I remember in Chemistry class being taught that Ozone (O3) was formed in the upper atmosphere by Cosmic Rays1 , Ultraviolet Light, or Alpha Particles from the Sun, bumping into Oxygen molecules (O2) according to the equation 3O2⇋ 2O3, a reversible reaction.
Reactive and unstable, Ozone decays pretty soon, back into O2 or an oxide of Nitrogen (NOx), there being plenty of Nitrogen around up there.
So imagine my surprise when I learned that in America Ozone is believed to come from automobile exhaust pipes in places like Los Angeles.
When, in the ‘80s a sharp eyed New York Times reporter first spotted the ‘Ozone Hole’ lurking over Patagonia in late October, I was curious. When, every year thereafter, the ‘Ozone Hole’ reappeared at the same time and place as reported in the NYT, I became suspicious.
Now it was common knowledge among my classmates that our schoolmasters were Neanderthals, nevertheless to avoid being caned we paid attention, (A.D.D. having not yet been invented). We also knew from paying attention that the Antarctic, being a continent, was 30o C, or more, colder than the Arctic which is an ocean.
With no sunlight for six months there are no ‘Cosmic Rays’ to generate fresh ozone over Antarctica. In addition the cold dense polar air mass descends over the South Pole and heads North in every direction creating the hurricane force katabatic winds. The Earth’s rotation or Coriolis effect, take your pick, gives the Northbound wind an Easterly kick and voila! the South Polar vortex is born, giving rise to the roaring forties, or screaming fifties depending how far south you go. All of this sucks more of the remaining ozone out of the upper atmosphere.
When in September, spring in the antipodes, the Sun pops its smiling face over the horizon to warm things up, relatively speaking, again the polar vortex weakens and the ozone depleted winter air mass spirals Northward to show up in Patagonia on cue for the annual October/November Ozone hole spotting!
To panic about the disappearing ‘ozone hole’, our shield against cancer causing UV radiation, seems strange given that UV radiation is absorbed in the process by creating the Ozone layer.
The energy needed to create the highly reactive Ozone molecule from the standard O2 Oxygen molecule reduces the high energy UV to a lower energy state with a corresponding longer and less harmful wavelength.(according to the formula E= H/λ, where E is ‘Energy’, λ is wavelength ( lambda) and H is Plank’s constant).
Other things too are going on in the upper atmosphere where most of the Sun’s damaging UV radiation is absorbed, among them the creation of Carbon 14 (the radioactive isotope of the normal Carbon 12) which is used to determine the age of fossils.
Since most (79%) of the atmosphere is Nitrogen (N2), these energetic little solar bullets bump into a lot of Nitrogen molecules in their hunt for the scarcer (20%) Oxygens to bump up into Ozones. When this happens, the hapless Nitrogen can lose a proton in its nucleus and miraculously absorbs an electron to become a neutron bringing its atomic number (protons in its nucleus) down from 7 to 6. Thus emasculated, our Nitrogen takes on the chemical characteristics of an overweight Carbon atom, a sort of nuclear transgenderification.
So modified, our freshly minted Carbon 14 sets out in search of a comely Oxygen molecule in the high energy stratospheric discos of Auroras – Borealis and Australis. After a successful high altitude courtship our newly mated CO2 couple settles out of the rarified air, dragged down by gravity and reality from the stratosphere to the lower troposphere. There, lured by the seductive sirens of house and home, they succumb to the Bankers and Realtors of water and photosynthesis and settle in eternal connubial bliss in their chosen cellulose molecule.
And that my friend is why they call it Carbon Dating.