Paul Krugman, the Nobel Prize-winning economist, had an op-ed in Monday's New York Times in which he called anyone who's skeptical of man-made global warming a “traitor to the Earth.”

Now, I don’t have a PhD in Economics (although I do have one in another field), nor do I have a Nobel Prize, but that accusation seems a bit over the top. Perhaps it's just another example of the growing societal acrimony frequently discussed on Minyanville.

I'd like to take a look at the evidence for global warming resulting from increased CO2 levels in the atmosphere: The argument is that more infrared radiation released by the Earth is captured given the higher concentration of CO2 in the air, thereby warming the planet. However, if you're looking for scientifically rigorous experiments linking CO2  to increased temperatures, I have bad news for you: It doesn’t exist.

What we have are computer models showing that increased CO2 levels will lead to catastrophic increases in global temperatures; an increase of as little as 10 degrees Fahrenheit will cause a lot of ice will melt, the sea level to rise, and Newfoundland to resemble Bermuda.

But that’s the model talking.

Can any model accurately capture the complexities of the Earth's atmosphere? There are certainly many sophisticated ones out there. Happily, most of them use actual physical experiments to verify their underlying assumptions. However, until the “Flux Capacitor” from Back to the Future gets built, any climate model will need decades to verify its assumptions using real data.

Climate simply refers to one day of weather after another. Global-warming true believers, let me ask you the following question: Do you view weather forecast projections for 2 weeks from today with the same certainty that you do a computer model that purports to predict the weather 100 years from now? If not, why not? After all, they're both based on computer models.

If your neighbor told you he were getting a tent for his daughter’s wedding reception 2 weeks from now, and you told him not to bother, because a computer model predicted sunny weather, do you think he'd take you seriously?

The key to good science -- not good politics -- is understanding the scientific method. Richard Feynmann, the Nobel Prize-winning physicist, put it this way: “It doesn't matter how beautiful your theory is; it doesn't matter how smart you are. If it doesn't agree with experiment, it's wrong.”