Here’s a vintage piece from Canada’s National Post, a long non sequitur that presumes to prove that CO2 is not threat – by calling it benign and by suggesting that there really isn’t that much of it around.

The case for CO2 being benign seems to be wrapped up in this statement: “We each expel it every time we exhale.” And that’s true, but I don’t see much merit in arguing for the safety of substances that the human body is designed to expel at its earliest convenience.

The case for there being only “a tiny amount” of CO2 in earth’s atmosphere is more than just silly, however. In Lorne Gunter’s flawed calculations, it is plain wrong – which we would have to blame on incompetence or dishonesty, take your pick.

Gunter says, “at most, 5% of carbon dioxide … comes from human sources.”

If he means five per cent per year, he should have said so – and then dealt with the problem of compounding interest. In fact, the most accurate measurement of CO2 in the atmosphere is currently about 380 parts per million, an increase of 36 per cent since the Industrial Revolution, when humans started pumping CO2 out of the ground and into the air.

Therefore, humans are responsible for about 26% of total CO2 in the atmosphere today (380 minus 280 divided by 380).

And CO2 is like water – benign up to a point. But when the best climate scientists in the world say that CO2 is now, officially, over our heads, it’s time to dismiss those whose phony arguments have nothing to do with science, or even garden variety common sense.

(With thanks to DeSmogger S Berg)