When did the Ozone hole appear?

[Epidemic]

When was the ozone hole discovered?

When did the Ozone hole begin?

How many times through out earths history has the ozone had holes over the south pole?

It may be a real problem but it appears as if we discovered the hole bout 20 to 25 years ago. I also think that caution might well be the most prudent course of action but,,,, did we make the hole in the ozone or is it a naturally occurring phenom.

Unless I missed something the theory that we caused the hole is not a fact but speculation as to one possible cause.

[J-Excel]

[Epidemic]

I have not seen anything in google which would indicate theories on ozones history prior to the hole being found.

I was enlisting the help of the combined mind power of techimo collective mind.

[J-Excel]

Just yanking your chain. Honestly I don't know.

[Epidemic]

Don't yank my chain. Shahani has practically broken it

[SiliconJon]

http://www.factmonster.com/ipka/A0769077.html

http://www.google.com/search?hl=en&l...timeline+earth

http://www.nasa.gov/lb/missions/earth/scisat.html

http://www.dailypast.com/nature/ozone-hole.shtml

[Epidemic]

That is nice silicon, thanks for the links.

but my point is that these events of finding the holes does not prove that these are not naturally occuring events.

I am interested in the explaination of why the holes were attributed to human intervention.

I mean when we discovered electricity we did not say that humans were the cause. Or when we first saw found dinosaur bones we did not say we killed em off.

Why is the hole in the ozone considered to be human in origin.

[SiliconJon]

We can only state as much factual information as we have observed or discovered, which isn't a pin prick in the history of the earth.

Much of it is theory, which may or may not be supported through calculations and observations. But even when calculations are "proven" correct and theories become accepted, further discoveries down the line can blow them out of the water.

Ask our government to change some of that 50% of our discretionary spending from military to science, and you'll be amazed at the progress we could make...

[osprey4]

Originally posted by Epidemic
Why is the hole in the ozone considered to be human in origin.

The central feature of this unusual chemistry is that the chlorine reservoir species HCl and ClONO2 (and their bromine counterparts) are converted into more active forms of chlorine on the surface of the polar stratospheric clouds. The most important reactions in the destruction of ozone are:

HCl + ClONO2 -> HNO3 + Cl2 (1)
ClONO2 + H2O -> HNO3 + HOCl (2)
HCl + HOCl -> H2O + Cl2 (3)
N2O5 + HCl -> HNO3 + ClONO (4)
N2O5 + H2O -> 2 HNO3 (5)

It's important to appreciate that these reactions can only take place on the surface of polar stratospheric clouds, and they are very fast. This is why the ozone hole was such as surprise. Heterogeneous reactions (those that occur on surfaces) were neglected in atmospheric chemistry (at least in the stratosphere) before the ozone hole was discovered. Another ingredient then, is these heterogeneous reactions which allow reservoir species of chlorine and bromine to be rapidly converted to more active forms.

[daveleau]

Great image, JE. I'll be saving that one for later use.

While this site is not an all-encompasing authority, it is an interesting site to get some insight into the ozone hole: http://www.junkscience.com/ .