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Global Warming: The Basics

Posted: March 8, 2013 at 3:00 pm   /   by

I was recently having a conversation with a friend when talk rambled onto the subject of global warming.  When I was dismissive of the idea, she asked “ you think Global Warming is a hoax?”  She wasn’t being snarky, she was genuinely surprised to hear me explain why I don’t buy into all the hysteria, or the admonitions that if we don’t all drastically cut back on our carbon-footprint, we are all doomed.

Sometimes I have to remember not everyone is such a wonk as me.  Not everyone is interested enough, or has the time or the background to take a critical, serious look at the science behind the theory of anthropogenic, or human-caused, global warming.  So with that in mind, here is a quick rundown of some of the basic theory, but at the end of it all there are really only two numbers you need to remember: .003 and .03.  With those two numbers, you should be able to explain to any of your friends or family why they should be skeptical of Global Warming.

What exactly is the theory of Global Warming? – The term Global Warming has become a convenient short-hand reference to the theory of Anthropogenic Global Warming (AGW) or that human activity is causing a change to the climate which if left unchecked will disrupt weather patterns, with disastrous results.  It is used somewhat interchangeably with Climate Change, which still refers to human activity.  The theory claims that due to the rise in industrial activity beginning in about 1850, humans have been emitting ever greater amounts of carbon dioxide (CO2) into the atmosphere, and this is causing the planet to get warmer.  They claim in fact that it is now much warmer than it has ever been, at least for the past 100 thousand years or so, and that this rise in temperature is due to human activity.

It’s All about the Carbon – The most important thing to remember about this theory is that it all revolves around CO2.  The operative part of the theory is that CO2 acts as some super-duper greenhouse gas, and has an enormous impact upon the amount of heat retained by our planet.  Nobody disputes that CO2 is a greenhouse gas, and can cause a retention of heat.  CO2 is also a Trace Gas, meaning there is only an extremely tiny amount of it present in our atmosphere.  In fact the amount of CO2 present is only about .003, or three-tenths of one percent.  Representing three tenths of a percent in a pie chart, the line is almost too small to see:


Another way to visualize it: if the entire atmosphere of our planet were represented by a stack of 1,000 blocks, the total content of CO2 would amount to only three of those blocks.  The other thing that is sometimes easy to forget is that there is a fixed amount of CO2 on our planet.  Except for an unimaginably small amount lost over time through outgassing, we have exactly the same amount of CO2 now as we had when the dinosaurs were stomping around.  No more is magically created, and it doesn’t come here from outer space.  Human activity doesn’t “make more CO2.”  The last important thing to know about CO2 for now is that when you hear people talking about carbon or CO2 emissions, what they are talking about is taking CO2 that already exists someplace, and emitting it into the atmosphere.  CO2 is constantly being emitted by natural processes.  Decaying plant and animal matter, volcanoes, and outgassing from the ocean all emit CO2.  In fact, natural processes emit vastly more CO2 every year than all human activity combined.  Humans emit approximately six to seven gigatons of CO2 each year, according to some estimates.  Natural processes emit more than thirty times as much.  In other words, the human contribution is about .03 or three percent..

So far everything I’ve talked about regarding CO2 is not in debate.  These are just the basic facts, and not even the people who believe in AGW theory argue with any of this.  Where disagreement begins is the central, most important assertion of AGW theory: CO2 acts as a “super” greenhouse gas, wielding an enormous effect on the climate through its extraordinary heat retention properties.  This is vitally important to the theory because there is such a tiny amount of CO2 present in the atmosphere.  There is so little of it present, it MUST have truly prodigious heat retention properties, otherwise its effect on the climate would be in proportion to its presence in the atmosphere.  This next thing I’m going to say is very important:

There is no scientific evidence supporting the assertion that CO2 has any such “super” greenhouse properties.  None.

That is correct.  It has never been demonstrated, either in laboratory experiments, or in nature, that CO2 has the ability to cause any change in global temperature through increasing its presence in the atmosphere in the miniscule amounts generated by human activity.  Remember how little CO2 there is in the atmosphere?  The amount of increase in atmospheric CO2 theorized to have accumulated over the past 100 years is .0001%  In other words, we have gone from approximately .03% to .031%, at least in theory.  Supposedly, this tiny increase is going to cause ocean levels to rise catastrophically, massive species extinction, enormous tracts of agriculturally productive land to be ruined—in short, utter devastation.

It all comes down to two (very!) little numbers.  In order for AGW theory to be true, you must believe that the 3% humans contribute to the total annual emissions of CO2 can substantially increase the .03% of CO2 present in the atmosphere, and that this miniscule increase is capable of catastrophic effects.