Nick said:
"Nature abhors a vacuum"

J-- The word vacuum refers to a condition of space, and mass combination, the greater the amount of space that is lacking in mass at a localized area, the greater the vacuum within that area. (Mentioned just in case you were not aware of that fact.)

Nick-- "If the atmospheric pressure scaled with the ozone then there would be a spectacular vortex sucking into the antarctic winter."

J-- You mean something like the vortex or fountain that is sucking the atmosphere into space from the poles of the planet, as explained at this site:

http://science.nasa.gov/newhome/headlines/ast09dec97_3.htm

Or are you thinking of a more profound event?

Nick-- "it happens on Mars, because there the atmosphere itself freezes in the winter. On Earth it doesn't and can't.

J-- I suspect that the freezing of the atmosphere can't happen on Earth because the thermosphere is hot from the nuclear excitations introduced there by humans. At least that is my guess.
What is your explanation of the reason that the Earth has a thermosphere and the planets Venus and Mars do not?

Nick-- "While you're at it, can you explain why an Antarctic ozone depletion is caused by mid-lattitude and northern hemisphere nuclear plants?"

As I understand it, the ozone has been depleting from the northern hemisphere also.
As you pointed out, a vortex at the poles can suck (radioactive) atmosphere from mid-latitudes, and there IS a vacuum or a vortex/fountain (see the above link) at the poles that can suck the radioactive atmosphere from the mid-latitudes.

Nick-- "If not, please remedy the vacuum that appears to be between your ears..."

As explained above a vacuum is related to the amount of space available, in other words, IF there is a vacuum between my ears, then it means that more information can still be placed in there, where as, the space between YOUR ears must be very DENSE, since it can not absorb any new information.

Johannes