CO2 forest debate continues

Don Baccus dhogaza at
Wed Dec 23 12:06:02 EST 1998

In article <3680E984.34745F0C at>,
Joseph Zorzin  <redoak at> wrote:

>The increase in CO2 certainly may decrease the percent of the atmosphere
>that consists of O2, but why should that have anything to do with fires
>burning? Unless CO2 itself is a fire depressant.

Well, it is, but I don't know where Wheeler got his figures, I've never
heard that another 1% increase in CO2 percentage will snuff fires.

CO2 has been used traditionally in fire extinguishment systems, it works
by displacing O2.  In concentrations high enough to snuff fires it can
also snuff people, which is one major reason why Halon became popular.
Halon outreacts oxygen in a combustion scenario (though I don't know
the exact chemistry), and can snuff fires in a very low concentration
which allows you to breath just fine as there's still plenty of oxygen
around.  CO2 systems just shove all the air out of the way and replace
it with CO2 which is why you can't breath...


- Don Baccus, Portland OR <dhogaza at>
  Nature photos, on-line guides, at

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