From climate deniers, there is one iron (as they think) argument, saying, remember the story with the ozone layer — have fanned the hype with freon, switched to production of other refrigerants, someone to make money, and then about ozone safely forgotten. So global warming is exactly the same, this game is unfair dealers trying to cash in on the warming hands.
The paradox of this argument is that in reality it was exactly the opposite. The story of the Montreal Protocol is an example of what humanity is capable of successfully taken separately to solve global problems.
Chlorine, ozone eater
In the early 1970-ies, the chemists Frank Sherwood Rowland and Mario Molina became interested in the fate of the chlorofluorocarbons (CFCs) in the atmosphere. Original they were going to use these inert and because of long-lived gases for the study of atmospheric circulation. Scientists have suggested that sooner or later these substances into the stratosphere, where their lives may be 40-150 years, and where they are gradually decomposed by ultraviolet light and chlorine is formed. They were also well-known works of Paul Crutzen and Harold Johnston, which around the same time studied the decomposition of ozone in the atmosphere by reaction with nitrogen oxides.
Rowland and Molina realized that chlorine with ozone may behave similarly and 28 June 1974 published short, only 2 pages, article in the journal Nature that human-produced CFCs can destroy the ozone layer. One of the most unpleasant conclusions of the article was the fact that in these reactions, chlorine acts as a catalyst: that is, one atom of chlorine can “kill” a lot of ozone molecules.
Why is the ozone the planet
Ozone is an unstable form of oxygen with the chemical formula O3.
Discovered it in the eighteenth century by the characteristic smell, but described only in the XIX-m. Ozone is formed from oxygen, but the reaction needs a lot of energy — so in nature ozone occurs when lightning discharges or under the influence of short-wave solar radiation, ultraviolet.
Ozone is a powerful oxidizer, effectively decomposes organic matter, and this property is successfully used for disinfection. But that does it for us, people, poisonous gas. Lethal concentration of the ozone — only 4,8 ppm (parts per million, i.e. 4.8 of the ozone molecule per 1 million air molecules). Fortunately, we recognize ozone in the air by smell long before he will be dangerous. (Don’t forget that when you use a home ozonator to breathe in that “smell of rain” we don’t have to leave the room!)
In the troposphere ozone is therefore considered a pollutant.
But the most part of atmospheric ozone is in the stratosphere: the highest concentration at the altitude of 20-25 km can reach 2-8 ppm, obrazujas there from oxygen under the action of sunlight — this is the “ozone layer”. Here ozone performs a very important function — it absorbs solar radiation in the hard ultraviolet range (UV-b, 280-315 nm), which, reaching the Earth’s surface, it is extremely dangerous to humans (causes skin cancer and cataracts), plants, and marine phytoplankton.
The ozone shield formed on our planet about a billion years ago when photosynthetic bacteria arranged on the Ground “the oxygen revolution”, after which life was able to get out of the sea onto land.
The screen is very thin: if you collect all the ozone of the atmosphere near the Earth’s surface and compressed to normal pressure, you get a layer with a thickness of only about 3 millimeters, which corresponds to 300 Dobson units (DE), which is generally measured content of the gas.