009. .

[2] Dawkins, Richard. Blind watchmaker why the evidence of evolution reveals a universe without design. New York: Norton, 1996. Print.

[3] Isaak, Mark. "CA602.1: An intellectually fulfilled atheist." TalkOrigins Archive: Exploring the Creation/Evolution Controversy. 30 Sept. 2000. Web. 09 Dec. 2009. .

[4] Grafen, Alan; Ridley, Mark (2006). Richard Dawkins: How A Scientist Changed the Way We Think. New York, New York: Oxford University Press. p. 72. ISBN 0199291160.

[5] Dawkins, Richard. "Richard Dawkins: The Selfish Gene." Interview. Audio blog post. BBC World Service | World Book Club. BBC, July 2007. Web. 8 Dec. 2009. .

[6] Meditations on First Philosophy, translated by John Cottingham (Cambridge: Cambridge University Press, 1996).

[7] "Animal Liberation - by Peter Singer - Man's Dominion ... a Short History of Speciesism Chapter 5 Only - Peter Singer - Athenaeum Library of Philosophy." Index - Athenaeum Library of Philosophy. Web. 08 Dec. 2009. .

[8] Paley, William. Natural Theology. 1800. Print.

[9] Jenkin, Fleeming. The Origin of Species [Review Article]. 1867. Print.

[10] Cavalieri, Paola, and Peter Singer. The Great Ape Project: Equality Beyond Humanity. London: Fourth Estate Limited, 1993. Print.

[11] "Gaps in the Mind, by Richard Dawkins." The Animal Rights Library. Web. 08 Dec. 2009. .

[12] Bentham, Jeremy. An Introduction to the Principles of Morals and Legislation. 1789. Print.

[13] "Kitzmiller, et al v. Dover School District, et al." Welcome to the U.S. District Court for the Middle District of PA. Web. 09 Dec. 2009. .

[14] "More Aggressive Proselytizing in the Military : Dispatches from the Culture Wars." ScienceBlogs. Web. 09 Dec. 2009. .

[15] "Update on Military Atheism Lawsuit : Dispatches from the Culture Wars." ScienceBlogs. Web. 09 Dec. 2009. .

[16] "Religious discrimination in state constitutions." by the Ontario Consultants on Religious Tolerance. Web. 09 Dec. 2009. .

[17] Friendly Atheist by @hemantsblog. Web. 09 Dec. 2009. .

[18] "Humanae Vitae - Encyclical Letter of His Holiness Paul VI on the regulation of birth, 25 July 1968." Vatican: the Holy See. Web. 09 Dec. 2009. .

[19] "Abortion." Catholic Answers: Catholic Apologetics, Catholic Evangelization, Catholic Teachings, Catholic Radio, Catholic Publishing, Catholic Truth. Web. 09 Dec. 2009. .

[20] "Afghanistan passes 'barbaric' law diminishing women's rights | World news |" Latest news, comment and reviews from the Guardian | Web. 09 Dec. 2009. .

[21] "Child Fatalities From Religion-motivated Medical Neglect -- Asser and Swan 101 (4): 625 -- Pediatrics." AAP - Journal of the American Academy of Pediatrics. Web. 09 Dec. 2009. .

[22] "Atheists and Anger." Greta Christina's Blog. Web. 09 Dec. 2009. .

[23] Dawkins, Richard. The God Delusion. Boston: Houghton Mifflin, 2006. Print.

[24] Dawkins, Richard. "Richard Dawkins - Science and the New Atheism." Interview by D.J. Grothe. Audio blog post. Point of Inquiry. Center for Inquiry, 7 Dec. 2007. Web. 8 Dec. 2009.

[25] "Richard Ryder: All beings that feel pain deserve human rights | World news | The Guardian." Latest news, comment and reviews from the Guardian | The Guardian. Web. 09 Dec. 2009. .

Saturday, December 5, 2009

Global Warming Denialists

Recently, global warming denialists have drawn attention to themselves by releasing of thousands of hacked e-mails and documents from the Climate Research Institute. These e-mails, sent over the course of 13 years purportedly show researchers manipulating data to create evidence that wasn’t actually there on behalf of global warming. In one e-mail a researcher writes, “I think we have to stop considering Climate Research as a legitimate peer-reviewed journal. Perhaps we should encourage our colleagues in the climate research community to no longer submit to, or cite papers in, this journal.” In another e-mail from November 1999 they write, “I've just completed Mike's Nature [the science journal] trick of adding in the real temps to each series for the last 20 years (ie, from 1981 onwards) and from 1961 for Keith's to hide the decline.” In yet a third e-mail they write, “The fact is that we can't account for the lack of warming at the moment and it is a travesty that we can't,”

These three quotes come from the personal correspondences of several researchers over the course of 13 years. One would expect to find quite a few anomalies if they searched through thousands of documents, and this, frankly, seems to be very few anomalies for such a large number of documents. Even still, the anomalies themselves are entirely within proper scientific procedure when read within their intended context.

The Peer review process is a very important one in science. Scientific journals employ peer reviewers to ensure that research was done with proper controls and blinding when applicable, and that all conclusions being drawn follow from the research conducted before publishing a study in their journal. By having stringent peer review standards journals maintain their reputations within their respective fields. When a journal begins to allow research with poor methods and analysis through their peer review process they lose the respect of the scientific community who may decide to stop viewing them as a legitimate peer-reviewed journal, and may even encourage their colleagues to no longer submit to, or cite papers in that journal. This is exactly what happened in the case of the Climate Research journal, which allowed a paper through its peer review process denying that the 20th century was abnormally warm in spite of the fact that this did not follow from the evidence collected by their research.

In the case of the “Mike’s Nature trick,” the “trick” being referred to by the scientists is to add in the data from recent years to older data so that the trend in the recent warming has some context it can be compared to.

The third quote, regarding the “inability to account for the lack of warming at the moment,” was later explained by its author. “Hackers cherry-picked from the stolen data and distributed selected documents to try to undermine scientific consensus on man-made climate change.” reported that, “bloggers are missing the point he’s making in the e-mail by not reading the article cited in it. That article – An Imperative for Climate Change Planning — actually says that global warming is continuing, despite random temperature variations that would seem to suggest otherwise.” The author explains his quote, “says we don’t have an observing system adequate to track it [global warming], but there are all other kinds of signs aside from global mean temperatures — including melting of Arctic sea ice and rising sea levels and a lot of other indicators — that global warming is continuing.”

Whether or not the authors adjusted any data to better show global warming says nothing as to the well-established scientific mechanisms behind global warming. At a distance of the earth, the sun’s output is equivalent to 1366 W/m^2. These units are a rate that energy is being transferred to any given unit area facing directly at the sun. For the earth, not all of the surface is facing directly towards the sun. Half of it is facing away, and the other half is mostly at odd angles relative to the sunlight. If we integrate over the entire earth, we get that only 1/4 of the 1366 value is reaching the average square meter of earth’s surface. Additionally a large portion of our surface is blocked by clouds which reflect light directly back into space. When all this is taken into account, the earth is, on average, absorbing 235 W/m^2 from the sun.

Objects with temperature give off blackbody radiation. The amount of radiation given off is given by the Stephan-Boltzmann law, and the amount of radiation given off in any portion of the spectrum is given by Planck’s law. The Stephan-Boltzmann law tells us that temperature radiated from an object is proportional to absolute temperature (temperature in Kelvin) to the fourth power. An object is in temperature equilibrium, if the radiation being absorbed by it is equal to the radiation being emitted. If we solve this equation for the equilibrium temperature of the earth, we get an equilibrium temperature equal to approximately -19 Celsius. If you’ve spent any time on earth before, you will likely have noticed that the average temperature is well above -19 Celsius. The earth only radiates about .5 W/m^2 from its core, thus this cannot account for any significant portion of the discrepancy we see. On Venus this discrepancy is far greater, so much so that Venus is known to have a much hotter surface than its cousin closer to the sun, Mercury.

The reason for these discrepancies is well understood. If you have ever opened your eyes before, you may have noticed that our atmosphere is largely transparent to light in the visible portion of the spectrum. Planck’s law tells us that objects at every day temperatures will radiate energy largely in the infrared part of the spectrum, and only once in a very long while will they radiate a photon of a visible wavelength. At higher temperatures however, the radiation will shift towards shorter wavelengths and far more of the radiation will be in the visible part of the spectrum. For temperatures around that of the surface of our sun, the blackbody radiation given off is centered near yellow visible light, tailing off in intensity in either direction. Our atmosphere is transparent to this light allowing it to radiate through to our surface, heating the surface, until it is given back off by our surface as largely infrared radiation. Infrared radiation, unlike visible radiation, cannot pass straight through our atmosphere.

There are discrete energies molecules can absorb because they induce vibration in the molecule. There are also rotational energies associated with molecules, but only the vibrational energies happen to fall in the infrared portion of the spectrum. An example of some absorption spectra can be seen here:

You will likely notice that water vapor (H2O) seems to be the most potent of these common gasses in the infrared region. Water vapor is also far more prevalent than carbon dioxide in the atmosphere. Thus, the majority of the discrepancy between our -19 Celsius predicted temperature and the actual global mean temperature is actually due to the presence of water vapor in the air. Carbon dioxide only makes a slight additional bump in temperature in addition to the boost we already receive from water. Carbon dioxide is still however a larger contributor to global warming, however, because water vapor concentrations have only changed a minuscule amount as a result of modern emission, whereas carbon dioxide concentrations have changed significantly. You may also notice that the absorption spectra provided appear to have 100% of the infrared radiation in carbon dioxide’s absorption bands being absorbed already. It is true that nearly all infrared radiation in these regions gets absorbed within the lower few kilometers of our atmosphere. What happens is a photon of the appropriate wavelength radiates upwards from our surface until it gets absorbed by a carbon dioxide molecule, raising the vibrational energy of the molecule. The vibrating molecule very quickly then radiates off a photon of the exact same wavelength absorbed in a random direction, returning to its original energy state. By increasing the concentration of carbon dioxide in the atmosphere we are catching more carbon dioxide lower down in the atmosphere, essentially thickening the infrared blanket we have covering the earth.

Different molecules such as methane, nitrous oxide, or sulfur hexafluoride have many times the warming potential of carbon dioxide or water vapor per molecule, but luckily these molecules are released in FAR smaller quantities than carbon dioxide or water vapor.

Humans are not the only sources of greenhouse gasses. Water vapor, carbon dioxide, methane, and nitrous oxide have all always been parts of earth’s environment, and our contribution has only been to increase concentrations of these gasses in our atmosphere by negligible to moderate amounts. Other human activities, such as the release of aerosols into the air actually contribute to global cooling, by reflecting more visible light straight back into space. At the moment the net effect is well within the range of our calculation capabilities, and the overall impact from anthropogenic effects has had a slight warming effect on our atmosphere, which is entirely consistent with the rise we have seen in mean global temperatures. While this has significant potential to change our environment, this trend is by no means out of our grasp, and proper understanding of the science behind this process can help us all determine better ways to enjoy our lives, while mitigating any undesired effects into the future.