Can a few parts per million really warm the Earth?

I know the Earth is getting warmer. I'll clarify how I know this at the end, but I get so aggravated by everything I read or see on this subject, both sides with a political spin, that it reminds me of something we are taught in med school: In God we trust, everyone else has to show data.

Anthropogenic (a good word -- it means caused by humans) global warming protagonists base most of their argument on the fact that humans are adding lots of carbon dioxide to the atmosphere by burning fossil fuels. The numbers are staggering: 26.6 billion tons of CO2 a year! CO2 can act as a blanket for the Earth, trapping heat energy and stopping it from being radiated back out into space. Such a big number, so I think, of course this hypothesis must be correct. Let's look more closely.

It turns out that the atmosphere is really pretty heavy. The range estimates I got off the Web are from 4.4 to 5.1 million billion tons (at 14.7 pounds per square inch at sea level). Our air is 78 percent nitrogen, 20.95 percent oxygen, 0.93 percent argon, and 0.038 percent CO2. The balance is mostly water vapor and trace gases. Pre-industrial CO2 levels as measured by analysis of ice core data show CO2 to have been around 0.027 percent. That means we have increased the CO2 content by 0.011 percent by burning oil and coal. Another way of saying this is that CO2 is present in the air at only 338 parts per million. Incredibly small.

My question is this: How can something present in such tiny amounts make a measurable difference in global temperature? There is 25 times as much argon in the air as CO2, and who ever heard of argon? It get even tougher to explain if you consider that CO2, as a molecule, has three basic quantum "spin states," and only one of these spin states acts as a greenhouse gas. It spends only 5 percent of the time in this spin state (or dipole moment). That means that 95 percent of the time CO2 doesn't even act as a greenhouse gas.

Let's do a thought experiment to picture how small an amount 338 parts per million really is. Right now the big river (Sacramento River in Redding, CA) is running at about 10,000 cubic feet per second (75,000 gallons). To get 338 parts per million I could pour 3.38 cubic feet of vodka off the Sundial Bridge and then bottle the water downstream and call it a martini! Or we can compare it to oxygen content at 209,500 parts per million. That's a lot more oxygen (and I sometimes wonder if I'm getting my share).

If it's not CO2, what could be responsible for the rising temperature? There are at least two elephants in the living room.

The amount of solar energy reaching the Earth on each cloudless day is 6,000 times greater than all the energy used by humans worldwide each day. In fact, the sum total energy released by all the fossil fuels burned since the industrial revolution is less than 30 cloudless days of sunshine. This makes me think that maybe the sun has something to do with it? Solar energy (insolation) varies by as much as 6.9 percent over one year due to sunspot and Milankovitch cycles, measured at the same latitude and longitude and same date year to year. Sunlight seems to be a more likely culprit than CO2.

The other elephant swinging its trunk is the slow cooker at the Earth's core. That radioactive molten iron spinning dynamo makes as much as 13 trillion watts of heat per second, and we're sitting on top of it. This heat reaches thermal equilibrium with our atmosphere, and because it's so difficult to study we know more about cosmology than we understand about the core of our planet. In addition, the magnetic field this dynamo generates is the primary reason our atmosphere doesn't just blow off into space.

So, what's my proof that the earth is warming? Easy. Last month I spent five days in a foreign country without a passport. When we stepped off the plane in Little Rock, Arkansas, it was 102 degrees and 90 percent humidity. And Southern hospitality is so warm that if I stood still for five minutes I had a new best friend. Those people are hot!

-Dr. Richard Malotky