ASK A SCIENTIST
Question: Why not create a manmade magnetic field or core that would act as a second layer under the ozone layer or at least a patch to make it stronger and keep radiation from reaching the earth?
There are big problems facing our planet these days – the hole in the Ozone Layer, global warming, diminishing production of oil, and global pandemics, just to name a few of the scientific ones – so keep thinking big! It may be your creative ideas that will help guide us through some of these crises.
The hole in the Ozone Layer, or depletion of stratospheric ozone in general, is indeed a serious problem. Ozone, a rare and fragile form of oxygen with 3 atoms per molecule rather than 2, is regularly created and destroyed high up in the atmosphere, in a layer about 30 kilometers above Earth's surface. Its production and destruction are accomplished by the more intense wavelengths of ultraviolet (UV) radiation that make up a small but lethal portion of the light from the Sun. These processes are possible because ozone molecules are just the right size to interact with that UV radiation, and they cause the UV energy to be absorbed. Without the Ozone Layer, intense UV would reach the ground, threatening plant and animal life with damage to their DNA (leading to genetic mutations), skin cancers, cataracts, and even weakening of the human immune system. (Mild UV can be dealt with using sun block and sunglasses.)
Nearly every year since its discovery in 1985, the Antarctic ozone hole, i.e. depletion of ozone in the stratosphere above Antarctica during southern hemisphere springtime, has worsened. By now, for example, significant depletion extends over an area twice as great as in 1985. And a similar 'hole' over the Arctic has grown nearly as large – with the potential to cause even more harm because the northern hemisphere is much more populated.
You are correct to identify the importance of keeping intense ultraviolet radiation from reaching Earth's surface. Unfortunately, magnetic fields cannot directly protect or restore the Ozone Layer, since they cannot control UV radiation or make stratospheric ozone more abundant.
Molina and Rowland won the 1996 Nobel Prize in chemistry for revealing the connection between ozone depletion and chemicals such as chlorofluorocarbons ("cfc's", including the cfc known as Freon and the cfc's used to make spray can propellant and Styrofoam insulation), which were widely produced beginning in 1950. Although CFC's are completely harmless under conditions at the Earth's surface, up in the stratosphere they can be disintegrated by sunlight to produce chlorine compounds that 'eat' ozone. When it is cold enough in the stratosphere to produce clouds of ice crystals, the chlorine can use those crystals as miniature staging areas to efficiently destroy ozone. Many countries of the world have united to ban CFC production, though it is estimated it will take another 50 years or so for the CFC's to work their way out of the atmospheric system. Unfortunately, not all countries subscribe to this ban, and some of them (like China) are likely to produce huge amounts of CFC as they industrialize.
Through the action of sunlight, the ozone holes have always managed to recover by summertime, so their danger is only seasonal. Perhaps more scary is the observation that ozone is becoming more depleted globally, not just near the poles. Since 1980 or so, worldwide stratospheric ozone has decreased systematically, year-round, by 2% - 4% per decade (implying UV will reach dangerous levels by the time your grandchildren are born!). No one knows whether this is related to continuing production of cfc by industrializing countries, or pre-existing cfc managing to destroy ozone even at latitudes too warm for stratospheric ice, or some other mechanism. Evidently normal processes of ozone production are not keeping up with this destruction.
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