The Scientific Basis for Anthropogenic Global Warming

In the past week, two prominent conservative writers - George Will and Charles Krauthammer - have published opinion pieces debating the merits of the global warming argument. I can't recommend either. Mr. Krauthammer makes the valid point that scientific theory is not dogma; it cannot be known for certain and must be open to criticism. However, that argument is a distraction and  irrelevant to our discussion of climate change. The evidence supporting anthropogenic global warming(henceforth AGW) is collected from almost every branch of science (physics, biology, chemistry, geology); to challenge it would require massive amounts of evidence to the contrary, which is not provided. George Will's column reads like an angry old man complaining about kids on his front lawn. He goes so far as to compare scientists who support AGW theory to Nazi propagandists; his piece has no merits. Yet, a thorough analysis of their columns will have to wait until everyone is on the same page with the science of global warming; so today's lesson will focus on the scientific theory for AGW. I plan on following this up with a look at skeptical criticism to engage arguments like Mr. Krauthammer's more directly, and then a final discussion of the (already) observable and theoretical effects of climate change. Before getting into the science, a little vocabulary. So buckle your seat belts.
Terms

AGW: Anthropogenic is an adjective meaning originating from human activity. Anthropogenic Global Warming is the theory that the average global temperature of the planet is increasing due to the increased concentration of greenhouse gases in the atmosphere caused by human activity.
Greenhouse Gases: Gaseous matter that has the ability to absorb infrared electromagnetic radiation.
Climate Change: The effect of AGW on a local climate. This is a term to use when discussing the impact AGW will have on any specific location.
I'd also like to have a quick talk about proof. There are two types of arguments: deductive and inductive. Nearly every scientific argument (with the exception of theoretical math) is inductive; it is built from the ground up with evidence and occasionally assumptions, and thus it does not set out to "prove" a fact, but to build a case supporting the probability that our understanding is accurate. So a good scientist will rarely say something is proven to be true, and will instead talk about how likely something is to be true. However, because scientists are not certain about something does not mean that they are not extraordinarily close to certain (in fact a statistician could tell you precisely how close to certain the scientific community is, but trust me, you don't want to talk to a statistician. They have poor social skills and will always try to figure out where you are on the bell curve).

Greenhouse Gases

So what exactly makes a gas a green house gas? As I've defined it, the gas must be able to absorb infrared radiation, but how does it do this and what does that mean? Don't freak out, we're going to need to talk about quantum mechanics to answer this, but I think it's actually pretty cool stuff.

Figure 1. EM Spectrum and Atmospheric Opacity

Figure 1. has a lot of information in it; we're going to go through it slowly. At the top, is the electromagnetic spectrum which is the model for representing all the different energy levels light exhibits. If light has high energy, it will have a short wavelength, and if it has low energy it will have a longer wavelength. You can think of this like someone bouncing on a trampoline; if they have a lot of energy they will bounce rapidly and the waves on the trampoline will be close together, but if they are tired the bouncing slows down and the waves spread out. Qualifying light like this allows a way to easily display how some interaction effects all types of light. In the chart above, the X axis plots out the various wavelengths of light from nanometers to kilometers, while the y axis shows what percentage of that light is blocked by our atmosphere. The dips in the graph are wavelengths of light that manage to penetrate our atmosphere and reach the surface of the planet. The peaks in the graph show wavelengths of light that are either absorbed or scattered away by matter in our atmosphere. Notice how high energy light is absorbed by the atmosphere (the upper atmosphere), so thankfully we don't have to deal with gamma radiation when we go outside. The small dip in the UV portion of the spectrum is what gives us a tan when sunbathing- and eventually cancer. The dip in the visible spectrum allows us to see, and the valley in the radio wave spectrum allows for clear communication signals through the atmosphere. Infrared is partially absorbed by the upper atmospheres, partially absorbed in the lower atmospheres, and partially reflected back out to space.

Now what's really cool, is that the effect light will have on matter is incredibly specific to the light's wavelength. Quantum Mechanics developed in part by trying to explain this phenomenon: light energy is packaged together in specific quant(um)ities. This means that high energy light doesn't necessarily have more of an effect on matter than low energy light does, they have completely different mechanisms for interacting. For example, when visible light interacts with matter, it induces an electron in the outer shell of an atom to move into an excited state. UV light does this too, but it's energy levels can target the electrons in a covalent bond, causing bonds to break. More energetic light than UV can penetrate further into an atom's electron shell, causing inner electrons to be ejected, and very high energy light will be powerful enough to target the atom's nucleus. Light less energetic than the visible spectrum is not powerful enough to to induce a change in an atom's electrons, but it still has very specific physical effects. Microwave radiation causes molecules to rotate (your microwave is causing water molecules in whatever is being heated to rotate and bump into each other, enough so that they start to boil- temperature is a macroscopic measurement of the microscopic kinetic energy of matter, or how much the molecules are moving). Finally, infrared radiation causes molecules to vibrate, and the molecules that vibrate best can absorb the most infrared energy and meet the qualification of a greenhouse gas.

Figure 2.  Molecular Vibrations of CO₂ and O₂.

Shape is important for a molecule's vibration; here's look at carbon dioxide and oxygen. In Figure 2., I have drawn three of the most easily visualized vibrational modes for carbon dioxide, though in reality there are a couple more. This shows that CO₂ can have the oxygen atoms vibrate around the carbon symmetrically, the carbon can vibrate between the two oxygen atoms asymmetrically, or the molecule can bend from a linear shape like an inchworm. On the other hand, Oxygen only can vibrate in a symmetrical stretch. Unlike the other vibrational modes, a symmetric stretch is not caused by infrared radiation (or molecular oxygen will not absorb infrared light. The explanation is rather complex conceptually, but it goes like this. Electromagnetic radiation produces an effect on an atom's electrons. In a symmetric stretch, the change in the distribution of electrons is also symmetric, and so the changes in electronic distribution cancel each other out and nothing happens. I don't really get it either, but more important than my understanding is that the effect can be observed.)

Figure 3. Infrared Absorption by Carbon Dioxide.
Provided by Van Bramer, Scott. "Carbon Dioxide, CO2." Carbon Dioxide, CO2. Widener University, 5 Jan. 1996. Web. 01 Mar. 2014.

Figure 3. shows what happens when infrared light passes through carbon dioxide. Ignore the funky units, they are wave numbers and equivalent to wavelength, but they make the math simpler for chemists which is why they are used here. This graph is very similar to the one at the topic of Figure 1. with a few distinctions. First this is zoomed in to only represent the infrared portion of the EM spectrum. Second, this is only for Carbon Dioxide, whereas the first was for then entire atmosphere. Last, this shows the ability of CO₂ to absorb light, while the first showed the inverse- light's ability to avoid absorption. So the peaks here are wavelengths of light that carbon dioxide will absorb. Notice that there are unique wavelengths for the unique vibrations and that the symmetric stretch is not observed with Infrared Spectroscopy (that's the fancy name for this type of light analysis.) This graph is all the "proof" (rather, evidence) needed to show that carbon dioxide is a greenhouse gas.

Greenhouse Gases and the Atmosphere.

So what is this increase in carbon dioxide doing to the atmosphere? This is where things get a little messy and where a lot of "skeptics" start to object. The problem is a lack of an applicable experiment to test what's going on. The only full test would be to find a planet equivalent to earth, and crank up the carbon dioxide there, and then have a control planet where the carbon dioxide remained constant, and then we would need a couple dozen more planets to establish statistical validity. Until that becomes feasible, the answer to this question will have to come a little indirectly.

The moon has no atmosphere but has about the same average orbit from the sun as the earth. The average temperature on the moon is about negative nine degrees Fahrenheit. A physicist could do the math by balancing the energy coming in from the sun with the energy reflected off the earth and show that the average temperature of the earth without the atmosphere would be about zero degrees Fahrenheit.* The average temperature of the surface of the earth is fifty seven degrees Fahrenheit. The atmosphere makes the planet that much warmer.

There were also times when earth's atmosphere made the planet much warmer than it does today. Before the evolution of single cellular life, the atmosphere is estimated to have have been about 35% carbon dioxide. The sun was also younger and burned about 25% dimmer. In spite of the earth receiving significantly less solar radiation, the atmosphere was still able to foster a habit suitable for the evolution of life, which implies that carbon dioxide had an extreme warming effect. Estimates of Earth's temperature during the age of the dinosaurs place it at around 20 degrees Fahrenheit hotter than today's because of a higher carbon dioxide concentration.

Venus is a extreme example of greenhouse effect. Estimates for Venus' surface temperature without an atmosphere place it at around 160 degrees Fahrenheit. The average surface temperature of Venus is over 900 degrees Fahrenheit. The atmosphere concentration of carbon dioxide is 96%. Also it's clouds are sulfuric acid- don't go there.

Now, the mechanism for carbon dioxide as a greenhouse gas has been establish. Some cases of  how greenhouse gases can manipulated their environment have been shown. All that is still required is evidence that this effect is happening now.

Figure 4. Fluctuations in temperature and atmospheric concentration of carbon dioxide over the past 649,000 years.

Figure 4. shows a clear correlation between carbon dioxide concentration and the temperature of Antarctica. We can assume that the Antarctic temperature is representative of the average global temperature. While, it is foolish to assume the correlation implies causation, I have already provided an accurate mechanism for the causation to occur, explaining the correlation. Unfortunately, though, this view skews the impact of man made carbon dioxide from the industrial revolution- could we zoom in?

Figure 5. Global Average Temperature vs Carbon Dioxide Concentration since 1880

Oh. Actually- that's kind of scary. Let's not look at that.


Skepticism is a critical part of the scientific process. There is a time and a place for it. It is necessary. It is not reasonable to be skeptical of something that has a broad consensus of agreement without substantial evidence to the contrary. Period. 97% of climate scientists are in agreement. The AAAS, ACS, APS, AMS, and AGU are in agreement along with other scientific societies. So please, skeptics, where is your evidence to the contrary?

Please, anyone skeptical, this is your time to shine. I will be addressing skeptical claims next time (after a minor intermission) and I would love your take on AGW. Otherwise I'll be going off of vocal skeptics in the media and it will be less fun. Anyone wanting to play devil's advocate to my argument is also welcomed to do so.

My argument borrows several facts presented in the fantastic textbook Chemistry in Context which describes the chemistry behind many everyday phenomena. Eubanks, Lucy Pryde. "3: The Chemistry of Global Warming." Chemistry in Context: Applying Chemistry to Society. New York: McGraw-Hill Higher Education, 2009. N. pag. Print.

*The moon's surface is more reflective than Earth's, so it would be a little colder.

Response to Creationists

So a couple of weeks ago, Bill Nye the Science Guy debated the CEO of the Creationist Museum, Ken Ham. There was a lot of interest in this event, and the website buzzfeed hosted these 22 images of creationists' questions for the Science Guy (you may want to keep that site open as I don't quote the questions when addressing them). These questions were rather elementary, so I tried to answer them as best I could. This is from a facebook post I made so it's not the most detailed explanation, but I consider most answers complete. Answers I give with a "*" have been altered from the original post on my facebook which I made before viewing the debate.

If anyone expresses interest I can update this with more details about the questions, their answers, or my overall impressions of the debate (which I thought was interesting on multiple levels), but really I just wanted to post something to hold people over while I prepare a multi-part topic on AGW, skepticism, and the effects of climate change to be published later this week when I have more time. So without further ado :

1) Yes, teaching science is essential, but I'm glad you're concerned for your children.

2) Evolution does not discount a creator, just his intervention post creation of the universe.

3) Pretty much, yes. *While you could jump through some hoops to make this situation logically consistent, it gives one no ability to make predictions of the future, and as such is less useful a world view as the one enriched by scientific knowledge.

4)Entropy in no way disproves evolution.

5)This would be the only question I'd like if your grammar was correct, but it would be sad if we could only find beauty in the world if it was specifically created for us.

6) They don't. Why should I believe you understand any thermodynamics if you can't grasp evolution which is MUCH more simple a theory.

7)What about Noetics? *Someone pointed out she may be talking about consciousness, and if there is room belief when thinking of the origin of thought. There is, but science is also examining neuroscience at a rapid pace, and there is much we know from its lessons. 

8)There is no such thing as an objective meaning of life. That's part of the meaning of life dude, we all get different experiences and treasures.

9) Not by chance alone, but also by favor. Before single cell life their was "life" consisting of proteins, ribozymes and other stuff, but they found they could do better together. 

10) Questions end with one of these "?".

11)Because Aliens could be observable whereas God by your definition cannot be. *Also it is not accepted scientific theory that we are descended from alien intervention, just a hypothesis.

12) If you're resting your entire argument for the existence of God on the gaps in the fossil record you are going to have increasingly less ground to stand on. The gaps get filled it.
13) Uhh, I guess.

14) Scientific theory means our best idea supported by evidence.

15) That is the opposite definition of science, what are you doing?

16) I'm guessing you have no idea what you're talking about, but it is called an insertion mutation and it is common. *I hope to do a post about David Liu's PACE experiment, which uses evolutionary methods to create new functions in bacteria proteins. Unfortunately, I have to wait for the buff state library to break the pay-wall first

17)I personally think i'm here to learn and grow and explore, but to each his own.

18)Because Lucy was an individual so there is only one of her, and she's from a rare period, but there are other proto-human examples out there. *I assumed this guy knew what he was talking about and that there was only one member of Lucy's species discovered. There are multiple. Which leads me to my next point, never assume a fool you're arguing with is correct only because you are too lazy to research if he is wrong; he probably is.

19)You can believe in the big bang with or without faith, it was first proposed by a priest, you goose.

20)Same as five. I personally think it would be more amazing if this world was not specifically created for us but was still capable of making us awed. *but that opinion has ultimately no say on the presence of a creator.  

21) It wasn't a star but a singularity of all matter and energy(*and time and space*). We don't know (*what caused it*), from God to a collision of universe-membranes, we just don't know. 

22) We didn't come from today's monkeys. We share a common ancestor with monkeys that lived about 25 million years ago.

Thanks for your questions, Per aspera ad astra.

It was the best of times it was the blurst of times.

The internet is currently in one of its weirder moments. Someone had the brilliant idea to take the text output from a chat room conversation, and program it into the controller input for a Gameboy emulator. Then all they needed to do was to set up a video to stream the game, and presto: you have a chatroom of people playing the Pokemon. And they're not playing their own separate instances of the game- no, everyone is controlling the same character, Red, as he battles across the world. This may end up being a novel phenomenon in the history of the internet and forgotten in a matter of weeks, but I have a hunch it may be remembered as one of the tube's more bizarre social experiments.

As I write this, over 75,00 people are in the Twitch Plays Pokemon chat room, most typing "up" "left" "a" "b" "start" into the chat to control Red. There is about a thirty second delay before any one person's input manages to reach the game, past the long queue of processing previous commands by other players across the planet. Thus, Red isn't very direct in his actions. He bumbles over the map in what can only be likened to an extremely drunken stupor- meandering every which way, dropping things everywhere, and endlessly repeating the same conversation with strangers. Watching the game can become aggravating if you are expecting anything significant to happen in the near future. Yet, somehow, after nearly seven days of continuous game time, the internet has managed to make significant progress through the game's story.



This journey has not been without its trials though. Due to the nearly random actions of the protagonist, skill and strategy have been thrown out the window. The starter Pokemon (a charmander named ABBBBBBK or Abby)- usually one of your strongest team members- was rendered almost immediately useless after learning a terrible move list of supporting techniques. Catching Pokemon- a task which requires a bit of planning and luck on a good day- became nearly impossible after the first few areas; so the remainder of the team was made up of the a pidgey and rattata, for the first few days. If you've never played pokemon, these are the equivalent of a pigeon and a rat and are not very exciting or strong, but they would end up becoming notorious in spite of that.

Pokemon battles which are the core challenge in the game traditionally have taken a backseat in cooperative Pokemon to the much more difficult task of walking a straight line. There is a route (9) in the game that takes about 30 seconds to cross if you know what your doing. However, there is a ledge in the middle of this path, and if you happen to walk one space too far, you will fall of the ledge and have to start over. It took over six hours for the internet to cross this route . Another difficulty unique to cooperative Pokemon is the simple action of cutting down a tree. For those who have never played, there are certain trees in the game which must be cut down by a Pokemon in order to progress further in the game. This requires a concerted action of walking to the tree and facing it, opening the menu, opening the Pokemon screen, picking the correct Pokemon and choosing to use the cut technique. It took three hours to cut a tree before the fourth badge. People joked that that tree was the hardest boss in the game. But, that was before Team Rocket's game corner.

Team Rocket's game corner has a maze in the basement. This maze consists of several tiles on the floor that, once stepped on, move the character in the certain direction. The maze isn't extraordinarily complicated, but there is only one path through and many wrong turns. The internet was stuck in this maze for over a full day. Many people had made strategies for tackling the maze, with specific commands to type depending on Red's location, but no progress was being made. In the end, the steamer intervened and introduced an additional game feature called democracy. If enough users voted for "democracy" by typing it in the chat, then Red's actions would change and instead be directed by the most popular command voted, over a 30 second period. Conversely, you could vote for "anarchy" to change the game back to it's initial state. Many people protested this alteration to the games mechanics feeling that it damaged the significance of their achievement so far. In order to stall the game from proceeding further under the democracy conditions, many users entered the command "start9" which would pause the game multiple times, interrupting any progress. The game is currently still using this democracy vs anarchy voting structure, though anarchy tends to be in effect.


A micro-culture has developed around the game due to the popularity of Pokemon and the nostalgia of playing through the original game. Fan-art and memes have been created regularly through the journey, and much of the fan-art can be found on the subreddit /r/twitchplayspokemon The biggest meme has been the rise of the helix fossil. This item is 99% useless in the game, but because it is useless it sticks around in the player's inventory, while useful items get used up in the chaos. It been one of the few items in Red's possession for nearly the entire game*, and it gets used often triggering the computer response, "This isn't the time to use that, Red!". Many viewers have imagined Red is turning to the helix fossil for guidance at these points. So "Praise Helix" and other testaments to the helix fossil as a deity can be found. Conversely, and for reasons I don't begin to understand, the S. S. ticket, another of the games more useless items, has been labeled a false idol, and it's followers as heretics.

There is a whole history of events that have happened along the way; every Pokemon in Red possession has developed a unique nickname because of this. Pidgeot (our thankfully evolved pidgey) has become the strongest Pokemon on the team and the backbone for gym battles, defeating Erika single-handedly. He's now known as Bird Jesus. The first rattata that was caught was named  JLVWNNOOOO or Jay Leno and many mourn his accidental release. Another rattata learned the move dig, which can be used outside of a battle to return you to the last city you visited. This happened on accident way too often so -Digrat. Eevee/flareon became known as the false prophet of the dome fossil- which has a very detailed explanation, but I don't want to open that can of worms so I just encourage you to look it up if you're interested.


For me though, the most interesting part of this experiment is not the random nature of the game-play, but how the character has somehow remained focused through the game. There is currently a simulation going, inspired by this setup, to run pokemon using a random input from a random number generator. The results are wildly different from those in cooperative pokemon. Cooperative pokemon has made much more progress. The intention of the many people collaborating experiences some interference, but it still comes through. You could probably just chalk it up to the average input still having a clear intention being dicussed by the players, in much the same way the democracy function allows for even less interference. But, to me, it still seems a little spooky, like the ghost in the machine or something. (I secretly think that one day the internet will become wake up and become an AI. Maybe, it will thank us for making one of it's first memories playing Pokemon.)

*The helix fossil was twice accidentally deposited in the PC. Using the PC presents unqiue challenges to cooperative Pokemon which you will discover if you read about eevee. But due to the signficance of the fossil to the players, twice it was rescued from the PC.
(Also, I really wanted to add photos, but I don't know how to deal with copyright business till next week; so you'll just have to make due till then)

Mission Statement

I guess a mission statement is a good way to get started. Remember for a moment the wonder you experienced when you first watched Cosmos (What? You haven't seen Cosmos! Go find it right now on hulu plus, or free clips here) Carl Sagan may have been the preeminent science professor of the 20th century. His words inspired Bill Nye the Science Guy, viewers across the country, and possibly even space aliens (a golden record is currently hurtling through interstellar space on the Voyager I containing Carl's ideas). I'd like to think of this blog as containing the same wondering inquisitive nature as Mr. Sagan (granted, after a night of heavy drinking- I'm no astrophysicist). Stay tuned for news and thoughts in science, thoroughly digested, and written for non-scientists. Per aspera as astra.