Remember the ozone layer?

That thin shell of O3 that forms in the stratosphere, that absorbs a lot of the more energetic radiation from our warm, friendly star, and helps keep all the DNA healthy?

Well, we were lucky with the (apparent) damage or decay, or destruction of this layer, by the now well-characterised low-temperature chemistry (ice-crystals in polar regions) that removes ozone preferentially; we know that halogens like Cl and F, attached to hydrocarbons, act as catalytic converters in polar cloud formations in the stratosphere. This chemistry was predicted as early as 1960-something, but it took another 25 or so years for the inertia to happen, the protests from the industrial conglomerates to die away, the scientific surveys, someone noticing that satellite data had been collected (but ignored) for many years, and so on.

What many people (who probably don't think ozone is a big deal any more, or think: "we've been there, done that") don't probably know about, is just how close we came to really screwing things up, up there in the upper atmosphere; just how delicately some things are balanced in nature (which has had a lot longer to settle into the regular, repetitive patterns and interactions we see).

If instead of Chlorine, Bromine had been used to make refrigerants, and we had let them go for decades (say 50 or 60 years worth of pollution that accumulates in the atmosphere), then there wouldn't be anything much we now could do to save the ozone layer. We would now be looking down the barrel of major extinctions and global UV mutations of DNA, not to mention skin cancers, and the ozone layer would be mostly gone.

Restoring it would not be a 'simple' matter of legislating against the production of more BFCs (bromoflourocarbons). Even by stopping the further accumulation, after say 50 years, there would still be a few tens of thousands of years to go (maybe a factor of ten more) before it got back to where it was.

It's recovering slowly today, but there are still CFCs around, there are still chemical plants making this shit, and it's still being used. There's a black market of course.

Personally I think it was caused by that U.S air nuke "test". Fucking retarded, then and now. It is recovering then?

From The British Antarctic Survey: www.antarctica.ac.uk/met/jds/ozone/ (http://www.antarctica.ac.uk/met/jds/ozone/)
Situation at 2008 July 17

The temperature of the ozone layer is coldest over Antarctica and warmest in the circum-polar region. It is cold enough for polar stratospheric clouds (PSCs) to form over Antarctica and they have been seen from Rothera on several occasions. Temperatures are slowly dropping further as winter progresses. Ozone values are above 350 DU in parts of the circum-polar regions as the circum-polar vortex builds, dropping to below 250 DU towards the pole and equator. Some ozone depletion is already taking place as the polar vortex changes shape and the stratospheric clouds are exposed to sunlight. Ozone values are dropping at Rothera.

See the final situation report for last year for information on the 2007 - 2008 season.

Notes: The Antarctic ozone hole is usually largest in early September and deepest in late September to early October. September 16 is world ozone day. 2007 was the International Year of the Ozone Layer. Prior to the formation of ozone holes, Antarctic ozone values were normally at their lowest in the autumn (ie March).
And
The Antarctic ozone hole is expected to continue for decades. Ozone concentrations in the lower stratosphere over Antarctica will increase by 5%–10% by 2020 and return to pre-1980 levels by about 2060–2075, 10–25 years later than predicted in earlier assessments. This is because of revised estimates of atmospheric concentrations of Ozone Depleting Substances — and a larger predicted future usage in developing countries. Another factor which may aggravate ozone depletion is the draw-down of nitrogen oxides from above the stratosphere due to changing wind patternsen.wikipedia.org/Ozone depletion (http://en.wikipedia.org/wiki/Ozone_depletion#Ozone_depletion_and_global_warming )

I always find it amusing when people say that the Ozone hole was a conspiracy engineered by Du-Pont.

Mostly because I live in a Southern Hemisphere country that gets whooped by the Ozone hole on a semi regular basis, and has the highest skin cancer rates in the world.

And still I advocate moderation rather then phobia, because Vitamin-D deficiency is being provisionally connected with things such as rising rates of Mutliple Sclerosis.

trippy where you from?

As far as i know its Australia with the highest level of skin cancer and vitamin D is not a huge issue here. As long as you go out occasionally in the late afternoon or early morning in summer and go out in winter you will produce enough Vitamin D (you do realise that its misslabled as a vitamin? its not really, its a hormone).

New Zealand.

And no, for the most part, Vitamin D deficiency is not as much of a problem down here as it is to those Northern Hemisphere types, but then, they get less UV during the summer then we do on account of the shape of the earths orbit.

And as I said, I advocate moderation (which is what you're describing) rather then phobia and stupidity - which are the two extremes that most people seem to migrate to.

Then again, my wife has a very english complexion, it takes her very little time to burn, so for her moderation isn't enough, she actually has to take suppliments.