Last weekend I took a whirlwind trip to Chicago. While there I visited the Museum of Science and Industry. It’s an amazing place, with full-sized airplanes, a full-sized combine, a full-sized train engine, and an entire German U-boat, the first U-boat ever captured.
But for me, the highlight was taking a tour through a replica of an old coal mine.
After descending "deep into the bowels of the earth," we were given a safety talk. The tour guide pointed to a tiny birdcage which, in one of those old-time mines, would have housed a canary.
As long as the canary continued to sing, the miners knew that carbon dioxide (CO2), carbon monoxide (CO), and methane (CH4) levels were safe. Canaries have very small lungs that are more quickly affected by these gases than human lungs.
If the canary stopped singing, the miners knew to skedaddle.
Too much CO would poison the miners, too much methane would explode, and too much CO2 would suffocate them.* (Carbon monoxide is far more lethal than CO2.)
The deeper into the ground the miners dug, the more dangerous it became, because these gases – which are heavier than air - have a tendency to accumulate at the bottoms of coal mines.
Lest you missed that, let me say it in a different way.
CO2 is heavier than air.
Isn’t CO2 supposed to be rising high into the sky and creating the greenhouse effect and therefore causing global warming? Isn’t CO2 supposed to be a thin layer of invisible gas lurking somewhere a hundred or so miles up in the sky, reflecting heat back onto our planet?
How in the world can CO2 be rising into the sky and creating the greenhouse effect if it’s heavier than air? Isn’t it more likely to be accumulating down around my feet?
“CO2 most certainly does not form some sort of magical layer in the atmosphere that then acts like a greenhouse,” says analytical chemist Hans Schreuder. “That is pure pseudo-science!”
Do you suppose, just maybe, that we’re not getting the full story?
Listen to the canary. If the canary is still
singing, we’re okay.
P.S. I’d love to hear from some underground miners on this.
British coal mines began phasing
out the canary in favor of electronic
detectors in 1986. Miners were said to be saddened by the decision,
because they often whistled to the birds and coaxed them as they
worked, treating them as pets.
See: 1986: Coal mine canaries made redundant
Thanks to Hans Schreuder for this link
* Current levels
of CO2 are said to be 385 ppm (parts per million).
Here is what wikipedia says about levels and their effect.
"CO2 is toxic in higher concentrations: 1% (10,000 ppm) will
make some people feel drowsy. Concentrations of 7% to
10% cause dizziness, headache, visual and hearing dysfunction,
and unconsciousness within a few minutes to an hour.
Notice this is at levels up to 70,000 and 100,000 ppm.