What is the ozone layer?
The ozone layer, or rather, stratospheric ozone, is essentially the planet’s sunscreen. It consists of a thick layer of the naturally occurring ozone gas (O3, a molecule comprising of three oxygen atoms) near the stratosphere, a layer of the atmosphere located between 10 and 31 miles above sea level.
Its primary function is to absorb some of the sun’s harmful ultraviolet radiations. Without the protection of the ozone layer, humans will have a higher chance of developing skin cancer, immune problems, cataracts, and a variety of other medical conditions.
Occasionally, ozone layers also form near the surface of earth. This is usually called smog, and serves no significant function beyond reducing visibility.
The images above illustrate the thickness of the Earth's ozone layer on every January 27th on irregular intervals between 1982 to 2012. Image courtesy of NASA.
The case of the missing ozone layer
Compounds such as chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), halons and chloroforms, which once were popularly used as refrigerants, aerosols and solvents, are able to contain its molecular integrity long enough until they are floated by the wind to the stratosphere. Once they arrive there, they began to fall apart. The bromine and chlorine atoms contained in the compound then began to repeatedly react with ozone, sometimes as frequently as a 100,000 times. This will strip of the oxygen atoms from the ozone gas and ultimately, leave a tiny, miniscule gap in the ozone layer.
Once a sufficient number of compounds successfully manage to ‘attack’ ozone, the gap in the layer becomes visible. By the mid-1970s, a growing number of scientists began to notice the gap, or rather, hole in the ozone layer.
Not surprisingly, it took politicians well over a decade before they were eventually convinced of the severity of the problem – possibly because of the discovery of a massive hole in the ozone layer by the British Antarctic Survey team in 1985.
In 1987, the United States government organised the Montreal Protocol which saw 31 countries signing a treaty to phase out the use of ozone depleting substances (ODS). By 2009, the 196 countries were signatory of the treaty.
Nevertheless, since ODS have been used for decades earlier, the damage had already been done. In 2006, scientists from NASA observed a 10.6 square miles hole in the ozone layer just above the South Pole.
Ozone holes are more visible in the Antarctic as the formation of ice clouds draws away the chlorine and bromine compounds on the ozone layer.
Are there ozone holes above the UK?
There are many smaller holes in the ozone layer that may appear depending on prevailing weather conditions. Many of them are virtually invisible, and it takes a fair amount of chance to stumble across them.
However, there is at least one confirmed major ozone hole over UK. It is imperative that people wear sunscreen when they plan to be out in the sun. Long sleeved shirts, summer hats and sun glasses are all useful attires to wear.
Thankfully though, recent studies indicate that the ozone layer is slowly healing itself. Researchers are even speculating that the giant hole above the South Pole will be mended by 2050.
NASA Evaluates New Threats to Earth’s Ozone Layer