In the 1970’s, the British Antarctic Survey was startled to discover that there was a hole in the Antarctic ozone layer. This was unexpected, and quite alarming, for the ozone layer protects us from the sun’s dangerous Ultraviolet Rays (UV-B). Since then, research has determined the root cause of this tragedy – manmade chemicals released into the atmosphere. The usage of these chemicals has been banned with the hope that the ozone hole may eventually heal itself naturally. More proactive restorative methods are also currently being investigated.
The decrease in ozone was first observed at the Antarctic hole, but actually, that area still has some of its ozone layer. Undoubtedly, saying that it was a ‘hole’ sounds much more dramatic on a press release, so the misnomer has remained since the beginning. Actually, the ozone layer has decreased all over the world, with the tropical zones experiencing a lower rate of reduction. With less ozone to block out UV-B rays, skin cancer, cataracts and other health problems will start to become more prevalent. The simplest species, like phytoplankton, may not fare well when exposed to more UV-B rays, thereby possibly affecting the entire future food chain. The world’s nations have collaborated to rectify the situation by: 1) understanding the phenomenon, 2) taking corrective action to eliminate the sources, and 3) finding ways to speed up the natural healing process.
Ozone is a natural component of our air. The stratosphere, ranging from 6 to 32 miles above the Earth’s surface, is where 90% of the ozone resides. The remaining amount mostly exists closer to the surface – on certain days, its bluish tinge manifests itself as a toxic component of smog! Ozone is similar to an oxygen molecule, which has 2 atoms of oxygen, but ozone has an additional atom, which makes its extremely reactive. Out of a million air atoms, the Environmental Protection Agency (EPA) says that there are only 2 to 8 ozone molecules. To put that into perspective, if all of the ozone in the 30+ miles of the atmosphere could be condensed into one area, it would be about ¼ inches thick! No wonder that small changes in the amount of ozone can have great consequences worldwide!
While sunlight constantly creates ozone, mankind’s developments have depleted the amount of available ozone. For the last 50 or so years, heavily industrialized countries have been releasing ozone depleting chemicals into the atmosphere. Per the EPA, these chemicals contain bromine, chlorine, fluorine, carbon and hydrogen in various forms and compounds. The most common, chlorofluorocarbons (CFCs), were once used as cooling refrigerants and pressurants in aerosol cans. In 1987, CFCs and many other chemicals were banned, regulated or phased out of existence by an agreement called the Montreal Protocol On Substances That Deplete The Ozone Layer. This international effort has drastically reduced dangerous chemical emissions and when necessary, replaced them with similar chemicals that are less damaging to the ozone. The end result: the EPA believes that within 50 years, the hole will heal itself, if everything goes according to plan.
In the U.S., the Clean Air Act of 1990 gave authority to the EPA to initiate regulations and voluntary programs that will eliminate ozone depleting substances, recycle and replace them, and educate the general public. The EPA website declares their mission regarding ozone depleting substances (ODS) as follows: 1) end ODS production and identify safe and effective alternatives, 2) ban the release of ODS refrigerant and halon gases and ensure their proper recycling, and 3) require that manufacturers identify ODS on the their product labels.
The ozone depletion process isn’t completely understood, so there may be unforeseen circumstances. Greenhouse gases, which contribute to the Greenhouse Effect, have raised average surface temperatures, but strangely enough, in the Antarctic, according to the National Oceanic & Atmospheric Administration, the stratospheric temperatures have gotten colder. The stratosphere is where ozone primarily resides, and, unfortunately, when temperatures become colder, the ozone depletion process increases. So, if the two phenomenons are related, the Greenhouse Gas effect may also influence the ozone depletion process. The reverse is certainly true: when less ozone is available to convert UV-B rays into upper atmospheric heat, the penetrating sunlight heats up more of the lower atmosphere. Perhaps by resolving the Greenhouse Gas problem, and thereby cooling the Earth, the ozone regeneration process may be accelerated?
Climate engineering is currently being researched, developed and tested to counter the effects of related global warming. A reduction in heat can be obtained by blocking and reflecting sunlight and reducing the amount of carbon dioxide in the air. According to Popular Mechanics, this may be accomplished by the following ambitious programs.
* The Copenhagen Consensus Center proposed injecting sulfur-dioxide particles into the atmosphere using floating airships or artillery blasts. Another of their ideas would use robotically-controlled ships to suck cool water from the ocean depths and vaporize it high into the sky through extremely tall dispersion towers. Both concepts would reduce sunlight and absorb incoming heat in the atmosphere, and therefore, decrease surface temperatures.
* The University of Bristol, UK and the U.S. Department Of Energy proposed painting many buildings and structures a white color and using food crops that have glossy leaves. These concepts would reflect sunlight back into space and reduce surface temperatures.
* NASA and the UK Institute of Mechanical Engineers proposed using a great many algae farms to absorb carbon dioxide from the atmosphere, thereby reducing the amount of carbon dioxide contributing to surface temperatures.
The ozone layer was damaged by the use of manmade chemicals, but with the international control, regulation and banning of ozone depleting substances, it’s estimated that the ozone deficiency will heal itself by the year 2050. More proactive methods of repairing the ozone hole are also currently being investigated. The process of healing the ozone hole will hopefully help us to discover new ways to live in harmony with our environment.