The atmosphere of the earth is multi-layered. The layer nearest to the surface is the troposphere. Followed by it is the stratosphere, where the ozone layer is located, which protects the earth, from ultraviolet-B (UV-B) radiation, considered to be harmful to all forms of life – humans, plants, and animals. Ozone depletion refers to two different phenomena. The first one is a decline in the total volume of ozone in the ozone layer. The second one is a seasonal decrease in the ozone layer in Polar Regions. This is what is called an ozone hole.
This ozone depletion is caused by the effusion of some industrial chemicals like halons, refrigerants, methyl bromide, etc. Fall in the stratospheric temperature heightens ozone depletion. Even with our best efforts to contain this process, the depleted layer will not begin to recover until about 2020, if at all. Since the ozone layer protects the earth from UVB ultraviolet light, its depletion will increase surface levels of UVB, thereby damaging all life forms.
The major concern over ozone depletion is its effects on surface UV and its health hazards for humans. Since, ozone depletion, so far, has mostly been very low, not many health hazards have been noted. However, if the levels rise and the hole becomes large, the hazards could be quite dramatic. Increased UV radiation can cause basal and squamous cell carcinomas, malignant melanoma, cortical cataracts, increased tropospheric Ozone, and adverse effect in growth in some crops like rice.
The terms, “global warming” and “climate change” are often interchangeably used. Effusion of gases, like carbon dioxide, methane, nitrous oxide, and refrigerants trap the heat in the troposphere and creates a greenhouse effect. This makes the earth warmer by allowing the sun’s rays to reach the earth but disallowing the heat to escape.
We are already in the process of witnessing widespread damages to our environment through the events of intense storms and floods, unseasonable weather, landslides and avalanches, dying forests and desertification, melting ice caps, and rising sea level. In intensity and magnitude, some are quite unexpected. These events will continue to rise even if measures are initiated immediately to forestall global warming.
There is a general concern that sustained global warming will accelerate ozone depletion. This depletion worsens when the stratospheric temperature falls. Global warming, by trapping tropospheric heat, allows less heat to reach the stratosphere thus making it colder. Therefore, we see that global warming can worsen ozone depletion at a time when it is expected to begin to recover around 2020. Ozone depletion is frequently related to global warming, although we can link them to some extent, their relationship is not very strong. Their areas of linkage are multifold.
The same gases, which produce global warming also, cool the stratosphere. This temperature change is supposed to heighten ozone depletion. Moreover, Ozone depletion has two opposing effects: Reduced ozone lessens the ability of the stratosphere to absorb solar radiation. This lowers the stratospheric temperature as well as heightens tropospheric temperature. As a result, the ozone’s holes enlarge and the greenhouse effect becomes stronger. Since both, the greenhouse effect and ozone depletion, are supposed to cool the stratosphere it is very difficult to separately observe their effects. The same gases are responsible for both ozone depletion as well as global warming. Thus, studying both processes is a long-term affair in terms of studying predicting and testing.