Scientists have recorded that the ozone hole above Antarctica, where UV from the Sun pass through the stratosphere without problems, has decreased to a record small size in the entire history of observations of it, since 1982.
Decades of observations made it possible to fix the pattern: closer to winter, this hole in the ozone layer increases up to 20 million square kilometers. So you can understand about the danger of scale: its size is larger than the whole of Russia.
Paul Newman, chief earth science scientist at the NASA Goddard Space Flight Center in Greenbelt, Maryland, explained this phenomenon by global warming. It’s funny that one of the most urgent threats to our planet partially dealt with another danger – the ozone hole.
“Warming – great news for the southern hemisphere, because ozone is more, and UV level is below” said Paul Newman, live on the Science Channel.
Why does warming positively affect the amount of ozone in the stratosphere, and why does the ozone hole expand by winter?
The fact is that with the arrival of winter in the southern hemisphere at an altitude of 10 to 50 kilometers above the Earth began to form clouds. Further sunlight splits chlorine gas chlorine atoms, these atoms then begin to destroy ozone molecules. Because of this, the ozone hole over Antarctica tend to expand in the winter months.
It is because of the warming polar stratospheric clouds to dissipate much faster than it was a few years ago. The fewer clouds in the stratosphere – the less the chemical reactions occur with them, thus decreasing the degree of destruction of the ozone layer.
Gaseous chlorine, ozone layer mainly comes from chlorofluorocarbons (CFCs), which were produced before the ban in the US since 1996 year. Despite this, some types of CFCs can remain in the atmosphere for over 100 years, Newman said.
However, does this mean that greenhouse gases in the atmosphere that trigger global warming, on the contrary useful to us? Not at all: carbon dioxide on the contrary lead to a cooling of the stratosphere, thus increasing the number of clouds and what happens next you already know.